Southwest Coast Of India Research Articles

Inter-annual variability in the phytoplankton abundance and community structure of a tropical monsoonal estuary in response to variable monsoonal patterns

The study elucidates the inter-annual and seasonal variability in the phytoplankton abundance and community structure concurrent to variable rainfall patterns in Chettuva, a tropical monsoonal estuary along the southwest coast of India. The phytoplankton community exhibited statistically significant inter-annual variation with a 1.2-fold increase in abundance (av. 19.44 ×104cellsL-1) in 2021 in comparison with 2019 (av. 15.30 ×104cellsL-1). A total of 87 phytoplankton species were observed during the study, among which Bacillariophyceae dominated with 52 species, followed by Dinophyceae (20 species), and to a lesser extent by Chlorophyceae (11 species) and Cyanophyceae (2 species). Phytoplankton community structure also showed variation, with 71 species contributing to the diversity in 2021 and 62 species in 2019. Though Bacillariophycea dominated during both years, the community was more diverse in 2021comparatively a more saline year Biddulphia sp. Coscinodiscus sp., Cyclotella striata, Melosira sulcata, Pleurosigma sp., and Skeletonema costatum were the diatoms common to both the years, though with varied abundance. Dinophyceae did not show a conspicuous change in community structure in both years, with mostly the same species contributing to the total phytoplankton population but showed slight variation in abundance. Cyanophycea was observed exclusively during the year 2021. The abundance and community structure of the species varied from year to year, but they also changed seasonally, with lower numbers observed during the monsoon compared to the post-monsoon period in both years. CCA analysis identified two groups of phytoplankton assemblages in relation to the prevailing environmental conditions. The Group I species preferred lower temperature and salinity and elevated nutrient concentrations and they dominated during the monsoon season. Group II species preferred high saline well oxygenated, nutrient-poor waters and they dominated during the post-monsoon. Furthermore, the trophic state index analysis indicated mesotrophic conditions during the monsoon, while eutrophic conditions were observed in the post-monsoon period.

Ecological impact of artificial barrage on calanoid copepods in the Vembanad Lake, Southwest Coast of India

The Vembanad Lake (VL) is a brackish water lagoon, an integral part of Ramsar site, Vembanad Kol Wetland ecosystem on the southwestern coast of India. VL faces escalating anthropogenic impact, notably worsened by the establishment of the Thanneermukkom barrage (TMB) in 1976. This study hypothesizes that the TMB has led to significant ecological changes in VL, specifically altering the distribution and abundance of calanoid copepods, which are vital as a food source for higher trophic levels, particularly fish. To test this hypothesis, zooplankton samples were collected from various sites along the lake, and environmental parameters such as salinity and chlorophyll-a concentration were measured. This investigation reveals a distinct limnetic zone in the southern region, in contrast to the oligo-mesohaline zone in the north, attributed to the TMB. The study identifies the prevalence of calanoid copepod species such as Heliodiaptomus cinctus, Allodiaptomus mirabilipes, and Acartiella gravelyi in the TMB-South region, reflecting a freshwater-dominated ecosystem. The low salinity and high chlorophyll-a content in this area create an optimal environment for these species. In contrast, the dominance of Acartia (Odontacartia) spinicauda, Pseudodiaptomus serricadatus, and Paracalanus sp. in the TMB-North indicates higher salinity levels, with species in this region adapting to a different ecological niche. Thus, the installation of the TMB has significantly altered the ecological balance of VL by dividing the water body into two distinct salinity zones. This separation has led to changes in the distribution and abundance of calanoid copepods, which are essential for energy transfer to higher trophic levels in the VL food web, consequently affecting fish populations and overall biodiversity.

An update on soil gas harvesting technique as a non-depleting source of 222Rn for a large volume calibration chamber for long-term exposure experiments

ObjectiveTo demonstrate the versatility of the natural soil gas harvesting technique, coupled with a semi-dynamic injection algorithm, as an efficient and reliable source for continuous 222Rn delivery to a large-volume calibration chamber across different soil conditions and climatic conditions. MethodsLong-term experiments were performed during three seasons of a year in a tropical monsoonal climatic region with high rainfall on the Southwest Coast of India. Soil gas extraction was performed using soil-gas probes, inserted to ∼ 1 m deep into the ground. Soil gas was harvested at a flow rate of 60 lpm, passed through a moisture trap, a 222Rn progeny filter, and a delay volume and pumped into a 222Rn calibration chamber of volume 22.7 m3. Continuous monitoring of 222Rn concentration in the chamber was performed using ionization chamber-based reference monitors. To achieve and maintain the desired 222Rn concentration values in the calibration chamber, the semi-dynamic injection method was adopted, in which the 222Rn concentration in the soil gas was monitored periodically, and injection into the chamber was controlled using a well-defined pumping algorithm. Three ranges of 222Rn concentration values were chosen as the target values to be maintained in the calibration chamber for long-term experiments (15 d): (i) low concentration (500 - 1,000 Bq/m3), (ii) medium concentration (1,000 - 10,000 Bq/m3), and (iii) high concentration (10,000 – 25,000 Bq/m3). ResultsThe achieved 222Rn concentration values were in good agreement with the target values, with deviations of 12%, 8% and 5% for the low, medium and high concentration exposures, respectively, during the summer season. During the monsoon season, the deviations between the target and the achieved concentration values were 12%, 10% and 5% for low, medium and high concentration exposures, respectively, and the corresponding deviations were 12%, 4%, and 5% for the winter season. These deviations are well within the cumulative uncertainty associated with the measurements. ConclusionsThe results of this study conclusively demonstrate that the soil gas harvesting method, when coupled with the semi-dynamic injection approach, is a reliable method for generating and maintaining the desired 222Rn concentration in the large volume calibration chamber during different seasons and environmental conditions.

Nutritional properties of commercially important cephalopods from the south-west coast of India

Cephalopods are widely regarded as healthy and nutritionally rich seafood resources. This study focuses on analysing the nutritional composition of six commercially important edible cephalopod species viz., Cistopus indicus, Amphioctopus marginatus, Amphioctopus aegina, Sepia pharaonis, Sepia elliptica and Sepia aculeata, from the Malabar coast of the Indian peninsula. The selected cephalopods were determined to be a rich source of protein ranging from 12.41 to 19.02 g 100 g-1. The amino acid profile demonstrated a balanced ratio of essential to non-essential amino acids (0.93-1.63) with a higher concentration of essential amino acids, attributing enhanced biological value of proteins in these cephalopods. S. pharaonis recorded the highest arginine-to-lysine ratio (~1.77), indicating excellent cholesterolemic index. Notably, octopus species had the lowest total cholesterol content (~100 mg 100 g-1) compared to cuttlefish species which recorded higher cholesterol levels (~160 mg 100 g-1). A. marginatus recorded more significant quantities of polyunsaturated fatty acids (PUFA) (36.85% total fatty acids) among all the species studied. Octopus species exhibited significantly greater Σn-3/Σn-6 ratio than cuttlefish species. The ideal atherogenicity/thrombogenicity indices (<1.0) in the edible tissues of the studied cephalopods qualify these species as potentially healthy food. A. aegina was found to exhibit greater vitamin E (α-tocopherol) contents (17.84 IU), whereas ascorbic acid was pronounced more in A. marginatus (47.06 μg 100 g-1). The higher vitamin D3 content in A. aegina (96.23 μg 100 g-1) among the species studied, highlights its potential role in preventing osteoporosis in adults. Among microelements such as iron and zinc were found in significant quantities in the cephalopod species studied. The findings from the current study provide valuable insights into the nutritional benefits of these species, positioning them as promising candidates for the seafood industry as possible healthy dietary options. Keywords: Amino acid composition, Atherogenicity index, Cephalopods, Fatty acid composition, Thrombogenicity index

Seasonal fluctuations in fatty acid profile and biochemical traits of edible deep-water shrimp Heterocarpus woodmasoni

Heterocarpus woodmasoni is an edible deep-sea caridean shrimp that holds significant commercial importance and is sourced from the south-west coast of India in the Arabian Sea. In this research study, we extensively examined the biochemical, mineral and seasonal fatty acid compositions of H. woodmasoni. ANOVA tests, unveiled noteworthy disparities (p < 0.05) in moisture, crude fat and protein content between male and female H. woodmasoni. In contrast, we observed no significant differences in ash, carbohydrate, and cholesterol levels. Regarding minerals, the prominent macro elements detected in H. woodmasoni included K, P, Na, Ca and Mg with Zinc (Zn) and manganese (Mn) emerging as the dominant micro elements followed by Copper (Cu) and Selenium (Se). Notably, these shrimp exhibited a well-balanced ratio of essential to non-essential amino acids. Within the n-6 series, linoleic acid (18:2n-6), dihomo-γ-linolenic acid (20:3n-6), and arachidonic acid (20:4n-6) were identified as the primary polyunsaturated fatty acids (PUFA), exhibiting distinct concentrations across sexes and seasons. Both male and female H. woodmasoni displayed lower atherogenicity and thrombogenicity indices, ranging between 0.4 and 0.6 and 0.2–0.4, respectively, indicating a favourable cardiovascular health profile. Principal component analysis resulted in a two-principal component model explaining 83.4 % and 67.3 % of the total data variance for amino acid and fatty acid indices, respectively. This comprehensive biochemical analysis of both male and female H. woodmasoni reaffirms the species' status as a valuable and healthful resource, characterized by its abundance of high-quality nutritional components.

Bioaccumulation of natural radionuclides in edible molluscs and associated risk from the Ashtamudi Estuary, situated in a high background natural radiation zone (HBNRA), Kerala, southwest coast of India

The study investigated various natural radionuclides, including 238U, 232Th, 210Po, and 210Pb, in edible molluscan species collected from different zones of the Ashtamudi estuary. Physicochemical and sedimentological factors played crucial roles in influencing the distribution of radionuclides in water and sediments. Notably, bivalve species, particularly those from the Cyrenidae family, exhibited significant bioaccumulation of 210Po (up to 432.8 Bq kg−1) and 210Pb (up to 121.3 Bq kg−1), with Zone VI recording the highest biological concentration factor (BCF) and biological sediment accumulation factor (BSAF). The calculated effective dose for humans consuming bivalve meat was moderate, falling above the lower end of the ICRP range of 1 mSv y−1 but well below the upper limit of 20 mSv y−1 for existing elevated radiation zones. The intake of radioactivity from some bivalves corresponded to a cancer risk of approximately 3.2 × 10−2 (total mortality + morbidity), exceeding the acceptable risk threshold reported by the USEPA. However, this level of exposure indicated that immediate action might not be necessary, especially if further dose reduction proved impractical, in line with the ICRP's approach to optimizing radiation protection.

Correction: A new insight into monsoon intraseasonal variability as revealed from distinct wind-precipitation regimes over the southwest coast of India

Correction: A new insight into monsoon intraseasonal variability as revealed from distinct wind-precipitation regimes over the southwest coast of India

Identification of novel genetic variants associated with oral squamous cell carcinoma (OSCC) in South-West coast of India using targeted exome sequencing

Oral squamous cell carcinoma (OSCC) is a subset of head and neck squamous cell carcinoma (HNSCC). This study explores the genetic landscape of oral squamous cell carcinoma (OSCC) in a cohort of 33 patients from Southern India using targeted exome sequencing. Our analysis revealed a diverse range of mutations across the cohort, with missense mutations being the most prevalent. Pathogenic mutations, as classified by ClinVar, exhibited significant individual variation, highlighting the heterogeneity of OSCC. Seventy-five genes were identified to harbor pathogenic or potentially pathogenic mutations, with notable recurrence in genes such as TP53, PDGFRA, and RAD50 among others. Comparison with high-frequency mutation genes in HNSCC from TCGA database revealed significant overlap, emphasizing the relevance of these mutations across different populations. Additionally, several novel mutations were identified, including those in CHD8, ITPKB, and HNF1A, shedding light on potential genetic risk factors specific to this population. Functional annotation and pathway analysis underscored the involvement of these mutated genes in various cancer-related pathways. Despite limitations such as sample size and the need for further validation, this study contributes to a deeper understanding of OSCC pathogenesis and highlights potential genetic markers for prognosis and targeted interventions, especially in the Indian context.

A multidecadal study of the Malabar upwelling system influencing Indian Mackerel landings along the coasts of Karnataka and Kerala, south-east Arabian Sea

Indian Mackerel (Rastrelliger kanagurta) is an essential small pelagic fishery resource, contributing to nearly 30 % of India's total marine fish landing. However, this species' life cycle and stock status are poorly understood and data deficient. Ocean mesoscale events are also known to influence their landing, besides the environmental factors like- salinity, chlorophyll, and sea surface temperature, affecting these small pelagic fishes' availability, migration, feeding, and reproductive activity. The Malabar upwelling region (southwest coast of India) is a significant upwelling system where upwelling occurs during the monsoon months. The nutrient-rich water increases the productivity of surface water, leading to plankton abundance. This productivity sustains a fishery for several commercially important fishes, mainly small pelagics such as sardines, mackerels, and anchovies, supporting India's most significant coastal pelagic fishery. For understanding the relationship between the target fish and the oceanographic events, in the present study, Pearson's correlation has been estimated between Indian Mackerel landing, rainfall, Sea water temperature at 0, 10, 20, 30, 45, and 50 m depths, mixed layer depth (MLD), their anomalies and occurrences of potential fishing zone (PFZ) lines along the Malabar upwelling region and corresponding coasts of Karnataka and Kerala. Mackerel landing time series showed a significant autocorrelation in four-quarter lag, correlation with rainfall anomaly in one-quarter lag, with PFZ line and MLD in three-quarter lag, and with SWT@50 (Seawater temperature@50 m depth) and SST anomaly in two-quarter lag both in Karnataka and Kerala. Upwelling events, as indicated by the presence of PFZ lines, were found to significantly impact the landings of Indian mackerel along the Karnataka and Kerala coasts. Polynomial equations were used to model the relationship between mackerel landings and these environmental factors, effectively capturing the influence of these parameters on mackerel catch trends.

Influence of cadmium and zinc contamination on the sediment microbiome of estuarine and coastal ecosystems in the Southwest Coast of India.

Metals and their nanoparticles can induce toxicities that influence the survival of both microorganisms and macroorganisms. The current study reports on the impact of heavy metal pollution on the microbiome of estuarine and coastal sediments, where the settling and final remineralization of organic matter occur. Sediment samples collected from the Cochin estuary along the southwest coast of India and its adjacent coast showed high concentrations of cadmium (Cd) and zinc (Zn). The contamination factor (CF), calculated by comparing the concentration of metals in each station with that of shale value for Cd and Zn, ranged from 5.2 to 8.7 and 1.5 to 2.0 respectively, in the estuarine and coastal stations. Microbiome analysis revealed that bacteria were common across all stations but varied in relative abundance. Proteobacteria, Chloroflexi, Actinobacteria, Desulfobacteria, and Acidobacteria were the major bacterial phylum found in all stations. More than 70% of the bacteria were tolerant to 1mM concentration of Cd. The findings of our study suggest that metal pollution can influence the microbiome of sediments in the estuaries and coasts. Bacteria with metal tolerance may dominate in polluted areas, but their participation in remineralization may be impaired, as evident in our previous reports. This impairment could ultimately influence the dynamics of the food web and the biogeochemical cycling of nutrients, necessitating further research.

Estimation of hydrochemical profile and trophic status of a coastal Ramsar site in south west coast of India

Coastal lakes are confronting a spectrum of threats arising from both natural processes and human activities. This study presents an investigation into the nutrient and trophic status of the Ramsar-designated (Ramsar site No. 1204) Ashtamudi Lake (ASL; area= 56 km2), situated along the southwest coast of India. To establish a comprehensive hydrochemical profile, 50 representative water samples comprising lake, surface and bottom layers were systematically collected from 25 distinct sites during the non-monsoon and monsoon seasons of 2017. Physcio-chemical characteristics were evaluated using standard protocols and procedures. The salinity observations consistently position the majority of the lake's area within the 'polyhaline' condition (18–30 PSU) throughout the year. The evaluation of nutrient ratios (DIN/DIP, DSi/DIN, and DSi/DIP) during the respective seasons highlights a prevalent phosphorus (P) and silicon (Si) limited scenario during non-monsoon period. This condition is marked by elevated dissolved inorganic nitrogen (DIN) concentrations juxtaposed with lower levels of dissolved inorganic phosphorus (DIP) and dissolved silicon (DSi). The computed Trophic Index (TRIX) unequivocally denotes a 'hypertrophic' state within the lake during the non-monsoon season. This characterization is upheld by TRIX values of 7.73±0.61 and 8.06±0.62 for surface and bottom water during non-monsoon. Further insight into the TRIX findings is derived from the supplementary Efficiency Coefficient (EF) index, which accentuates ASL's limited nutrient assimilation in conjunction with a substantial input of DIN. Overall, the sustained condition of occurrence of low dissolved oxygen and elevated DIN/DIP ratios exacerbates the hypertrophic state. This complex interplay heightens ecological strain, thereby imperiling aquatic organisms, particularly valuable fishery resources. Unfortunately, this situation invariably curtails the essential ecosystem services furnished by ASL. Therefore, the adoption of strategic interventions aimed at ameliorating nutrient influx and restoring a balanced trophic equilibrium stands imperative to mitigate ecological degradation and uphold the lake's pivotal contributions to its surrounding environment.

Metal Geochemistry and Contamination Assessment of Tropical Mangrove Sediments

ABSTRACT The objective of this study was to evaluate the metal geochemistry and contamination assessment of the metals such as Fe, Co, Cd, Pb, Ni, Zn, Mg, Ca, and Sr from the surface sediment samples collected from seven stations from a tropical mangrove area in the Southwest coast of India. Metals like Ni and Fe were found in higher concentrations but never exceeded the contamination level in all the seasons whereas Cd was highly contaminated in all the seasons as well as stations. Pollution levels were measured using the indices including contamination Factor (CF), potential ecological risk coefficient (Eir), Enrichment Factor (EF), geoaccumulation index (Igeo), Pollution load index (PLI), Contamination degree (Cdegree), modified contamination degree (mCd) and Hazard Quotient (HQ). However, the level of contamination highlighted Cd has the maximum risk factors from the selected study area. All stations are contaminated by anthropogenic inputs. The pollution load index (PLI) revealed Pazhayangady, Valapattanam, Dharmadom (stations 1,2 and 3), Kumbalam (station5) and Munroe Thuruth (station 7) showed the presence of polluted sediments (PLI> 1).

A new insight into monsoon intraseasonal variability as revealed from distinct wind-precipitation regimes over the southwest coast of India

A new insight into monsoon intraseasonal variability as revealed from distinct wind-precipitation regimes over the southwest coast of India

Occurrence, virulence, and AMR profile of Vibrio parahaemolyticus isolated from shellfish growing areas located along the south-west coast of India.

Vibrio parahaemolyticus is a leading cause of human gastroenteritis associated with seafood consumption. The present study aimed to investigate the occurrence and risk assessment of V. parahaemolyticus isolated from live Indian black clams, sediment, and water samples collected from shellfish harvesting areas located along the south-west coast of India. Out of the total 72 samples collected, 55.6% revealed the presence of V. parahaemolyticus; the highest occurrence was observed in shellfish samples. The presence of tdh and trh virulence genes was screened by multiplex PCR. Virulence genes could be detected in 25.8% of the strains; 19.35% of them were trh positive and 3.2% were tdh positive, while 3.2% of strains exhibited the coexistence of both virulence genes. Antimicrobial resistance (AMR) determined by the disk diffusion method revealed that 87% of the strains were multiple drug resistant and exhibited 21 diverse resistance patterns. The overall multiple antibiotic resistance (MAR) index values ranged from 0 to 0.8. To the best of our knowledge, this is the first report to document the presence of pathogenic and multidrug-resistant V. parahaemolyticus in shellfish harvesting areas of the Indian sub-continent. The study reveals possible health hazards associated with consuming shellfish harvested from the study area.

An Investigation on the Presence and Risk Assessment of Microplastics in Quilon Beach, South West Coast of India

Microplastics (MPs) are the most serious emerging pollutant around the globe. Anthropogenic activities are the major contributor of MPs in beach sediments. MPs are widely distributed along beaches and pose a serious threat to the marine food chain including human health. The present study aims to investigate, for the first time, the occurrence, quantification of abundance and risk assessment of MPs in Quilon beach, India and also identifies the potential sources along with the assessment of degree of MPs contamination using Pollution load index (PLI) and Pollution Hazard index (PHI) parameters. Sampling was conducted in dry season in the beach. A total of thirty-three samples were collected establishing a 20m grid pattern along the study area. MPs of size range 5mm - < 0.25mm were considered. The average abundance of MPs in the study area is 3145±2515 MPs/kg of sand. Polyester (PES), Acrylonitrile butadiene styrene (ABS) are the major polymer types in the study area. Fibre was the most dominant shapes. The frequent colours found were white and transparent. MPs of size <0.25mm were the most common of all the samples. Anthropogenic activities including sewage effluents, fishing and tourism activities might be the main sources of MPs pollution in this area.

Copepod community in the coastal waters off Kochi (India) signify the enhanced estuarine flushing during the Southwest Monsoon

Even though many studies refer to copepods as potential indicators of hydrographical settings and/or water masses, focused studies on this aspect are very scarce in Indian waters. Hence, this study assesses the hydrography and the copepod composition in a cross-shore transect (7–30 m depth zone) off Kochi along the southwest coast of India during different seasons to understand how seasonal hydrography alters the composition of copepods. The copepod community in the study area was found to consist of 36 species (26 dominant) during the Southwest Monsoon [(SWM) June to September], 31 species (16 dominant) during the Northeast Monsoon [(NEM) November to February], and 39 species (26 dominant) during the Pre-Monsoon [(PRM) March to May]. The salient observations in this study are (a) a higher contribution of cyclopoids (45–50%) during the oligotrophic PRM when the microbial food web was dominant; (b) the dominance of several truly estuarine copepods (Acartia plumosa, Acartiella keralensis, Pseudodiaptomous annandalei, and P. serricaudatus) during the SWM when the flushing of the adjacent estuarine system (Kochi backwaters) was the seasonal highest; and (c) the dominant occurrence of Temora turbinata, commonly referred to as an indicator of coastal upwelling, during both the SWM and the NEM indicates their conducive conditions in the study area during both seasons and (d) the occurrence of copepods Acartia danae, A. erythraea, Acrocalanus gibber, A. gracilis, Centropages orsinii, C. tenuiremis, Corycaeus catus, C. speciosus, Oithona similis, O. spinirostris, Oncaea venusta, Paracalanus parvus, and Undinula vulgaris in the study area regardless of seasons. The study concludes that, while the presence of truly estuarine copepods in the study area can be attributed to estuarine watermass indicators, the presence of several other dominant species found regardless of the season cannot, as their occurrence is widespread in the eastern Arabian Sea and the western Bay of Bengal, owing to seasonal water mass exchange between the two regions.

Feeding habits of the deep-sea shrimp Plesionika quasigrandis Chace, 1985 (Decapoda: Caridea: Pandalidae) in the southeastern Arabian Sea

ABSTRACT Species of PlesionikaSpence Bate, 1888 holds significant importance in the commercial harvesting of deep-sea shrimps along the southern coasts of India. Despite Plesionika quasigrandisChace, 1985 being a crucial resource on the southwest coast of India, there is a need for comprehensive information on its food and feeding habits. We investigated the diet of P. quasigrandis in relation to sex, size, and season. The species exhibited a diet primarily consisting of crustaceans, foraminiferans, and detritus. Both males and females showed a noteworthy reliance on detritus, as indicated by an index of preponderance values exceeding 45.8. The species displayed active scavenging behaviour alongside predatory dietary habits. We observed a decrease in feeding intensity from pre-monsoon to post-monsoon in both males and females. Permutational multivariate analysis of variance (PERMANOVA) revealed significant differences in the diets of P. quasigrandis, considering the combined effects of size and sex (P &amp;lt; 0.01). No significant distinctions were noted in the diet composition between males and females in relation to season.

Ecological assessment of microplastic contamination in surface water and commercially important edible fishes off Kadalundi estuary, Southwest coast of India.

This study focuses on the Kadalundi estuary, Kerala's first community reserve, investigating the prevalence and impacts of microplastics on both the estuarine environment and selected fish species. This study presents the initial evidence indicating the consumption of microplastic particles by 12 commercially important edible fish species inhabiting the Kadalundi estuary. Analysis revealed significant accumulations of microplastic fibers within the surface water. In examining 12 fish species from demersal and pelagic habitats, microplastics were found in both the gastrointestinal tracts and gills. In the digestive tracts, microplastic fragments constituted the highest proportion (46%), while in the gills, microplastic fibers were dominant (52.4%). This study observed a prevalence of blue microplastics over other colors in both water and fish samples. Notably, demersal species showed a higher incidence of ingested microplastics. Polymer analysis identified Polypropylene (PP), Nylon, Low-Density Polyethylene (LDPE), Polyethylene (PE), Polypropylene isotactic (iPP), PE 1 Octene copolymer, and Rayon in water samples, while fish samples predominantly contained LDPE, PP, PE, and Nylon. Risk assessment utilizing the Polymer Hazard Index (PHI) categorized certain polymers as posing minor to moderate risks. Pollution Load Index (PLI) computations indicated moderate to high levels of microplastic contamination across various sampling sites in the estuary. Principal Component Analysis (PCA) revealed a lack of correlation between fish size and microplastic ingestion, underscoring environmental factors' influence on microplastic intake. The study emphasizes the implications of microplastic pollution on the fragile ecosystem of the Kadalundi estuary, posing potential risks to biodiversity and human health.

Ephemeral analysis on microphytobenthos in an estuarine system along the southwest coast of India

Ephemeral analysis on microphytobenthos in an estuarine system along the southwest coast of India

Description of Sandythoa gen. nov., a fish parasitic branchial cymothoid (Crustacea: Isopoda: Cymothoidae) from the Indian Ocean, with five species including one new species

The comparative analysis of records of Elthusa samariscii (Shiino, 1951) from Japan and India, alongside corresponding illustrations, indicates that the records of E. samariscii from Samaris cristatus Gray in India represent a distinct and previously undescribed species. This study introduces Sandythoa tirangagen. and sp. nov., providing comprehensive descriptions of various lifecycle stages, including the female, male, transitional, premanca, and manca larvae. The following combinations of characters identify the genus: cephalon anterior margin with acute rostrum; pleonite 1 is distinctly narrow, not extending laterally; presence of a narrow gap between pleonites; antenna with more than 10 articles; maxilliped with oostegital lobe. Sandythoa tirangasp. nov. is specifically identified along the southwest coast of India. Furthermore, we propose transferring the following species from Elthusa: Sandythoa arnoglossi (Trilles and Justine 2006) comb. nov.;Sandythoa parabothi (Trilles and Justine, 2004) comb. nov.; Sandythoa samariscii (Shiino, 1951) comb. nov.; Sandythoa moritakii (Saito and Yamauchi, 2016) comb. nov. A revised key to the global marine branchial cymothoid genera is provided.