Patterns and variability in the microplastic contamination along the southwest coast of India with emphasis on submarine groundwater discharge sites.

Beach sediments of the southwest coast of India were analysed to estimate the microplastic contamination with emphasis on the submarine groundwater discharge (SGD) zones. Both SGD and non-SGD sites were assessed for abundance, morphotype and polymer type of microplastics. Microplastic load was 230.429 ± 62.87 particles per 100 g. Fibre, mainly blue, was the abundant morphotype, followed by fragment, foam and film. The polymer types were POLYETHYLENE (PE) (30.77 %), POLYPROPYLENE (PP) (26.92 %), POLYAMIDE (PA) (19.23 %), POLYSTYRENE (PS) (11.54 %), ETHYLENE VINYL ACETATE (EVA) (7.692 %) and POLYVINYL CHLORIDE (PVC) (3.846 %). The SGD zones exhibited higher microplastic contamination with statistically significant variations from non SGD sites. The study accounts the levels of microplastic contamination along the southwest coast of India, a major fishery zone. The higher abundance of microplastic in the SGD zones indicates the significance of subterranean groundwater through flow as a pathway of anthropogenic contaminants towards marine ecosystems.

The seasonal distribution and pollution potential of dissolved heavy metals and nutrients in subterranean estuaries in southern India.

In order to better understand the distribution pattern, pollution degree and the submarine groundwater discharge (SGD) of dissolved heavy metals, 15 subterranean estuaries (STEs) along southwest Indian coast were sampled over three contrasting seasons. The average concentration of metals were ranked as, pre-monsoon > monsoon > post-monsoon with 3 to 12-fold higher groundwater metal concentrations than the adjacent seawater. Average SGD derived essential metal fluxes were five times higher than the toxic metal fluxes of which Fe and Zn together contributed >90 %. Using the Single Factor Contamination Index, the majority of sites were minimally contaminated with only two sites indicating moderate ecological risk due to As. Higher fluxes of Fe, Cu and Zn were likely a result of rising anthropogenic activities. The SGD derived nutrient fluxes were an important source of DIP for primary production in coastal waters and represented 30 % and 44 % of the DIN and DIP inputs respectively.

A new species of Batillipes (Arthrotardigrada: Batillipedidae) from the mid littoral zone of the southeast coast of India.

Studies of marine tardigrades from Indian waters is very limited and relatively obscure. A new species of marine tardigrade is described from the southeast coast of India as part of an effort to better understand the marine tardigrade biodiversity of the Indian subcontinent. Batillipes kalami sp. nov. described from the sandy sediments of the mid littoral zone can be differentiated from all its congeners by the presence of unconstricted primary clavae, two pairs of lateral body projections between leg II and leg III, long and blunt ended lateral body projections between leg III and leg IV, shape of leg IV sensory organs and the presence of dorsal indentations in its head.

A new Tardigrade species, Stygarctus keralensis sp. nov. (Arthrotardigrada: Stygarctidae) from the intertidal zone of Southwest coast of India.

Stygarctus keralensis sp. nov. (Arthrotardigrada: Stygarctidae), is described from the intertidal sandy sediments of Vadakara beach, Kerala, Southwest coast of India. To a certain extent, this new species shows morphological similarity with Stygarctus gourbaultae Renaud-Mornant, 1981, however it can be differentiated by some significant distinguishable characters like double looped seminal receptacle ducts and the presence of a bow shaped internal thickening in between the opening of seminal receptacles situated below the level of gonopore and above the anus; unsculptured body plates I-III; paired sub-cephalic pore/muscle attachment; shape and structure of caudal processes. Presence of minute spikes on third lateral processes in the new species is another unique character by which it can be easily differentiated from S. gourbaultae.