MEPS 371:155-164 (2008)  -  doi:10.3354/meps07693

Trophic modes of large Antarctic Foraminifera: roles of carnivory, omnivory, and detritivory

Stephanie B. Suhr1,2,6,**, Stephen P. Alexander1,3, Andrew J. Gooday2, David W. Pond2,4, Samuel S. Bowser3,5,*,**

1Raytheon Polar Services Co, 7400 S. Tucson Way, Centennial, Colorado 80112, USA
2National Oceanography Centre, Southampton, University of Southampton Waterfront Campus, European Way, Southampton SO14 3ZH, UK
3Wadsworth Center, New York State Department of Health, Albany, New York 12201, USA
4British Antarctic Survey, Biological Sciences Division, Madingley Road, Cambridge CB3 0ET, UK
5Department of Biomedical Sciences, School of Public Health, The University at Albany, State University of New York, Albany, New York 12201, USA
6Present address: Inter-Research, Nordbünte 23, 21385 Oldendorf/Luhe, Germany
**Corresponding author. Email: **‑The first and corresponding authors contributed equally to this work

ABSTRACT: Astrammina rara, Crithionina delacai, and Notodendrodes hyalinosphaira are 3 of the largest and most abundant members of the foraminiferal assemblage at a shallow-water (28 to 32 m) site in Explorers Cove, Antarctica. This study summarizes observations from 2 decades of research, during which we employed laboratory-based feeding experiments and fatty acid biomarker analysis to characterize trophic dynamics and ecological roles of the 3 species. In feeding experiments, A. rara consumed a variety of co-occurring metazoans (several Crustacea, Mollusca, Echinodermata, and a Nephtys species). C. delacai, N. hyalinosphaira, and a number of other foraminiferal species from Explorers Cove successfully trapped Artemia sp. nauplius prey in a setup designed to examine the efficiency of prey capture. Fatty acid analyses on samples from early (November 7, 2001) and late (January 31, 2002) austral summer revealed that the 3 species contained substantial amounts (33 to 45.5%) of polyunsaturated fatty acids (PUFAs), which are produced by microalgae, indicating the downwards transfer of carbon from sea-ice associated primary production. In the case of A. rara, this may be due to the ingestion of herbivorous metazoa, rather than direct uptake of microalgal material. A. rara contained significantly (p < 0.05) higher amounts of the zooplankton biomarkers 20:1(n–9) and 22:1(n–11), and C. delacai contained more PUFAs early, compared to  late, in the season. Two morphotypes of N. hyalinosphaira had different fatty acid profiles, indicating distinct trophotypes. Our results illustrate specific adaptations to different trophic resources in these protists, and they demonstrate the potential impact that large carnivorous species of Foraminifera may have on the structure of benthic communities where they are abundant.


KEY WORDS: Foraminifera · Trophic ecology · Benthic · Food web · Carnivory · Antarctic · Explorers Cove · Community structure


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Cite this article as: Suhr SB, Alexander SP, Gooday AJ, Pond DW, Bowser SS (2008) Trophic modes of large Antarctic Foraminifera: roles of carnivory, omnivory, and detritivory. Mar Ecol Prog Ser 371:155-164

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