Southwest Coast Of Kerala Research Articles

A first report on the distribution of Ostracod taxa in the Ashtamudi Lake, southwest coast of Kerala, India

The present study is the first taxonomical account of Ostracoda occurring in the sediments of the Ashtamudi Lake in Kerala, intending to generate a baseline for future palaeo-ecological or palaeoenvironmental applications. A total of 22 Ostracod species belonging to 16 genera, 11 families, 5 superfamilies and 2 suborders of the order Podocopida have been identified from 66 surface sediment samples collected across the lake. Sedimentological parameters, such as CaCO3, organic matter, sand silt and clay, were estimated and their distribution is discussed. The ratio between the carapaces and open valves has been taken into consideration for determining the rate of sedimentation in the study area.

Seasonal abundance of zooplankton in the Ashtamudi lake – southwest coast of Kerala, India

Seasonal abundance of zooplankton in the Ashtamudi lake – southwest coast of Kerala, India

A study of saltwater intrusion in the Kallada River, southwest coast of Kerala, India

AbstractMunroe Island in Kollam District of Kerala is a typical backwater village situated at the confluence of the Ashtamudi backwater and the Kallada River system. It is an amalgamation of eight small islands with a total area of 13.4 km2. Salinity intrusion has been a serious threat in the downstream areas of Kallada River for more than one and half decades, affecting the groundwater quality of Munroe Island. The present study focuses on the seasonal variation in physico-chemical characteristics of the underground water system of Munroe Island and Kallada River with special reference to saline water intrusion. Physico-chemical analysis of ground water revealed that samples were unsuitable for drinking due to higher content of Na, Ca, and K. Microbiological analysis of island groundwater showed the presence of coliform and E. coli bacteria above the permissible limit. Results indicated a significant correlation between salinity and major anions viz., Cl− and SO42 and cations viz., Mg, Na, Ca, and K of both river surface and island groundwater. In the present study it is clearly evident the occurrence of saltwater intrusion in Kallada River from Ashtamudy Lake and the its severity become higher during premonsoon season. The results also indicated that the salinity increase in Kallada River has a negative impact on island groundwater quality. The paper also suggests suitable management strategies for overcoming the saltwater intrusion thereby upgrading island sustainability.

Prevalence of Vibrio mimicus in Fish, Fishery Products, and Environment of South West Coast of Kerala, India.

Vibrio mimicus is a seafood-borne bacterium involved in incidences of human infections following consumption of raw or undercooked seafood. Regular monitoring of seafood for V.mimicus is necessary for risk assessment and to establish mitigation measures. During the period 2017-2020, a total of 250 samples comprising finfish, shellfish, water, ice, and sediment samples were collected from fish markets, fish landing centers, and fish farms in the Ernakulum district on the Southwest coast of Kerala, India. V. mimicus was isolated using enrichment in alkaline peptone water for 18 h followed by plating on thiosulfate citrate bile salts sucrose agar and then incubated at 37°C for 18-24 h. The presumptive V. mimicus isolates were confirmed by biochemical characterization and molecularly with vmh gene-specific for V. mimicus. The study revealed that the prevalence of V. mimicus is 5.6% in the total of samples screened. The highest occurrence was observed in brackish water fish (19%) followed by freshwater fish (18%) and marine fish (2%) samples. The study points out the risk of brackish water fishes as potential carriers of this pathogen. This requires preventive measures to mitigate health hazards associated with V. mimicus entering into the seafood production chain.

C-band Doppler weather radar observations during the passage of tropical cyclone ‘Ockhi’

Recently, a C-band polarimetric Doppler weather radar (DWR) was installed and commissioned at Thumba (8.5° N, 77° E), a west coastal station in the southern peninsula of India known as ‘Gateway of Indian Summer Monsoon’, for monitoring severe weather events and tropical cyclones. The DWR operates in the frequency range of 5.6 to 5.65 GHz with a peak transmitting power of 250 kW and employs state-of-the-art technology for both transmitter and receiver subsystems. Apart from providing regular base products such as reflectivity (Zh), radial velocity (V) and spectral width (σ), the DWR being equipped with dual polarization capability provides additional products such as differential reflectivity (Zdr), differential phase shift (ϕdp) and correlation coefficient (ρhv), which are used to study the microphysical properties of rain bearing clouds. The ‘Ockhi’ cyclone was the most recent one from 29th November to 2nd December 2017, which caused large devastation in terms of both economic and human life in Kerala coastal places. The C-band polarimetric DWR provides an opportunity to investigate the spatial and vertical structure of ‘Ockhi’ cyclone over the south-west coast of Kerala. The cyclone ‘Ockhi’ developed near the west of Srilanka and later advanced and stretched out near south-east of Kanyakumari through the Arabian Sea and impacted the coastal places of Kerala on 1st December 2017. During its formative stage, the eyewall was not clearly visible. The cyclone eye was clearly seen at the well-developed stage of cyclone, when it was in the vicinity of DWR range. The overall spatial extent of cyclone is ~ 1000 km as seen in INSAT-3D images. The maximum surface wind speed was observed to be around 30 m/s near to the Kerala coast. The outer fringes of the cyclone were located above the Trivandrum and caused heavy rainfall on 30 November 2017 around 17 h. The C-band DWR has captured the various stages of cyclone ‘Ockhi’ and its primary bands. Observations of C-band polarimetric DWR indicates that the vertical cross section of reflectivity along the cyclone eye showed that the size of cyclone is around 20 km and the precipitating cloud top heights reaching as high as 10–12 km. The cyclone’s outer rainbands are slanted outward and were more intense than the inner rainbands. The area surrounding the cyclone eye is the eyewall, characterized by very strong wind and torrential rainfall. The large differential reflectivity values ranging from 2 to 3 dB are found in the eyewall and rainbands regions. The outer rainband is characterized by large Zdr values with high reflectivity above the melting layer. The different values of Zdr are observed in the eyewall and outer rainband regions, which suggest that different microphysical characteristics prevail. As time progress, the cyclone system gradually intensified and the eyewall became more intense compared to the outer ones. The present study utilizes the C-band polarimetric DWR observations to characterize the spatial and vertical structure of cyclone ‘Ockhi’ and provides the ample information on the polarimetric signatures of cyclone structure to improve the better understating on the microphysical characteristics of tropical cyclones.

Distribution, sources and potential toxicological significance of polycyclic aromatic hydrocarbons (PAHs) in the south west coast of Kerala, India

To assess the potential eco-risk of PAHs along the study sites (Site1 – characterized by tourist influx and a religious pilgrimage centre resulting in domestic and organic pollution and massive foot traffic. Site 2 – Neendakara characterized by oil pollution since it is a fishing harbour and port with large scale motor boat / trawler traffic. Site 3 –characterized by inorganic pollution of heavy metals, trace metals, polycyclic aromatic hydrocarbons and organochlorins due to discharge of effluents from KMML Titanium dioxide industrial factory. Site 4 –control site since it is presumed to be near pristine being post tsunami and lacking any industrial / agricultural enterprise in the vicinity. The concentrations of N, B (a) A, Fl, ACN, and Ph cases were higher than effects range low (ERL) values, lower than the effects range median (ERM) values, except for Naphthalene and Acenaphthene. At site 2, the sampling areas are found to be stagnant with limited water circulation. Woefully, without attaining any pre-treatment on the issue, the regional industries and shipping harbor are still discharging their wastes into the area, resulting in high ∑ PAH concentration. An alarming fallout of the study is that site 4 also recorded appreciable concentrations of PAHs in the sediment, though it was found negligible in the water column. These results indicated that pessimistic eco-risks are likely to occur, although with a likelihood of 50% effects in this area. However, the remaining compounds were recorded below ERL values, which revealed the low risk of biological impairments. The study has disclosed various concentrations of PAH pollutants of low, moderate, and very high levels from the study sites signaling, effective sustainable management measures, and as a first step for long-term goals, the evaluation of water and sediments along the Kerala coastal ecosystem is recommended.

Assessment of Ingestion Dose and Lifetime Cancer Risk through Marine Food Samples of South West Coast of Kerala

Assessment of Ingestion Dose and Lifetime Cancer Risk through Marine Food Samples of South West Coast of Kerala

Seasonal variation of radon concentration in water and assessment of whole-body dose to the public along South-west coast of Kerala, India

The South-west coast of Kerala is a well-reported high background radiation area. Hence, the radiological protection of the population in this region has great concern. In view of this, the study has been undertaken to understand the distribution of radon ( 222 Rn) concentration in drinking water collected from the region. The seasonal variation of radon concentration in drinking water also forms part of the study. Emanometry method is used for the quantification of dissolved radon concentration in water collected from various open wells. The mean values of radon concentration obtained for pre- and post-monsoon were 0.95 Bq/l and 0.58 Bq/l, respectively. The whole-body dose ranges from 0.39 to 29.34 μSv/y for premonsoon and 1.33–18.76 μSv/y for postmonsoon. The average value of effective dose was below the recommended limit of 0.1 mSv/y suggested by WHO and EU council, and the water from the region can be safely consumed from the radiological protection point. All the results are presented and discussed in the manuscript.

Comparison of Lipid Profile in Three Species of Myctophids from the South West Coast of Kerala, India

Three important myctophid species of fish viz., Diaphus watasei, Diaphus luetkeni and Myctophum obtusirostre from commercial deep-sea shrimp trawlers operated off Quilon, Kerala, India were collected and analysed for lipid profile to elucidate its importance a dietary component with a view to understand its health benefits. Immediately after catch the fishes were iced immediately and were transported to the laboratory in 24 hours. The lipid profile of myctophids showed that they are rich in triacylglycerides (TAG). Saturated fatty acids were the predominated fatty acids (45–47 %) followed by monounsaturated (27–31 %) and polyunsaturated fatty acids (21–25 %). Docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA) and arachidonic acid were major PUFAs. Myctophids were a good source of fat soluble vitamins.

Cytogenetic studies on newborns from high and normal level natural radiation areas of Kerala in southwest coast of India

Purpose: To study, characterize and compare chromosome aberrations and karyotype anomalies among newborns from high (> 1.5 mGy/y) and normal (≤ 1.5 mGy/y) level natural radiation areas of monazite-sand bearing southwest coast of Kerala in India.Materials and methods: Cord blood samples from newborns were collected from selected Government hospitals in heparinized vials and cultures were set up employing standard microculture techniques, slides were prepared, coded and stained with giemsa. Well spread metaphases were analyzed for chromosome aberrations and karyotype anomalies.Results: A total of 1,267,788 metaphases from 27,295 newborns of mothers aged 17–45 years (17,298 from high and 9,997 from normal level radiation areas) were analyzed during 1986–2007. Frequencies of dicentrics in high and normal level radiation areas were 1.90 ± 0.14 and 2.01 ± 0.26 per 10,000 cells, respectively (Relative frequency [RF] = 0.94; 95% CI: 0.71–1.26). Karyotype anomalies had a frequency of 5.49‰ and 6.7‰, respectively (RF = 0.82; 95% CI: 0.60–1.12). No dose-related trend was observed in chromosome aberrations or karyotype anomalies.Conclusion: Frequencies of chromosomal aberration and karyotype anomalies between the newborns from the high level natural radiation area (HLNRA) and normal level natural radiation areas (NLNRA) were very similar.

Inhalation and external doses in coastal villages of high background radiation area in Kollam, India

The observational evidence for radiation-induced health effects in humans comes largely from the exposures to high doses received over short periods of time. The rate of induction of any health risk at low doses and dose rates is estimated by extrapolation from observations at high doses. Effects of low dose/low dose rate could be done by the study of populations that have been exposed to slightly above-average natural radiation doses. Southwest coastal line of the Kerala state in India is one such region known to have elevated levels of background radioactivity mainly due to the mineral-rich sand available with high abundance of thorium. In the present work, a study was conducted to investigate the inhalation and external radiation doses to human beings in the high background radiation area along the southwest coast of Kerala. Five hundred dwellings were selected for the study. All the selected houses were at least 10 y old with similar construction. Long-term integrated indoor measurements of the external gamma dose using thermoluminescent dosemeters (TLDs) and the inhalation dose with the SSNTD-based twin-cup dosemeters were carried out in the dwellings simultaneously. Ambient gamma dose measurements were also made with a GM tube-based survey meter while deploying and retrieving the dosemeters. The data show a high degree of heterogeneity. The inhalation dose was found to vary from 0.1 to 3.53 mSv y(-1) and the external dose rates had a range of 383-11419 µGy y(-1). The external doses measured by the survey meter and TLDs showed an excellent correlation.

Study of stillbirth and major congenital anomaly among newborns in the high-level natural radiation areas of Kerala, India

Monitoring newborns for adverse outcomes like stillbirth and major congenital anomalies (MCA) is being carried out in government hospitals since 1995 in and around high-level natural radiation areas, a narrow strip of land on the southwest coast of Kerala, India. Natural deposits of monazite sand containing thorium and its daughter products account for elevated levels of natural radiation. Among 141,540 newborns [140,558 deliveries: 139,589 singleton, 957 twins (6.81‰), 11 triplets (0.078‰), and one quadruplet] screened, 615 (4.35‰) were stillbirth and MCA were seen in 1,370 (9.68‰) newborns. Clubfoot (404, 2.85‰) was the most frequent MCA followed by hypospadias (152, 2.10‰ among male newborns), congenital heart disease (168, 1.19‰), cleft lip/palate (149, 1.05‰), Down syndrome (104, 0.73‰), and neural tube defects (72, 0.51‰). Newborns with MCA among stillbirths were about 20-fold higher at 190.24‰ (117/615) compared to 8.89‰ (1,253/140,925) among live births (P < .001). Logistic regression was carried out to compare stillbirth, overall, and specific MCA among newborns from areas with dose levels of ≤1.5, 1.51-3.0, 3.01-6.0 and >6mGy/year after controlling for maternal age at birth, gravida, consanguinity, ethnicity, and gender of the baby. Clubfoot showed higher prevalence of 3.26‰ at dose level of 1.51-3.0mGy/year compared to 2.33‰ at ≤1.5mGy/year (OR = 1.39; 95% CI, 1.12-1.72), without indication of any clear dose-response. Prevalences of stillbirth, overall MCA, and other specific MCA were similar across different dose levels and were relatively lower than that reported elsewhere in India, probably due to better literacy, health awareness, and practices in the study population.

Empowerment of coastal communities in cultivation and processing of Kappaphycus alvarezii—a case study at Vizhinjam village, Kerala, India

The Science & Society Division of Department of Science & Technology, Government of India sanctioned a project in 2005 under the Woman Scientist Program (DST WOS-B) with an objective to develop technologies for the cultivation of high-value seaweeds widely used for industrial purposes/human consumption with empowerment of the coastal communities in Kerala. The project was divided into two phases: an experimental/investigational phase and an extension phase. In the experimental phase, pilot-scale culture experiments were conducted to evaluate the possibility and feasibility of the cultivation of the red alga, Kappaphycus alvarezii, in the southwest coast of Kerala. Pilot-scale studies of seaweed culture were conducted in the shallow subtidal waters on the Vizhinjam Harbor area in two bamboo rafts tied with seeds of K. alvarezii (100 ± 1.20 g) following accepted culture and growth monitoring procedures. The first harvest was carried out after 45 days and the growth was nearly eight times the initial biomass (826 ± 2.80 g). A group of local fishermen were trained in the fabrication of culture rafts, implanting seed material, rearing the seedlings with periodical monitoring, harvesting, and post-harvest technologies like drying, sorting, packing, etc. as part of the pilot-scale study. The pilot-scale efforts showed good scope for the further expansion of the large-scale cultivation of K. alvarezii in the southwest coast of Kerala by imparting training and adopting fishermen families for their additional employment/alternative livelihood. Success in the pilot-scale cultivation led to the second phase of the project, the extension phase, which fulfilled the main objectives of the DST WOS-B programme. Vizhinjam Gramapanchayat (village), where the pilot-scale cultivation was carried out successfully and headed by a woman president, came forward to pool resources of the project to be implemented as a Model Seaweed Cultivation Programme. A training/workshop on “seaweed farming technology” was conducted and nearly 60 people were trained. Mangalam purusha sahaya sangham, a registered self-help group (SHG) of Vizhinjam, came forward to start the culture operations at Vizhinjam with technical backup from the DST-WOS-B Programme. Some seaweed entrepreneurs from inside and outside Kerala also came forward with a 100% buyback guarantee for the produce. Nationalised banks like the State Bank of India offered loans to trained SHGs for starting seaweed cultivation at commercial scale.

Seasonal Variability of Dissolved Nutrients in Mangrove Ecosystems along South West Coast of Kerala, India.

The mangroves of Kerala are fast disappearing due to developmental activities. There are very few studies conducted in the chemical aspects of these ecosystems. The main objective of this study is to assess the spatial and seasonal variation of hydrographical as well as nutrients in mangrove ecosystems along Kerala coast. Five sampling sites least intervened by industries were selected for the study. Sampling was done for a period of six months in monthly intervals. A monsoonal hike of dissolved nutrients was observed in all ecosystems except in the constructed mangrove wetland. The constructed wetland exhibited a different hydrography and nutrient level in all seasons. The mangrove forest in this area consists of the species Bruguiera gymnorrhiza which has been planted since forty years. Key words: wetlands; mangroves; nutrients; season; constructed wetland DOI: 10.3126/jowe.v3i0.2264 Journal of Wetlands Ecology, (2009) Vol. 3, pp 32-42

A new species of Pseudostomella (Gastrotricha: Macrodasyida: Thaumastodermatidae) from a sandy beach of Kerala, India

During an interstitial faunal survey along the south-west coast of Kerala, India, gastrotrich fauna were found in abundance. Together with species of the genera Xenotrichula, Halichaetonotus and Tetranchyroderma, were present several undescribed thaumastodermatid gastrotrichs belonging to the buccal palp bearing genus Pseudostomella. Adults of the new species are characterized by the following traits: total body length of about 300 μ m; cuticular armature made up of medium sized pentancres covering the entire dorsolateral surface; pre-buccal, grasping palps bearing five, large papillae dorsally and 4-6 smaller papillae ventrally; adhesive apparatus made up of six anterior, 22-24 ventrolateral, two dorsolateral and six posterior adhesive tubes; caudal organ pear-shaped; frontal organ spherical. Pseudostomella cheraensis sp. nov. is the fourth taxon of the genus known from India; however, all the previous species reported hitherto from India have tetrancres instead of pentancres.