New records of brittle stars (Echinodermata: Ophiuroidea) from the Lakshadweep atolls, northern Indian Ocean, with notes on Indophioderma ganapatii Sastry, Marimuthu amp; Rajan, 2019.

The paper presents three new records of brittle stars for Indian waters, collected from the Lakshadweep atolls (northern Indian Ocean)-Ophiarachnella septemspinosa (Müller Troschel, 1842), Ophiocoma cynthiae Benavides-Serrato O'Hara, 2008 Ophiomoeris obstricta (Lyman, 1878). Further, this paper also discusses the validity of two recently described taxa from this archipelago, the genus Indophioderma with the species Indophioderma ganapatii Sastry, Marimuthu Rajan, 2019. A checklist of brittle stars reported so far from the Lakshadweep Islands is provided, which includes 40 valid species-32 from shallow (reef) areas and 8 deep-sea (>200m) species.

Microbial diversity from the continental shelf regions of the Eastern Arabian Sea: A metagenomic approach.

The marine microbiome is a complex and least-understood habitat, which play a significant role in global biogeochemical cycles. The present study reported the culture-independent assessment of microbial diversity from the Arabian Sea (AS) sediments (from Gujarat to Malabar; at 30 m depth) by using metagenome sequence analysis. Our results elucidated that bacterial communities in the Malabar coastal region are highly diverse than the Gujarat coast. Moreover, Statistical analysis (Spearman rank correlation) showed a significant correlation co-efficient value (r = P < 0.001) between microbial communities and physicochemical parameters (salinity and dissolved oxygen) in the water column. A total of 39 bacterial phyla were recorded from the eastern side of AS, of which six phyla Proteobacteria, Bacteroidetes, Actinobacteria, Cyanobacteria, Firmicutes, and Planctomycetes were found to be the most dominant group. The most dominant genus from Valapad region (Malabar Coast) was found to be Halomonas sp., while other regions were dominated with Psychrobacter pulmonis. The subsequent Principal Coordinate Analysis (PCoA) showed 99.53% variance, which suggests that, highly distinct microbial communities at Valapad (Malabar Coast) sampling location than other sites. Moreover, the microbial metabolic activity analysis revealed the important functions of microbial communities in the AS are hydrocarbon degradation, polymer degradation, nutrient oxidation and sulphate reduction (biodegradation process). Further extended studies are needed to be carried out for better understanding the functional diversity of microbial communities from the marine sediments.

Polyclad fauna of Agatti Island, Lakshadweep, India: new records and description of two new species.

The present paper deals with the first study of polyclad fauna from Agatti Island, Lakshadweep. Through this study, Pseudobiceors apricus, Pseudobiceros hymanae and Pseudoceros bolool are recorded for the first time from Lakshadweep waters while Pseudoceros bicolor is recorded for the first time from Indian waters. Description of two new species, Pseudoceros agattiensis sp. nov. and Pseuodoceros stellans sp. nov. is also provided with good quality photographs of external and internal details. Pseudoceros agattiensis sp. nov. is characterized by a brown to black background colour, with minute white spots, marginal band thick and black with minute white spots present at very edge of the margin, three dorsal longitudinal white bands, out of which, two are laterally branched. Pseudoceros stellans sp. nov. displays a brown background colour with a black marginal band and completely covered with lighter microdots and a unique pattern of white dorsal blotches. This study adds to the knowledge of Indian polyclads, which are still an understudied group from Indian waters.

Periclimenella agattii sp. nov., a new Palaemonid shrimp (Crustacea, Decapoda, Palaemonidae) from Lakshadweep Islands, India.

The recent collection of Palaemonid shrimps from Agatti Island, Lakshadweep, Arabian Sea, have provided further additions to the Indian marine fauna. In the manuscript, a new species, Periclimenella agattii sp. nov. is described and illustrated. The new species is morphologically most similar to P. spinifera among other congeners, but it strongly differs from that species by having upper the antennular flagellum with 14-16 segments, short free ramus with 12-13 segments, lower antennal flagellum thin and bearing 35-37 segments; 4 minute lateral spines on basal segment of 3rd maxilliped; male palm:carpus ratio of second pereopod higher than in female, propodus of 3rd pereopod with 7-8 ventral spines and hepatic spine with groove. Genetic analysis using the mitochondrial COI and 16S rRNA genes sequences proved that, the new species is significantly distinct from the closed related species.

Remote sensing of bacterial response to degrading phytoplankton in the Arabian Sea.

A remote sensing technique has been developed to detect physiological condition of phytoplankton using in situ and moderate imaging spectroradiometer (MODIS)-Aqua data. The recurring massive mixed algal bloom of diatom and Noctiluca scintillans in the Northern Arabian Sea during winter-spring was used as test bed to study formation, growth and degradation of phytoplankton. The ratio of chlorophyll (chl) to particulate organic carbon (POC) was considered as an indicator of phytoplankton physiological condition and used for the approach development. Algal blooms represent the areas of new production, and therefore, knowledge of their degradation is important to the study microbial loop and export carbon flux. Relation of chl/POC ratio with bacterial abundance revealed Gaussian distribution. Bacteria were strongly correlated with POC, and hence, the latter which is available from satellite data could be used as a proxy for remote assessment of bacteria. Thresholds for active and degrading phytoplankton were determined using the ratio computed from the satellite data. The criteria were implemented on MODIS data to generate an image representing distribution of degrading algal bloom. Bacteria abundance data from two validation cruises during dinoflagellate and cyanobacteria bloom confirmed well match up of phytoplankton degradation information from the satellite. Comparison of environmental parameters during decay phase of dinoflagellate (N. scintillans bloom (winter) and Trichodesmium bloom (summer) revealed that degradation after active Trichodesmium bloom was more severe as compared to the N. scintillans. The present study also highlights the prediction capability of phytoplankton degradation using a time series of satellite retrieved chlorophyll/POC images.