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Naik S.,Berhampur University | Mishra R.K.,National Institute of Oceanography of India | Mahapatro D.,Wetland Research and Training Center | Panigrahy R.C.,Berhampur University
Journal of Environmental Biology | Year: 2014

Distribution of phytoplankton, productivity and chlorophyll-a concentration in relation to physico-chemical parameters viz. water temperature, pH, total suspended solid, turbidity, dissolved oxygen, biochemical oxygen demand, salinity and nutrients (NO2-N, NO3-N, PO4-P and SiO4-Si) were studied for pre-monsoon, monsoon and post-monsoon during the year 2005. The major groups of phytoplankton species were diatoms followed by dinoflagellates and other algae. A total of 43 species of phytoplankton comprising 32 diatoms, 6 dinoflagellates and 5 other algae were recorded during the entire study period. The species Nitzschia, Chaetoceros and Coscinodiscus were identified as dominant diatoms group. Higher values of phytoplankton (28612 nos I-1) with high rate of photosynthesis were observed during post-monsoon season, which was responsible for increasing DO (8.72 mg I-1) and pH(8.24) of the water column. R-mode factor analysis revealed that there were two factors or PCs that explained 93.0%, 95.2% and 94.4% of the total variance for pre-monsoon, monsoon and post-monsoon respectively. Generally, the trend distribution of phytoplankton closely followed the distribution of salinity, pH and DO of estuarine water. © 2014 Triveni Enterprises, Lucknow (India).

Srichandan S.,Wetland Research and Training Center | Kim J.Y.,Pusan National University | Kumar A.,University of Georgia | Mishra D.R.,University of Georgia | And 4 more authors.
Marine Pollution Bulletin | Year: 2015

One of the main challenges in phytoplankton ecology is to understand their variability at different spatiotemporal scales. We investigated the interannual and cyclone-derived variability in phytoplankton communities of Chilika, the largest tropical coastal lagoon in Asia and the underlying mechanisms in relation to environmental forcing. Between July 2012 and June 2013, Cyanophyta were most prolific in freshwater northern region of the lagoon. A category-5 very severe cyclonic storm (VSCS) Phailin struck the lagoon on 12th October 2013 and introduced additional variability into the hydrology and phytoplankton communities. Freshwater Cyanophyta further expanded their territory and occupied the northern as well as central region of the lagoon. Satellite remote sensing imagery revealed that the phytoplankton biomass did not change much due to high turbidity prevailing in the lagoon after Phailin. Modeling analysis of species-salinity relationship identified specific responses of phytoplankton taxa to the different salinity regime of lagoon. © 2015 Elsevier Ltd.

Robin R.S.,ICMAM Project Directorate | Robin R.S.,National Center for Sustainable Coastal Management | Kanuri V.V.,ICMAM Project Directorate | Muduli P.R.,ICMAM Project Directorate | And 7 more authors.
Geomicrobiology Journal | Year: 2016

An effort has been made for the first time in Asia's largest brackish water lagoon, Chilika, to investigate the spatio-temporal variability in primary productivity (PP), bacterial productivity (BP), bacterial abundance (BA), bacterial respiration (BR) and bacterial growth efficiency (BGE) in relation to partial pressure of CO2 (pCO2) and CO2 air–water flux and the resultant trophic switchover. Annually, PP ranged between 24 and 376 µg C L−1 d−1 with significantly low values throughout the monsoon (MN), caused by light limitation due to inputs of riverine suspended matter. On the contrary, BP and BR ranged from 11.5 to 186.3 µg C L−1 d−1 and from 14.1 to 389.4 µg C L−1 d−1, respectively, with exceptionally higher values during MN. A wide spatial and temporal variation in the lagoon trophic status was apparent from BP/PP (0.05–6.4) and PP/BR (0.10–18.2) ratios. The seasonal shift in net pelagic production from autotrophy to heterotrophy due to terrestrial organic matter inputs via rivers, enhanced the bacterial metabolism during the MN, as evident from the high pCO2 (10,134 µatm) and CO2 air–water flux (714 mm m−2 d−1). Large variability in BGE and BP/PP ratios especially during MN led to high bacteria-mediated carbon fluxes which was evident from significantly high bacterial carbon demand (BCD >100% of PP) during this season. This suggested that the net amount of organic carbon (either dissolved or particulate form) synthesized by primary producers in the lagoon was not sufficient to satisfy the bacterial carbon requirements. Lagoon sustained low to moderate autotrophic–heterotrophic coupling with annual mean BCD of 231% relative to the primary production, which depicted that bacterioplankton are the mainstay of the lagoon biogeochemical cycles and principal players that bring changes in trophic status. Study disclosed that the high CO2 supersaturation and oxygen undersaturation during MN was attributed to the increased heterotrophic respiration (in excess of PP) fuelled by allochthonous organic matter. On a spatial scale, lagoon sectors such as south sector, central sector and outer channel recorded “net autotrophic,” while the northern sector showed “net heterotrophic” throughout the study period. © 2016 Taylor & Francis Group, LLC

Ganguly D.,ICMAM Project Directorate | Ganguly D.,National Center for Sustainable Coastal Management | Patra S.,ICMAM Project Directorate | Muduli P.R.,Wetland Research and Training Center | And 6 more authors.
Journal of Earth System Science | Year: 2015

Ecosystem level changes in water quality and biotic communities in coastal lagoons have been associated with intensification of anthropogenic pressures. In light of incipient changes in Asia’s largest brackish water lagoon (Chilika, India), an examination of different dissolved nutrients distribution and phytoplankton biomass, was conducted through seasonal water quality monitoring in the year 2011. The lagoon showed both spatial and temporal variation in nutrient concentration, mostly altered by freshwater input, regulated the chlorophyll distribution as well. Dissolved inorganic N:P ratio in the lagoon showed nitrogen limitation in May and December, 2011. Chlorophyll in the lagoon varied between 3.38 and 17.66 mg m−3. Spatially, northern part of the lagoon showed higher values of DIN and chlorophyll during most part of the year, except in May, when highest DIN was recorded in the southern part. Statistical analysis revealed that dissolved NH+4 –N and urea could combinedly explain 43% of Chlorophyll-a (Chl-a) variability which was relatively higher than that explained by NO−3 –N and NO−2 –N (12.4%) in lagoon water. Trophic state index calculated for different sectors of the lagoon confirmed the intersectoraland inter-seasonal shift from mesotrophic to eutrophic conditions largely depending on nutrient rich freshwater input. © Indian Academy of Sciences.

Baliarsingh S.K.,Indian National Center for Ocean Information Services | Lotliker A.A.,Indian National Center for Ocean Information Services | Trainer V.L.,National Oceanic and Atmospheric Administration | Wells M.L.,University of Maine, United States | And 7 more authors.
Marine Pollution Bulletin | Year: 2016

An intense bloom of red Noctiluca scintillans (NS) occurred off the Rushikulya estuarine region along the east coast of India, an important site for mass nesting events of the vulnerable Olive Ridley sea turtle. At its peak, densities of NS were 3.3×105 cells-l-1, with low relative abundance of other phytoplankton. The peak bloom coincided with high abundance of gelatinous planktivores which may have facilitated bloom development by their grazing on other zooplankton, particularly copepods. Ammonium concentrations increased by approximately 4-fold in the later stages of bloom, coincident with stable NS abundance and chlorophyll concentrations in the nano- and microplankton. This increase likely was attributable to release of intracellular ammonium accumulated through NS grazing. Dissolved oxygen concentrations decreased in sub-surface waters to near hypoxia. Micro-phytoplankton increasingly dominated chlorophyll-a biomass as the bloom declined, with diminishing picoplankton abundance likely the result of high predation by the ciliate Mesodinium rubrum. Together, these data illustrate factors that can disrupt ecosystem balance in this critically important Indian coastal region. © 2016 Elsevier Ltd.

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