Tamil Nadu Coast Research Articles

Adaptation Practices of Dairy Farmers to Climate Change in Coastal Tamil Nadu, India

An investigation was conducted to evaluate the adaptation strategies of dairy farmers in light of climate change in Tamil Nadu. For this research, four out of the 13 coastal districts—Villupuram, Cuddalore, Ramanathapuram, and Thoothukudi—were chosen at random. Two blocks were randomly picked from each district for analysis. From each selected block, two villages were randomly identified from the existing villages. Consequently, 16 villages were included in this study. Fifteen dairy farmers were randomly selected from each village, yielding a total of 240 respondents for the research. Data were gathered using a predesigned interview schedule. The information collected was analyzed with suitable statistical tools to interpret the results of this research. It can be concluded that the area studied was primarily populated by crossbred cattle due to their high productivity, and “no distinct alterations of forage in the diet” were observed by fewer than half (48.33%) of the dairy farmers during periods of heat or cold stress. A notable 62.92 percent of dairy farmers did not employ feed additives during these distressing times, opting instead for a feeding strategy that involved “crop residues + unconventional materials” in drought conditions. It emerged that they were compelled to source water from open areas as adequate drinking water was not consistently available during drought periods. The majority of dairy farmers (70.42%) opted for a combination of “consult veterinarian + ethno veterinary practices” for addressing reproductive issues amid extreme weather events.

Comparative Analysis of Gear Efficiency for Portunus sanguinolentus Fishing along the Ramanathapuram Coast of Tamil Nadu, India

Comparative Analysis of Gear Efficiency for Portunus sanguinolentus Fishing along the Ramanathapuram Coast of Tamil Nadu, India

Distribution, ecological risk assessment, and source identification of potential toxic elements (PTEs) in Muttukadu backwater sediments, Southern India

Muttukadu Backwater is a robust estuary on the east coast of Tamil Nadu is contaminated by industrial, residential, and tourism-related activity (especially boat houses). In this present research, we investigated the heavy metal pollution, spatial distribution and statistical analysis of muttukadu coastal sediments, east coast of the Bay of Bengal in south India. In this study, we present the distribution of heavy metals in backwater sediments reveals enhanced levels of Fe, Mn, Cr, Zn, Cu, Ni, Pb, and Co and the highest concentrations of these metals are found at stations 2, 4, and 8. Based on contamination indices such as CD, Igeo, and PLI, moderate contamination is clear evident. However, the present data of Cr, Cu, and Pb metals have indicated low to moderate anthropogenic influence. We have identified the metals of Cr, Cu, and Pb indicated the High habitat risks are highlighted by ecological risk assessments, and it is due to the anthropogenic factors. Cu, Mn, Zn, and Cr are sourced from anthropogenic sources, while Pb, As, Co, and Ni originate from natural sources, according to spatial distribution analysis. A significant disturbance to the aquatic environment is caused by human activity. In this present study, underscores the necessity of pre-flooded dataset for future comparative research and ecological conservation in Muttukadu Backwater and their environments.

Distribution and Characterization of Heavy Mineral Placer Deposits along the Central Tamil Nadu Coast, India

Distribution and Characterization of Heavy Mineral Placer Deposits along the Central Tamil Nadu Coast, India

Fish Fauna Diversity in Relation to Environmental Parameters in Muthukuda Mangroves Southeast Coast of Tamil Nadu, India

Fish Fauna Diversity in Relation to Environmental Parameters in Muthukuda Mangroves Southeast Coast of Tamil Nadu, India

Long-term shoreline and LULC change computational analysis in part of the east coast of Tamilnadu using geoinformation tools

Long-term shoreline and LULC change computational analysis in part of the east coast of Tamilnadu using geoinformation tools

Fishery, Biology, and Dynamics of Parapenaeopsis maxillipedo (Alcock, 1905) off the SE Coast of Tamil Nadu (India)

Fishery, Biology, and Dynamics of Parapenaeopsis maxillipedo (Alcock, 1905) off the SE Coast of Tamil Nadu (India)

Role of assimilation of microwave humidity sounder (MHS) satellite radiance in forecast of structure and intensity of VSCS Vardah 2016

The present study evaluated the performance of the Weather Research and Forecasting (WRF) model in the forecast of a very severe cyclonic storm (VSCS) Vardah that developed over the Bay of Bengal (BoB) and make landfall over the Tamil Nadu coast on 12 December 2016. The study examined the impact of microwave humidity sounder (MHS) satellite radiance data assimilation to forecast of structure, intensity and rainfall of Vardah cyclone near to the coast using two different land surface model (LSM; Noah and Noah-MP). The mean track error is about 33 and 38 km with data assimilation using Noah and Noah-MP LSM respectively and this error is about 41 km in without data assimilation using Noah and Noah-MP LSM. The predicted intensity of the storm in terms of the maximum surface wind is also slightly better predicted in data assimilation experiment with Noah LSM, this is due to the improved initial condition. Accumulated rainfall and the maximum reflectivity in terms of spatial distribution and magnitude of the VSCS Vardah is well simulated in all the experiments but slightly better in data assimilation experiments. Hovmoller diagram is also presented to see the shifting pattern of accumulated rainfall across the region during simulation period.

A High-Resolution Digital Bathymetric Elevation Model Derived from ICESat-2 for Adam’s Bridge

This data descriptor elaborates the details of a high-resolution digital bathymetric elevation model generated for the region, namely, Adam’s Bridge, which encompasses a chain of shoals between Rameswaram Island, off the southeastern coast of Tamil Nadu, India, and Mannar Island, off the northwestern coast of Sri Lanka. The proposed dataset has taken advantage of the photon penetrability in the shallow waters by the green laser of ICESat-2 LiDAR to derive the seabed topography. Seafloor depths from ~0.2 million geolocated photons of ICESat-2 for the study area were accrued and interpolated to generate a 10 m digital bathymetric elevation model. Adam’s Bridge, an isthmus and submerged reefal assemblage in shallow and super-shallow waters, is a feature of scientific curiosity. Our dataset has the potential to enhance the understanding of Adam’s Bridge structure by providing substantial information to reconstruct its evolution.

Catch Composition of Portunus pelagicus from Different Fishing Gear Used along Palk Bay Water of Ramanathapuram Coast of Tamil Nadu, India

Catch Composition of Portunus pelagicus from Different Fishing Gear Used along Palk Bay Water of Ramanathapuram Coast of Tamil Nadu, India

Spatiotemporal analysis in brown seaweed diversity and abundance at selected coastal locations on the Southern coast of Tamil Nadu, India: A way forward for conservation and sustainable utilization

Tamil Nadu and its southern coast are well-known for seaweed diversity and abundant resources in India. Brown seaweeds are primary habitat producers in reef environments. The objective of this study was to assess the spatiotemporal variation in diversity and abundance of brown seaweed species along the intertidal region at selected coastal locations on the southern coast of Tamil Nadu, India. The sampling was performed monthly at six coastal locations, namely Hare Island (HI), Tuticorin Harbour (TH), Chinna Muttom (CM), Arockiapuram (AP), Vedhalai (VD), and Mandapam (MP), along the intertidal region during low tides between January 2021 and December 2021. A total of 36 brown seaweed species were identified at six locations, namely Sargassum (9 species), followed by Padina (5 species), Turbinaria (3 species), Dictyota (3 species) and 16 species each of others. In the context of different locations, the highest species diversity was observed at HI (35) and the lowest at CM (21) during the study period. The highest abundance was recorded at CM (19.80 kg wt m−2), while the lowest was reported at AP (9.51 kg wt m−2). Sargassum and Turbinaria exhibited the highest prevalence across all the locations. Among different seasons, the maximum species diversity was recorded during PoMoN (26), whereas the minimum species diversity was recorded during PrMoN (11). Similarly, the highest abundance was seen during PoMoN, whereas the lowest abundance was reported during PrMoN. These findings offer crucial foundational data for the preservation and exploitation of brown seaweeds.

Length-weight Relationship and Condition Factors of Seven Penaeus Shrimp Species along the Southeast Coast of Tamil Nadu (Southern India)

Background: The present study of the length-weight relationship and condition factors of seven shrimp species on the southeast coast of Tamil Nadu between July (2022) and February (2023) also estimated the coefficient of determination (r2). Methods: For shrimp species, the length-weight relationship shows some species have significant positive coefficients which have a determination by (r2 greater than 0.5) like Penaeus indicus, Penaeus mergiuensis, Penaeus canaliculatus, Penaeus latisulcatus, Penaeus monodon, some species have shown negative as (r2 greater than 0.5) value like Penaeus japonicas and Penaeus semisulcatus. Result: All shrimp species have heterogeneity evident in intercept (a). The growth exponent (b) varied between 0.278 and 2.289 and it significantly (p=0.05) deviated from the value of less than 3 which denoted negative allometric growth for all Penaeus shrimp species.

Extended Spectrum Beta Lactamase Profile of Citrobacter Species Isolated from Various Samples in the North East Coast of Tamil Nadu, India: A Cross-sectional Study

Introduction: Citrobacter species play a significant role in causing hospital-acquired infections, especially those affecting the urinary and respiratory systems, and they are commonly present in faeces. Healthcare systems are facing a major challenge due to the rise of antibiotic-resistant Gram-negative infections resistant to antibiotics. Aim: To identify the genotypic characterisation of the resistant gene blaTEM-1 in Citrobacter spp. obtained from a range of clinical samples. This investigation seeks to provide insights into the patterns of antibiotic resistance exhibited by these bacteria. Materials and Methods: This cross-sectional study was conducted between August 2021 and February 2022. Preliminary examinations included screening as well as confirmatory tests for Extended Spectrum Beta Lactamase (ESBL) production, which were confirmed by the combination disk method and double disc synergy test. Genotypic detection of the blaTEM-1 gene was done using the Polymerase Chain Reaction (PCR) technique. Demographic parameters like gender and age were assessed. Statistical analysis was done using the Statistical Package for the Social Sciences (SPSS) Software version 21.0. Results: Citrobacter koseri (66 isolates, 54.5%) was found to be the predominant species among the Citrobacter spp., followed by Citrobacter freundii (55 isolates, 45.5%). Urine samples were the primary source of Citrobacter spp. isolates, comprising 52 isolates (43%) of the total. In this study, the prevalence of ESBL producers was reported to be 49 isolates (77.8%) identified as ESBL producers. Tigecycline demonstrated a 100% effectiveness rate, followed by Piperacillin-Tazobactam (96% sensitivity) and Amikacin (95% sensitivity). Out of the 20 Citrobacter spp. isolates that tested positive for ESBL, 15 isolates (75%) were found to be positive for blaTEM-1. Conclusion: The results of this study provide insight into the changing patterns of antibiotic resistance in Citrobacter spp., with particular emphasis on ESBL profiles. Thus, it is imperative to implement intervention techniques to reduce the ongoing selection and spread of these more resistant bacteria, as well as efficient infection-control measures to manage epidemics. These results advance the comprehension of antibiotic resistance patterns and guide initiatives to combat the increasing threat of antibiotic resistance.

Temporal evolution of shoreline changes from 1972 to 2020 along the coast between Pondicherry and Point Calimere, East Coast of Tamil Nadu, India

The aim of this study was to estimate the changes in shoreline evolution that have occurred between 1972 and 2020. The intervals of analysis were 1980, 1991, 2000, 2005, and 2020. The findings suggest that there were hotspots of erosion along the coasts of Gunduppalavadi, Thandavarayan, Kattur, and Rajamadam, while there was accretion along Cuddalore, Kothattai, Pudupattinam, and the eastern parts of Thiruppoondi. The study highlights that most of the regions from Portonova to Point Calimere are at risk from a sea level rise of 2 m, and almost all the coastal stretches are at risk from a sea level rise of 2 to 5 m. The results of the study show that the shoreline changes from 1972 to 2020 were estimated and represented as 29.84% stable, 66.74% as accretion, and 3.45% as erosion during 1980. For 1991, the nature of the coast shared 69.66% accretion and 30.34% stability. In 2000, the coast represented 35.73% stability, 62.76% accretion, and 1.51% erosion. The findings suggest that the behavioral change on the coast during 2005 was 54.80% stable, 19.31% accretion, and 25.90% erosion. In 2020, the percentage of stable, accretion, and erosion represented 56.76%, 28.88%, and 14.37%, respectively. The study provides important insights into the changes in shoreline evolution that have occurred over time and the potential risks associated with sea level rise.

Performance of land surface schemes on simulation of land falling tropical cyclones over Bay of Bengal using ARW model

The present study encompasses the performance of Land Surface Model (LSM) physics on simulation of Tropical Cyclones (TCs) key characteristics - track, mean sea level pressure (MSLP), maximum sustained wind (MSW) and rainfall. The impact of four LSM schemes - Thermal Diffusion, Noah, RUC and Noah-MP, is evaluated for the simulation of Severe Cyclonic Storm (SCS) ‘Vardah’ that crossed Tamil Nadu coast, near Chennai on 12 December, 2016 and Extremely Severe Cyclonic Storms (ESCS) ‘Fani’ that crossed Odisha coast, close to Puri on 03 May, 2019. For this purpose, the Advanced Weather Research and Forecasting (ARW) model, configured with a single domain of 9 km horizontal resolution covering the Bay of Bengalis considered. The initial and lateral boundary conditions to the model integration are taken from National Centers for Environmental Prediction (NCEP) Final Analysis (FNL). The model simulated track is verified with India Meteorological Department (IMD) observed track for both the cases. The model simulated MSW and MSLP at the landfall location is validated with IMD best estimation along with fifth generation European Centre for Medium-Range Weather Forecasts (ECMWF) Re-analysis (ERA5) products. The rainfall associated with both the cyclones are compared with ERA5 and Global Precipitation Measurement (GPM) rainfall for its validation. The track of TCs Vardah and Fani are well simulated with all the four land surface schemes with reasonable accuracy in landfall position and time of landfall of the systems. The Along Track Error (ATE) and Cross Track Error (CTE) are minimal for the unified Noah LSM scheme. The landfall position error (about 2 km only) is significantly improved with the unified Noah scheme. In case of rainfall forecast, LSMs tend to overestimate the rainfall during landfall of both systems. It is also noticed that overestimation is more towards inland than on the coast. Out of all four LSMs, rainfall estimation from the RUC is closest to the GPM and ERA5 rainfall estimates during landfall. In addition to this, RUC scheme intensifies the cyclones in terms of MSLP and MSW during the landfall of the system as compared to the other parameterization schemes.

Identity, sociality and mobility: understanding internal fisher migration along India’s east coast

Fisher movement in the pursuit of fish is a well-established truism. In this paper, we explore the motivations and mechanisms deployed for internal migration within the fishing sector in coastal Tamil Nadu, rather than only on the seas, as a strategy for both economic and social mobility. Marine fisheries in India is a caste-based occupation, with its own social and political hierarchy, responsible for the governance and management of common resources. For those belonging to the subordinate fishing castes, excluded from decision-making processes, migration is an important strategy for gaining economic resources, social power and recognition as skilled and successful marine fishermen. Using qualitative research methods, the paper explores the migration of fishermen from Rajakuppam, a small fishing village in Cuddalore district, belonging to such a subordinate fishing caste, to Kasimedu, in the capital city of Chennai, the largest fishing harbour in the state of Tamil Nadu. We find that family and its social organization, in particular kinship and marriage ties, brokered by senior women, are significant factors in facilitating successful migration. Recognizing women’s contributions to the sector, both direct and through their social reproductive and networking activities, invisible in both the larger maritime literature and production-centric fisheries’ policy-making, is crucial for achieving wellbeing and sustainability outcomes.

Screening of Antiviral Efficacy of Few Seaweeds of Tamil Nadu Coast

Lately there has been a lot of interest worldwide in studies on the antiviral activities of marine natural secondary metabolites, notably marine polysaccharides. It has been established that polysaccharides made from marine sources and their derivatives have antiviral effects against potent viruses. Agricultural, biological, food, and pharmaceutical industries all make extensive use of goods obtained from algae. The most well-known chemical components found in algae are polysaccharides, which have been the subject of a variety of studies because of their varied bioactivities. Polysaccharides made from algae have recently risen to the top of pharmaceutical research due to their fascinating antiviral potential. Currently, COVID-19 can be prevented with vaccination, but the brown alga Sargassum wightii has several bioactive compounds that have the following qualities and may be a better option. S. wightii is one of the marine algae species that is rich in sulfated polysaccharides, the secondary metabolites which have antiviral action and the capacity to prevent viral proliferation. Fucoidan, a long-chain sulfated polysaccharide found in various brown algae, has potent antiviral effects. Additionally, sulfated polysaccharides from green algae (such as ulvans) and red algae (such as carrageenan), and lectins from red algae (such as griffithsin) have antiviral therapeutic agents against coronaviruses and other viruses. This research focuses on screening seaweeds for possible antiviral compounds to treat viral infections notably COVID-19.

Assessment of shoreline changes and associated erosion and accretion pattern in coastal watersheds of Tamil Nadu, India

The coastal region is not a constant and depends on several physical elements. Analogous to the world trend, the coastal areas of Tamil Nadu are encountering sea level rise and associated shoreline changes. However, the rate of change is not uniform and varies considerably. The study revealed such differences in shoreline changes during the past 30 years and identified erosion and accretion patterns trends in Tamil Nadu's coastal watersheds, from Pulicat (Thiruvallur district) to Kodyar (Kanyakumari district). The study used remotely sensed Landsat TM (Thematic Mapper) and OLI (Operational Land Imager) datasets to analyse shoreline changes from 1988 to 2018. The Digital Shoreline Analysis System (DSAS) tool is used to derive trends of shoreline changes by End Point Rate (EPR) and Net Shoreline Movement (NSM). The mean EPR is- 0.26 ​m/yr and NSM is-8.03 ​m/yr, suggesting the overall shoreline of the Tamil Nadu coast is shifting landward. However, the annual rates of EPR and NSM vary considerably from watershed to watershed, and therefore, these indices were used to categorise the coastal watersheds based on erosions and accretions. The results identified a high erosion rate in the watersheds of Coleroon, Arasalar (Nagapattinam), Gundar (Ramanathapuram), Vembar, Lower Vaippar (Thoothukkudi), Nambiyar, Hanuma (Tirunelveli), and Putian, Kodyar (Kanyakumari). Field surveys were conducted to verify ground conditions at 139 random locations along the 1000 ​km shoreline stretch. About 75% of respondents said they experience a very high to high risk of coastal erosion. The rates estimated by the study and categorisation of the coastal watersheds could be most helpful in evaluating the cumulative impact of coastal hazards and preparing sustainable development plans. The outcomes may also help to create awareness in more susceptible areas.

Multi-Criterion Analysis of Cyclone Risk along the Coast of Tamil Nadu, India—A Geospatial Approach

A tropical cyclone is a significant natural phenomenon that results in substantial socio-economic and environmental damage. These catastrophes impact millions of people every year, with those who live close to coastal areas being particularly affected. With a few coastal cities with large population densities, Tamil Nadu’s coast is the third-most cyclone-prone state in India. This study involves the generation of a cyclone risk map by utilizing four distinct components: hazards, exposure, vulnerability, and mitigation. The study employed a Geographical Information System (GIS) and an Analytical Hierarchical Process (AHP) technique to compute an integrated risk index considering 16 spatial variables. The study was validated by the devastating cyclone GAJA in 2018. The resulting risk assessment shows the cyclone risk is higher in zones 1 and 2 in the study area and emphasizes the variations in mitigation impact on cyclone risk in zones 4 and 5. The risk maps demonstrate that low-lying areas near the coast, comprising about 3%, are perceived as having the adaptive capacity for disaster mitigation and are at heightened risk from cyclones regarding population and assets. The present study can offer valuable guidance for enhancing natural hazard preparedness and mitigation measures in the coastal region of Tamil Nadu.

Assessment of phytoplankton diversity, distribution, and environmental variables along the southeast coast of India

Coastal waters are dynamic because of anthropogenic activities that contribute nutrients and contaminants. These changes have the potential to alter patterns of primary production and thus pelagic food webs. Here, we investigated the spatial variation of the phytoplankton community and its response to changing environmental variables at 84 stations along the five coastal districts of Tamil Nadu (TN). During the present study, 85 phytoplankton species were recorded, such as diatoms (64), dinoflagellates (18), silicoflagellates (1), and Cyanophyceae (2). The maximum phytoplankton abundance was recorded on the Thanjavur coast and gradually decreased towards the south coast of Tamil Nadu. Among the phytoplankton community, 50% was dominated by pennate diatoms, attributed to higher NO3− concentrations in the coastal waters due to agricultural discharge. Cluster analysis revealed that Ramanathapuram and Tirunelveli formed a closed cluster, whereas Thanjavur and Pudukottai formed a separate closed cluster associated with higher nutrient and metal concentrations, highlighting the difference in physicochemical parameters between the northern and southern districts of the TN coast. Relatively high nutrient concentrations in the coastal waters of northern districts are of greater concern, which could impact the coastal ecosystem. Coastal eutrophication is becoming a widespread phenomenon, causing disruption in the food chain and ecosystem balances and hence requiring regular monitoring and management.