Spatiotemporal distribution in phytoplankton community with distinct salinity regimes along the Mandovi estuary, Goa, India

Abstract

Seasonal variations in the composition and abundance of phytoplankton were investigated fortnightly at 3 different regions along the Mandovi estuary from June 2007 to May 2008 in relation to salinity and nutrients. A total of 209 species belonging to 7 divisions were identified during the study period. The highest phytoplankton cell density (5.17 × 10 4 cells L -1 ) and biomass (7.68 mg m -3 chlorophyll a) were observed in the upper sections during the nonmonsoon period, while the highest diversity (3.46) was observed in the upper section during the monsoon period. Bacillariophyta was the dominant phytoplankton group at 71% of the total species identified. This group was dominated by Pennales (88) over Centrales (60) at all 3 stations. Contributions of Dinophyta, Chlorophyta, Cyanophyta, Haptophyta, Chromophyta, and Chrysophyta to the total species were 25%, 0.5%, 1%, 0.5%, 1%, and 1%, respectively. Dinophyta did not show significant variations in percentage distribution among the 3 sections and seasons. Twenty-six dominant species of phytoplankton, representing all seasons with cell density of >1000 cells L -1 , showed spatial adaptability patterns with respect to salinity. Protoperidinium acbromaticum and Alexandrium ostenfeldii were found to grow only during nonmonsoon periods in upper sections and were reported for first time in the present study. Euryhaline Skeletonema costatum and Thalassiothrix frauenfeldii were present throughout the study period. A total of 36 harmful algal bloom-forming species, with 11 toxin-producing species, have been identified. The presence of Streptotheca thamensis acts as an indicator to evaluate water quality.

Phytoplankton community structure in local water types at a coastal site in north-western Bay of Bengal

“…However, among 22 potential toxin producing species, 14 are reported to be toxic during bloom conditions (Perumal et al 1999;Carmichael et al 1988;D'Silva et al 2012;Kiteresi et al 2013;Pednekar et al 2014). In type 1, 43 number of potential bloom forming species were observed.…”

Spatiotemporal distribution and composition of phytoplankton assemblages in a coastal tropical lagoon: Chilika, India

“…The dominance of pennate over the centric appears to be a common feature in many estuaries. For example, in Mandovi estuary, Goa, India, pennate dominated over centric (Pednekar et al 2014).…”

“…The ability of Bacillariophyta to adapt rapidly to changing environmental conditions and adjust their community composition with respect to physical, chemical, and biological conditions is responsible to place them as the most important primary producer in estuarine ecosystem (Gowda et al 2001). Bacillariophyta have been shown to be a major eukaryotic chromophytic phytoplankton group in estuarine systems including Chilika lagoon (Brogueira et al 2007;Panigrahi et al 2009;Pednekar et al 2014). In the northern sector of the lagoon which is a freshwater zone of Chilika, phytoplankton population was mostly dominated by the Euglenophyta.…”

Dynamics and succession of plankton communities with changing nutrient levels in tropical culture ponds of whiteleg shrimp

“…Diatoms emerged as the major group in both ponds during 96 DoC. This is primarily because of their presence in the source water taken from the estuarine region off the west coast of India which is rich in diatoms (Pednekar et al 2014). The high nitrate concentration, which ranged from 4−105 µM in the ponds, is favorable for the growth of diatoms (Malone 1980).…”