National Institute of Oceanography, India

About: National Institute of Oceanography, India is a facility organization based out in Panjim, Goa, India. It is known for research contribution in the topics: Monsoon & Population. The organization has 4713 authors who have published 6927 publications receiving 174272 citations.

Response of infaunal macrobenthos to the sediment granulometry in a tropical continental margin–southwest coast of India

Abstract: Surficial sediment samples, collected from the continental margin of the southwest coast of India in July 2004, were examined for the grain size and soft-bottom macrobenthic fauna, to understand the sediment granulometry and its effect on the faunal distribution. Samples were collected using Smith-McIntyre Grab, from 20 to 200 m depth range, consisting of mid-shelf, outer shelf and slope. Fine-grained sediment located in the mid shelf and supported low faunal abundance. Polychaetes constituted the bulk of the fauna. Feeding guild changed with depth and sediment granulometry. Coexistence of deposit feeders and carnivores in outer shelf and deposit feeders and filter feeders in the slope region indicated the effective utilization of different food resources. In general, richness and diversity were high in the southern region. Depth wise, the diversity and abundance were relatively high in the 50–75 m depth range. Correlation and BIO-ENV analysis showed that combination of different factors such as sediment texture, sediment sorting and depth were found to influence the distribution of macrobenthos. Hence, spatial variations observed in benthic community were presumably linked to the variations in sediment granulometry and the energy level conditions prevailing in the area.

A unique isotopic fingerprint of sulfate-driven anaerobic oxidation of methane

Abstract: The largest reservoir of the powerful greenhouse gas methane is in marine sediments, and catastrophic release of this methane has been invoked to explain climate perturbations throughout Earth history. Marine methane oxidation is mainly coupled anaerobically to microbial sulfate reduction, which both limits and controls the release of methane from this sedimentary reservoir to the rest of Earth’s surface. Methane can be transported within the pore space of marine sediments either via diffusion or as bubbles. When methane travels in bubbles, these bubbles often are not completely oxidized and reach the overlying water where the methane emerges from the sediment in cold seeps. Although paleo–cold seeps can be identified by geological features such as carbonate mounds, a geochemical signature for cold seeps remains elusive. We demonstrate, using the sulfur and oxygen isotope composition of sulfate, that a unique isotopic signature emerges during microbial sulfate reduction coupled to methane oxidation in bubbling cold seeps. This isotope signature differs from that when sulfate is reduced by either organic matter oxidation or by the slower, diffusive flux of methane within marine sediments. We also show, through a comparison with the literature, that this unique isotope fingerprint is preserved in the rock record in authigenic buildups of barite associated with methane cold seeps.

Glutathione S-transferase, catalase, superoxide dismutase, glutathione peroxidase, and lipid peroxidation as biomarkers of oxidative stress in snails: A review

Abstract: Antioxidant defense plays a crucial role in the response of an organism to pollutants. Severalprocesses stimulate the production of free radicals or deplete the antioxidant defense, which if not regulated properly, may cause oxidative stress in the organisms, leading to damage in DNA, proteins or lipids. Free radicals are also beneficial as it plays an important role in defense against infectious agents, and signal transduction. Hence a delicate balance between antioxidants and free radicals is required. Oxidative stress biomarkers are very useful in disease etiology and environmental toxicological studies. The increase in anthropogenic activities and environmental awareness has resulted in an explosive increase of research in the field of oxidative stress. Snails are excellent organisms for environmental biomonitoring and contribute a major proportion of the invertebrate biomass. In our article, we have summarized the research carried out using glutathione S-transferase (GST), catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and lipid peroxidation (LPO) in snails exposed to various toxicants and their implication in the environmental monitoring programs. In the end, we have discussed different factors affecting the variations in oxidative biomarkers response for a better understanding of the phenomenon.