Variation of Bacterial Metabolic Rates and Organic Matter in the Monsoon-Affected Tropical Estuary (Godavari, India)

Gawade, L.; Sarma, V. V. S. S.; Rao, Y. Venkateshwara; Hemalatha, K.

doi:10.1080/01490451.2017.1326989

Cited by 10 publications

(1 citation statement)

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“…During this period, despite the high nutrient concentrations, phytoplankton biomass is very low due to the high suspended load which limits light availability (Acharyya et al, 2012). Based on the values of the photosynthesis to respiration ratio, Sarma et al (2009) estimated that 40-60% and 70-95% of the heterotrophic production is supported by organic matter of terrestrial orifin during the wet and dry periods, respectively (Gawade et al, 2017). The contribution of different taxa to the phytoplankton assemblages in the Godavari estuary varies according to the magnitude of freshwater discharge rather than to nutrient concentrations (Bharati et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Influence of river discharge on zooplankton diet in the Godavari estuary (Bay of Bengal, Indian Ocean)

et al. 2018

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In estuaries, detrital (i.e., non-living) organic matter (OM) contributes significantly to the particulate organic matter (POM) pool and we hypothesize that it may be a major source of estuarine zooplankton diet. To test this hypothesis, the isotopic composition of carbon (d13C) and nitrogen (d15N) of phytoplankton, zooplankton, and POM was assessed in the Godavari estuary (Bay of Bengal, Indian Ocean) during wet (November) and dry periods (January). As a result of higher riverine discharge, POM concentrations and values of the C/Chl-a ratio during the wet period were higher than those measured during the dry one. Relatively lower δ13CPOM values were observed during wet than dry period and contrasting to that was found for δ15NPOM. Detritus from fresh water algae and C3 plants contributed significantly to the POM pool during the wet and dry period, respectively. Based on isotopic mixing model, detrital OM and phytoplankton mostly characterized the POM pools during the wet and dry periods, respectively. Accordingly, our results suggest also that the zooplankton diet was mostly supported by detrital OM during the wet period and by both phytoplankton and detrital OM during the dry one. The zooplankton trophic level (TL, 2.7) during the wet period was relatively higher than that (1.9) during the dry one, suggesting a relative higher preference for detritus than phytoplankton during the wet period. The results of this study allowed us confirming that detrital OM can significantly support zooplankton production in the Godavari estuary.

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