G.V.M. Gupta

G.V.M. Gupta
Centre For Marine Living Resources and Ecology | CMLRE

M.Sc., Ph.D

About

72
Publications
29,461
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
1,457
Citations
Introduction
Hi! I am currently working on the project 'Marine Ecosystem Dynamics of eastern Arabian Sea (MEDAS)'.
Additional affiliations
October 2020 - present
Ministry of Earth Sciences
Position
  • Managing Director
Description
  • Marine and Estuarine Biogeochemistry, Ocean Deoxygenation, Greenhouse Gases, Ecosystem Dynamics
August 2020 - present
Ministry of Earth Sciences
Position
  • Researcher
Description
  • Marine Biogeochemistry, Oxygen Minimum Zones, Ecosystem dynamics
July 2015 - July 2020
Ministry of Earth Sciences
Position
  • Researcher
Description
  • Marine Biogeochemistry, Greenhouse Gases, Oxygen dynamics, Estuarine-Coastal-Ocean integrated processes.
Education
March 1993 - May 1998
National Institute of Oceanography, Visakhapatnam, India
Field of study
  • Marine Science

Publications

Publications (72)
Article
Full-text available
Observations along ten shelf transects in 2012 near 10°N in the southeastern Arabian Sea revealed the usual warm oligotrophic conditions during the winter monsoon (WM) and upwelling of oxygen-deficient, nutrient-rich cool water during the summer monsoon (SM). By changing an oligotrophic to a nutrient-replete condition, the upwelling is the major pr...
Article
Full-text available
Repeat measurements of dissolved nitrous oxide (N2O) along two transects of the western continental shelf of India in 2012 revealed high concentrations of 45±32 nM (off Kochi) and 73±63 nM (off Mangalore) during the summer monsoon (SM). N2O concentrations increased non-linearly during the peak of the SM upwelling, when low O2 (<25 µM) conditions pr...
Article
Full-text available
Repeat observations over the Kochi and Mangalore shelves of the southeastern Arabian Sea (SEAS) during April to December 2012 revealed substantial accumulation of methane (CH4) in the nearshore waters (48.6±34.4 nM) compared to the outer shelf (2.9±0.7 nM). Sediment methanogenesis and estuarine discharge appear to be the major sources of CH4 in the...
Article
Full-text available
The growing number of oxygen-deficient coastal zones around the world and their impacts on marine life has always been a controversial issue as their development is largely attributed to anthropogenic activities which can be mitigated by human actions. However, contrary to this prevailing understanding, we show here for the first time, using new co...
Article
Full-text available
The oxygen minimum zone (OMZ) in the eastern Arabian Sea (EAS, ∼6° to 21°N), within Indian Exclusive Economic Zone (EEZ), is mapped, for the first time, for one year through ten repeated ship-based observations between December 2017 and January 2019 at seven to ten stations along the 2000 m depth contour. On an annual basis, the OMZ (<20 µM oxygen)...
Article
Full-text available
Particulate organic carbon (POC) and its variability were studied to assess the accuracy of ocean colour retrieval algorithms over the eastern Arabian Sea (EAS) as it controls the carbon sequestration, oxygen minimum zone and biogeochemical (C, N and P) cycles. The seasonality in the physical and biological processes strongly influenced the distrib...
Article
Even though the seasonal pattern of phytoplankton biomass distribution in the seas around India is reasonably well understood, there is relatively little information on phytoplankton size classes. The current study shows how phytoplankton of different size classes respond to nutrient enrichment caused by vertical convective mixing during the Northe...
Article
Full-text available
Changes in macrozoobenthic standing stock and composition along the south-eastern Arabian Sea continental shelf (30–200 m) are investigated, based on data collected from the same sites during the same season 14 years apart (winter monsoon, 1998 and 2012), using the same platform, sampling gear, methods etc. During both surveys, polychaetes dominate...
Article
Dynamic stability (Brunt-Vaisala frequency) has marked control on the formation of deep chlorophyll maximum (DCM) layers when it occurs in shallow euphotic zone. In this work, the monthly timeseries hydrographic data collected during December, 2017 to January, 2019 were used to investigate the relationship between vertical structure of dynamic stab...
Article
Full-text available
The lesser known coastal upwelling in the North Eastern Arabian Sea (NEAS) during summer monsoon, its associated dynamics and forcing mechanisms is elucidated for the first time using basin scale monthly time-series in-situ and satellite data. The presence of cool upwelled waters along northwest coast of India from July to early October with an ass...
Article
Full-text available
The Gulf of Mannar (GoM), located between India and Sri Lanka, has astonishing faunal richness and diversity. Two oceanographic data sets supplemented with satellite remote sensing observations are discussed here to show the unique ecological setting in the GoM sustaining a rich and diverse fauna. We tested the hypothesis that a specific stretch of...
Article
Full-text available
The Indian Ocean presents two distinct climate regimes. The north Indian Ocean is dominated by the monsoons, whereas the seasonal reversal is less pronounced in the south. The prevailing wind pattern produces upwelling along different parts of the coast in both hemispheres during different times of the year. Additionally, dynamical processes and ed...
Article
The baseline study of Microplastics (MPs) in zooplankton (copepods, chaetognaths, decapods, and fish larvae) from six different zones along India's west coast (off Kanyakumari/Cape Comorin, Kochi, Mangalore, Goa, Mumbai, and Okha) in the Eastern Arabian Sea (EAS) is presented here with their vast ecosystem impacts. This investigation revealed that...
Article
The quantity of floating plastic debris (FPD) is continuously being increased in the oceans. To assess their size, structure, and composition along the eastern Arabian Sea (EAS), FPD samples were collected by using a surface plankton net. The microplastic size fraction (0.5–5mm) was the most prevalent accounting for >50% of the total, followed by m...
Article
Coastal upwelling that occurs in the eastern Arabian Sea (EAS) drive the complex dynamics of the food chain. Macrofauna plays a key role in the functioning of coastal ecosystems, but few studies explored the taxonomic and functional patterns of macrofaunal communities under upwelling influence. These patterns have been investigated in this study by...
Article
Coastal upwelling in the south eastern Arabian Sea (SEAS) leads to oxygen depletion over the continental shelf during the summer monsoon season (June–September), with latitudinal gradients in intensity. Based on two surveys in the onset (June) and peak (August) phases of the summer monsoon, the present study evaluates the response of macrozoobenthi...
Preprint
Full-text available
The Indian Ocean presents two distinct climate regimes. The North Indian Ocean is dominated by the monsoons, whereas the seasonal variation is less pronounced in the south. The prevailing wind pattern produces upwelling along different parts of the coast in both hemispheres during different times of the year. Additionally, dynamical processes and e...
Article
The paper describes the community composition of phytoplankton in the eastern Arabian Sea (EAS) during winter monsoon (WM, January-February 2018), encompassing the entire eastern part of the Arabian Sea basin (~ 6-22°N and 77-67°E) with high-resolution sampling (7 transects, 56 sites), from coastal to offshore regions. The phytoplankton pigment con...
Article
This study describes an assessment of an ocean-ecosystem model in simulating marine ecosystemdynamics in the Indian coastal waters. Long-term sustainedin-situobservations of temperature,salinity, chlorophyll-a and dissolved oxygen (DO) collected in the coastal waters of India, andship-based observations are used for this assessment. The model captu...
Article
Full-text available
Marine soft-sediments sustain functionally important benthic assemblages that are critical for remineralization of organic matter and supply of nutrients to the water column. While these assemblages are well studied along continental margins, investigations from insular margin that surround oceanic islands are very limited. This paper examines the...
Article
The resolution of the model emerges to be an important factor in simulating the real oceanic features. In this paper, the performance of two coupled bio-physical models, having spatial resolutions 1/12° (~9 km) and 1/4° (~25 km) configured using Regional Ocean Modeling System (ROMS), have been evaluated in simulating upper ocean dynamics of the Ara...
Article
Upwelling enhances pCO2 levels due to injection of carbon rich water to the surface despite the removal of carbon due to increase in primary production supported by enhanced nutrients. It is hypothesized that in the Bay of Bengal, upwelling may decrease pCO2 due to existence of low saline and pCO2 poor waters in the subsurface layer. In order to te...
Article
As projected by climate change models, increase in sea surface temperature and precipitation in the future may alter nutrient cycling in the coastal regions due to potential changes in phytoplankton community structure and their ability to assimilate nitrogen (N) and carbon (C). An experiment simulating different temperature and salinity conditions...
Article
The South Eastern Arabian Sea (SEAS) margin represents a tropical eastern boundary upwelling system, which is subjected to intense seasonal hypoxia in the continental shelf, and impingement of oxygen minimum zone (OMZ) along the continental slope. This paper provides the first comprehensive information on abundance, diversity and distribution patte...
Article
The response of the plankton community (micro- herein after MZP and mesozooplankton) to the seasonal intrusion of Bay of Bengal (BoB) water into the Arabian Sea from November (Initial Phase-IP) to January (Peak Phase-PP) and resultant stratification was tracked in the present study. During the winter monsoon (November –February) as part of seasonal...
Article
Bioavailable dissolved organic carbon (B-DOC), nitrogen (B-DON) and their degradation rate constants were measured for the Chilika Lagoon, India. Long-term laboratory incubation experiments (90 days) were conducted at a constant temperature (25 °C) to quantify the bioavailable dissolved organic matter (DOM) and the possible degradation rate coeffic...
Article
Carbon isotopic composition of dissolved inorganic carbon (δ13CDIC) in the Cochin estuary, a tropical eutrophic estuary along the southwest coast of India, and the adjacent coastal Arabian Sea was measured to understand spatiotemporal variability in sources and processes controlling inorganic carbon (C) dynamics in this estuarine-coastal system. δ1...
Article
Full-text available
Winter cooling and persistent mixing for more than a quarter of year (November to early March) along the North Eastern Arabian Sea (NEAS) results in nutrient enrichment of the euphotic column thereby triggering biological production. Hydrographic characteristics of NEAS during Late Winter Monsoon (LWM) and Early Spring Inter Monsoon (ESIM) and the...
Article
Full-text available
The state of the ocean simulated through a numerical model is extremely sensitive to the forcing and hence, the choice of appropriate forcing is essential, in particular wind-fields. We compared Regional Ocean Modeling System (ROMS) simulations when forced with two different wind-fields derived from satellite sensors (scatterometers), namely QuickS...
Article
Full-text available
Carbon uptake rates in a tropical eutrophic estuary (Cochin estuary) and the adjacent coastal Arabian Sea were measured for the first time using 13C-NaHCO3 labelling technique. The rates in the estuarine water (pre-monsoon: 3.0-20.4; monsoon: 2.55-12.4; post-monsoon: 3.1-16.3 µmol C l-1 h-1) were significantly higher than the coastal locations (pre...
Article
Full-text available
The core objective of the Marine Living Resource Program (MLRP) has been to delineate and quantify marine living resources of the country’s vast exclusive economic zone (EEZ), to understand the complex environmental regimes influencing their distribution, and to conduct R&D activities related to marine living resources. The programme was initiated...
Article
The objectives of the present study were to evaluate the ecological status of tropical coastal waters using the temperate benthic indices and examine the effect of seasonal variability on the performance of benthic indices. Macrobenthic samples were collected from northwest to southeast coast of India during 2003–2012 and we tested different univar...
Article
Full-text available
Detailed measurements of carbon (C) isotopic composition in dissolved inorganic ( 13CDIC) and particulate organic ( 13CPOC) fractions were conducted at 18 stations in the Cochin estuary during the post-monsoon season. In general, C biogeochemistry of different regions of the Cochin estuary appears to be regulated by different sources and processe...
Research
Full-text available
Please read it full online at "EOS - Earth & Space Science News" doi:10.1029/2016EO046753. Off the coast of southwestern India, seasonal upwelling affects seawater composition and biological activity. Understanding these changes is important for predicting the potential impacts of human activity in the Arabian Sea, a tropical marine ecosystem. In...
Data
Full-text available
Supplementary Figures of the article 'Evolution to decay of Upwelling and associated Biogeochemistry over the southeastern Arabian Sea shelf', Journal of Geophysical Research - Biogeosciences, 121, 159-175, doi: 10.1002/2015JG003163
Article
Quantification of nitrogen (N) transformation rates in tropical estuarine-coastal waters coupled systems undergoing anthropogenic disturbances is scant. A thorough understanding of these metabolic rates is required to evolve a mitigation strategy to save such systems from further degradation. Here, we report the first measurements of ammonium (NH4+...
Article
Characteristics of a cold-core eddy and its influence on the mesozooplankton community were studied along the central (87°E) Bay of Bengal during winter monsoon (November, 2008) based on in situ data. The thermo-haline structure and the satellite derived sea level anomaly maps showed the presence of a cyclonic eddy between 16°N and 20°N. The nutrie...
Article
The south eastern Arabian Sea is characterized by intense coastal upwelling, high biological production and subsurface oxygen depletion during the southwest monsoon (June-September). Concurrently, a seasonal closure to trawling activities (15th June to 31st July) is implemented here, as a sustainable ecosystem management practice. The effects of mo...
Article
Coastal lagoons around the world have become increasingly vulnerable to eutrophication and often the impingement is severe with regard to plankton. In this study, we measured how environmental heterogeneity persuades mesozooplankton (MSP) community dynamics in a large tropical coastal lagoon wrought by human impingement, including the creation of a...
Conference Paper
The winter monsoon season, spanning from November to February usually represents a quiescent period of the South Eastern Arabian Sea (SEAS). Seasonally reversing circulation plays an important role in exchanging water mass between the Arabian Sea and Bay of Bengal. lntrusion of BoB low saline water starts in November concurrent with the initial pha...
Conference Paper
Full-text available
Coastal lagoons are known to have high physico-chemical and biological variability over both spatial and temporal scales often as a result of anthropogenic effects. Chilka Lake, Asia’s largest brackish water lagoon on the east coast of India, is one such example of human intervention (e.g. creation of a new inlet opening) affecting its hydrochemist...
Article
Full-text available
Symbiotic diatom-diazotrophic cyanobacteria association (DDA) of Rhizosolenia hebetata and Rhizosolenia formosa with endosymbiotic cyanobacteria Richelia intracellularis was noticed and documented for the first time during a bloom of the cyanobacterium Trichodesmium erythraeum in the oligotrophic shelf waters along Kochi and Mangalore transects, so...
Article
Full-text available
The influence of anthropogenic loading on the distribution of soft bottom benthic organisms of a tropical estuary (Cochin backwaters) was examined. The industrial activities were found to be high in the northern and central part of the estuary, where dissolved inorganic nitrogen (DIN > 210 μM) and phosphorus (DIP > 6.5 μM) have caused high abundanc...
Article
Full-text available
Carbon biogeochemistry of a tropical ecosystem (The Cochin Estuary, India) undergoing increased human intervention was studied during February (premonsoon), April (early monsoon) and September (monsoon) 2005. The Cochin estuary sustains high levels of pCO2 (up to 6000 μatm) and CO2 effluxes (up to 274 mmolC m−2 d−1) especially during monsoon. A fir...
Article
Carbon biogeochemistry of a tropical ecosystem (The Cochin Estuary, India) undergoing increased human intervention was studied during February (premonsoon), April (early monsoon) and September (monsoon) 2005. The Cochin estuary sustains high levels of pCO sub(2) (up to 6000 mu atm) and CO sub(2) effluxes (up to 274 mmolC m sup(-2) d sup(-1)) especi...
Article
Bacterial productivity (BP) and respiration (BR) were examined in relation to primary productivity (PP) for the first time in a shallow tropical ecosystem (Cochin Estuary), India. The degree of dependence of BP (6.3–199.7 μg C L−1 d−1) and BR (6.6–430.4 μg C L−1 d−1) on PP (2.1–608.0 μg C L−1 d−1) was found to be extremely weak. The BP/PP (0.05–8.5...
Article
Biolog plates were used to study the changes in the metabolic capabilities of bacterioplankton over a complete tidal cycle in a tropical ecosystem (Cochin Estuary, Kerala, India) along southwest coast of India. The pattern of utilization of carbon sources showed a definite shift in the community metabolism along a salinity gradient. Multivariate st...
Article
Full-text available
Studies on biogeochemical cycling of carbon in the Chilka Lake, Asia’s largest brackish lagoon on the east coast of India, revealed, for the first time, strong seasonal and spatial variability associated with salinity distribution. The lake was studied twice during May 2005 (premonsoon) and August 2005 (monsoon). It exchanges waters with the sea (B...
Article
Full-text available
Cochin backwaters, a micro tidal estuary, undergo a characteristic transformation from a river dominated system during summer monsoon to a tide-dominant system during pre-monsoon season. The present study observes that as the river flow weakens after monsoon, the flushing of the estuary diminishes and the nitrogen and phosphorous loadings through a...
Article
Bacterial productivity (BP) and respiration (BR) were examined in relation to primary productivity (PP) for the first time in a shallow tropical ecosystem (Cochin Estuary), India. The degree of dependence of BP (6.3-199.7 mg C L-1 d-1) and BR (6.6-430.4 mg C L-1 d-1) on PP (2.1-608.0 mg C L-1 d-1) was found to be extremely weak. The BP/PP (0.05-8.5...