Estuarine diversity of tintinnids (planktonic ciliates)
Dolan, J.R.; Gallegos, C.L. (2001). Estuarine diversity of tintinnids (planktonic ciliates). J. Plankton Res. 23: 1009-1027
In: Journal of Plankton Research. Oxford University Press: New York,. ISSN 0142-7873; e-ISSN 1464-3774, meer
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| Auteurs | | Top |
- Dolan, J.R., meer
- Gallegos, C.L.
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| Abstract |
In Chesapeake Bay, a large eutrophic and partially stratified estuary, we investigated diversity amongtintinnids (Ciliophora, suborder Tintinninia) in September 1999. In contrast with the typical estuarinepattern, tintinnid diversity was high and increased with decreasing salinity from the mouth ofthe bay to the mid-bay region. Peak species numbers and diversity values [20-25 species, H’ (ln)= 2.4-2.5] were found in stations in the mesohaline (14-17‰) portion of the bay. Within thebay, diversity was not correlated with abundance or food levels, as measured by chlorophyllfluorescence, nor with predator (copepod) concentration. However, because high copepod concentrationscorresponded to the less diverse southern bay populations, we examined the influence of copepodson tintinnid diversity in two field experiments using natural populations and a size-fractionationapproach. Similar copepod predation rates on abundant tintinnid species (0.4-1 ml cleared copepod-1h-1) were found in the experiments, but with distinct impacts on tintinnid diversity. In a slow-growingcommunity of tintinnids, copepod predation decreased diversity relative to changes in communitieswithout copepods, while in a community highly dominated by a rapidly growing tintinnid species,copepod predation increased diversity. Our results show that not all taxa found in estuaries are speciespoor, and in the highly dynamic plankton the relative influence of factors influencing diversity maychange rapidly. Species richness in the Chesapeake Bay appears predictable from latitude. |
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