Comparative Analysis of Phytoplankton Composition and Abundance over a Two-Decade Period at the Land–Ocean Boundary of a Tropical Mangrove Ecosystem

Abstract

Inter-annual variations of phytoplankton abundance and community organization were observed over a two-decade period along with the ancillary parameters at the land-ocean boundary associated with the Sundarban mangrove forest (21°32′ and 22°40′ N and 88°05′ and 89°E), along the NE Coast of the Bay of Bengal. The number of definable Bacillariophyceae species exceeded Dinophyceae taxa, and the total number of bloom-forming species declined from a maximum of ten in 2000 and a minimum of two in 2007. Blooms of the diatom Coscinodiscus radiatus were common in 2000 and 2007. Tide cycles and the onset of the monsoon season played important roles in diurnal and seasonal variability of phytoplankton. Phytoplankton biovolume showed seasonality, with the highest levels during post-monsoon periods and lowest levels during the monsoon period. Phytoplankton abundance was correlated to rainfall patterns, which may be altered by long-term changes in climate.

Interplay of Physical, Chemical and Biological Components in Estuarine Ecosystem with Special Reference to Sundarbans, India

“…Noticeable variation of phytoplankton forms was also observed in seasons and sampling locations due to variations of water quality parameters, like pH, salinity, TSS and nutrients and DO. Phytoplankton community was observed to be dominated by diatoms (Biacillariophyceae) followed by Pyrrophyceae (Dinoflagellates) and Chlorophyceae and higest abundance was noticed in postmonsoon (Biswas et al 2010;Manna et al 2010) Centric Diatoms predominated in winter months and Pennates in summer whereas Chlorophyceae, Cyanohyceae and Euglenoids dominated the estuary in monsoon. During premonsoon the dominant phytoplankton were species of Ditylum, Ceratium, Biddulphia, Chaetoceros, Coscinodiscus, Thalassiothrix, Rhizosolenia Nitzschia and Thalassionema.…”

“…al., 2010;Biswas et al, 2010) ( Table 7). The study indicates estuary remained eutrophic during winter and meso-eutrophic during monsoon and premonsoon (Manna et.…”

Sundarban mangroves: diversity, ecosystem services and climate change impacts

“…The sea level rise coupled with other global warming mediated probable future changes in physicochemical properties of both wetlands and swamp forests, e.g., salinity invasion, massive shoreline erosion, shifting of mud flats and sand dunes, increase in sediment load, temperature, tidal amplitude, and decrease in transparency, nutrients and pH, will probably exert considerable bio-ecological stresses on Sundarban ecosystems resulting substantial changes in species composition. A salient impact of salinity intrusion on phytoplankton species diversity, with gradual increase in the abundance of S. costatum, comprising from 1.5% to 19.0% of total phytoplankton, during 1990 to 2007 in the Sundarban wetlands is already evident (Biswas et al, 2010). In the long run, the shift in population dynamics and species diversity of the primary producers will have profound impacts on the ecosystems food web, with probable decline in the abundance and diversity of many mangrove dependent detritivores, herbivores and other secondary consumers (Ghosh et al, 2015).…”

“…However, intra-Family variations in species diversity may also happen, e.g., for diatoms, monsoon rainfall may drastically Coscinodiscus spp. but at the same time instigate Skeletonema costatum (Biswas et al 2010;Manna et al 2010). The zooplankton species richness is usually higher in monsoon, followed by premonsoon, and lowest in post-monsoon.…”

Bloom of the two dinoflagellates Ceratium furca and Diplopsalis lenticula in a mangrove estuary of Thailand

“…Extreme environmental changes occur in the rainy season in the tropics due to the large climate change from the dry season (Goodbody 1961;Goes 1988, 1989). For this reason, the appearance of phytoplankton around the estuaries of mangrove forests shows wide variation, because diatoms are likely to be dominated by the silicate supply from terrestrial areas in the rainy season, and dinoflagellates are likely to appear during low supply of silicate in the dry season (Biswas et al 2010). However, little is known about the plankton species that appear in the tropical mangrove estuary, so data based on the accumulation of case reports on the occurrence of the various species is important to clarify the ecosystem of the mangrove estuary.…”