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

Suhr, Stephanie B.; Alexander, Stephen P.; Gooday, Andrew J.; Pond, David W.; Bowser, Samuel S.. 2008 Trophic modes of large Antarctic Foraminifera: roles of carnivory, omnivory, and detritivory. Marine Ecology Progress Series, 371. 155-164. 10.3354/meps07693

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Abstract/Summary

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.

Item Type: Publication - Article
Digital Object Identifier (DOI): 10.3354/meps07693
Programmes: BAS Programmes > Global Science in the Antarctic Context (2005-2009) > DISCOVERY 2010 - Integrating Southern Ocean Ecosystems into the Earth System
ISSN: 0171-8630
Additional Keywords: Foraminifera; Trophic ecology; Benthic; Food web; Carnivory; Antarctic; Explorers Cove; Community structure
NORA Subject Terms: Marine Sciences
Biology and Microbiology
Ecology and Environment
Date made live: 20 Jan 2011 13:44
URI: http://nora.nerc.ac.uk/id/eprint/11631

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