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|Title:||Influence of river influx on phytoplankton community during fall inter – monsoon in the coastal waters off Kakinada, east coast of India|
|Authors:||Sooria, P. M.|
Reny, P. D.
|Keywords:||Phytoplankton community;Size variation;River influx;Salinity;Nitrate;Coastal water off Kakinada;Bay of Bengal|
|Abstract:||Significant changes in phytoplankton community structure were observed in the coastal waters off Kakinada (Bay of Bengal) during fall intermonsoon (October) of 2006 and 2007. River influx was more in October 2007 compared to those in October 2006. Phytoplankton showed marked changes in composition and abundance between the two periods of observation. Abundance was considerably higher in October 2007 (av. 150.9 ± 54.8 X 103 cells l-1) compared to that of October 2006 (av.7.9 ± 4.8 X 103 cells l-1). Phytoplankton community was formed by larger diatoms in October 2007, dominated by Hemidiscus hardmannianus and Ditylum brightwellii (300-500 μm in diameter) whereas in October 2006 smaller diatoms such as Lioloma elongatum (2 - 4 μm), Thalassiossira subtilis (15 - 32 μm) and T. favus (60 - 140 μm) dominated. Both H. hardmannianus and D. brightwellii occurred in bloom density throughout the study area (av.> 50´103 cells l-1). Agglomerative hierarchical cluster analysis of phytoplankton species abundance showed two well separated clusters (similarity ≤ 10 %) for 2006 and 2007. It reveals the variation in community structure between the two periods of observation. Multidimensional scaling of species abundance superimposed on scaled values of salinity and nitrate has shown that the community shift was directly related to environmental factors. Coastal waters of western Bay of Bengal receive high freshwater inputs, particularly during the southwest monsoon and the internal variations observed in the Coastal waters of Kakinada could as well be relevant to the entire east coast of India.|
|ISSN:||0975-1033 (Online); 0379-5136 (Print)|
|Appears in Collections:||IJMS Vol.40(4) [August 2011]|
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