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ANDEEP

ANDEEP stands for ANtarctic benthic DEEP-sea biodiversity: colonization history and recent community patterns

 

Project leaders: Angelika Brandt, Zoological Museum Hamburg, Brigitte Ebbe, Senckenberg Institute, German Centre for Marine Biodiversity Research, Wilhelmshaven 

Objectives

The Southern Ocean is the most remote ocean on Earth, and before ANDEEP, by far the largest part, the deep sea, was nearly unexplored. The project was therefore designed to study: 

· evolutionary processes and oceanographic changes which have resulted in the present biodiversity and distributional patterns

· colonisation and exchange processes of the deep-sea fauna in relation to changes in sea-bed geography over geological time

· the influence of sea-floor habitat diversity on species and genetic diversity

· the importance of the Antarctic region as a possible source for deep-sea benthic taxa in other oceans

 

 

How did we get our material?

Three expeditions took place in 2002 (ANDEEP-I and II) and 2005 (ANDEEP-III) to Drake Passage, Scotia Arc, and Weddell Sea and along two transects from the Cape Basin to Kapp Norvegia (eastern Weddell Sea) and another one crossing the Weddell Sea to King George Island, respectively. ANDEEP is the first comprehensive survey of the micro-, meio-, macro- and megafaunal communities and thus contributes to the pole-to-pole transect through Atlantic abyssal plains, designed to investigate distributional patterns of the benthic fauna at different scales from local to global.

Results to far

Generally, biodiversity is high in all size classes, but denisites are very low, which means that as a consequence nearly all species are rare. To date, some 1500 species have been identified and at least provisionally named, most of which are new to science. Depending on the taxon, the percentage of new species varies between 50 and nearly 90 percent. The species count may go up even higher than seen at first sight by the discovery of cryptic species which can only be told apart with genetic methods, but not by traditional morphology. Already it can be stated that there is no latitudinal gradient in biodiversity from the equator to the pole on the southern hemisphere.

Distributional patterns were investigated both bathymetrically and geographically. The Antarctic shelf reaches down to about 800 m, which is much deeper than in other oceans, due to the heavy ice cover on the continent. Probably related to this deep lower boundary of the shelf, a faunal shift to deep-sea (in this case, abyssal) species lies at greater depths than known from other oceans, around 2500 to 3000 m. The level of eurybathy depends on the taxon, as does the level of endemicity. The latter can be related to the reproductive biology of the different organisms, particularly the presence of larvae as dispersal stages.

Evolution happens even in these dark depths, as we could show alredy with the isopods. The very high number of species which, to our current knowledge, occur only in the deep Southern Ocean suggests a radiation. 

Outlook of the future

 Between March 2007 and March 2009, the International Polar Year (IPY) is taking place. A follow-up project of ANDEEP called SYSTCO will represent CeDAMar during this prestigeous event. SYSTCO stands for system coupling and will investigate how atmosphere, water column and deep-sea floor are linked together. Results from this project will hopefully help to predict how global climate change will affect the deep-sea benthos.

The IPY project SYSTCO will be conducted in cooperation with the Census of Antarctic Marine Life (CAML) and the Arctic Ocean Diversity project ArcOD.

 

 

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