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Preponderance of a few diatom species among the highly diverse microphytoplankton assemblages in the Bay of Bengal

DRS at CSIR-National Institute of Oceanography

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Title Preponderance of a few diatom species among the highly diverse microphytoplankton assemblages in the Bay of Bengal
 
Creator Paul, J.T.
Ramaiah, N.
Gauns, M.
Fernandes, V.
 
Subject chlorophyll concentration
Bay of Bengal
 
Description The microphytoplankton assemblages were studied from water samples collected at eight discrete depths in the top 120 m at five central [open ocean] and four western [shelf/slope region] locations in the Bay of Bengal. The Bay is a low-productive warm pool regime with poor inorganic nutrient inputs to its intensely stratified surface layer despite the very large riverine influx. In addition, the prolonged cloud cover has an adverse effect in the top 25-40 m, on primary production, chlorophyll concentration and phytoplankton assemblages. Microphytoplankton were the most abundant in the northern area of the Bay. A total of 153 phytoplankton species were identified during this study. The most abundant species (at least 1800 individual cells belonging to a given species or >= 2% of the total counts of identified specimens) during this study were: Thalassiothrix longissima, Thalassiothrix fauenfeldii, Rhizosolenia styliformis, Nitzschia angularis, Thalassionema nitzschoides, Coscinodiscus radiatus, Chaetoceros eibenii, Skeletonema costatum, Coscinodiscus concinnus and Chaetoceros coarctatus. Similarly, there were 20 moderately abundant (>= 0.5 but < 2%) species. Thirty three of the least abundant species (< 0.5%) occurred at one station. Diatom species, T. fauenfeldii and T. longissima were ubiquitous in the study area. The exclusive occurrence of Skeletonema costatum in the northern most stations suggests that it proliferates only in the lowsalinity regions with adequate silica from the land inputs. Abundance of pennate diatoms was higher in the open Bay compared to that of centric diatoms in the more productive northern locations and the western Bay. There appears to be a basic difference between near shore flora and offshore flora. This first analysis of phytoplankton assemblages from the offshore Bay suggests that while there is predominance of only a few species, the Bay harbors very diverse diatom communities that seem to be syntrophic, non-competitive and co-habiting in the generally low nutrient, stratified surface waters.
 
Date 2007-07-25T11:10:38Z
2007-07-25T11:10:38Z
2007
 
Type Journal Article
 
Identifier Marine Biology, vol.152(1), 63-75p.
http://drs.nio.org/drs/handle/2264/637
 
Language en
 
Rights An edited version of this paper was published by Springer. Copyright [2007] Springer
 
Format 509063 bytes
application/pdf
 
Publisher Springer