Ingestion of a bacterivorous ciliate by the oyster Crassostrea gigas: Protozoa as a trophic link between picoplankton and benthic suspension-feeders
The linked concepts of 'microbial loop' and 'protozoan trophic link' have been very well documented in filter-feeding microzooplankton such as copepods, but have not been applied to energy transfer to benthic suspension-feeding macrofauna, with the exception of the recent demonst...
| Published in: | Marine Ecology Progress Series |
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| Main Authors: | , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Inter-research
1997
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| Subjects: | |
| Online Access: | https://archimer.ifremer.fr/doc/00337/44788/44482.pdf https://doi.org/10.3354/meps152301 https://archimer.ifremer.fr/doc/00337/44788/ |
| Summary: | The linked concepts of 'microbial loop' and 'protozoan trophic link' have been very well documented in filter-feeding microzooplankton such as copepods, but have not been applied to energy transfer to benthic suspension-feeding macrofauna, with the exception of the recent demonstration of heterotrophic flagellate assimilation by mussels. The oyster Crassostrea gigas obtains energy resources by filtering microalgae (similar to 5 to 100 mu m). However, in turbid estuaries, light-limited phytoplanktonic production cannot entirely account for oyster energy requirements. Conversely, picoplankters (<2 mu m), which are main effecters of coastal energy flow and matter cycling, are not efficiently retained by oyster filtration. Ciliate protozoal as both micro-sized cells (similar to 5 to 100 run) and bacteria grazers, may represent a major intermediary in trophic transfer between picoplankton and metazoa. The ciliate Uronema was intensely cultured and labelled, using the cyanobacteria Synechococcus as an auto-fluorescent biomarker. The labelled ciliates were offered as potential prey to oysters. We report here the first experimental evidence of a significant retention and ingestion of ciliates by oysters, supporting the role of protozoa as a realistic trophic link between picoplankters and filter-feeding bivalves and thus enhancing their potential importance in estuarine microbial food webs. |
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