Meiobenthic biodiversity of the formerly iceshelf-covered Larsen A and B areas east of the Antarctic Peninsula

The project, proposed in the framework of the International Polar Year (IPY), benefits from a unique natural experiment: the recent break-up of the Antarctic Larsen B iceshelf caused by regional climate warming. As an initial benchmark study the project will be fundamental for future research on changes of the meiobenthos (seafloor organisms with size between 0.032 mm and 1 mm) in this region.

With the data obtained by multicorer sampling meiobenthic assemblages from inside the former iceshelf will be compared to those outside the iceshelf-covered area. It will also be investigated if meiobenthic shelf assemblages of the low-productive Larsen B area resemble those of the Antarctic deep sea, for which some evidence exists regarding aspects of the macrobenthos. Furthermore, the meiobenthos of a cold seep (a spot where methane and sulphide seeps from the sea ground) recently discovered in the Larsen B area, the only one known from the Antarctic shelf, will be studied.

This for the first time offers a chance to compare meiobenthos of an Antarctic cold seep and a similar arctic habitat. Finally and proving critical for estimates on biodiversity in the region, the number and proportion of harpacticoid copepod species new to science will be evaluated. The results of this project will show the effects of climate change on marine communities in a drastically affected area of our planet. Results will not only enhance our knowledge on the colonisation speed of meiobenthos in Antarctic waters, but also bring up new insight to the productivity-diversity-hypothesis.

First results:

Regarding the harpacticoid copepods we got first interesting results on family level: The family Rometidae occured in most cores of the innermost sampling site within the former Larsen B iceshelf area, but at no other site. This is fascinating since the Rometidae are supposed to be a typical deep-sea family of Harpacticoida. Since no Rometidae were found at any other site further outwards relative to the former iceshelf position we surely found an element of the fauna that inhabited the seafloor under the iceshelf before the collapse. And the presence of Rometidae supports our hypothesis that due to similarily low productivity conditions the fauna under the former Larsen iceshelves resembled a typical deep-sea fauna in some aspects. But this has started to change after the iceshelf disintegration.

The investigations on species level are just at the beginning, but first data lead to the assumption that about 90 percent of several hundred Harpacticoida species found in the Larsen A and B areas are new to science.

Scientists

Dr. Armin Rose
Forschungsinstitut und Naturmuseum Senckenberg, DZMB, Wilhelmshaven

Research areas

Antarctic Peninsula: Former Larsen A and B Iceshelves

Publications

Rose A, Raes M, 2008. Meiofaunal communities in the Larsen A/B area and west of the Antarctic Peninsula. Berichte zur Polar- und Meeresforschung 569, 69-75.

Gutt J, Barratt I, Domack E, d´Udekem d´Acoz C, Dimmler W, Grémare A, Heilmayer O, Isla E, Janussen D, Jorgensen E, Kock KH, Lehnert LS, López-Gonzáles P, Langner S, Linse K, Manjón-Cabeza ME, Meißner M, Montiel A, Raes M , Robert H, Rose A, Sañé Schepisi E, Saucède T, Scheidat M, Schenke HW, Seiler J, Smith C, 2010. - Biodiversity change after climate-induced ice-shelf collapse in the Antarctic. - Deep- Sea Research II: doi:10.1016/j.dsr2.2010.05.024.

Raes M, Rose A, Vanreusel A, 2010. - Response of nematode communities after large-scale iceshelf collapse events in the Antarctic Larsen area. - Global Change Biology 16:1618-1631.

Rose A, Vanreusel A, 2010. Harpacticoida under collapsed ice shelves near the Antarctic Peninsula: a multiscale approach on family level. - VLIZ Special Publication 44:68.

Homepage

---

Research funding organisation

German Research Foundation

Project number: RO 3004/2-1
Funding period: October 2008 to September 2010