Southwestern India Research Articles

Seasonal variation of microplastics in tropical mangrove waters of South-western India

The current study investigates the seasonal variations in microplastic (MP) contamination, specifically those ranging in size from 0.1 mm to 5 mm, within the tropical mangroves of Kota, South-western India. Mean concentrations ( ± standard deviation) of 1.42 ± 0.92 MPs/L (post-monsoon), 0.62 ± 0.38 MPs/L (pre-monsoon), and 0.19 ± 0.08 MPs/L (monsoon) were observed. Fibers emerged as the most abundant category across all samples, with a dominant size fraction of less than 1 mm. Fourier Transform Infrared Spectroscopy-Attenuated Total Reflectance (FTIR-ATR) analyses identified various polymer types, including polypropylene (PP), polyethylene terephthalate (PET), high-density polyethylene (HDPE), low-density polyethylene (LDPE), polystyrene (PS), and polyvinyl chloride (PVC). Potential sources of microplastic contamination in the region could be ascribed to tourism, marine product-related industries, prawn farming, and residents. The findings of this study offer crucial insights into the seasonal fluctuations of microplastic contamination in the Kota mangrove ecosystem.

Lithotectonic architecture of the Paleoproterozoic intracratonic Kaladgi rift basin, southwestern India: Inference from a magnetotelluric study

Peninsular India is traversed by several major Paleoproterozoic rift basins, among which the Kaladgi rift basin is a prominent one. Here, we present results from Magnetotelluric (MT) studies in the eastern section of this rift basin. The data were acquired along a ∼120 km long profile passing through Belavanik-Bagalkot-Ukkali regions covering the Paleoproterozoic intracratonic Kaladgi rift basin, the Cretaceous Deccan volcanic province and the Archean gneisses/granites/greenstones of the Dharwar craton. The lithospheric electrical structure was obtained from joint inversion of TE- and TM-modes data using a 2-D nonlinear conjugate gradient algorithm. The results reveal that the Kaladgi sediments are ∼500–1000 m in thickness overlying a highly fractured crystalline basement. Proterozoic sediments are exposed beneath the Deccan basalt cover and in the shallow fractured zones. The conductive-resistive transitions in the model at the crustal depths correspond to major tectonic faults and deformed crustal rocks. The transition boundary at ∼50 km depth defines the electrical Moho. At the same time, a ∼25 km wide, steep conductive feature from ∼75 km to upper mantle lithosphere depths (∼180–200 km) is interpreted as the trace of the Chitradurga Suture Zone (CSZ). The observed crustal heterogeneity, conductivity variations, and resistive lithosphere are attributed to the geological history of the region, including Archean collisional events and subsequent reactivation associated with the Reunion hotspot. The crustal conductors are associated with mafic intrusions from the underplated basalts, and also the high conductivity may be due to the sulfide mineralization in the fault zones. The MT study provides valuable insights into the deep tectonic framework of the region.

Heavy metals in wetlands of southwestern India: from sediments through invertebrates to migratory shorebirds

Heavy metal pollution in Indian wetlands is rising due to industrial, agricultural and urban development activities. Shorebirds occupy upper trophic levels and are therefore especially vulnerable to heavy metal pollution. We evaluated the concentration of heavy metals (zinc, copper, cobalt, chromium, lead and cadmium) in 22 common species of migrant shorebirds (220 shorebird dropping samples) with diverse foraging behaviors, in their different prey (55 prey samples) and in the sediments (90 sediment samples) in different habitat types (mudflats, mangroves and sand beaches) between 2019 and 2021. Further, we analyzed a total of 10 biofilm samples from mudflats and mangroves. We detected relatively low concentrations of heavy metals in the sediments (Zn concentration range: 9.11–40.91 mg/kg; Cu: 5.74–21.38 mg/kg; Co: 2.00–4.04 mg/kg; Cr: 4.05–41.03 mg/kg; Pb: 1.02–7.19 mg/kg; Cd: 0.56–4.35 mg/kg). However, we measured relatively high concentrations of heavy metals in invertebrate prey species (Zn concentration range: 84.72–224.74 mg/kg; Cu: 26.63–170.36 mg/kg; Co: 13.98–14.42 mg/kg; Cr: 14.78–98.16 mg/kg; Pb: 18.95–157.29 mg/kg; Cd: 9.33–60.56 mg/kg). In addition, we found high concentrations of heavy metals in shorebird droppings (Zn concentration range: 41.33–58.8 mg/kg; Cu: 31.42–52.11 mg/kg; Co: 36.34–55.68 mg/kg; Cr: 52.3–68.21 mg/kg; Pb: 25.94–43.13 mg/kg; Cd: 5.53–16.4 mg/kg). It is evident that concentration of heavy metals increased successively moving from sediment to prey to shorebird species, likely through trophic transfer. The biofilm samples contained very high concentrations of Cr, Pb and Cd (22.64, 28.09 and 18.46 mg/kg respectively) which could be harmful to biofilm grazing shorebirds. Since bioaccumulation of heavy metals entail risks in living species, we suggest that increasing concentrations may detrimentally affect physiological processes in invertebrates and shorebirds. There is an urgent need to identify the sources of pollution and to reduce the discharge of heavy metals and other pollutants into coastal and inland wetlands.

Long-term anthropogenic stressors cause declines in kingfisher assemblages in wetlands in southwestern India

Fragile wetland habitats are susceptible to multiple threats from anthropogenic activities. Direct waste deposition, habitat modification and overexploitation of fish have caused alternations in food webs in wetlands. Kingfishers are ecological indicators with the potential ability to respond to the minute changes in their microenvironment. Their abundance and distribution at wetland habitats are affected by multiple environmental factors. We studied the kingfisher assemblages in India to determine proximate and ultimate causes of their decline. We recorded the abundance of five species of kingfishers across five wetland habitats from 2011 to 2020 in Kerala, southwest coast of India. Kingfishers were counted twice in a month between 6.00 and 12.00 hrs. Air temperature, water temperature, humidity and turbidity were recorded. We measured fish diversity and abundance and organic waste as an additional explanatory variable. One-way ANOVA, Autoregressive Integrated Moving Average model and structural equation modelling were used to determine which explanatory variables affected kingfisher populations. Air temperature, water temperature and turbidity increased significantly during the study and had negative effects on the abundance of kingfishers. Humidity decreased significantly but had no effect on the kingfisher abundance. Fish abundance declined and had a strong positive effect on the abundance of kingfishers. The analysis of incidence of wastes across the study areas revealed that, all the sites were severely polluted. We also observed drastic decline in the abundance of all the species of kingfishers studied across the sites with a rapid decline in Pied Kingfisher and slower decline in White-throated Kingfisher. Black-capped Kingfisher is a local migrant to the study areas and is already red listed and categorized as Vulnerable (VU). This study suggests that kingfisher assemblages are declining along with the health status of the habitat. Urgent action is needed to help in designing and implementing effective management strategies for the sustainability of wetlands in the region.

Unveiling the molecular identity of the diminutive cyprinid, Horadandia brittani (Teleostei: Cyprinidae), a species endemic to Southern India.

Horadandia brittani is a small cyprinid fish species initially discovered in the coastal floodplains of southern India. For almost 50 years, the genus Horadandia was monotypic with a single species confined to Sri Lanka. In 1992, a new species H. brittani was described from south-western India. Despite being described as a separate species, H. brittani was later considered a synonym of H. atukorali, but in 2013, researchers recognized it as a distinct species based on morphological differences. Despite this clarification, there was still a need to validate the identity of H. brittani and determine its evolutionary relationship with its closely related species using DNA sequences. To address the uncertainties surrounding the identity of H. brittani, the present study utilized molecular techniques to generate DNA sequences. Sample collection involved obtaining specimens of H. brittani from their natural habitats. Subsequently, DNA was extracted from the collected samples, and the mitochondrial cytochrome C oxidase (COI) gene was amplified using appropriate methods. The analysis of DNA sequences obtained from the COI gene revealed significant genetic distinctions between H. brittani and H. atukorali. The genetic distance values between these two species ranged from 3.21 to 3.63%, clearly indicating that these two species are genetically separate entities. The study successfully established the phylogenetic relationships between H. brittani and H. atukorali based on the COI gene sequences, further confirming the validity of H. brittani as a distinct and separate species. The findings of this study conclusively demonstrate that H. brittani is a valid and separate species, distinct from H. atukorali. The genetic analysis based on mitochondrial COI gene sequences provided strong evidence for the differentiation between these two species. The molecular data generated in this research can be used to identify H. brittani quickly and accurately in the future.

Deep electrical structure over the Paleoproterozoic intracratonic Kaladgi rift basin in southwestern India imaged from magnetotelluric studies

The disintegration of the Columbia supercontinent during the late Paleoproterozoic generated major rift basins in the constituent continental fragments. The Kaladgi basin, located between the southern part of the Deccan volcanic province (DVP) and the northern part of the Dharwar craton, is a Columbia rift-related basin in southwestern India that preserves a complex history from initial fault-controlled mechanical subsidence during rifting, thermal subsidence along a collision zone, crustal thinning due to stretching and erosion associated with doming. The Paleoproterozoic basins worldwide show higher uranium concentration and many deposits are also established in the Purana basins of India. In the present study, the lithotectonic architecture of this basin using broadband magnetotelluric (∼320 Hz–3000 s) soundings in the western segment of the Kaladgi rift basin along two profiles. Two-dimensional (2-D) inversion of data using a 2-D nonlinear conjugate gradient algorithm along both profiles provides insights into the deeper structure of the basin. Our results reveal a thin sheet of Deccan volcanic, sedimentary successions belonging to the Badami and Bagalkot groups, and Proterozoic sediments from top to bottom beneath this basin. The crustal structure is highly heterogeneous and associated with deep-seated faults, and its thickness increases from the eastern Dharwar craton (∼30 km) to the western Dharwar craton (∼45 km). The crustal conductors are interpreted as mafic intrusions derived from the underplated basalts. The moderate conductive features may correspond to carbonate fluids trapped within the faults/fractures zone during basin initiation. The conductive features in the lower crust and the Moho are interpreted as fluids derived from underplated intrusions through plume impact. The NNW trending Chitradurga Suture Zone (CSZ) signature and the Bababudan-Nallur Shear (BNS) in the crust and upper mantle depth are imaged along both MT profiles. This study provides insights into the lithology and tectonic architecture of a long-lived rift basin involved in multiple tectonic events from the late Paleoproterozoic to the late Cretaceous.

On seven undescribed leaf insect species revealed within the recent "Tree of Leaves" (Phasmatodea, Phylliidae).

With the recent advance in molecular phylogenetics focused on the leaf insects (Phasmatodea, Phylliidae), gaps in knowledge are beginning to be filled. Yet, shortcomings are also being highlighted, for instance, the unveiling of numerous undescribed phylliid species. Here, some of these taxa are described, including Phylliumiyadaonsp. nov. from Mindoro Island, Philippines; Phylliumsamarensesp. nov. from Samar Island, Philippines; Phylliumortizisp. nov. from Mindanao Island, Philippines; Pulchriphylliumheraclessp. nov. from Vietnam; Pulchriphylliumdelisleisp. nov. from South Kalimantan, Indonesia; and Pulchriphylliumbhaskaraisp. nov. from Java, Indonesia. Several additional specimens of these species together with a seventh species described herein, Pulchriphylliumanangusp. nov. from southwestern India, were incorporated into a newly constructed phylogenetic tree. Additionally, two taxa that were originally described as species, but in recent decades have been treated as subspecies, are elevated back to species status to reflect their unique morphology and geographic isolation, creating the following new combinations: Pulchriphylliumscythe (Gray, 1843) stat. rev., comb. nov. from Bangladesh and northeastern India, and Pulchriphylliumcrurifolium (Audinet-Serville, 1838) stat. rev., comb. nov. from the Seychelles islands. Lectotype specimens are also designated for Pulchriphylliumscythe (Gray, 1843) stat. rev., comb. nov. and Pulchriphylliumcrurifolium (Audinet-Serville, 1838) stat. rev., comb. nov. from original type material.

Clinical, laboratory, and molecular epidemiology of Orientia tsutsugamushi infection from Southwestern India.

Scrub typhus is a vector borne disease which in a proportion of patients causes multiorgan involvement and death if untreated. Infecting genotype and virulence factors play a role in severity of infection and outcome. The current prospective cohort study was undertaken to elucidate the severity of illness in scrub typhus patients and to identify the circulating genotypes in Karnataka, India. A total of 214 patients of either gender from 9 districts of Karnataka and one patient each from Andhra Pradesh and Kerala, India were enrolled in the study. With a predefined severity criterion, 132 patients were segregated to the severe group. Multi organ involvement was seen in 59 (44.69%) patients. Phylogenetic analysis revealed JG-v like (48.97%), Karp-like (26.53%), JG-like (22.44%), and Kato-like (2.04%) strains in Karnataka. Patients infected with Orientia tsutsugamushi Karp-like strains had respiratory involvement (69.2%), cardiovascular involvement (46.2%) and thrombocytopenia (23.1%) and required higher hospital resource utilization.

Revision of the Western Indian Ocean Angel Sharks, Genus Squatina (Squatiniformes, Squatinidae), with Description of a New Species and Redescription of the African Angel Shark Squatina africana Regan, 1908.

Sampling efforts on the Saya de Malha Bank (part of the Mascarene Plateau, western Indian Ocean) unveiled three unusual small juvenile angel shark specimens, that were a much paler color than the only known western Indian Ocean species, Squatina africana Regan, 1908. However, it took many years before further specimens, including adults of both sexes, and tissue samples were collected. The present manuscript contains a redescription of S. africana based on the holotype and additional material, as well as the formal description of the new species of Squatina. All specimens of the new species, hereafter referred to as Squatina leae sp. nov., were collected in the western Indian Ocean off southwestern India and on the Mascarene Plateau at depths of 100-500 m. The new species differs from S. africana in a number of characteristics including its coloration when fresh, smaller size at birth, size at maturity, and adult size, genetic composition, and distribution. Taxonomic characteristics include differences in the morphology of the pectoral skeleton and posterior nasal flap, denticle arrangement and morphology, vertebral counts, trunk width, pectoral-pelvic space, and clasper size. A key to the species of Squatina in the Indian Ocean is provided.

Rock Magnetic and Mineralogical Properties of Lateritic Soil Profiles Developed on Two Different Parent Rocks in Northern Kerala, South-Western India

The rock magnetic and mineralogical properties of two lateritic soil profiles developed on two different parent rocks (khondalite and granite) in northern Kerala, south-western India were investigated to better understand pedogenic processes under tropical climate. Field investigations reveal the presence of various horizons in the lateritic profiles, such as saprolite, mottled zone, pebble horizon and top soil. The particle size, rock magnetic, Vibrating Sample Magnetometer (VSM), Scanning Electron Microscopy (SEM)-Energy-Dispersive X-ray Spectrometer (EDS) and X-Ray Diffraction (XRD) analyses were performed on samples collected from different horizons of the two profiles. Magnetic susceptibility (χlf) values of the lateritic profiles vary from 9.97 to 1717.04 x 10-8 m3 kg-1, with the granitic profile exhibiting overall higher values. The percentage frequency-dependent susceptibility (χ %) ranges between 0 % and 13.9 %. The XRD data reveal the presence of kaolinite, gibbsite (except for top soil layer) and quartz along with magnetic minerals like magnetite, hematite and goethite. The upper horizons (top-soil and pebble horizon) exhibit high values for concentration dependent magnetic parameters like χlf and χfd%, whereas, the lower horizons (saprock, saprolite, pallid zone horizons) exhibit low values. The tropical soils in the region have undergone a higher degree of pedogenesis with increased magnetic mineral concentration compared to temperate soils. The magnetic enhancement in the topsoil may be due to the neoformation of ultra fine-grained SP magnetite/maghemite (with minor anti-ferro magnetic component), aided by sufficient Fe supply, alternate wetting and drying cycles, dehydration, oxidation and redox conditions. Keywords: Lateritic Soils; Soil Magnetism; XRD; SEM; Magnetic Enhancement; Pedogenesis; Southern India

Improving Turnaround Time for the Issue of Blood Components in Case of Emergency

Background and Objectives: During a surgical or medical emergency, the timely issue of crossmatched blood is crucial for efficient and satisfactory patient revival. Turnaround time (TAT) is the duration taken from the time blood requests, and samples are received in the blood center until the blood is crossmatched and available for blood transfusion. The study aimed to audit the TAT in our center, analyze and study the factors delaying TAT, and formulate plans to improve it by implementing corrective measures. These actions would directly or indirectly impact the outcomes of the delivery of patient care in emergency services. Methods: A record-based prospective study was performed in a tertiary care teaching hospital with trauma and all emergency services in Southwestern India. TAT was calculated for all emergency blood requests received over 16 months in a systematic sampling method. Cases with prolonged TATs, where the product issue TAT exceeded the internal policy and quality indicator standards (15 min for emergency packed red blood cells issue), were further evaluated for causes of delay and analyzed at frequent intervals. Results: The mean TAT at the start of the study was 17.1 min (standard deviation [SD] 1.05 min), gradually reducing to 14.9 min (SD 0.62 min) by the end of the study, and it was statistically significant with P = 0.01. Conclusion: It is essential to deduce the causes for delayed TAT and work on those variables amenable to modifications based on priority to improve the TAT regarding pretransfusion testing and the issue of blood products, which is crucial in emergency services.

Geoelectrical and hydrochemical characteristics of a shallow lateritic aquifer in southwestern India

• The resistivity values of 50-200 Ω·m in second layer denote the groundwater zone. • The chemical parameters and elements except pH are within BIS and WHO standards. • The groundwater samples belong to Ca-Mg-Cl and Na-Cl type hydrochemical facies. Laterites are one of the important aquifers in the southwestern Indian region, which exhibit declining water levels and acute water shortage during the summer season. In this context, a micro-level study was conducted through vertical electrical sounding (VES) and chemical analyses to assess the characteristics and hydrochemistry of shallow lateritic aquifers of northern Kerala. The VES data indicate the presence of three layers in most of the study area with a H-type curve. The three layers include (1) dry topsoil and/or hard, unsaturated laterite of high resistivity (687-1200000 Ω·m), (2) porous, soft lateritic layer saturated with water exhibiting low resistivity (55.5-1374 Ω·m), (3) hard rock with the highest resistivity (8186-1600000 Ω·m). The resistivity values of 50 to 200 Ω·m are assumed to indicate the presence of groundwater in the region. The groundwater is present in the second layer (6 to 60 m thick) of weathered laterite at a depth ranging from 4.4 to 57.7 m. The spatial distribution maps of various resistivity layers indicate that the northern and north-western parts of the study area are favourable for groundwater exploration through open wells. The interpretations based on resistivity data are corroborated by the depth to water table map prepared from water level data of open wells in the region. The geochemical analysis indicates that the groundwater in the lateritic aquifers is slightly acidic in nature. The cation and anion concentration in most of the samples follow the order Na + > Mg 2+ > K + and HCO 3− > Cl − > SO 4 2− respectively. However, all chemical parameters except pH and elemental concentrations are within the standards of the World Health Organization (WHO) and Bureau of Indian Standards (BIS) for drinking purposes. The groundwater samples in the area predominantly belong to Ca-Mg-Cl (Mixed type) and Na-Cl type hydrochemical facies. The US salinity diagram indicates that all the groundwater samples belong to the category of low salinity and low sodium hazard. The ions in the groundwater mostly originate from rock-water interaction and a few samples belong to the category of precipitation dominance. However, the type of parent rock does not exhibit a significant relationship with groundwater chemistry. The study also highlights the usefulness of electrical resistivity methods for the characterization of shallow lateritic aquifers and assessing the depth of groundwater occurrence in the region.

A first report on the spatial and temporal variability of microplastics in coastal soils of an urban town in south-western India: Pre- and post-COVID scenario

We present a first study on the temporal changes (2019–2021) in the microplastic abundance in the coastal soils of an urban town in the south-western part of India. All sampling stations exhibited higher abundances of microplastics in soils collected during 2021 (959.7 ± 277.7 particles/kg) compared to those collected in 2019 (515.1 ± 182.7 particles/kg). Morphologically, flakes, fibres, and films are the most abundant types documented in the soil environment. The microplastics of 0.3–5 mm size are relatively more abundant (60.6 %) compared to those of 0.03–0.3 mm size (39.4 %) in 2021. The three main types of polymers (polypropylene and high- and low-density polyethylene) in the soil exhibited an increase in abundance during an interval of 15 months (October 2019 to March 2021). In addition to packaging materials, the enhanced use of surgical masks during the COVID-19 period might have acted as a source of microplastic contamination in the soils.

A new subspecies of Caltoris Swinhoe, 1893 (Lepidoptera, Hesperiidae) from the Malabar Coast, Kerala, India

The Indo-Australian genus Caltoris has over 15 species distributed from India through south China and SE Asia into New Guinea and Solomon Islands. Based on wing colouration, characters of male genitalia, and early larval stages on the host plant Phragmites karka, a new subspecies of Caltoris bromus (Leech, 1894), Caltoris bromus sadasiva ssp. nov., is described from the coastal lakes and mangrove associated swamps of Kerala, southern India on the western slopes of the Western Ghats. This is the first record of C. bromus from Western Ghats and Peninsular India. This extends the distribution range of the species from NE India to south-western India, adding it to the butterfly fauna of the Western Ghats.

A New Spotted Species of the Cyrtodactylus (Geckoella) collegalensis (Beddome, 1870) (Reptilia: Squamata) Complex from Coastal Kerala, Southwestern India

We describe a new spotted species of ground-dwelling gecko of the genus Cyrtodactylus (Geckoella) from coastal Kerala, southwestern India, by using an integrative taxonomic approach. The new species is a member of the C. collegalensis species complex, with 10.0–13.5% uncorrected mitochondrial sequence divergence from the other six members of the C. collegalensis complex. The new species is also recognized in tree-based delimitation methods and can be morphologically diagnosed by a spotted dorsal pattern of four to six pairs of spots (occasionally fused into figure 8–shaped markings) from the banded species C. speciosus, C. rishivalleyensis, and C. yakhuna and from the spotted C. collegalensis, C. srilekhae, and C. varadgirii by the presence of a few scattered enlarged dorsal scales. This is the only Indian member of the C. collegalensis complex with a relatively broad distribution at low elevations, other than C. varadgirii from western India (distributed in Maharashtra, southern Gujarat, and western Madhya Pradesh). The sister species to the new species is the Sri Lankan C. yakhuna, which is a banded form from low elevations. The new species is the second gecko to have been described from Chengodumala and endemic to northern and central Kerala, highlighting the importance of this area, which is under increasing anthropogenic pressure. We also provide notes on the dorsal pholidosis of C. rishivalleyensis, which was overlooked in its original description.

Seasonality in groundwater recharge in Coastal Southwestern India and its hydrological implications based on stable isotopes (δ18O, δD)

This study observes and interprets the spatio-temporal variation in the oxygen and hydrogen isotopic composition (δ18O, δD) of shallow groundwater in the Southwestern Coastal state of India, Kerala, in terms of seasonally varying rainfall, physiography, and hydrogeological settings of this region. This study identifies effective groundwater recharge sources and their relative contributions and provides first-order estimates of submarine groundwater discharge by interpreting the spatio-temporal variations in the stable isotopes of oxygen and hydrogen in groundwater, collected from 225 locations for pre-monsoon and post-monsoon seasons in conjunction with the isotopic composition of rainfall. Spatio-temporal variations in the δ18O and d-excess, with other hydrogeological data, reveals that: (1) ∼4.9 Billion Cubic Meter (BCM) of fresh water from rainfall during May to October mixes with ∼5.9 BCM of residual pre-monsoon groundwater across Kerala. (2) ∼ 11% area of Kerala is additionally recharged by the NE monsoon rainfall. (3) The annual groundwater recharge varies physiographically from ∼2.2 BCM in the lowland to ∼1.5 BCM in the midland and ∼1.2 BCM in highland regions. (4) On an annual basis, 41% of replenishable groundwater is drained as SGD into the Arabian Sea.

Large submarine groundwater discharges to the Arabian Sea from tropical southwestern Indian Coast: Measurements from seepage meters deployed during the low tide

Submarine Groundwater Discharge (SGD) is the flow of fresh groundwater and recirculated seawater to the sea. SGD plays a crucial role in the transport of solute-rich terrestrial groundwater as well as recirculated seawater. We conducted seasonal investigations for two years on a tropical, high-rainfall occurring coastline in southwestern India to quantify the SGD from the nearshore. A combination of subsurface seepage meters and porewater samplers was used for an entire tidal cycle to estimate the seepage rates and to understand the processes controlling the discharge. The estimated seepage rates from this region are one of the highest reported in the world. This could be due to the large span of the highly porous coastal aquifer and the high annual rainfall (over 450 cm) in this region. The seepage rates are 754 cm/day, 572 cm/day and 296 cm/day for the pre-monsoon (February 2020), post-monsoon (December 2020) and pre-monsoon (February 2021) seasons, respectively and showed high spatial and temporal variability. The end-member concentrations of groundwater and seawater were used to delineate the fresh and recirculated SGD from the total seepage. The recirculated SGD (rSGD) dominates during all the seasons taking up to 99 % of the total SGD during the pre-monsoon seasons (February) and 70 % during the post-monsoon (December) season. The fresh SGD (fSGD) is low (∼1 %) during the pre-monsoon season and increases up to 30 % during the post-monsoon. A considerable amount (0.1–10 % of the total SGD) of salinity enrichment was observed at the upper saline plume. We suspect this could be due to the evaporation of recirculated seawater due to ambient weather conditions. The fSGD in the study area is mainly controlled by the high inland hydraulic head, and the rSGD is regulated by the tides. The subsurface seepage meters used in this study eliminate the instabilities in seepage measurements and can be replicated in less-studied tropical coastal zones to quantify the volume of SGD entering the world oceans. The inferences reported can benefit the public and decision-makers in managing coastal groundwater resources and are interesting to the researchers working on delineating the hydrological and geochemical processes in the nearshore.

Early Miocene (Burdigalian) Dinoflagellate Cysts from the Kerala Basin, Southwest India: Indicators of Marine Ingression at the Onset of the Mid-Miocene Climate Optimum (MMCO)

Abstract In the present study, the assemblages of organic walled dinoflagellate cyst (dinocysts) and calcareous nannofossils from Quilon Formation, Kerala Basin, south-western India are analyzed for age interpretation and reconstruction of the depositional environment. The integrated biostratigraphy based on dinocysts and calcareous nannofossils from the same sediment samples indicates that the studied succession was deposited during the early Miocene (middle Burdigalian, ~19-17.5 Ma) time. The dinocyst assemblages contain abundant taxa (Cleistosphaeridium, Polysphaeridium, Lingulodinium, Homotryblium and Spiniferites) that range from shallow inner to outer neritic marine zone. The abundance of autotrophic, thermophilic taxa suggests relatively high surface water temperatures and high nutrient availability. The dinocyst assemblage in the lower part of the studied succession is dominated by Cleistosphaeridium spp., Polysphaeridium spp., Spiniferites spp., Homotryblium spp. and Lingulodinium spp. An increase in the relative abundances of outer neritic dinocyst taxa such as Spiniferites, Achomosphaera and Hystrichokolpoma in the upper part of the succession suggests a change towards more open marine conditions created during marine ingression. The interpreted marine ingression along the south-western Indian coast probably corresponds to the initial small pulses of transgression at the onset of the long-term global sea-level maximum related to the Mid-Miocene Climatic Optimum (MMCO).

Food and feeding strategies of the deep-sea shrimpHeterocarpus woodmasoni, Alcock 1901 (Decapoda: Pandalidae) from southwestern India

AbstractDiet composition and feeding strategies of deep-sea caridean shrimp Heterocarpus woodmasoniAlcock,1901 are described from gut contents of 4,116 specimens collected from the southwestern coast of India. Knowledge of the species diet plays a prime effect on its biological aspects and its role in the ecological energetics of the community. All the analyses were performed in accordance with ecological (season) and biological factors (sex, size, and gonadal stages). The species was found to prey on diversified components such as detritus, foraminiferans, other crustaceans, molluscs, echinoderms, and fishes in their declining order of preponderance. Multivariate analysis of variance showed a significant difference (P<0.05) in the diet components according to the combination of sex along with season and gonadal stages. Values of the gastro-somatic index (GSI) showed a positive correlation with feeding activity, and its intensity. GSI, feeding intensity, and activity reached their peak values during the post-monsoon season. High vacuity index was recorded in almost all conditions, which is a highlighted feature of this species. These observations provide fundamental information on the feeding pattern of H. woodmasoni, which aims to develop suitable fishing strategies in the future.

Dulong People's Traditional Knowledge of Caryota obtusa (Arecaceae): a Potential Starch Plant with Emphasis on Its Starch Properties and Distribution Prediction.

The greatest global challenge is to ensure that all people have access to adequate and nutritious food. Wild edible plants, particularly those that provide substitutes for staple foods, can play a key role in enhancing food security and maintaining a balanced diet in rural communities. We used ethnobotanical methods to investigate traditional knowledge on Caryota obtusa, a substitute staple food plant of the Dulong people in Northwest Yunnan, China. The chemical composition, morphological properties, functional, and pasting properties of C. obtusa starch were evaluated. We used MaxEnt modelingto predict the potential geographical distribution of C. obtusa in Asia. Results revealed that C. obtusa is a vital starch species with cultural significance in the Dulong community. There are large areas suitable for C. obtusa in southern China, northern Myanmar, southwestern India, eastern Vietnam, and other places. As a potential starch crop, C. obtusa could substantially contribute to local food security and bring economic benefit. In the future, it is necessary to study the breeding and cultivation of C. obtusa, as well as the processing and development of starch, to solve long-term and hidden hunger in rural areas.