Estuaries, which serve as vital links between land and coastal ecosystems, play a significant part in facilitating the transfer of plastic waste from the land to the ocean. In this research, we ...examined the prevalence, characteristics, and ecological risks of microplastics (MPs) in the extensively urbanized Cochin Estuarine System (CES), India. Additionally, it represents one of the initial evidence-based examinations of MPs ingestion by jellyfish in Indian waters, focusing on Acromitus flagellatus, Blackfordia virginica, and Pleurobrachia pileus species. The abundance of MPs found in the surface water of the Cochin Estuarine System (CES) varied between 14.44 ± 9 to 30 ± 15.94 MP/m3, with an average of 21.6 ± 11 MP/m3. In both surface waters and jellyfish from the Cochin Estuarine System (CES), fibers were the most prevalent type of MPs, with polyethylene (PE), polypropylene (PP), and polyamide (PA) being the most common polymer varieties. To evaluate the current levels of MPs and their effect on the CES, the Pollution Load Index (PLI), Potential Ecological Risk Index (PERI), and Polymeric Risk Index (H) were utilized. The high PLIestuary values (20.33), high Hestuary values (234.02), and extreme PERIestuary value (1646.06) indicate that the CES is facing an extreme ecological risk. Among the 280 jellyfish individuals examined, 118 (42.14%) were recognized to contain MPs with an average of 1.54 ± 2.68 MPs/individual. Pearson bivariate analysis revealed a significant correlation between the jellyfish bell size and number of plastics per individual. Comparison between jellyfish species revealed, the majority (66%) of the MPs identified in jellyfish were from A. flagellatus and 44 among the 50 jellyfish examined (88%) had MPs. These findings suggest that A. flagellatus may be a potential sink for MPs and may be utilized to be a bioindicator for monitoring MPs contamination in estuarine systems, aiding in future plastic pollution mitigation efforts.
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•The Cochin Estuarine System faces severe ecological risk due to microplastic pollution, as evident by high pollution indices.•Microplastic prevalence in jellyfish Acromitus flagellatus, Blackfordia virginica, and Pleurobrachia pileus from Indian coast.•Significant correlation between bell size of jellyfish and MPs/individual.•Polyamide (PA) and Polyethylene (PE) are the dominant polymers in jellyfish.•A. flagellatus Could serve as a valuable bioindicator for monitoring microplastic contamination in estuarine environments.
The toxicities of the trace metals copper and zinc on the fish Puntius parrah were assessed based on standard renewal bioassay methods, and the 96 h LC50 values for copper and zinc were 0.5 mg/L and ...9 mg/L, respectively. The zinc and copper concentrations in water and sediment were high in a highly industrialized area compared with those in non-industrialized zones of the Periyar River. The fish exposed to a sublethal concentration of 0.05 mg/L of Cu and 0.9 mg/L of Zn showed a higher accumulation of both of the metals in the liver than in the kidneys, gills, and muscles. The histological changes induced by copper and zinc on the test organism under sublethal concentrations on the 3rd, 7th, 14th, and 28th -days of exposure were also studied. There was a significant decrease (p < 0.001) in the erythrocyte count after exposure to sublethal concentrations, whereas the hemoglobin, hematocrit, and mean corpuscular hemoglobin concentrations were significantly decreased after 28 days of exposure. Effective management strategies need to be developed and implemented to protect water bodies and aquatic organisms from trace metal pollution and its toxic effects.
•The toxicity of copper and zinc on Puntius parrah was assessed.•Zn and Cu in water and sediment showed high level in the highly industrialized area.•Several histopathological alterations are induced by the trace metals.•There was a decrease in erythrocyte count after exposure to Cu and Zn.•WBC count increased whereas hemoglobin, hematocrit, MCV and MCHC decreased.
In order to better understand the distribution pattern, pollution degree and the submarine groundwater discharge (SGD) of dissolved heavy metals, 15 subterranean estuaries (STEs) along southwest ...Indian coast were sampled over three contrasting seasons. The average concentration of metals were ranked as, pre-monsoon > monsoon > post-monsoon with 3 to 12-fold higher groundwater metal concentrations than the adjacent seawater. Average SGD derived essential metal fluxes were five times higher than the toxic metal fluxes of which Fe and Zn together contributed >90 %. Using the Single Factor Contamination Index, the majority of sites were minimally contaminated with only two sites indicating moderate ecological risk due to As. Higher fluxes of Fe, Cu and Zn were likely a result of rising anthropogenic activities. The SGD derived nutrient fluxes were an important source of DIP for primary production in coastal waters and represented 30 % and 44 % of the DIN and DIP inputs respectively.
•Toxicity and fluxes of 17 metals were estimated along the SW coast of India.•Essential metal fluxes were five times higher than the toxic metal fluxes.•Two groundwater samples indicated moderate ecological risk due to As.•Fe, Cu and Zn toxicity in groundwater was likely due to anthropogenic activities.•SGD accounted for 44 % of terrestrial DIP input into Arabian Sea.
Beach sediments of the southwest coast of India were analysed to estimate the microplastic contamination with emphasis on the submarine groundwater discharge (SGD) zones. Both SGD and non-SGD sites ...were assessed for abundance, morphotype and polymer type of microplastics. Microplastic load was 230.429 ± 62.87 particles per 100 g. Fibre, mainly blue, was the abundant morphotype, followed by fragment, foam and film. The polymer types were POLYETHYLENE (PE) (30.77 %), POLYPROPYLENE (PP) (26.92 %), POLYAMIDE (PA) (19.23 %), POLYSTYRENE (PS) (11.54 %), ETHYLENE VINYL ACETATE (EVA) (7.692 %) and POLYVINYL CHLORIDE (PVC) (3.846 %). The SGD zones exhibited higher microplastic contamination with statistically significant variations from non SGD sites. The study accounts the levels of microplastic contamination along the southwest coast of India, a major fishery zone. The higher abundance of microplastic in the SGD zones indicates the significance of subterranean groundwater through flow as a pathway of anthropogenic contaminants towards marine ecosystems.
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•Microplastics (MP) contamination in beach sediments of SW coast of India assessed with variations in SGD and non SGD zones•Microplastic abundance in the study area was 230.429 ± 62.87 particles per 100 g.•Fibre was major morphotype with blue colour and Polyethylene and polypropylene polymer type.•SGD sites observed higher microplastic abundance than non SGD with significant statistical variations.•Pollution indices PHI, CMPI and PRI values indicated substantial MP contamination in study area.
Epibenthic harpacticoid studies are generally ignored in Indian waters. Centred on the investigation carried out in Agatti and Kavaratti waters of Laccadive Sea during the winter monsoon 2015 and ...spring intermonsoon 2016, spatiotemporal assemblage pattern and environmental variables influencing the same were objectivized and hypothesized the habitat preferences of the harpacticoid community. Our collections encountered epibenthic fauna that included 14 major (meiofaunal) taxa, which showed a maximum density (2484 ind m
−3
) in Agatti and (2074 ind m
−3
) in Kavaratti atoll. Total of 23 harpacticoid species were encountered, primarily recorded
Onychocamptus armiger
from the Indian Ocean. The greater abundance and diversity of harpacticoid species in the coral area and inner lagoon can likely be due to the presence of algal tuffs and seagrass beds which provided suitable habitats and resources. Taxonomic distinctness (TAXDTEST) showed 95% confidence limits, depicting a diverse condition with unique harpacticoid representatives. Canonical correspondence analysis was used to relate the spatiotemporal pattern of the harpacticoid assemblages along with the environmental drivers. This pioneer investigation would serve as a stepping stone to the database of the hitherto unravelled harpacticoid copepod assemblages of Lakshadweep islands, one of India's biodiversity hotspots.
Abstract A new planktonic copepod assigned to the subgenus Tortanus (Atortus) Ohtsuka, 1992 is described from Great Nicobar Island, Andaman and Nicobar archipelago. The new species Tortanus (Atortus) ...dhritiae sp. nov. belongs to the tropicus-group. The new species can be distinguished from all other species of the tropicus-group by the presence of a notch on the left lateral joining of fourth and fifth pedigerous somites, asymmetrical caudal rami with a rounded process originating from the anterior portion of the left ramus produced over to the right, and an elliptical shaped exopodal lobe of leg 5 with distolateral curved seta in female. In male, serrated ridge on the anterior one-third surface of segment XX of the right antennule, obtuse trapezoid-shaped right leg 5 coxa with triangle-shaped medial process, semi-circular basis with slight curve near base and crocodilian head-shaped medial process with small process distally and bearing one distal and one medial setae.
The new species is the third of genus Victoriopisa from Indian waters.The species is described from the Valanthakad mangrove area of Vembanad backwater. Victoriopisa cusatensis sp. nov differs from ...other species of Victoriopisa by presenting: (1) a characteristic projection at dorsolateral margin of peduncle article 2 of antenna 1in male while smooth in female; (2) broad, triangular lateral cephalic lobe; (3) posteroventral tooth in epimeral plates; (4) presence of lateral and subapical spines in telson (5) smooth palm of gnathopod 2 without any excavations.
Vembanad wetland ecosystem — the largest Ramsar site on the South West Coast of India, located in the most populous coastal segments of Kerala, serves as the rice bowl of the state that forms a major ...hotspot of biological diversity. Alterations in natural hydrologic regime of Vembanad wetland started with the commissioning of Thanneermukkom barrage (TMB) across the backwater system in 1976, to prevent saline water intrusion, which adversely affected the eco-biology of the water body. The study was conducted during March 2011 to February 2012 on a monthly basis to evaluate the eco-hydrological status of this multifunctional ecosystem. Reclamation of estuarine areas for agriculture and other interventions has led to drastic decline in water holding capacity (2.4 to 0.6 km3) and depth (av. 4.02 m) of the estuary over the years. Water quality on an average reflects a neutral (7.11) and well oxygenated (7.4 mg L−1) nature; the salinity varying from 0.01 to 31.8 ppt. TMB plays a crucial role in influencing the salinity pattern of Vembanad wetland; with an oligohaline (0.5–5 ppt) in southern whereas meso and polyhaline (5–18 ppt) condition prevailing in northern stations. The estuary is nutrient rich with nitrate-nitrogen and phosphate-phosphorus ranging between 0.05–5.9 μmol L−1 and 0.18–6.49 μmol L−1 respectively. Trophic index (TRIX value 6.39 ± 0.75) indicated an impacted water quality condition leading to an accelerated eutrophication in the system. Bacillariophyceae (83.55%), Chlorophyceae (8.98%), Cyanophyceae (6.92%) and Zygnemophyceae (0.55%) were the major phytoplankton. Zooplankton community was composed of calanoids (63%), rotifers (22.5%), copepodites (2%), amphipoda (2%), crustacean naupli (1.5%) and cladocerans (1.2%) showing a declining trend in post barrage phase. Benthic polychaetes like Spionidae and Capitellidae were opportunistic bio-indicators of organic enrichment. Decline in fishery diversity and production (4387.31 t), reflects considerable ecological impacts on lower trophic levels. Thus the study presents an over view on a degrading coastal wetland system of India and signifies the need for enhanced restoration programmes for long term management and conservation objectives.
•The study presents an over view on a degrading coastal wetland system of India and signifies the need for its conservation.•Thanneermukkom Barrage plays a crucial role in influencing the salinity pattern of Vembanad estuarine system.•Trophic index (TRIX value) indicated an impacted water quality condition leading to an accelerated eutrophication in the estuarine system.•Decline in fishery diversity and production reflects considerable ecological impacts on lower trophic levels.
Coastal estuarine habitats are currently facing significant anthropogenic impacts, which have significantly influenced the biodiversity and ecosystem characteristics of benthic organisms. The aim of ...this study was to investigate the community structure and composition of polychaetes in the Vembanad estuarine system, which is the largest Ramsar site on the southwest coast of India. An artificial salinity barrier, the Thaneermukkom Barrage (TMB), was constructed in the estuarine ecosystem in 1975, resulting in a division of the system into a northern estuarine sector and a southern freshwater sector. By comparing the main ecological parameters of the Vembanad estuary before and after the construction of the barrage, it was evident that salinity experienced a drastic change. Spatially, the southern stations exhibited an oligohaline condition, while the northern stations displayed a mesohaline condition. Over three decades, there was a threefold increase in the amount of organic carbon in the sediment. A total of 19 polychaete species from 13 families and 19 genera were detected in the surface sediment samples from the ten selected stations. The time-scale study unveiled a significant shift in the distribution of polychaete species in the estuary. In the southern low salinity zone, only seven species of polychaetes were observed, most of which are considered classic indicators of disturbances and are responsive to organic enrichment. The decreasing salinity and increasing organic matter, particularly in the southern zone, may have contributed to a reduction in polychaete species diversity over the last 30 years. Based on the findings, the study suggests the need for effective policy formulation to manage the operation of TMB and control the discharge of waste from agriculture fields, houseboat tourism, and other developmental activities in the Vembanad estuarine system. Such measures are essential to safeguard the ecological integrity and biodiversity of this vital coastal ecosystem.
