Information

Why there is such low diversity of higher plants in sea?

Why there is such low diversity of higher plants in sea?


We are searching data for your request:

Forums and discussions:
Manuals and reference books:
Data from registers:
Wait the end of the search in all databases.
Upon completion, a link will appear to access the found materials.

I think it could be because of mycorrhiza or maybe because of the problem with flowering and seeds. But really, I don't know.

edit: by higher plants I meant Embryophytes


Biodiversity higher in the tropics, but species more likely to arise at higher latitudes

A new study of 2300 species of mammals and nearly 6700 species of birds from across the globe helps explain why there are so many more species of plants and animals in the tropics than at higher latitudes. In a study supported by the National Evolutionary Synthesis Center in North Carolina, researchers found that while the tropics harbor a greater diversity of species, the number of subspecies -- potential stepping stones in the process by which one species becomes two -- is actually greater in the harsher environments typical of higher latitudes.

The surprising results suggest that the latitudinal diversity gradient may be due higher species turnover -- a higher potential for speciation counterbalanced by a higher potential for extinction -- towards the poles than near the equator, the researchers say.

Scientists have known for more than a century that species diversity increases towards the equator. Think tropical rainforests -- which house two thirds of the world's species -- teeming with buzzing insects, screeching birds and howling monkeys, versus the frigid tundra, where life is largely limited to scattered trees and only a few dozen kinds of mammals, such as caribou and foxes.

Numerous hypotheses have been proposed to explain this pattern. One idea is that tropical regions harbor greater biodiversity because they are especially fertile grounds for the formation of new species -- i.e., "cradles of diversity." Another idea is that biodiversity hotspots are less likely to lose the species they already have.

"There's a lot of controversy over what explains the global pattern of biodiversity," said lead author Carlos Botero of North Carolina State University.

In a study to appear in the November 22 issue of Molecular Ecology, Botero and colleagues assembled a data set of climate and weather patterns across the globe, and combined it with genetic data other information for nearly 50% and 70% of all mammals and birds known to be alive today.

The team was surprised to find that while the number of bird and mammal species increases closer to the equator, the number of genetically distinct groups within each species -- known as subspecies -- is greater in the harsher environments typical of higher latitudes.

"These are environments that are colder and drier, and where the differences between the hottest and coolest months are more extreme," Botero explained.

Animals in these environments are more likely to freeze during cold winters or die during usually hot summers. "If extreme weather events wipe out a population every now and then, but don't wipe out an entire species, the populations that survive will be geographically separated and could start to diverge from one another," Botero said.

The results are consistent with a 2007 study by researchers at the University of British Columbia suggesting that -- contrary to conventional wisdom -- species arise faster in temperate zones than in the tropics. "It may be that species come and go more frequently in the temperate zones," Botero said.

Comparing biodiversity in the temperate zones with that in the tropics is like comparing the coins in your pocket with the coins in your piggy bank, he added. "There are usually more coins in your piggy bank than in your pocket. But you're always spending the coins in your pocket, and receiving new coins in the form of change. The coins in your piggy bank turn over less often, but over time they add up."


Viewpoint: Yes, greater species diversity does lead to greater stability in ecosystems.

The concept of the balance of nature is an old and attractive one for which there is much evidence. Living things are always changing, so the communities of species in ecosystems are always subject to change. However, those who see stability as an important characteristic of healthy ecosystems focus on the fact that some level of stability is usually associated with a well-functioning ecosystem, that fluctuations occur within limits and that they are usually around some average, some balanced state. This is important to keep in mind in any discussion of stability in ecosystems: stability is never absolute.

The idea that the balance of nature is the norm and that wild fluctuations in populations are a sign of disruption in ecosystems comes from the work of many biologists, including that of the English biologist Charles Elton (1900-1991), one of the great ecologists of the twentieth century. Elton wrote about how foreign species, those that are not native to a particular area, can invade an ecosystem and throw it into imbalance. An example of this is the zebra mussel that has invaded lakes and rivers in the Midwestern United States, leading to the loss of many native species and the clogging of waterways. As a result, species diversity has been seriously affected and ecosystems reduced to a dangerously depleted state, where they are much more likely to be unstable.

Question of Definition

One problem in the debate over the relationship between species diversity (often called biodiversity) and stability is a question of definition. The general definition of stability is the resistance to change, deterioration, or depletion. The idea of resistance to change is related to the older concept of the balance of nature. Resistance to change also brings with it the concept of resilience, that is, being able to bounce back from some disturbance, and this meaning of stability is the one many ecologists focus on today. They ask: Is there a relationship between resilience and biodiversity? They accept the idea that stability is not the same as changelessness, and that an ecosystem is not unchanging, though it may appear to be so to casual human observation. A young person may be familiar with a forested area, and then revisit that area years later when it appears to be the same ecosystem, which has remained seemingly unchanged over a period of 30 or 40 years. But in reality many trees have died during that time, and others—perhaps belonging to different species—have grown up to replace them there may even have been forest fires and tornado damage. What remains however, is a stable ecosystem in the sense that the later forest has about the same number of species as the earlier one, and about the same productivity in terms of biomass (living material such as new plant growth) produced each year. Ecologists would regard this ecosystem as stable. Many would argue that if the forest's biodiversity were compromised, if for example, all the trees were cut down and replaced by a plantation of trees of one species to be used for lumber, the forest as a whole would be much more unstable, that is, more susceptible to a disturbance such as the outbreak of an insect pest and much less able to rebound.

In the 1970s mathematical models of ecosystem processes seemed to show that biodiversity did not stabilize ecosystems, but that it had just the opposite effect—diverse ecosystems were more likely to behave chaotically, to display wild shifts in population size, for example. These mathematical models had a dramatic effect on the thinking of ecologists and brought the whole idea of the balance of nature into question. But it must be remembered that a model is a construction of the human mind. It may be intended to represent some part of the natural world, but it is a simplified, abstract, view of that world. Models are useful they eliminate many of the "messiness" of real life and make it easier for the human mind to grasp complex systems. However, that simplification can be dangerous, because by simplifying a situation, some important factor may be eliminated, thus making the model of questionable value. Although there is some evidence that species diversity can at times increase the instability of an ecosystem, there is also a great deal of evidence against this.

The Benefits of Species Richness

Increasing species diversity leads to an increase in interactions between species, and many of these interactions have a positive effect on the ecosystem because they are mutually supportive. For example, a new plant species in a community may provide food for insect species, harbor fungi in its roots, and afford shade under which still another plant species may grow. Such interactions, though perhaps insignificant in themselves, can make the ecosystem as a whole more stable by preventing other plant or insect or fungal species from overgrowing.

If an ecosystem is species-rich, this means that most of its niches are filled. A niche is an ecological term meaning not only the place where an organism lives, but how it utilizes that place. For example, an insect that feeds on a single plant species has a very specific niche, while one that can survive by eating a variety of foliage has a broader niche. In general, only one species can occupy a particular niche, so two bird species may both live in the same area but eat different kinds of prey, one specializing in worms, for example, and another in beetles. If an ecosystem is species poor, this means that a number of niches are open and available to be filled by generalist species such as weeds or foreign invaders that may fill several niches at one time and overwhelm native species. In a species-rich ecosystem it is more difficult for such a takeover to occur, because invaders would have to compete with the present niche occupants. In other words, more balanced ecosystems are more likely to remain in balance. They are also more likely to recover successfully from environmental disruptions such as fires, storms, and floods.

Experimental Evidence

In the 1990s, several groups of researchers produced solid evidence that there is indeed a link between diversity and stability. Some of the most convincing information came from field experiments carried out by the ecologist David Tilman and his colleagues at the University of Minnesota. They created test plots in open fields and added varying numbers of plant species to some of these plots. They found that the plots with the most species, that is, those that had greater diversity, were most resistant to the effects of drought, and also were most likely to have a growth rebound after the drought ended. In other words, the more diverse plots produced more biomass. A careful analysis of Tilman's results did reveal that rebound was also related to the particular species that were added, not just to the number of species plants that were more productive, that grew faster, contributed more to the rebound. This analysis does not completely negate the basic finding about diversity, because the more species in an ecosystem, the greater the likelihood that among those species will be highly productive.

Another group of researchers who also explored the link between biodiversity and stability was led by Shahid Naeem of the University of Washington at Seattle. These researchers also took an experimental approach, but their work was carried out in the laboratory. In the 1980s, they built indoor chambers and showed that the chambers with more species tended to be more productive and more stable. Recently, the same researchers have produced similar results with microbial communities of algae, fungi, and bacteria. They found that an increase in the number of species leads to an increase in the predictability of growth. In another set of experiments, an increase in the number of species was related to a decrease in fluctuations in the production of CO 2 (carbon dioxide), which was used as a measure of microbial function. Both these studies on microbial communities indicate that an increase in the number of species at each trophic level (the function an organism performs in the ecosystem) was important to stability. So not only is the number of species in the ecosystem important, but it is also important that each trophic level—producer, consumer, and decomposer—has a variety of species represented. These studies are particularly important because in many ways they mimic the kinds of communities found in soil, an area of biodiversity which has lagged behind the study of communities above ground. There is also increasing evidence that biodiversity in the soil may also enrich biodiversity above ground. For example, soil fungi can enhance the uptake of nutrients by plants. These studies also show that while the population size of individual species may vary widely, the fluctuations can actually contribute to overall stability of the ecosystem. It may be that these population changes compensate for other changes within the ecosystem and thus enhance stability. Studies such as these, carried out on well-defined ecosystems, explore the link between diversity and stability. The advantage of microbial systems is that they can be assembled from many species and run for many generations within a reasonable period of time and at reasonable expense.

Critics of Tilman's and Naeem's work argue that their results often depend on the species chosen, in other words, the relationship of bio-diversity with productivity and stability is not true for just any grouping of species. However, this criticism points up the importance of diversity, of having a variety of organisms with many different growth and resource-use characteristics. It would be helpful to be able to perform field studies on the link between biodiversity and stability, rather than having to rely on the artificiality of experimental plots and chambers. Again the problem of complexity arises—natural ecosystems, especially those in tropical areas where biodiversity is likely to be greatest, are so filled with species and so rich in their interactions, that it is difficult to decide what to measure. Nevertheless, many observations in such ecosystems suggest that a depletion in species can lead to instability, with large increases in the populations of some species being more common. For example, invasion by foreign species is easier in disturbed ecosystems, where species have already been lost. This explains why agricultural areas are so susceptible to invasion. Other research has shown that invasion by non-native species is more likely to occur in less diverse ecosystems, at least on small plots.

It may be that diversity is particularly important in ecosystems that are structurally diverse such as layered rain forests, where essentially different ecosystems exist at distinct levels above ground. But diversity can be important even in simple ecosystems. One large-scale experiment in China showed that growing several varieties of rice together, rather than the usual practice of growing just one variety, prevented crop damage due to rice blast, a fungus that can seriously disrupt production. It appears that rice blast cannot spread as easily from plant to plant when several varieties are interspersed, so production is more stable. A rice field is obviously far from a natural ecosystem, but this is still one more piece of evidence for the diversity-stability link. The multi-variety approach also has the benefit of reducing the need for pesticides and thus slows further deterioration of the ecosystem. Benefits have also been found for another example of diversity in agriculture, the substitution of mixed perennial grasses for the traditional planting of one annual grass, such as wheat. One benefit of mixed perennials is that there is less opportunity for large numbers of one insect pest to decimate an entire crop. Again, stability comes with diversity, because greater numbers of species provide a buffer against disruption.

As with much scientific research, not all data support the diversity-stability link, but scientific results are rarely unanimous. Although the idea of the balance of nature may have been too simplistic, there is still validity to the idea that stability is beneficial, and the values of biodiversity are many. More species not only contribute to more stable ecosystems, but provide a source of chemicals that could be useful as drugs, help to detoxify noxious substances in the environment, and provide a rich source of positive aesthetic experiences. There is enough evidence for the diversity-stability link to make it a viable idea in ecology, and as David Tilman has said, data indicate that it would be foolish to lose diversity from ecosystems. Once that diversity vanishes, it is almost impossible to bring it back, especially because many of the species involved may have become extinct.


7: Alpha, Beta, and Gamma Diversity

  • Contributed by Nora Bynum
  • Instructor and Vice Provost for Duke Kunshan University (Environmental Science & Policy Division) at Duke University

Whittaker (1972) described three terms for measuring biodiversity over spatial scales: alpha, beta, and gamma diversity. Alpha diversity refers to the diversity within a particular area or ecosystem, and is usually expressed by the number of species (i.e., species richness) in that ecosystem. For example, if we are monitoring the effect that British farming practices have on the diversity of native birds in a particular region of the country, then we might want to compare species diversity within different ecosystems, such as an undisturbed deciduous wood, a well-established hedgerow bordering a small pasture, and a large arable field. We can walk a transect in each of these three ecosystems and count the number of species we see this gives us the alpha diversity for each ecosystem see Table (this example is based on the hypothetical example given by Meffe et al., 2002 Table 6.1).

If we examine the change in species diversity between these ecosystems then we are measuring the beta diversity. We are counting the total number of species that are unique to each of the ecosystems being compared. For example, the beta diversity between the woodland and the hedgerow habitats is 7 (representing the 5 species found in the woodland but not the hedgerow, plus the 2 species found in the hedgerow but not the woodland). Thus, beta diversity allows us to compare diversity between ecosystems.

Gamma diversity is a measure of the overall diversity for the different ecosystems within a region. Hunter (2002: 448) defines gamma diversity as "geographic-scale species diversity". In the example in Table, the total number of species for the three ecosystems 14, which represent the gamma diversity.

Hypothetical species Woodland habitat Hedgerow habitat Open field habitat
A X
B X
C X
D X
E X
F X X
G X X
H X X
I X X
J X X
K X
L X X
M X
N X
Alpha diversity 10 7 3
Beta diversity Woodland vs. hedgerow: 7 Hedgerow vs. open field: 8 Woodland vs. open field: 13
Gamma diversity 14

Table (PageIndex<1>) Alpha, beta and gamma diversity for hypothetical species of birds in three different ecosystems


Having one is not a guarantee that the others are also present in the ecosystem

You could have high species richness but low abundance and therefore, low species diversity in an ecosystem. An aquarium with many different species of animals, but very few individuals of each species confined to a small space is an example.

Likewise, you could have an ecosystem with high abundance, low species richness and therefore, low species diversity. An Oak forest is an example of this. Most of the trees in the forest are Oak other tree species are limited in numbers and have poor distribution throughout the forest.

Such conditions (high-low) are commonly found in man-made ecosystems.

Having any one or two of the above conditions is not ideal in a natural ecosystem.


Why is biodiversity higher at the equator than it is near the poles?

Scientists aren't in agreement about what causes higher diversity at the equator.

Explanation:

This idea is also referred to as the latitudinal diversity gradient, meaning that as you move from the equator towards the poles, diversity lessens.

There are multiple theories as to why this is the case.

One of the more recent studies on this issue concluded that species turnover is higher in temperate regions.

Other theories explaining the latitudinal diversity gradient include that there is greater habitat diversity towards the equator, creating more niches for species to inhabit.

Some also believe greater primary productivity at the equator has lead to greater biodiversity. Having more energy available in this area means more consumers can be supported.

That the are is relatively stable in terms of environment when compared to polar regions has also been suggested as a reason for increased biodiversity at the equator. This stability has meant species are less likely to go extinct.

To read a lot more about this topic, see this article or check out this great read.


Why Are There So Many More Species on Land When the Sea Is Bigger?

Most of the Earth’s surface is ocean. Life began there. But marine life accounts for only 15 percent of the world’s species.

Half a billion years ago on Earth, after the Cambrian explosion had created an astonishing array of new species, there was still no life on land. No complex life anyway. No plants, no animals, certainly nothing that even compared to the great diversity of life in the sea, which teemed with trilobites, crustaceans, bristly worms, and soft squid-like creatures. Most major animals groups that exist today originated in the sea at this time.

Fast forward to the present, and it is now the land that has a dizzying array of species. In particular: flowering plants, fungi, and insects, so many damn insects. By one estimate, there are five times as many terrestrial species as marine species today. So how did biodiversity in the ocean—despite its head start, despite its larger share of the Earth’s surface area—come to fall so far behind biodiversity on land?

Why more species live on land than in the ocean has puzzled biologists for a long time. Robert May, a ecologist at the University of Oxford, appears to be the first to put the conundrum down in writing in a 1994 article titled, “Biological Diversity: Differences between Land and Sea (and Discussion).”

The question has held for the two decades since, even as humans have explored more and more of the deep ocean. Scientists now estimate that 80 percent of Earth’s species live on land, 15 percent in the ocean, and the remaining 5 percent in freshwater. They do not think this difference is entirely an artifact of land being better explored. “There are oodles and oodles of species in the sea, but to make up that difference would take an awful lot,” says Geerat Vermeij, a marine ecologist and paleoecologist who has written about the land-sea species discrepancy with his collaborator Rick Grosberg, another ecologist at the University of California, Davis. So this seeming lack of ocean diversity is not just the bias of us land-based creatures, Vermeij and Grosberg argue—a bias that they as marine researchers are all too keenly aware of.

What then is intrinsically different about the land’s ability to support biodiversity?

(We’re going to put aside microbial diversity in this discussion, which is not meant as a slight to microbes. But rather, they are too different to generalize together with multicellular life. Single-celled microbes are governed by different forces and even the concept of “species” is different. They deserve their own discussion.)

One reason May and others since have suggested is the physical layout of terrestrial habitats, which may be both more fragmented and more diverse. For example, as Charles Darwin famously documented in the Galapagos, islands are hotbeds for diversification. Over time, natural selection and even chance can turn two different populations of the same species on two islands into two species. The ocean is, in contrast, one big interconnected body of water, with fewer physical barriers to keep populations apart. It also doesn’t have as many temperature extremes that can drive diversification on land.

Land may also be “architecturally elaborate,” to use May’s term. Forests, for example, have covered much of the Earth’s land surface, and the leaves and stems of trees create new niches for species to exploit. Coral do the same in the ocean, of course, but they do not cover nearly as much of the seafloor.

Plants definitely play a major role. The Earth’s tipping point from predominantly marine to terrestrial life came around about 125 million years ago, during the Cretaceous period, where early flowering plants evolved to be extraordinarily successful on land. Plants need sunlight for photosynthesis, but there’s little sun in the ocean outside of shallow coastal areas. For this reason, land is simply more productive that the cold, dark depths of the sea. “The deep sea is basically a big fridge with the door closed for a long time,” says Mark Costello, a marine biologist at the University of Auckland, who recently published an overview of marine biodiversity. Sure there is life in the deep sea, but not nearly as much as on the sunny coast and land.

Interestingly, Costello notes, increased productivity on land after the diversification of flowering plants also seems to have fed back into increased diversity in the oceans. Pollen, for example, can be an important source of food on the floor of the deep sea. A recent study found pollen likely from pine plantations in New Zealand in a deep sea trench 35,000 feet below the surface of the Pacific Ocean.

The diversification of flowering plants also has everything to do with their coevolution with insects. Plants, for example, evolved features like flowers with long tubes that could only be reached by long-tongued bees that pollinate them. “It’s kind of a big race between the plants and the insects,” says Costello. This coevolution helped create an astonishing number of species: The vast majority of plants on Earth are flowering plants, and the vast majority of animals on Earth are insects. By one estimate, insects alone account for 80 percent of all species on the planet.

Yet insects, so successful on land, are marginal in the sea. Vermeij and Grosberg trace the lack of diversity among small animals to the differences in air and water as a medium. Small animals, like an insect, have more difficulty moving around in water because it is thicker than air. (This applies less so to bigger animals due to the laws of physics.) Mating scents and even visual information don’t travel as well through water—limiting the potential for sexual selection to drive diversification. Sexual selection drives traits that may not seem beneficial but for whatever reasons are preferred by mates. The peacock’s tail is a classic example.

Drawing on the work of Richard Strathmann, Vermeij and Grosberg also try to get at why something like the relationship between flowering plants and insects could not exist in the ocean. The seawater is teeming with potential food sources like zooplankton. While going from one hypothetical sea flower to another, a marine creature would encounter plenty of food floating in the water along the way. Why swim all the way to the other sea flower? On the other hand, an insect flying from one flower with nectar to another would just be flying through air. There is no food floating in the air. And this has evolutionary consequences: A hypothetical sea flower would have to offer much more nectar to attract pollinators lazily feeding on floating food—so much so that it’s not worth it.


References

  1. 1. Gage JD, Tyler PA (1991) Deep sea biology: A natural history of organisms at the deep-sea floor. Cambridge: Cambridge University Press. 504 p.
  2. 2. Snelgrove PVR (1999) Getting to the bottom of marine biodiversity: Sedimentary habitats. BioScience 49: 129–138.
    • View Article
    • Google Scholar
  3. 3. Grassle JF, Maciolek NJ (1992) Deep-sea species richness: Regional and local diversity estimates from quantitative bottom samples. Am Nat 139: 313–341.
    • View Article
    • Google Scholar
  4. 4. Etter RJ, Grassle JF (1992) Patterns of species diversity in the deep sea as a function of sediment particle size diversity. Nature 369: 576–578.
    • View Article
    • Google Scholar
  5. 5. Blake JA, Grassle JF (1994) Benthic community structure on the US South Atlantic slope off the Carolinas: Spatial heterogeneity in a current-dominated system. Deep Sea Res II 41: 835–874.
    • View Article
    • Google Scholar
  6. 6. Gambi C, Vanreusel A, Danovaro R (2003) Biodiversity of nematode assemblages from deep-sea sediments of the Atacama Slope and Trench (Southern Pacific Ocean). Deep Sea Res I 50: 103–117.
    • View Article
    • Google Scholar
  7. 7. Lambshead PJD, Tietjen J, Ferrero T, Jensen P (2000) Latitudinal diversity gradients in the deep-sea with special reference to North Atlantic nematodes. Mar Ecol Progr Ser 194: 159–167.
    • View Article
    • Google Scholar
  8. 8. Lambshead PJD, Brown CJ, Ferrero T, Mitchell NJ, Smith CR, et al. (2002) Latitudinal diversity patterns of deep-sea marine nematodes and organic fluxes: A test from the central equatorial Pacific. Mar Ecol Progr Ser 236: 129–135.
    • View Article
    • Google Scholar
  9. 9. Levin LA, Gage JD, Martin C, Lamont PA (2000) Macrobenthic community structure within and beneath the oxygen minimum zone, NW Arabian Sea. Deep Sea Res II 47: 189–226.
    • View Article
    • Google Scholar
  10. 10. Rex MA, Stuart CT, Hessler RR, Allen JA, Sanders HL, et al. (1993) Global-scale latitudinal patterns of species diversity in the deep-sea benthos. Nature 365: 636–639.
    • View Article
    • Google Scholar
  11. 11. Gooday AJ, Bett BJ, Shires R, Lambshead PJD (1998) Deep-sea benthic foraminiferal diversity in the NE Atlantic and NW Arabian sea: A synthesis. Deep Sea Res II 45: 165–201.
    • View Article
    • Google Scholar
  12. 12. McClain CR, Etter RJ (2005) Mid-domain models as predictors of species diversity patterns: bathymetric diversity gradients in the deep sea. Oikos 109: 555–566.
    • View Article
    • Google Scholar
  13. 13. Sardà F, Calafat A, Flexas MM, Tselepides A, Canals M, et al. (2004) An introduction to Mediterranean deep-sea biology. Sci Mar 68 (3): 7–38.
    • View Article
    • Google Scholar
  14. 14. Vanney JR, Gennesseaux M (1985) Mediterranean seafloor features: Overview and assessment. In: Stanley DJ, Wezel F-C, editors. Geological evolution of the Mediterranean Basin. New York: Springer. pp. 3–32.
  15. 15. Canals M, Puig P, Durieu de Madron X, Heussner S, Palanques A, et al. (2006) Flushing submarine canyons. Nature 444: 354–357.
    • View Article
    • Google Scholar
  16. 16. Stanley DJ, Wezel FC (1985) Geological evolution of the Mediterranean basin. New York: Springer. 589 p.
  17. 17. Emig CC, Geistdoerfer P (2004) The Mediterranean deep-sea fauna: Historical evolution, bathymetric variations and geographical changes, Carnets de Géologie/Notebooks on Geology, Maintenon, Article 2004/01 (CG2004_A01_CCE-PG)
    • View Article
    • Google Scholar
  18. 18. Danovaro R, Dinet A, Duineveld G, Tselepides A (1999) Benthic response to particulate fluxes in different trophic environments: A comparison between the Gulf of Lions-Catalan Sea (Western Mediterranean) and the Cretan Sea (Eastern Mediterranean). Progr Oceanogr 44(1–3): 287–312.
    • View Article
    • Google Scholar
  19. 19. Psarra S, Tselepides A, Ignatiades L (2000) Primary productivity in the oligotrophic Cretan Sea (NE Mediterranean): Seasonal and interannual variability. Progr Oceanogr 46: 187–204.
    • View Article
    • Google Scholar
  20. 20. Tselepides A, Papadopoulou N, Podaras D, Plaiti W, Koutsoubas D (2000) Macrobenthic community structure over the continental margin of Crete (South Aegean Sea, NE Mediterranean). Progr Oceanogr 46(2–4): 401–428.
    • View Article
    • Google Scholar
  21. 21. Yacobi YZ, Zohary T, Kress N, Hecht A, Robarts RD, et al. (1995) Chlorophyll distribution throughout the southeastern Mediterranean in relation to the physical structure of the water mass. J Mar Syst 6: 179–190.
    • View Article
    • Google Scholar
  22. 22. Krom MD, Kress N, Brenner S, Gordon LI (1991) Phosphorus limitation of primary productivity in the Eastern Mediterranean. Limn Oceanogr 36: 424–432.
    • View Article
    • Google Scholar
  23. 23. Myers N, Mittermeier RA, Mittermeier CG, da Fonseca Gustavo AB, Kent J (2000) Biodiversity hotspots for conservation priorities. Nature 403: 853–858.
    • View Article
    • Google Scholar
  24. 24. Bianchi N, Morri C (2000) Marine biodiversity of the Mediterranean Sea: Situation, problems and prospects for future research. Mar Poll Bull 40 (5): 367–376.
    • View Article
    • Google Scholar
  25. 25. WWF/IUCN, World Wildlife Fund/International Union for Conservation of Nature (2004) The Mediterranean deep-sea ecosystems: An overview of their diversity, structure, functioning and anthropogenic impacts. Málaga: IUCN and Rome: WWF. 64 p.
  26. 26. Ramirez-Llodra E, Company JB, Sardà F, Rotllant G (2009) Megabenthic diversity patterns and community structure of the Blanes submarine canyon and adjacent slope in the Northwestern Mediterranean: A human overprint? Mar Ecol 1–16.
    • View Article
    • Google Scholar
  27. 27. Coll M, Piroddi C, Kaschner K, Ben Rais Lasram F, Steenbeek J, et al. (2010) The biodiversity of the Mediterranean Sea: Status, patterns and threats. PLoS ONE 5(8): e11842.
    • View Article
    • Google Scholar
  28. 28. Forbes E (1844) Report on the Mollusca and Radiata of the Aegean Sea, and on their distribution, considered as bearing on geology. Report of the 13th British Association for the Advancement of Science, London 13: 130–193.
    • View Article
    • Google Scholar
  29. 29. Anderson TR, Rice T (2006) Deserts on the sea floor: Edward Forbes and his azoic hypothesis for a lifeless deep ocean. Endeavour 30(4): 131–137.
    • View Article
    • Google Scholar
  30. 30. Risso A (1816) Histoire naturelle des Crustacés des environs de Nice.175.
    • View Article
    • Google Scholar
  31. 31. Holthuis LB (1977) The Mediterranean decapod and stomatopod Crustacea in A. Risso's published works and manuscripts. Annales du Museum d'Histoire naturelle de Nice 5: 37–88.
    • View Article
    • Google Scholar
  32. 32. Zugmayer E (1911) Poissons provenant des campagnes du yacht Princesse Alice. Résultats des Campagnes Scientifiques accomplies par le Prince Albert I, Monaco 35: 174.
    • View Article
    • Google Scholar
  33. 33. Geistdoerfer P, Rannou M (1972) Poissons benthiques récoltés en Méditerranée occidentale par le N.O. Jean Charcot (campagne Polymède). Bulletin du Museum National d'Histoire Naturelle Series 3 25 (19): 101–110.
    • View Article
    • Google Scholar
  34. 34. Klausewitz W (1989) Deep-sea and deep water fish of the Eastern Mediterranean, collected during the METEOR-Expedition 1987. Senckenb Marit 20 (5/6): 251–263.
    • View Article
    • Google Scholar
  35. 35. Pérès JM, Picard J (1958) Recherches sur les peuplements benthiques de la Mediterranée Nord - Orientale. Annales de l' Institute Océanographie Paris 34: 213–281.
    • View Article
    • Google Scholar
  36. 36. Tchukhtchin VD (1964) Quantitative data on benthos of the Tyrrhenian Sea. Trudy Sevastopol Biological Station 17: 48–50.
    • View Article
    • Google Scholar
  37. 37. Vamvakas C (1970) Peuplements benthiques des substrats meubles du sud de la Mer Egée. Tethys 2: 89–129.
    • View Article
    • Google Scholar
  38. 38. Tselepides A, Eleftheriou A (1992) South Aegean (Eastern Mediterranean) continental slope benthos: macroinfaunal - environmental relationships. In: Rowe GT, Pariente V, editors. Deep-sea food chains and the global carbon cycle. Dordecht: Kluwer Academic Publications. pp. 139–156.
  39. 39. Koutsoubas D, Koukouras A, Karakassis I, Dounas C (1992) Contribution to the knowledge of Gastropoda and Bivalvia (Mollusca) of Crete island (S. Aegean Sea). Boll Malacol 28: 69–82.
    • View Article
    • Google Scholar
  40. 40. Koutsoubas D, Tselepides A, Eleftheriou A (2000) Deep sea molluscan fauna of the Cretan sea (Eastern Mediterranean): Faunal, ecological and zoogeographical remarks. Senckenb Marit 30: 85–98.
    • View Article
    • Google Scholar
  41. 41. Karakassis J, Eleftheriou A (1997) The continental shelf of Crete: Structure of macrobenthic communities. Mar Ecol Progr Ser 160: 185–196.
    • View Article
    • Google Scholar
  42. 42. Eleftheriou A, Smith CJ, Tselepides A (1996) Food Chains in the Aegean Sea. 134 p. NATO SFS FISHECO Project, Final Report.
  43. 43. Kroncke I, Turkay M, Fiege D (2003) Macrofauna communities in the Eastern Mediterranean deep sea. P.S.Z.N. Mar Ecol 24 (3): 193–216.
    • View Article
    • Google Scholar
  44. 44. Sardà F, Cartes JE, Norbis W (1994) Spatio-temporal structure of the deep-water shrimp Aristeus antennatus Risso, 1816 (Decapoda: Aristeidae) population in the Western Mediterranean. Fish B NOAA 92: 599–607.
    • View Article
    • Google Scholar
  45. 45. Sardà F, Cartes JE, Company JB (1994) Spatio-temporal variations in megabenthos abundance in three different habitats of the Catalan deep-sea (Western Mediterranean). Mar Biol 120: 211–219.
    • View Article
    • Google Scholar
  46. 46. Sardà F, D'Onghia G, Politou C-Y, Tselepides A (2004) Mediterranean deep-sea biology. Monographs Sci Mar 63 (3): 204.
    • View Article
    • Google Scholar
  47. 47. Sardà F, D'Onghia G, Politou CY, Company JB, Maiorano P, et al. (2004) Maximum deep-sea distribution and ecological aspects of Aristeus antennatus (Risso 1816) in the Balearic and Ionian Mediterranean Sea. Sci Mar 68 (3): 117–127.
    • View Article
    • Google Scholar
  48. 48. Sardà F, Company JB, Bahamon N, Rotllant G, Flexas MM, et al. (2009) Relationship between environment and the occurrence of the deep-water rose shrimp Aristeus antennatus (Risso, 1816) in the Blanes submarine canyon (NW Mediterranean). Progr Oceanogr 82: 227–238.
    • View Article
    • Google Scholar
  49. 49. Sardà F, Company JB, Rotllant G, Coll M (2009) Biological patterns and ecological indicators for Mediterranean fish and crustaceans below 1,000 m: A review. Rev Fish Biol Fish 19: 329–347.
    • View Article
    • Google Scholar
  50. 50. Galil BS, Goren M (1994) The deep sea Levantine fauna, new records and rare occurrences. Senckenb Marit 25 (1/3): 41–52.
    • View Article
    • Google Scholar
  51. 51. Goren M, Galil BS (1997) New records of deep-sea fishes from the Levant Basin and a note on the deep-sea fishes of the Mediterranean. Isr J Zool 43: 197–203.
    • View Article
    • Google Scholar
  52. 52. Goren M, Galil BS (2002) On the occurrence of Cataetyx laticeps Koefoed, 1927 and Ophidion barbatum Linnaeus, 1758 in the Levant Basin, Eastern Mediterranean, with a note on the deep sea fish community in this region. Cybium 26(2): 150–152.
    • View Article
    • Google Scholar
  53. 53. Galil BS (2004) The limit of the sea: The bathyal fauna of the Levantine Sea. Sci Mar 68: 63–72.
    • View Article
    • Google Scholar
  54. 54. Sardà F, Cartes JE, Company JB, Albiol T (1998) A modified commercial trawl used to sample the deep-sea megabenthos. Fish Sci 64: 492–493.
    • View Article
    • Google Scholar
  55. 55. Golani D (1987) On deep-water sharks caught off the Mediterranean coast of Israel. Isr J Zool 34: 23–31.
    • View Article
    • Google Scholar
  56. 56. Dinet A (1976) Etude quantitative du méiobenthos dans le secteur Nord de la mer Egée. Acta Adriatica 18: 83–88.
    • View Article
    • Google Scholar
  57. 57. Vivier MH (1978) Influence d'un déversement industriel profound sur la nématofaune (Canyon de Cassidaigne, Méditerranée). Téthys 8: 307–321.
    • View Article
    • Google Scholar
  58. 58. de Boveé F, Guidi LD, Soyer J (1990) Quantitative distribution of deep-sea meiobenthos in the northwestern Mediterranean (Gulf of Lions). Cont Shelf Res 10: 1123–1145.
    • View Article
    • Google Scholar
  59. 59. Soetaert K, Heip C, Vincx M (1991) Diversity of nematode assemblages along a Mediterranean deep-sea transect. Mar Ecol Progr Ser 75: 275–282.
    • View Article
    • Google Scholar
  60. 60. Grémare A, Medernach L, de Bovée F, Amouroux JM, Vétion G, et al. (2002) Relationships between sedimentary organics and benthic meiofauna on the continental shelf and the upper slope of the Gulf of Lions (NW Mediterranean). Mar Ecol Progr Ser 234: 85–94.
    • View Article
    • Google Scholar
  61. 61. Danovaro R, Gambi C, Lampadariou N, Tselepides A (2008) Deep-sea nematode biodiversity in the Mediterranean basin: testing for longitudinal, bathymetric and energetic gradients. Ecography 31: 231–244.
    • View Article
    • Google Scholar
  62. 62. Danovaro R, Gambi C, Dell'Anno A, Corinaldesi C, Fraschetti S, et al. (2008) Exponential decline of deep-sea ecosystem functioning linked to benthic biodiversity loss. Curr Biol 18: 1–8.
    • View Article
    • Google Scholar
  63. 63. Danovaro R, Canals M, Gambi C, Heussner S, Lampadariou N, et al. (2009) Exploring patterns and hot spots of benthic biodiversity on the slopes of European margins. Oceanography 22(1): 16–25.
    • View Article
    • Google Scholar
  64. 64. Danovaro R, Bianchelli S, Gambi C, Mea M, Zeppilli D (2009) α-, β-, γ-, δ and ε-diversity of deep-sea nematodes in canyons and open slopes of the Northeast Atlantic and Mediterranean margins. Mar Ecol Progr Ser 396: 197–209.
    • View Article
    • Google Scholar
  65. 65. Guidi-Guilvard LD (2002) DYFAMED-BENTHOS, a long time-series benthic survey at 2347-m depth in the northwestern Mediterranean: General introduction. Deep Sea Res II 49: 2183–2193.
    • View Article
    • Google Scholar
  66. 66. Tselepides A, Lampadariou N (2004) Deep-sea meiofaunal community structure in the Eastern Mediterranean: Are trenches benthic hot-spots? Deep Sea Res I 51: 833–847.
    • View Article
    • Google Scholar
  67. 67. Gambi C, Danovaro R (2006) A multiple-scale analysis of metazoan meiofaunal distribution in the deep Mediterranean Sea. Deep Sea Res I 53: 1117–1134.
    • View Article
    • Google Scholar
  68. 68. Lampadariou N, Tselepides A (2006) Spatial variability of meiofaunal communities at areas of contrasting depth and productivity in the Aegean Sea (NE Mediterranean). Progr Oceanogr 69: 19–36.
    • View Article
    • Google Scholar
  69. 69. Gilat E, Gelman A (1984) On the sharks and fishes observed using underwater photography during a deep-water cruise in the Eastern Mediterranean. Fish Res 2: 257–271.
    • View Article
    • Google Scholar
  70. 70. Priede IG, Bagley PM (2000) In situ studies on deep-sea demersal fishes using autonomous unmanned lander platforms. Oceanogr Mar Biol Annu Rev 38: 357–392.
    • View Article
    • Google Scholar
  71. 71. Galil BS, Zibrowius H (1998) First benthos samples from Eratosthenes Seamount, Eastern Mediterranean. Senckenb Marit 28 (4/6): 111–121.
    • View Article
    • Google Scholar
  72. 72. Tursi A, Mastrototaro F, Matarrese A, Maiorano P, D'Onghia G (2004) Biodiversity of the white coral reefs in the Ionian Sea (Central Mediterranean). Chem Ecol 20(1): 107–116.
    • View Article
    • Google Scholar
  73. 73. Taviani M, Freiwald A, Zibrowius H (2005) Deep coral growth in the Mediterranean Sea: An overview. In: Freiwald A, Roberts JM, editors. Cold water corals and ecosystems. Heildelberg: Springer. pp. 137–156.
  74. 74. Taviani M, Remia A, Corselli C, Freiwald A, Malinverno E, et al. (2005) First geo-marine survey of living cold-water Lophelia reefs in the Ionian Sea (Mediterranean basin). Facies 50: 409–417.
    • View Article
    • Google Scholar
  75. 75. Freiwald A, Beuck L, Rüggerberg A, Taviani M, Hebblen D (2009) The white coral community in the Central Mediterranean Sea revealed by ROV surveys. Oceanography 22 (1): 36–52.
    • View Article
    • Google Scholar
  76. 76. Massiotta R, Cita MB, Mancuso M (1976) Benthonic foraminifers from bathyal depths in the Eastern Mediterranean. Maritime sediments, Special publication 1: 251–262.
    • View Article
    • Google Scholar
  77. 77. Wright WC, Rupert FP (1981) Late neogene and recent bathyal foraminifera of Mediterranean: AAPG Bulletin, 65: 1009.
    • View Article
    • Google Scholar
  78. 78. Jorrisen FJ (1988) The distribution of benthic foraminifera in the Adriatic Sea. Utrecht Micropaleontological Bulletins 37: 1–174.
    • View Article
    • Google Scholar
  79. 79. De Stigter HC (1996) Recent and fossil benthic foraminifera in the Adriatic Sea: Distribution patterns in relation to organic carbon flux and oxygen concentration at the seabed. Geologica Ultraiectina 144: 254.
    • View Article
    • Google Scholar
  80. 80. Parisi E (1981) Distribuzione dei foraminiferi bentonici nelle zone batiali del Tirreno e del Canale di Sicilia. Rivista Italiana di Paleontologia 87(2): 293–328.
    • View Article
    • Google Scholar
  81. 81. Bizon G, Bizon JJ (1984) Les foraminifères des sediments profonds. Pétrole et Techniques 301: 84–94.
    • View Article
    • Google Scholar
  82. 82. Schmiedl G, de Bovee F, Buscail R, Charrière B, Hemleben C, et al. (2000) Trophic control of benthic foraminiferal abundance and microhabitat in the bathyal Gulf of Lions, Western Mediterranean Sea. Mar Micropaleontol 40: 167–188.
    • View Article
    • Google Scholar
  83. 83. Heinz P, Kitazato H, Schmiedl G, Hemleben C (2001) Response of deep-sea benthic foraminifera from the Mediterranean Sea to simulated phytoplankton pulses under laboratory conditions. J Foram Res 31: 210–227.
    • View Article
    • Google Scholar
  84. 84. Fontanier C, Jorissen FJ, Lansard B, Mouret A, Buscail R, et al. (2008) Live (stained) foraminiferal faunas from open slope environments separating submarine canyons in the Gulf of Lions (NW Mediterranean): Diversity, density and microhabitats. Deep Sea Res I 55: 1532–1553.
    • View Article
    • Google Scholar
  85. 85. Cita MB, Zocchi M (1978) Distribution patterns of benthic foraminifera on the floor of the Mediterranean Sea. Oceanol Acta 1: 445–462.
    • View Article
    • Google Scholar
  86. 86. De Rijk S, Troelstra SR, Rohling EJ (1999) Benthic foraminiferal distribution in the Mediterranean Sea. J Foram Res 29: 93–103.
    • View Article
    • Google Scholar
  87. 87. De Rijk S, Jorissen FJ, Rohling EJ, Troelstra SR (2000) Organic flux on bathymetric zonation of Mediterranean benthic Foraminifera. Mar Micropaleontol 40: 151–166.
    • View Article
    • Google Scholar
  88. 88. Luna GM, Dell'Anno A, Giuliano L, Danovaro R (2004) Bacterial diversity in deep Mediterranean sediments: Relationship with the active bacterial fraction and substrate availability. Environ Microb 6: 745–753.
    • View Article
    • Google Scholar
  89. 89. Polymenakou PN, Bertilsson S, Tselepides A, Stephanou EG (2005) Links between geographic location, environmental factors and microbial community composition in sediments of the Eastern Mediterranean Sea. Microb Ecol 49: 367–378.
    • View Article
    • Google Scholar
  90. 90. Amann RI, Ludwig W, Schleifer KH (1995) Phylogenetic identification and in situ detection of individual microbial cells without cultivation. Microbiol Rev 59: 143–169.
    • View Article
    • Google Scholar
  91. 91. Li L, Kato C, Horikoshi K (1999) Bacterial diversity in deep-sea sediments from different depths. Biodiversity Conserv 8: 659–677.
    • View Article
    • Google Scholar
  92. 92. Li L, Kato C, Horikoshi K (1999) Microbial diversity in sediments collected from the deepest cold-seep area, the Japan Trench. Mar Biotechnol 1: 391–400.
    • View Article
    • Google Scholar
  93. 93. Lauro FM, Bartlett DH (2008) Prokaryotic lifestyles in deep Sea habitats. Extremophiles 12: 15–25.
    • View Article
    • Google Scholar
  94. 94. Hugenholtz P, Goebel BM, Pace NR (1998) Impact of culture independent studies on the emerging phylogenetic view of bacterial diversity. J Bacteriol 180: 4765–4774.
    • View Article
    • Google Scholar
  95. 95. Polymenakou PN, Bertilsson S, Tselepides A, Stephanou EG (2005) Bacterial community composition in different sediments from the Eastern Mediterranean Sea: A comparison of four 16S Ribosomal DNA clone libraries. Microb Ecol 50: 447–462.
    • View Article
    • Google Scholar
  96. 96. Polymenakou PN, Lampadariou N, Mandalakis M, Tselepides A (2009) Phylogenetic diversity of sediment bacteria from the southern Cretan margin, Eastern Mediterranean Sea. Syst Appl Microbiol 32: 17–26.
    • View Article
    • Google Scholar
  97. 97. Danovaro R, Corinaldesi C, Luna GM, Magagnini M, Manini E, et al. (2009) Prokaryote diversity and viral production in deep-sea sediments and seamounts. Deep Sea Res II 56: 738–747.
    • View Article
    • Google Scholar
  98. 98. Bowman JP, McCuaig RD (2003) Biodiversity, community structural shifts, and biogeography of prokaryotes within Antarctic continental shelf sediment. Appl Environ Microbiol 69: 2463–2483.
    • View Article
    • Google Scholar
  99. 99. Yakimov MM, La Cono V, Denaro R (2009) A first insight into the occurrence and expression of functional amoA and accA genes of autotrophic and ammonia-oxidizing bathypelagic Crenarchaeota of Tyrrhenian Sea. Deep Sea Res II 56 (11–12): 748–754.
    • View Article
    • Google Scholar
  100. 100. Luna GM, Stumm K, Pusceddu A, Danovaro R (2009) Archaeal diversity in deep-sea sediments estimated by means of different terminal-restriction fragment length polymorphisms (T-RFLP) protocols. Curr Microbiol 59: 356–361.
    • View Article
    • Google Scholar
  101. 101. Urakawa H, Kita-Tsukamoto K, Ohwada K (1999) Microbial diversity in marine sediments from Sagami bay and Tokyo bay, Japan, as determined by 16S rRNA gene analysis. Microbiology 145: 3305–3315.
    • View Article
    • Google Scholar
  102. 102. Amann RI (1995) Fluorescently labeled, ribosomal-RNA-targeted oligonucleotide probes in the study of microbial ecology. Mol Ecol 4: 543–553.
    • View Article
    • Google Scholar
  103. 103. Barns SM, Takala SL, Kuske CR (1999) Wide distribution and diversity of members of the bacterial kingdom Acidobacterium in the environment. App Environ Microb 65: 1731–1737.
    • View Article
    • Google Scholar
  104. 104. Zaballos M, Lopez-Lopez A, Ovreas L, Bartual SG, D'Auria G, et al. (2006) Comparison of prokaryotic diversity at offshore oceanic locations reveals a different microbiota in the Mediterranean Sea. FEMS Microbiol Ecol 56: 389–405.
    • View Article
    • Google Scholar
  105. 105. Gage JD, May RM (1993) A dip into the deep seas. Nature 365: 609–610.
    • View Article
    • Google Scholar
  106. 106. Gray JS (1997) Marine biodiversity: Patterns, threats and conservation needs. Biodiversity Conserv 6: 153–175.
    • View Article
    • Google Scholar
  107. 107. Fredj G, Laubier L (1985) The deep Mediterranean benthos. In: Moraitou-Apostolopoulou M, Kiortsis V, editors. Mediterranean marine ecosystems. NATO Conference Series. New York: Plenum Press Volume 8. pp. 109–145.
  108. 108. Tecchio S, Ramirez-Llodra E, Sardà F, Company B (2010) Biodiversity patterns of deep-sea benthic megafauna on western and central Mediterranean basins. Sci Mar.
    • View Article
    • Google Scholar
  109. 109. Janssen R (1989) Benthic molluscs from the deepwater of the Eastern Mediterranaean Sea, collected during “METEOR” - cruise 5 (1987). Senckenb Mar 20: 265–276.
    • View Article
    • Google Scholar
  110. 110. Van Harten D (1987) Ostracodes and the early Holocene, anoxic event in the Eastern Mediterranean: Evidence and implications. Mar Geol 75: 263–269.
    • View Article
    • Google Scholar
  111. 111. Macpherson E (2002) Large-scale species-richness gradients in the Atlantic. Oceanographic Proceeding of the Royal Society of London B 269: 1715–1720.
    • View Article
    • Google Scholar
  112. 112. Abelló P, Cartes J (1992) Population characteristics of the deep-sea lobster Polycheles typhlops and Stereomastis sculpta (Decapoda: Polychelidae) in a bathyal mud community of the Mediterranean Sea. Mar Biol 114: 109–117.
    • View Article
    • Google Scholar
  113. 113. Bouchet P, Taviani M (1992) The Mediterranean deep-sea fauna: Pseudopopulations of Atlantic species? Deep Sea Res A 39: 169–184.
    • View Article
    • Google Scholar
  114. 114. Fishelson L, Galil BS (2001) Gonad structure and reproductive cycle in the deep-sea herpaphrodite tripodfish, Bathypterois mediterraneus (Chlorophthalmidae, Teleostei). Copeia 2: 556–560.
    • View Article
    • Google Scholar
  115. 115. D'Onghia G, Lloris D, Sion L, Capezzuto F, Labropoulou M (2004) Observations on the distribution, population structure and biology of Bathypterois mediterraneus Bauchot, 1962 in three areas of the Mediterranean Sea. Sci Mar 68(3): 163–170.
    • View Article
    • Google Scholar
  116. 116. D'Onghia G, Politou CY, Bozzano A, Lloris D, Rotllant G, et al. (2004) Deep-water fish assemblages in three areas of the Mediterranean Sea. Sci Mar 68(3): 87–99.
    • View Article
    • Google Scholar
  117. 117. D'Onghia G, Sion L, Maiorano P, Mytilineou Ch, Dalessandro S, et al. (2006) Population biology and life strategies of Chlorophthalmus agassizii Bonaparte, 1840 (Pisces: Osteichthyes) in the Eastern-Central Mediterranean Sea. Mar Biol 149: 435–446.
    • View Article
    • Google Scholar
  118. 118. Matarrese A, D'Onghia G, Basanisi M, Mastrototaro F (1998) Spawning and recruitment of Phycis blennoides (Brunnich, 1768) from the north-western Ionian Sea (middle-eastern Mediterranean). Italian Journal of Zoology 65: 203–209.
    • View Article
    • Google Scholar
  119. 119. Company JB, Sardà F (1997) Reproductive patterns and population characteristics in five deep-water pandalid shrimps in the Western Mediterranean along a depth gradient (150–1100m). Mar Ecol Progr Ser 148: 49–58.
    • View Article
    • Google Scholar
  120. 120. Company JB, Cartes JE, Sardà F (2001) Biological patterns and near-bottom population characteristics of two pasiphaeid decapod crustacean species, Pasiphaea sivado and Pasipahea multidentata, in the Northwestern Mediterranean Sea. Mar Biol 139: 61–73.
    • View Article
    • Google Scholar
  121. 121. Company JB, Sardà F, Puig P, Cartes J, Planques A (2003) Duration and timing of reproduction in decapod crustaceans of the NW Mediterranean continental margins: Is there a general pattern? Mar Ecol Progr Ser 261: 201–216.
    • View Article
    • Google Scholar
  122. 122. D'Onghia G, Basanisi M, Matarrese A, Megli F (1999) Reproductive strategy of macrourid fish: Seasonality or not? Mar Ecol Progr Ser 184: 189–196.
    • View Article
    • Google Scholar
  123. 123. D'Onghia G, Lloris D, Politou C-Y, Sion L, Dokos J (2004) New records of deep-water teleost fish in the Balearic Sea and Ionian Sea (Mediterranean Sea). Sci Mar 68 (3): 171–183.
    • View Article
    • Google Scholar
  124. 124. Maiorano P, D'Onghia G, Capezzuto F, Sion L (2002) Life-history traits of Plesionika martia (Decapoda: Caridea) from the Eastern-Central Mediterranean Sea. Mar Biol 141: 527–539.
    • View Article
    • Google Scholar
  125. 125. Maiorano P, Pastore M, D'Onghia G, Latorre F (1998) Note on the population structure and reproduction of Polycheles typhlops (Heller, 1862) (Decapoda: Polychelidae) on the upper slope of the Ionian Sea. J Nat Hist 32: 1609–1618.
    • View Article
    • Google Scholar
  126. 126. Rotllant G, Moranta J, Massutí E, Sardà F, Morales-Nin B (2002) Reproductive biology of three gadiform fish species through the Mediterranean deep-sea range (147–1850 m). Sci Mar 66: 157–166.
    • View Article
    • Google Scholar
  127. 127. Ramirez-Llodra E, Company JB, Camps M, Rotllant G (2007) Spatio-temporal variations in reproductive patterns and population structure of Pasiphaea multidentata (Decapoda: Caridea) in the Blanes canyon and adjacent margin, Northwestern Mediterranean Sea. Mar Ecol 28: 470–479.
    • View Article
    • Google Scholar
  128. 128. Company JB, Maiorano A, Tselepides T, Politu CY, Plaity W, et al. (2004) Population characteristics of deep-sea decapod crustacean at four different sites of the Mediterranean Sea. Sci Mar 68(3): 73–86.
    • View Article
    • Google Scholar
  129. 129. Ramirez-Llodra E, Ballesteros M, Company JB, Dantart L, Sardà S (2008) Spatio-temporal variations of biomass and abundance in bathyal non-crustacean megafauna in the Catalan Sea (Northwestern Mediterranean). Mar Biol 153: 297–309.
    • View Article
    • Google Scholar
  130. 130. Jones EG, Tselepides A, Bagley PM, Collins MA, Priede IG (2003) Bathymetric distribution of some benthic and benthopelagic species attracted to baited cameras and traps in the deep Eastern Mediterranean. Mar Ecol Progr Ser 251: 75–86.
    • View Article
    • Google Scholar
  131. 131. Galil B S, Clark PF (1993) A new genus and species of axiid (Decapoda, Thalassinidea) from the Levantine basin of the Mediterranean. Crustaceana 64(1): 48–55.
    • View Article
    • Google Scholar
  132. 132. Stefanescu C, Lloris D, Rucabado J (1993) Deep-sea fish assemblages in the Catalan Sea (western Mediterranean) below a depth of 1000 m. Deep Sea Res I 40: 695–707.
    • View Article
    • Google Scholar
  133. 133. Abelló P, Valladares F, Castellón A (1988) Analysis of the structure of decapod crustaceans assemblages off the Catalan coast (North-West Mediterranean). Mar Biol 98: 39–49.
    • View Article
    • Google Scholar
  134. 134. Cartes JE, Sardà F (1992) Abundance and diversity of decapod crustaceans in the deep-Catalan Sea (Western Mediterranean). J Nat Hist 26: 1305–1323.
    • View Article
    • Google Scholar
  135. 135. Sardà F, Cartes JE (1997) Morphological features and ecological aspects of early juvenile specimens of the aristeid shrimp Aristeus antennatus (Risso, 1816). Marine Freshwater Research 48: 73–77.
    • View Article
    • Google Scholar
  136. 136. Maynou F, Cartes JE (2000) Community structure of bathyal decapod crustaceans off south-west Balearic Islands (western Mediterranean): Seasonality and regional patterns in zonation. J Mar Biol Ass UK 80: 789–798.
    • View Article
    • Google Scholar
  137. 137. Pérès JM (1985) History of the Mediterranean biota and the colonization of the depths. In: Margalef R, editor. Key Environments: Western Mediterranean. Oxford: Pergamon Press. pp. 198–232.
  138. 138. Laubier L, Emig C (1993) La faune benthique profonde de Méditerranée. NFR Della Croce. Symposium Mediterranean Seas. 2000. : 397–424.
  139. 139. Morales-Nin B, Massutí E, Stefanescu C (1996) Distribution and biology of Alepocephalus rostratus from the Mediterranean Sea. J Fish Biol 48: 1097–1112.
    • View Article
    • Google Scholar
  140. 140. Moranta J, Stefanescu C, Massutí E, Morales-Nin B, Lloris D (1998) Fish community structure and depth-related trends on the continental slope of the Balearic Islands (Algerian basin, western Mediterranean). Mar Ecol Progr Ser 171: 247–259.
    • View Article
    • Google Scholar
  141. 141. Stefanescu C, Rucabado J, Lloris D (1992) Depth-size trends in western Mediterranean demersal deep-sea fishes. Mar Ecol Progr Ser 81: 205–213.
    • View Article
    • Google Scholar
  142. 142. Massutí E, Morales-Nin B, Stefanescu C (1995) Distribution and biology of five grenadier fish (Pisces: Macrouridae) from the upper and middle slope of the northwestern Mediterranean. Deep Sea Res I 42: 307–330.
    • View Article
    • Google Scholar
  143. 143. Moranta J, Palmer M, Massutí E, Stefanescu C, Morales-Nin B (2004) Body fish size tendencies within and among species in the deep-sea of the western Mediterranean. Sci Mar 68(3): 141–152.
    • View Article
    • Google Scholar
  144. 144. Capezzuto F, Carlucci R, Maiorano P, Sion L, Battista B, et al. (2010) The bathyal benthopelagic fauna in the NW Ionian Sea: structure, patterns and interactions. Chem Ecol 26(1): 199–217.
    • View Article
    • Google Scholar
  145. 145. Goren M, Mienis H, Galil BS (2006) Not so poor - New records for the deep sea fauna of the Levant Sea, Eastern Mediterranean. J Mar Biol Ass UK 2: 1–4.
    • View Article
    • Google Scholar
  146. 146. Bogi C, Galil BS (2004) The bathyenthic and pelagic molluscan fauna off the Levantine coast, Eastern Mediterranean. Boll Malacol 39(5–8): 79–90.
    • View Article
    • Google Scholar
  147. 147. Sorbe JC, Galil BS (2002) The bathyal Amphipoda of the Levantine coast, Eastern Mediterranean. Crustaceana 75(8): 957–968.
    • View Article
    • Google Scholar
  148. 148. Danovaro R, Dell' Anno A, Fabiano M, Pusceddu A, Tselepides A (2001) Deep-sea ecosystem response to climate changes: The Eastern Mediterranean case study. Trends Ecol Evol 16: 505–510.
    • View Article
    • Google Scholar
  149. 149. Basso D, Thomson J, Corselli C (2004) Indications of low macrobenthic activity in the deep sediments of the eastern Mediterranean Sea. Sci Mar 68(3): 53–62.
    • View Article
    • Google Scholar
  150. 150. Levin LA, Sibuet M, Gooday AJ, Smith CR, Vanreusel A (2010) The roles of habitat heterogeneity in generating and maintaining biodiversity on continental margins: an introduction. Mar Ecol 31: 1–5.
    • View Article
    • Google Scholar
  151. 151. Puig P, Palanques A, Guillen J, García-Ladona E (2000) Deep slope currents and suspended particle fluxes in and around the Foix submarine canyon (NW Mediterranean). Deep Sea Res I 47: 343–366.
    • View Article
    • Google Scholar
  152. 152. Puig P, Ogsto AS, Mullenbach BL, Nittrouer CA, Sternberg RW (2003) Shelf-to-canyon sediment transport processes on the Eel Continental Margin (Northern California). Mar Geol 193: 129–149.
    • View Article
    • Google Scholar
  153. 153. Gili JM, Bouillon J, Pagès F, Palanques A, Puig P (1999) Submarine canyons as habitats of prolific plankton populations: Three new deep-sea Hydrodomedusae in the Western Mediterranean. Zool J Linn Soc 125: 313–329.
    • View Article
    • Google Scholar
  154. 154. Gili JM, Pagès F, Bouillon J, Palanques A, Puig P, et al. (2000) A multidisciplinary approach to the understanding of hydromedusan populations inhabiting Mediterranean submarine canyons. Deep Sea Res I 47: 1513–1533.
    • View Article
    • Google Scholar
  155. 155. Stefanescu C, Morales-Nin B, Massutí E (1994) Fish assemblages on the slope in the Catalan Sea (western Mediterranean): Influence of a submarine canyon. J Mar Biol Ass UK 74: 499–512.
    • View Article
    • Google Scholar
  156. 156. Tudela S, Sardà F, Maynou F, Demestre M (2003) Influence of submarine canyons on the distribution of the deep-water shrimp (Aristeus antennatus, Risso 1816) in the northwestern Mediterranean. Crustaceana 76: 217–225.
    • View Article
    • Google Scholar
  157. 157. Vetter EW, Dayton PK (1998) Macrofaunal communities within and adjacent to a detritus-rich submarine canyon system. Deep Sea Res II 45: 25–54.
    • View Article
    • Google Scholar
  158. 158. Zúñiga D, Flexas MM, Sánchez-Vida A, Coenjaerts J, Calafat A, et al. (2009) Particle fluxes dynamics in Blanes submarine canyon (Northwestern Mediterranean). Progr Oceanogr 82: 239–251.
    • View Article
    • Google Scholar
  159. 159. Greene HG, Wiebe PH, Burczynski J, Youngbluth MJ (1988) Acoustical detection of high-density krill demersal layers in the submarine canyons off georges bank. Science 241: 359–361.
    • View Article
    • Google Scholar
  160. 160. Harrold C, Light K, Lisin S (1998) Organic enrichment of submarine-canyon and continental-shelf benthic communities by macroalgal drift imported from nearshore kelp forests. Limn Oceanogr 43: 669–678.
    • View Article
    • Google Scholar
  161. 161. Vetter EW (1994) Hotspots of benthic production. Nature 372: 47.
    • View Article
    • Google Scholar
  162. 162. Bianchelli S, Gambi C, Pusceddu A, Danovaro R (2008) Trophic conditions and meiofaunal assemblages in the Bari Canyon and the adjacent open slope (Adriatic Sea). Chem Ecol 24 (S1): 101–109.
    • View Article
    • Google Scholar
  163. 163. Margalef R (1997) Turbulence and marine life. Sci Mar 61: 109–123.
    • View Article
    • Google Scholar
  164. 164. Trincardi F, Foglini F, Verdicchio G, Asioli A, Correggiari A, et al. (2007) The impact of cascading currents on the Bari Canyon System, SW-Adriatic Margin (Central Mediterranean). Mar Geol 246 (2–4): 208–230.
    • View Article
    • Google Scholar
  165. 165. Selli R (1985) Tectonic evolution of the Tyrrhenian Sea. In: Stanley DJW, editor. Geological Evolution of the Mediterranean Basin. pp. 131–151. Springer, New York.
  166. 166. Acosta J, Canals M, Lòpez-Martìnez J, Munõz A, Herranz P, et al. (2002) The Balearic Promontory geomorphology (western Mediterranean): morphostructure and active processes. Geomorphology 49: 177–204.
    • View Article
    • Google Scholar
  167. 167. Christiansen B (1989) Acanthephyra sp. (Crustacea: Decapoda) in the Eastern Mediterranean Sea 9 captured by baited traps. Senkenb Mar 20: 187–193.
    • View Article
    • Google Scholar
  168. 168. Hsü KJ (1972) When the Mediterranean dried up. Sci Am 227: 27–36.
    • View Article
    • Google Scholar
  169. 169. Wezel FC (1985) Structural features and basin tectonics of the Tyrrhenian Sea. In: Stanley DJ, Wezel FC, editors. Geological evolution of the Mediterranean Basin. New York: Springer-Verlag. pp. 153–194.
  170. 170. Pusceddu A, Gambi C, Zeppilli D, Bianchelli S, Danovaro R (2009) Organic matter composition, meiofauna and nematode biodiversity in deep-sea sediments surrounding two seamounts. Deep Sea Res II 56: 755–762.
    • View Article
    • Google Scholar
  171. 171. Hovland M (2008) Deep-water coral reefs: Unique biodiversity hot-spots. Chichester: Springer. 278 p.
  172. 172. Zibrowius H (2003) The “White Coral Community”, canyon and seamount faunas of the deep Mediterranean Sea. 39 p. Project Report for the preparation of a Strategic Action Plan for the Conservation of Biological Diversity in the Mediterranean Region (SAP BIO).
  173. 173. Freiwald A, Fossa JH, Grehan A, Koslow T, Roberts JM (2004) Cold-water coral reefs. Cambridge: UNEP-WCMC Biodiversity Series No 22. 88 p.
  174. 174. Zibrowius H (1980) Les Scléractiniaires de la Méditerranée et de l'Atlantique nord-oriental. Mémoires de l'Institut Océanographique Monaco 11: 1–227.
    • View Article
    • Google Scholar
  175. 175. Pérès JM, Picard J (1964) Nouveau manuel de bionomie benthique de la mer Méditerranée. Recueil des Travaux de la Station Marine d'Endoume 31 (47): 1–137.
    • View Article
    • Google Scholar
  176. 176. Schönberg CHL, Beuck L (2007) Where Topsent went wrong: Aka infesta a.k.a. Aka labyrinthica (Demospongiae: Phloeodictyidae) and implications for other Aka spp. J Mar Biol Ass UK 87: 1459–1476.
    • View Article
    • Google Scholar
  177. 177. Rosso A, Vertino A, Di Geronimo I, Sanfilippo R, Sciuto F, et al. (2010) Hard- and soft-bottom thanatofacies from the Santa Maria di Leuca deep-water coral province, Mediterranean. Deep Sea Res II 57: 360–379.
    • View Article
    • Google Scholar
  178. 178. Vertino A, Savini A, Rosso A, Di Geronimo I, Mastrototaro F, et al. (2010) Benthic habitat characterization and distribution from two representative sites of the deep-water SML coral mound province (Mediterranean). Deep Sea Res II 57: 380–396.
    • View Article
    • Google Scholar
  179. 179. Mastrototaro F, D'Onghia G, Corriero G, Matarrese A, Maiorano P, et al. (2010) Biodiversity of the white coral and sponge community off Cape Santa Maria di Leuca (Mediterranean Sea). Deep Sea Res II 57: 412–430.
    • View Article
    • Google Scholar
  180. 180. D'Onghia G, Maiorano P, Sion L, Giove A, Capezzuto F, et al. (2010) Effects of deep-water coral banks on the abundance and size structure of the megafauna in the Mediterranean Sea. Deep Sea Res II 57: 397–411.
    • View Article
    • Google Scholar
  181. 181. Bourcier M, Zibrowius H (1973) Les «boues rouges» déversées dans le canyon de la Cassidaigne (région de Marseille). Observations en soucoupe plongeante SP 350 (juin 1971) et résultats de dragages. Tethys 4: 811–842.
    • View Article
    • Google Scholar
  182. 182. Zabala M, Maluquer P, Harmelin J-G (1993) Epibiotic bryozoans on deep-water scleractinian corals from the Catalonian slope (Western Mediterranean, Spain, France). Sci Mar 57(1): 65–78.
    • View Article
    • Google Scholar
  183. 183. Zibrowius H, Taviani M (2005) Remarkable sessile fauna associated with deep coral and other calcareous substrates in the Strait of Sicily, Mediterranean Sea. In: Freiwald A, Roberts JM, editors. Cold Water Corals and Ecosystems. Heildelberg: Springer. pp. 807–819.
  184. 184. Schembri PJ, Dimech M, Camilleri M, Page R (2007) Living deep-water Lophelia and Madrepora corals in Maltese waters (Strait of Sicily, Mediterranean Sea). Cah Biol Mar 48: 77–83.
    • View Article
    • Google Scholar
  185. 185. Buhl-Mortensen L, Mortensen PB (2004) Symbiosis in deep-water corals. Symbiosis 37: 33–61.
    • View Article
    • Google Scholar
  186. 186. Mortensen PB, Fosså JH (2006) Species diversity and spatial distribution of invertebrates on deep-water Lophelia reef in Norway. pp. 1849–1868. Proceedings of 10th International Coral Reef Symposium.
  187. 187. Husebo A, Nottestand L, Fosså JH, Furevik DM, Jorgensen SB (2002) Distribution and abundance of fish in deep-sea coral habitats. Hydrobiologia 471: 91–99.
    • View Article
    • Google Scholar
  188. 188. Krieger KJ, Wing B (2002) Megafauna associations with deep-water corals (Primnoa spp.) in the Gulf of Alaska. Hydrobiologia 471: 83–90.
    • View Article
    • Google Scholar
  189. 189. Reed JK (2002) Deep-water Oculina coral reefs of Florida: Biology, impacts, and management. Hydrobiologia 471: 43–55.
    • View Article
    • Google Scholar
  190. 190. Costello MJ, McCrea M, Freiwald A, Lundälv T, Jonsson L, et al. (2005) Role of cold-water Lophelia pertusa coral reefs as fish habitat in the NE Atlantic. In: Freiwald A, Roberts JM, editors. Cold water corals and ecosystems. Heildelberg: Springer. pp. 771–805.
  191. 191. Ross SW, Quattrini AM (2007) The fish fauna associated with deep coral banks off the southeastern United States. Deep Sea Res I 54: 975–1007.
    • View Article
    • Google Scholar
  192. 192. D'Onghia G, Mastrototaro F, Matarrese A, Politou C-Y, Mytilineou Ch (2003) Biodiversity of the upper slope demersal community in the Eastern Mediterranean: Preliminary comparison between two areas with and without trawl fishing. J Northwest Atl Fish Soc 31: 263–273.
    • View Article
    • Google Scholar
  193. 193. Yakimov MM, Cappello S, Crisafi E, Tursi A, Savini A, et al. (2006) Phylogenetic survey of metabolically active microbial communities associated with the deep-sea coral Lophelia pertusa from the Apulian plateau, Central Mediterranean Sea. Deep Sea Res I 53: 62–75.
    • View Article
    • Google Scholar
  194. 194. Kellogg CA (2004) Tropical Archaea: diversity associated with the surface microlayer of corals. Mar Ecol Progr Ser 273: 81–88.
    • View Article
    • Google Scholar
  195. 195. Dando PR, Stüben D, Varnavas SP (1999) Hydrothermalism in the Mediterranean Sea. Progr Oceanogr (44): 333–367.
    • View Article
    • Google Scholar
  196. 196. Uchupi C, Ballard A (1989) Evidence of hydrothermal activity on Marsili Seamount, Tyrrhenian Basin. Deep Sea Res A 36(9): 1443–1448.
    • View Article
    • Google Scholar
  197. 197. Corselli C, Basso D (1996) First evidence of benthic communities based on chemosynthesis on the Napoli mud volcano (Eastern Mediterranean). Mar Geol 132: 227–239.
    • View Article
    • Google Scholar
  198. 198. Salas C, Woodside J (2002) Lucinoma kazani n. sp. (Mollusca, Bivalvia): Evidence of a living community associated with a cold seep in the Eastern Mediterranean Sea. Deep Sea Res I 49: 991–1005.
    • View Article
    • Google Scholar
  199. 199. Coleman DF, Ballard RD (2001) A highly concentrated region of cold hydrocarbon seeps in the southeastern Mediterranean Sea. Geo-Mar Lett 21: 162–167.
    • View Article
    • Google Scholar
  200. 200. Olu-Le Roy K, Sibuet M, Fiala-Médioni A, Gofas S, Salas C, et al. (2004) Cold seep communities in the deep eastern Mediterranean Sea: composition, symbiosis and spatial distribution on mud volcanoes. Deep Sea Res I 51: 1915–1936.
    • View Article
    • Google Scholar
  201. 201. Zitter TAC, Huguen C, Woodside JM (2005) Geology of mud volcanoes in the eastern Mediterranean from combined sidescan sonar and submersible surveys. Deep Sea Res I 52: 457–475.
    • View Article
    • Google Scholar
  202. 202. Charlou JL, Donval JP, Zitter T, Roy N, Jean-Baptiste P, et al. (2003) Evidence of methane venting and geochemistry of brines on mud volcanoes of the eastern Mediterranean Sea. Deep Sea Res I 50 (8): 941–958.
    • View Article
    • Google Scholar
  203. 203. Huguen C, Foucher JP, Mascle J, Ondréas H, Thouement M, et al. (2009) Menes caldera, a highly active site of brine seepage in the Eastern Mediterranean Sea: “In situ” observations from the NAUTINIL expedition (2003). Mar Geol 261 (1–4): 138–152.
    • View Article
    • Google Scholar
  204. 204. Bayon G, Loncke L, Dupré S, Caprais JC, Ducassou E, et al. (2009) Multi-disciplinary investigation of fluid seepage on an unstable margin: The case of the Central Nile deep sea fan. Mar Geol 261 (1–4): 92–104.
    • View Article
    • Google Scholar
  205. 205. Dupré S, Woodside J, Foucher J-P, de Lange G, Mascle J, et al. (2007) Seafloor geological studies above active gas chimneys off Egypt (Central Nile Deep Sea Fan). Deep Sea Res I 54 (7): 1146.
    • View Article
    • Google Scholar
  206. 206. Sturany R (1896) Zoologische Ergebnisse VII. Mollusken I (Prosobranchier und Opisthobranchier Scaphopoden Lamellibranchier) gesammelt von SM Schiff “Pola” 1890–18. Denkschriften der Kaiserlichen Akademie der Wissenschaften, Mathematische-Naturwissenschaftlischen Classe 63 (1–36): pl.31–32.
    • View Article
    • Google Scholar
  207. 207. Southward E, Andersen A, Hourdez SLamellibrachia anaximandri n.sp., a new vestimentiferan tubeworm from the Mediterranean (Annelida). Zoosystema.
    • View Article
    • Google Scholar
  208. 208. Duperron S, de Beer D, Zbinden M, Boetius A, Schipani V, et al. (2009) Molecular characterization of bacteria associated with the trophosome and the tube of Lamellibrachia sp., a siboglinid annelid from cold seeps in the eastern Mediterranean. FEMS Microb Ecol 69 (3): 395–409.
    • View Article
    • Google Scholar
  209. 209. Duperron S, Fiala-Médioni A, Caprais JC, Olu K, Sibuet M (2007) Evidence for chemoautotrophic symbiosis in a Mediterranean cold seep clam (Bivalvia: Lucinidae): Comparative sequence analysis of bacterial 16S rRNA, APS reductase and RubisCO genes. FEMS Microb Ecol 59: 64–70.
    • View Article
    • Google Scholar
  210. 210. Duperron S, Halary S, Lorion J, Sibuet M, Gaill F (2008) Unexpected co-occurrence of six bacterial symbionts in the gills of the cold seep mussel Idas sp. (Bivalvia: Mytilidae). Environ Microb 10 (2): 433–445.
    • View Article
    • Google Scholar
  211. 211. Sibuet M, Olu K (1998) Biogeography, biodiversity and fluid dependence of deep-sea cold-seep communities at active and passive margins. Deep Sea Res II 45: 517–567.
    • View Article
    • Google Scholar
  212. 212. Sibuet M, Olu-Le Roy K (2002) Cold seep communities on continental margins: structure and quantitative distribution relative to geological and fluid venting patterns. In: Wefer G, Billett D, Hebbeln D, Jorgensen B, Schlüter M, van Weering T, editors. Ocean Margin Systems, Springer, Berlin. pp. 235–251.
  213. 213. Ritt B, Sarrazin J, Caprais JC, Noel P, Gauthier O, et al. (2010) First insights into the structure and environmental setting of cold-seep communities in the Marmara Sea. Deep Sea Res I:
    • View Article
    • Google Scholar
  214. 214. Zitter TAC, Henry P, Aloisi G, Delaygue G, Çagatay MN, et al. (2008) Cold seeps along the main Marmara Fault in the Sea of Marmara (Turkey). Deep Sea Res I 55(4): 552–570.
    • View Article
    • Google Scholar
  215. 215. Hsü KJ, Montadert L, Bernoulli D, Cita MB, Erickson A, et al. (1977) History of the Mediterranean salinity crisis. Nature 267: 399–403.
    • View Article
    • Google Scholar
  216. 216. van der Wielen PWJJ, Bolhuis H, Borin S, Daffonchio D, Corselli C, et al. (2005) The enigma of prokaryotic life in deep hypersaline anoxic basins. Science 307: 121–123.
    • View Article
    • Google Scholar
  217. 217. Hallsworth JE, Yakimov MM, Golyshin PN, Gillion JLM, D'Auria G, et al. (2007) Limits of life in MgCl2-containing environments: Chaotropicity defines the window. Environ Microb 9: 801–813.
    • View Article
    • Google Scholar
  218. 218. Daffonchio D, Borin S, Brusa T, Brusetti L, van der Wielen PWJJ, et al. (2006) Stratified prokaryote network in the oxic–anoxic transition of a deep-sea halocline. Nature 408: 203–207.
    • View Article
    • Google Scholar
  219. 219. van der Wielen PWJJ, Heijs SK (2007) Sulfate-reducing prokaryotic communities in two deep hypersaline anoxic basins in the Eastern Mediterranean deep sea. Environ Microb 9: 1335–1340.
    • View Article
    • Google Scholar
  220. 220. Yakimov MM, Lo Cono V, Denaro R, D'Auria G, Decembrini F, et al. (2007) Primary producing prokaryotic communities of brine, interface and seawater above the halocline of deep anoxic lake L'Atalante, Eastern Mediterranean Sea. ISME J 1: 743–755.
    • View Article
    • Google Scholar
  221. 221. Yakimov MM, Giuliano L, Cappello S, Denaro R, Golyshin PN (2007) Microbial community of a hydrothermal mud vent underneath the deep-sea anoxic brine Lake Urania (Eastern Mediterranean). Origins of Life and Evolution of Biospheres 37: 177–188.
    • View Article
    • Google Scholar
  222. 222. Borin S, Brusetti L, Mapelli F, D'Auria G, Brusa T, et al. (2009) Sulfur cycling and methanogenesis primarily drive microbial colonization of the highly sulfidic Urania deep hypersaline basin. PNAS 106: 9151–9156.
    • View Article
    • Google Scholar
  223. 223. Danovaro R, Dell'Anno A, Pusceddu A, Gambi C, Heiner I, Kristensen RM (2010) The first metazoa living in permanently anoxic conditions. BMC Biology 8: 30. http://www.biomedcentral.com/1741-7007/8/30 .
    • View Article
    • Google Scholar
  224. 224. Rex MA (1981) Community structure in the deep-sea benthos. Annual Annu Rev Ecol Syst 12: 331–353.
    • View Article
    • Google Scholar
  225. 225. Levin LA, Etter RJ, Rex MA, Gooday AJ, Smith CR, et al. (2001) Environmental influences on regional deep-sea species diversity. Annu Rev Ecol Syst 32: 51–93.
    • View Article
    • Google Scholar
  226. 226. Rex MA, Crame JA, Stuart CT, Clarke A (2005) Large-scale biogeographic patterns in marine molluscs: A confluence of history and productivity? Ecology 86: 2288–2297.
    • View Article
    • Google Scholar
  227. 227. Rex MA, Etter RJ, Morris JS, Crouse J, McClain CR, et al. (2006) Global bathymetric patterns of standing stock and body size in the deep-sea benthos. Mar Ecol Progr Ser 317: 1–8.
    • View Article
    • Google Scholar
  228. 228. Buhring SI, Lampadariou N, Moodley L, Tselepides A, Witte U (2006) Benthic microbial and whole –community responses to different amounts of C-13 enriched algae: in situ experiments in the deep Cretan Sea (Eastern Mediterranean). Limn Oceanogr 51(1): 157–165.
    • View Article
    • Google Scholar
  229. 229. Hausmann K, Hulsmann N, Polianski I, Schade S, Weitere M (2002) Composition of benthic protozoan communities along a depth transect in the Eastern Mediterranean Sea. Deep Sea Res I 49: 1959–1970.
    • View Article
    • Google Scholar
  230. 230. Gooday AJ (2003) Benthic foraminifera (Protista) as tools in deep-water palaeoceanography: A review of environmental influences on faunal characteristics. Adv Mar Biol 46: 1–90.
    • View Article
    • Google Scholar
  231. 231. Jorissen FJ, de Stigter HC, Widmark JGV (1995) A conceptual model explaining benthic foraminiferal microhabitats. Mar Micropaleont 26: 3–15.
    • View Article
    • Google Scholar
  232. 232. Van der Zwaan GJ, Duijnstee IAP, den Dulk M, Ernst SR, Jannink NT, et al. (1999) Benthic foraminifers: proxies or problems? A review of paleoecological concepts. Earth Sci Rev 46: 213–236.
    • View Article
    • Google Scholar
  233. 233. Fontanier C, Jorissen FJ, Chaillou G, Anschutz P, Gremare A, et al. (2005) Live foraminiferal faunas from a 2800 m deep lower canyon station from the Bay of Biscay: Faunal response to focusing of refractory organic matter. Deep Sea Res I 52: 1189–1227.
    • View Article
    • Google Scholar
  234. 234. Risgaard–Petersen N, Langezaal AM, Ingvardsen S, Schmid MC, Jetten MS, et al. (2006) Evidence for complete denitrification in a benthic foraminifer. Nature 443: 93–96.
    • View Article
    • Google Scholar
  235. 235. Høgslund S, Revsbech NP, Cedhagen T, Nielsen LP, Gallardo VA (2008) Denitrification, nitrate turnover and aerobe respiration by benthic foraminifera in the oxygen minimum zone off Chile. J Exp Mar Biol Ecol 359(2): 85–91.
    • View Article
    • Google Scholar
  236. 236. Vincx M, Bett BJ, Dinet A, Ferrero T, Gooday AJ, et al. (1994) Meiobenthos of the deep Northeast Atlantic. In: Blaxter JHS, Southward AJ, editors. Advances in Marine Biology vol. 30. pp. 2–88. Academic Press, London.
  237. 237. Bianchelli S, Gambi C, Zeppilli D, Danovaro R (2009) Metazoan meiofauna in deep-sea canyons and adjacent open slopes: A large-scale comparison with focus on the rare taxa. Deep Sea Res I 57: 420–433.
    • View Article
    • Google Scholar
  238. 238. Gage J (2003) Food inputs, utilisation, carbon flow and energetics. In: Tyler PA, editor. Ecosystems of the world: The deep ocean. Amsterdam: Elsevier. pp. 313–426.
  239. 239. Massutí M, Gordon JDM, Moranta J, Swan SC, Stefanescu C, et al. (2004) Mediterranean and Atlantic deep-sea fish assemblages: Differences in biomass composition and size-related structure. Sci Mar 68(3): 101–115.
    • View Article
    • Google Scholar
  240. 240. Lampitt RS, Billett DSM, Rice AL (1986) Biomass of the invertebrate megabenthos from 500 to 4100 m in the northeast Atlantic Ocean. Mar Biol 93: 69–81.
    • View Article
    • Google Scholar
  241. 241. Sion L, Bozzano A, D'Onghia G, Capezzuto F, Panza M (2004) Chondrichthyes species in deep waters of the Mediterranean Sea. Sci Mar 68(3): 153–162.
    • View Article
    • Google Scholar
  242. 242. Tosti L, Danovaro R, Dell'Anno A, Olivotto I, Bompadre S, et al. (2006) Vitellogenesis in the deep-sea shark Centroscymnus coelolepis. Chem Ecol 22: 335–345.
    • View Article
    • Google Scholar
  243. 243. Sibuet M (1979) Distribution and diversity of Asteroids in Atlantic abyssal basins. Sarsia 64: 85–91.
    • View Article
    • Google Scholar
  244. 244. Vetter EW, Dayton PK (1999) Organic enrichment by macrophyte detritus and abundance patterns of megafaunal populations in submarine canyons. Mar Ecol Progr Ser 186: 137–148.
    • View Article
    • Google Scholar
  245. 245. Tyler PA, Ramirez-Llodra E (2002) Larval and reproductive strategies on European continental margins. In: Billett DSM, Wefer G, Hebbeln D, Jorgensen BB, Schluter M, Van Weering TCE, editors. Ocean Margin Systems. Berlin: Springer. pp. 339–350.
  246. 246. Bellan-Santini D (1990) Mediterranean deep-sea Amphipoda: Composition, structure and affinities of the fauna. Progr Oceanogr 24: 275–387.
    • View Article
    • Google Scholar
  247. 247. Ramirez-Llodra E, Brandt A, Danovaro R, Escobar E, German CR, et al. (2010) Deep, diverse and definitely different: unique attributes of the world's largest ecosystem. Biogeosciences Discuss 7: 2361–2485.
    • View Article
    • Google Scholar
  248. 248. Derraik JGB (2002) The pollution of the marine environment by plastic debris: A review. Mar Poll Bull 44: 842–852.
    • View Article
    • Google Scholar
  249. 249. Galil BS, Golik A, Türkay M (1995) Litter at the bottom of the sea: A sea bed survey in the Eastern Mediterranean. Mar Poll Bull 30(1): 22–24.
    • View Article
    • Google Scholar
  250. 250. Galgani F, Jaunet S, Campillo A, Guenegan X, His E (1995) Distribution and abundance of debris on the continental shelf of the northwestern Mediterranean Sea. Mar Poll Bull 30(11): 713–717.
    • View Article
    • Google Scholar
  251. 251. Galgani F, Souplet A, Cadiou Y (1996) Accumulation of debris on the deep sea floor off the French Mediterranean coast. Mar Ecol Progr Ser 142: 225–234.
    • View Article
    • Google Scholar
  252. 252. Richter TO, de Stigter HC, Boer W, Jesús CC, van Weering TCE (2009) Dispersal of natural and anthropogenic lead through submarine canyons in the Portuguese margin. Deep Sea Res I 56: 267–282.
    • View Article
    • Google Scholar
  253. 253. Rotllant G, Abad Holgado E, Sardà F, Ábalos M, Company JB, et al. (2006) Dioxin compounds in the deep-sea rose shrimp Aristeus antennatus (Risso, 1816) throughout the Mediterranean Sea. Deep Sea Res I 53: 1895–1906.
    • View Article
    • Google Scholar
  254. 254. Unger MA, Harvey E, Vadas GG, Vecchione M (2008) Persistent pollutants in nine species of deep-sea cephalopods. Mar Poll Bull 56: 1486–1512.
    • View Article
    • Google Scholar
  255. 255. Béthoux JP, Durrieu de Madron X, Nyffeler F, Tailliez D (2002) Deep water in the western Mediterranean: Peculiar 1999 and 2000 characteristics, shelf formation hypothesis, variability since 1970 and geochemical inferences. J Mar Syst 33–34: 117–131.
    • View Article
    • Google Scholar
  256. 256. Ivanov VV, Shapiro GI, Huthnance JM, Aleynik DL, Golovin PN (2004) Cascades of dense water around the world ocean. Progr Oceanogr 60: 47–98.
    • View Article
    • Google Scholar
  257. 257. Roether W, Klein B, Manca BB, Theocharis A, Kioroglou S (2007) Transient Eastern Mediterranean Deep waters in response to the massive dense-water output of the Aegean Sea in the 1990s. Progr Oceanogr 74: 540–571.
    • View Article
    • Google Scholar
  258. 258. Danovaro R, Dell'Anno A, Pusceddu A (2004) Biodiversity response to climate change in a warm deep Sea. Ecol Lett 7: 821–828.
    • View Article
    • Google Scholar
  259. 259. Levin LA, Dayton PK (2009) Ecological theory and continental margins: Where shallow meets deep. Trends Ecol Evol 24: 606–617.
    • View Article
    • Google Scholar
  260. 260. Company JB, Puig P, Sardà F, Palanques A, Latasa M, et al. (2008) Climate control on deep-sea fisheries. PLoS ONE 3(1): e1431.
    • View Article
    • Google Scholar
  261. 261. Smith CR, De Leo FC, Bernardino AF, Sweetman AK, Martinez Arbizu P (2008) Abyssal food limitation, ecosystem structure and climate change. Trends Ecol Evol 23: 518–528.
    • View Article
    • Google Scholar
  262. 262. Smith KL Jr, Ruhl HA, Bett BJ, Billet DSM, Lampitt RS, et al. (2009) Climate, carbon cycling, and deep-ocean ecosystems. PNAS 106: 19211–19218.
    • View Article
    • Google Scholar
  263. 263. Palanques A, Marín J, Puig P, Guillén J, Company JB, et al. (2006) Evidence of sediment gravity flows induced by trawling in the Palamós (Fonera) submarine canyon (northwestern Mediterranean). Deep Sea Res I 53: 201–214.
    • View Article
    • Google Scholar
  264. 264. Martín J, Puig P, Palanques A, Masqué P, García-Orellana J (2008) Effect of commercial trawling on the deep sedimentation in a Mediterranean submarine canyon. Mar Geol 252: 150–155.
    • View Article
    • Google Scholar
  265. 265. Danovaro R, Luna GM, Dell'Anno A, Pietrangeli B (2006) Comparison of two fingerprinting techniques, Terminal Restriction Fragment Length Polymorphism and Automated Ribosomal Intergenic Spacer Analysis, for determination of bacterial diversity in aquatic environments. Appl Environ Microbiol 72: 5982–5989.
    • View Article
    • Google Scholar
  266. 266. Murray JW (1991) Ecology and palaeoecology of benthic foraminifera. Longman Scientific and Technical 397.
    • View Article
    • Google Scholar
  267. 267. Jannink NT (2001) Seasonality, biodiversity and microhabitats in benthic foraminifera. Geologica Ultraiectina 203 191.
    • View Article
    • Google Scholar
  268. 268. Rucabado J, Lloris D, Stefanescu C (1991) OTSB14: Un arte de arrastre bentónico para la pesca profunda (por debajo de los mil metros). Inf Tech de Sci Mar CSIC 165: 1–27.
    • View Article
    • Google Scholar
  269. 269. Relini G (1998) Valutazione delle risorse demersali. Biologia Marina Mediterranea 5: 3–19.
    • View Article
    • Google Scholar
  270. 270. Bertrand JA, Gil de Sola L, Papaconstantinou C, Relini G, Souplet A (2002) The general specifications of the MEDITS surveys. Sci Mar 66 (2): 9–17.
    • View Article
    • Google Scholar
  271. 271. D'Onghia G, Capezzuto F, Mytilineou Ch, Maiorano P, Kapiris K, et al. (2005) Comparison of the population structure and dynamics of Aristeus antennatus (Risso, 1816) between exploited and unexploited areas in the Mediterranean Sea. Fish Res 76: 22–38.
    • View Article
    • Google Scholar
  272. 272. Politou C-Y, Mytilineou Ch, D'Onghia G, Dokos J (2008) Demersal faunal assemblages in the deep waters of the Eastern Ιonian Sea. J Nat Hist 42 (5–8): 661–672.
    • View Article
    • Google Scholar
  273. 273. Mytilineou Ch, Politou C-Y, Papaconstantinou C, Kavadas S, D'Onghia G, et al. (2005) Deep-water fish fauna in the Eastern Ionian Sea. Belgian Journal of Zoology 135 (2): 229–233.
    • View Article
    • Google Scholar
  274. 274. Politou C-Y, Maiorano P, D'Onghia G, Mytilineou Ch (2005) Deep-water decapod crustacean fauna of the Eastern Ionian Sea. Belgian Journal of Zoology 135 (2): 235–241.
    • View Article
    • Google Scholar
  275. 275. D'Onghia G, Maiorano P, Capezzuto F, Carlucci R, Battista D, et al. (2009) Further evidences of deep-sea recruitment of Aristeus antennatus (Crustacea: Decapoda) and its role in the population renewal on the exploited bottoms of the Mediterranean. Fish Res 95 (2): 236–245.
    • View Article
    • Google Scholar
  276. 276. Sanders HL (1968) Marine benthic diversity: A comparative study. Am Nat 102: 243–282.
    • View Article
    • Google Scholar
  277. 277. Gray JS (2000) The measurement of marine species diversity, with an application to the benthic fauna of the Norwegian continental shelf. J Exp Mar Biol Ecol 250: 23–49.
    • View Article
    • Google Scholar
  278. 278. Heijs SK, Laverman AM, Forney LJ, Hardoim PR, van Elsas JD (2008) Comparison of deep-sea sediment microbial communities in the Eastern Mediterranean. FEMS Microb Ecol 64 (3): 362–377.
    • View Article
    • Google Scholar
  279. 279. Álvarez-Pérez G, Busquets P, De Mol B, Sandoval NG, Canals M, et al. (2005) Deep-water coral occurrences in the Strait of Gibraltar. In: Freiwald A, Roberts JM, editors. Cold water corals and ecosystems. Heildelberg: Springer. pp. 207–221.
  280. 280. Orejas C, Gori A, Gili JM (2008) Growth rates of live Lophelia pertusa and Madrepora oculata from the Mediterranean Sea maintained in aquaria. Coral Reefs 27: 255.
    • View Article
    • Google Scholar
  281. 281. Reyss D (1964) Observations faites en soucoupe plongéante dans deux vallées sous-marines de la Mer Catalane: le rech du Cap et le rech Lacaze-Duthiers. Bulletin de l'Institut Océanographique. Fondation Albert I, Prince de Monaco 63: 1–8.
    • View Article
    • Google Scholar
  282. 282. Tunesi L, Diviacco G, Mo G (2001) Observation by submersible on the Biocoenosis of the deep-sea corals off Portofino Promontory (Northwestern Mediterranean Sea). In: Martin Willison JH, et al., editor. Proceedings of the First International Symposium on Deep-Sea Corals, Ecology Action Centre and Nova Scotia Museum, Halifax, Nova Scotia. pp. 76–87.
  283. 283. Azouz A (1973) Les fonds chalutables de la région nord de la Tunisie. 1. Cadre physique et biocoenoses benthiques. Bull. Inst. Océanogr. Pêche. Salammbô 2(4): 473–559.
    • View Article
    • Google Scholar
  284. 284. Vafidis D, Koukouras A, Voultsiadou-Koukoura E (1997) Actiniaria, Corallimorpharia, and Scleractinia (Hexacorallia, Anthozoa) of the Aegean Sea, with a checklist of eastern Mediterranean and Black Sea species. Isr J Zool 43: 55–70.
    • View Article
    • Google Scholar
  285. 285. Cartes JE (1997) Dynamics of the bathyal Benthic Boundary Layer in the northwestern Mediterranean: depth and temporal variations in macrofaunal–megafaunal communities and their possible connections within deep-sea trophic webs. Progr Oceanogr 41(1): 111–139.
    • View Article
    • Google Scholar
  286. 286. Cartes JE, Sorbe JC (1999) Deep-water amphipods from the Catalan Sea slope (western Mediterranean): Bathymetric distribution, assemblage composition and biological characteristics. Journal of Natural History 33(8): 1133–1158.
    • View Article
    • Google Scholar

Subject Areas

For more information about PLOS Subject Areas, click here.

We want your feedback. Do these Subject Areas make sense for this article? Click the target next to the incorrect Subject Area and let us know. Thanks for your help!

Is the Subject Area "Biodiversity" applicable to this article? Yes No

Is the Subject Area "Species diversity" applicable to this article? Yes No

Is the Subject Area "Sediment" applicable to this article? Yes No

Is the Subject Area "Large animals" applicable to this article? Yes No

Is the Subject Area "Mediterranean Sea" applicable to this article? Yes No

Is the Subject Area "Canyons" applicable to this article? Yes No

Is the Subject Area "Corals" applicable to this article? Yes No

Is the Subject Area "Seamounts" applicable to this article? Yes No


Background

Dogs factored greatly into Darwin’s conception of evolution (Townshend 2009) and he specifically pondered the similarities of human races and dog breeds in The Descent of Man (1871). As an integral and influential player in Darwin’s legacy, evolutionary biologist J.B.S. Haldane posed a question to a group of anthropologists at the Royal Society in 1956 that reads as if it were posted on social media today: “Are the biological differences between human groups comparable with those between groups of domestic animals such as greyhounds and bulldogs…?”

In the U.S., and likely beyond, the human race-dog breed analogy is not merely an academic question about patterns of variation today, it factors substantially into the popular debate about whether race is fundamentally biological as opposed to a social construct, and it carries forward an ugly American tradition. Inherent to the analogy is the transference of beliefs about pure-bred dogs onto notions of human racial “purity” (e.g. Castle 1942 Harrington 2009), which helped U.S. legislators pass anti-miscegenation laws in the early twentieth century (Lombardo 1987). In 2016, Mother Jones demonstrated how mainstream and persistent the analogy is when they published their interview with a leading white supremacist who equated human races to dog breeds (Harkinson 2016). The American familiarity with dogs helps make their relevance to human “race” seem natural. It sounds like science, but as we demonstrate below it is not.

Here we investigate how the biological variation among dogs and humans compare and contrast, answering Haldane’s question while rebuking the illegitimate appeal to science and the erroneous “logic” of the widespread analogy. To start, we compare genotypic and phenotypic variation within and between human groups and within and between dog breeds. After we demonstrate the fundamental biological differences between patterns of variation in the two different species (parts 1, 2, and 3), as well as the fundamental distinctions between “race” in humans and dog breed categories (part 4), we discuss the sociocultural significance of this analogy and the importance of its refutation (parts 4 and 5). That is, a goal of this paper is to reveal why equating the category we culturally call “race” to patterns of human biological variation is non-sensical and equating “race” to the categories we know for dogs is pernicious and racist, despite the comparison appearing obvious to many individuals. We counter the seemingly innocent belief that because dogs are distinguishable, on sight, by breed that therefore human racial categories are just as biologically-based. As many readers know all too well, the breed-race analogy sits in close cultural and mental proximity to the non-innocent racism that lowers targeted minorities to the status of nonhuman animals (see Weaver 2013). Readers are urged to consult the vast and rich literature discussing the cultural-historical-political context of categorizing humans, and the social construction of the race concept, including and especially by scientists, some of which we cite throughout this paper (e.g. Sussman 2014 Marks 2012a, b, 2017 Brace 2005 Koenig et al. 2008 and many others). This context is imperative, but that the race-breed analogy persists means that there are individuals who are either unfamiliar with that knowledge or are unconvinced by it, perhaps willfully so.

Here, for the purposes of demonstrating that the race-breed analogy is not supported by science (despite it being used by some as scientific-sounding justification for race-based social injustices), we must use the conceptions of race and breed dictated by the terms of the analogy itself. That is, we will consider the biological variation within and between groups acknowledged by the 2010 U.S. census (United States Census Bureau) and the American Kennel Club (AKC), respectively. The AKC lists 192 dog breeds. The number of dog breeds has varied over time, increasing as institutions recognize new breeds among the some four hundred to a thousand breeds described globally. The five racial categories used most recently by the United States Census Bureau (White, Black or African American, American Indian or Alaska Native, Asian, and Native Hawaiian or Other Pacific Islander) reflect the current perception of race in the U.S. However, the number of human races has varied throughout U.S. history, reflecting the shifting social and political motivations, including slavery and immigration, a fact that highlights the significant ways that race concepts are driven by social forces. Presently, racial categorizations vary across cultures—for just one example, there are at least 18 terms to describe a person’s race or skin color in Brazil (Santos et al. 2009).

As noted above and as will be discussed in this paper, “race” is far more than ancestral/inherited DNA and is far more than geographically patterned morphological variation like skin color. But because the analogy between races and dog breeds incorrectly privileges biology over the social and historical factors that have led to the development of racial constructs, here we demonstrate how genetic data fails to substantiate the racial categorizations used in the U.S. today and their equivalence to dog breeds.


Why Do We See More Species in Tropical Forests? The Mystery May Finally Be Solved

When Charles Darwin first sailed into the tropics aboard the HMS Beagle in 1835, he was stunned. The 26-year-old naturalist had expected to find the same level of diversity of plants and animals as he had left behind in the higher latitudes of Plymouth, England. Instead, on the balmy Galapagos Islands, he found a multitude of strange and diverse creatures thriving together.

Related Content

Rowing ashore to explore, Darwin jotted in his notes that the number of different “vegetable and animal” inhabitants on tiny tropical islands was strikingly higher than at other sites along his voyage. He wondered: How was it possible that the tropics seemed to hold so much more diversity than the more northerly forests of Europe? Shouldn't these tightly packed creatures have battled it out to extinction long ago?

Darwin never found out the answer to that particular mystery (after all, he had a lot on his mind), and so the question persisted for another century. Finally, in the early 1970s, two ecologists independently came up with the same hypothesis to explain the mysterious phenomenon—at least with trees. 

Daniel Janzen and Joseph Connell put forth a seemingly counterintuitive explanation. Perhaps, they posited, the astonishing plant diversity we find in tropical forests is enabled by two factors: the presence of “natural enemies” that target specific species and keep population size in check, and the tendency of youngsters of one species to settle far away from their parents, beyond those predators' reach.

Until recently, researchers have only been able to prove that the Janzen-Connell hypothesis holds true in localized studies. The problem was, they lacked access to the kind of global datasets necessary to explain the broader planetary pattern of decreasing diversity from equator to poles. Now, in a new study published last week in the journal Science, researchers show that this hypothesized mechanism is indeed responsible for global trends in forest biodiversity.

Myers holds a tropical tree seedling in the Amazon Rain Forest in Peru. (Jonathan Myers)

Last year, forest ecologists Jonathan Myers and Joe LaManna traveled to a workshop in Hainan, China focused on analysis of data generated by the Smithsonian’s Forest Global Earth Observatory (ForestGEO), a network of 60 forests across the planet that are exhaustively monitored. Myers and LaManna, both of Washington University in Saint Louis, Missouri, knew that ForestGEO could provide the global dataset they needed to answer the question that has been vexing them and other ecologists since Darwin’s voyage.

“One of the striking differences between temperate and tropics is that all of those 'extra' species are very rare,” says LaManna, a post-doctoral researcher and first author of the new study. Consider that temperate forests can be packed wall to wall with redwood trees, whereas the tropics are dotted with a bevy of unique trees that often exist in isolation from others in their species.  “How can those rare species persist in the face of extinction?” asks Myers, a professor of biology and co-author on the study. 

Answering that question required a massive undertaking. The dataset tallied 2.4 million trees from 3,000 species in an exacting fashion to ensure comparability across each forest. More than㺲 co-authors from 41 institutions including the Smithsonian then analyzed the data, which spanned㺘 ForestGEO plots around the planet. “It was a lot,” says LaManna. “Every stem down to one centimeter in diameter is mapped, measured, tagged and identified.” 

The herculean effort paid off. After analyzing the data, they found a surprising trend: In areas with higher numbers of adult trees, there were fewer young saplings of the same species. This pattern was strikingly more pronounced in the tropics than in the temperate regions they sampled. 

This means that, unlike in higher latitude ecosystems, near the equator trees are less likely to coexist around neighbors in the same family. It’s as if, at some point, the tree parents and their sapling kids unanimously agreed that was time to move out of the basement. Except in a forest, living farther apart doesn't just allow the parent trees to luxuriate in their empty nest. It’s a matter life and death for the species. 
 
“With trees it’s less a direct effect of the parent tree on the offspring,” Myers says. “It’s an indirect effect where the natural enemies that attack the adults also attack the offspring.” These enemies could be pathogens, seed predators or herbivores that target one species. Just as dense human populations in cities enable the rapid spread of communicable diseases, these enemies can rapidly devastate a dense forest of the same species. 

If your saplings settle down farther away, however, it’s less likely that any one enemy will wipe them all out. “You think of enemies as being bad influences on trees, especially ones of low abundance,” LaManna says. “But they can be a strong stabilizing force—[enemies] can actually buffer them and keep them from going extinct.” You might say: With enemies like this, who needs friends?

“It’s changed the way I think about ecology,” Myers says. “The enemy can actually have a beneficial effect in maintaining the rare species in these communities, especially in the tropics.” 

Herbiverous predators leave behind holey leaves in Madidi, Bolivia. (Jonathan Myers)

The data provides compelling explanation for why we see the global biodiversity patterns we do, says Gary Mittelbach, a forest ecologist and professor of integrative biology at Michigan State University who was not involved in the study. “The fact that they were able to show it on a worldwide basis with standardized methods helps solidify the idea,” says Mittelbach. 

One weakness of the study is that, while it implies a global trend, there are no samples from north of Central Europe or south of Papua New Guinea. “I kind of wish they had more [forests] in Asia and Europe so not all the high latitude ones are in North America,” says Mittelbach. Even with the dearth of samples from high latitudes, however, “I’m still pretty convinced of the pattern,” he says. 

Though the researchers succesfully showed that the trend put forth by Janzen and Connell holds true, the question of what exactly is causing the tropics to be so diverse still remains. 

Myers speculates that the stability of the tropical climate may contribute to its rich biodiversity, compared to the drastic changes that have taken place over geologic time in the higher latitudes. “There’s been a lot more disturbance in the temperate zone” over the past thousands of years, he says. By “disturbance,” Myers means ice sheets that repeatedly bulldozed across North America in Earth’s past. 

The tropics have not endured such disturbances. Researchers attribute the high reproduction and low extinction rates in tropical species of plants and animals to the relatively comfy climate. That’s worked out well for them until now, but forests around the world are changing as a result of more volatile climate patterns. For instance, as higher latitudes become warmer, temperate trees are migrating slowly north.

“There might be a direct or indirect influence of climate in mediating the strength of the biotic interactions between enemies and trees,” Myers says. “Where it’s warmer or wetter you might expect pathogens to have a stronger influence.” 

The global trend these researchers have uncovered illustrates just how much the diversity of biological life on Earth can hinge on small-scale interactions. “This mechanism is a global scale process, and we’re talking about interactions between adults, young and their specialized enemies at the scale of 10 meters,” LaManna says. “That very local-scale interaction is contributing to a pattern of biodiversity across the entire globe.”

About Kyle Frischkorn

Kyle Frischkorn is a graduate student in oceanography at Columbia University, and a 2017 AAAS Mass Media fellow at Smithsonian Magazine. In between being in the lab, on a boat, or in a lab on a boat, he’s written about science for GQ, Lucky Peach, Eater, Scientific American and Atlas Obscura.


Data Accessibility

Fitting neutral model: key information and references uploaded as Supporting Information. Examples of Species by sample matrices used to generate Fig. 2: uploaded as Supporting Information. R script to estimate beta diversity and create the null distribution for the test proposed in the paper: uploaded as Supporting Information. Example data files and relevant meta data to apply the proposed analysis: uploaded as Supporting Information. Faunistic data (e.g., species names) and details on the soil animal datasets here used to apply the proposed method: data archived in Migliorini et al. ( 2002 ) Caruso et al. ( 2005 ) Caruso and Migliorini ( 2006 ) Caruso et al. ( 2009 ).

Filename Description
ece31313-sup-0001-DataS1.docxWord document, 129.2 KB Data S1. Supplementary methods to fit neutral models and test predictions of Beta diversity (BD).
ece31313-sup-0002-DataS2.Rtext/r, 17.9 KB Data S2. r scripts to calculate BD and perform a null model test based on neutral model predictions.
ece31313-sup-0003-DataS3.txtplain text document, 1.1 KB Data S3. Observed species by sample matrix of Heathland (Figure 2, S1d). See Data S1.
ece31313-sup-0004-DataS4.txtplain text document, 924.6 KB Data S4. Simulated neutral species by sample matrices for Heathland. See Data S1.

Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.


Watch the video: Εμβολιασμένα φυτά καρυδιάς. Ποικιλίες Chandler, Franquette,Fernor. (December 2022).