Confirmation of pygmy sperm whale, Kogia breviceps from Palk Bay, India through Cytochrome Oxidase1 (COI) sequence

The identity of a stranded cetacean from the Palk Bay has been confirmed as a pygmy sperm whale (Kogia breviceps) by the partial sequencing of mitochondrial gene cytochrome oxidase subunit-I (COI). The specimen was unambiguously discriminated from the COI sequence of Kogia sima by matching exactly with the sequence of K. breviceps. Stranding events of the pygmy whales are considered to be uncommon. The sequence developed for K. breviceps is the first of its kind attempt from Indian waters.

Sources, spatial distribution, and abundance of marine debris on Thondi coast, Palk Bay, Southeast coast of India

Background The Thondi coast is rich in valuable natural marine resources and socio-economically significant activities like agriculture, aquaculture, and fishing. The area receives an excess of untreated solid and liquid waste as a result of these activities. The study focuses on the abundance, distribution, and status of the Clean-Coast Index (CCI) of marine debris from the Thondi coast, Palk Bay, Southeast coast of India. This is the first research work focused on assessing the type and quantity of marine debris on the Thondi coast. Results A total of 1636 marine debris items/m2 and their 4.09 concentration of the items/m2 were determined in the marine debris: plastics (77.49%), cotton swabs (8.62%), cigarette butts (10.15%), and food containers (3.73%). From the result, the CCI had ranged between 4.25 (clean) and 20.4 (extremely dirty) with a mean of 8.92 (moderate) in the Thondi coast assessed. Conclusion This study was conducted for the first time in this region. Finally, the high CCI value of 20.4 on the coast indicated that the marine debris pollution levels were high at the time of sampling in the middle part of the Thondi coast (most of the beaches are covered with plastic) due to land-based marine debris (62.45%), sea-originated marine debris (21.14%), and unknown sources (16.41%) of the items. Our findings served as a baseline for potential evaluations of the marine environment. Input prevention should be the goal of management efforts, including proper waste management, plastic recycling, and stringent penalties for illegal waste dumping.

Sources, spatial distribution and abundance of marine debris on Thondi coast, Palk Bay, Southeast coast of India

Background: The Thondi coast is a rich source of valuable natural marine resources, as well as many socioeconomically significant activities like agriculture, aquaculture, and fishing. The area receives an excess of untreated solid and liquid waste as a result of these activities. The study focus on the abundance, distribution, and status of the Clean - Coast Index (CCI) of marine debris from the Thondi coast, Palk Bay, Southeast coast of India. This research was the first to assess the type and quantity of marine debris on the Thondi coast. Results: A total of 1636 marine debris items/m2 and 4.09 density of the items/m2 were determined in the marine debris: plastics (77.49%), cotton swabs (8.62%), cigarette butts (10.15%), and food containers (3.73%). From the result, the CCI is ranged between 4.25 (clean) and 20.4 (extremely dirty) with a mean of 8.92 (moderate) in the Thondi coast assessed. Conclusion: These studies were conducted for the first time in this region. Finally, the high CCI value of 20.4 in the coast indicates that the marine debris pollution levels are high at the time of sampling in the middle part of the Thondi coast (most of the beach is covered with plastic) due to land – based marine debris (62.45%), sea – originated marine debris (21.14%) and unknown sources (16.41%) of the items. Our findings serve as a baseline for potential evaluations of marine environments. Input prevention should be the goal of management efforts, which include proper waste management, plastic recycling, and stringent penalties for illegal waste dumping.

Heavy metal pollutants and their spatial distribution in surface sediments from Thondi coast, Palk Bay, South India

Background The concentration of heavy metals and their spatial distribution in surface sediments collected from the Thondi coast, Palk Bay, South India were analysed in this study. The sediment grain size, pH, EC, and major elements (Fe, and Al), heavy metal concentrations (Mn, Cr, Zn, Cd, Ni, Cu, and Pb) were determined and the values for the geoaccumulation index (Igeo), enrichment factor (EF), potential contamination index (Cp), potential ecological risk index (RI), contamination factor (CF), modified contamination degree (mCd), degree of contamination (Cd), and potential contamination factors (Cp) were calculated based on their background values to determine the pollution level of the study area. Multivariate analysis such as Pearson’s correlation coefficient, principal component analysis/factor analysis (PCA/FA), cluster analysis, and regression analysis are a versatile method for identifying heavy metal sources and determining the relationship between pollutants in marine sediment. Results The pollution indices, namely EF, CF, Cd, mCd, CP, RI, and Igeo, revealed that the heavy metal contamination was due to Cd, while a moderate level of contamination was caused by Cu, Zn, Pb, and Cr. The principal component analysis and correlation matrix analysis showed a strong positive loading for Cd due to its high level of contamination in the study area. Anthropogenic inputs such as municipal wastewater, domestic sewage discharge, fishing harbour activities, and industrial and aquaculture wastes led to the increased Cd concentration in the study area. Moreover, the pollution load index revealed that the sediments were polluted by heavy metals. Conclusion The findings of this study revealed that the increased concentration of heavy metals in the study area increases the toxicity in the marine environment, thus affecting the ecosystem.

Marine mammal strandings in the northern Palk Bay from 2009 to 2020

Globally, the marine mammal population has been under threat due to various human activities. Data on stranding of these animals that are important for effective conservation planning and management, however, are not available in most of the developing countries. This paper presents observations on marine mammal strandings in northern Palk Bay, the southeastern coast of India over the last decade. In total, 21 stranding events consisting of 23 marine mammals were observed from 2009 to 2020. These stranded mammals include a Humpback Dolphin, a Blue Whale, two Finless Porpoises, and 19 Dugongs. The evident reason for the death of the dugongs and the porpoise being fishing activities, regulations on fishing practices, and intensive monitoring of the existing dugong population and their habitats are necessary. This study recommends for establishment of conservation reserve, and setting up district-level marine mammal rescue and release units in Nagapattinam, Tiruvarur, Thanjavur, Pudukkottai, and Ramanathapuram districts, comprising fishers and line departments. These units need to be sufficiently equipped in terms of equipment and infrastructure, and periodical technical training and workshops on marine mammal rescue and release procedures to quickly respond and handle marine mammal strandings in the area.

AHL-Lactonase Producing Psychrobacter sp. From Palk Bay Sediment Mitigates Quorum Sensing-Mediated Virulence Production in Gram Negative Bacterial Pathogens

Quorum sensing (QS) is a signaling mechanism governed by bacteria used to converse at inter- and intra-species levels through small self-produced chemicals called N-acylhomoserine lactones (AHLs). Through QS, bacteria regulate and organize the virulence factors’ production, including biofilm formation. AHLs can be degraded by an action called quorum quenching (QQ) and hence QQ strategy can effectively be employed to combat biofilm-associated bacterial pathogenesis. The present study aimed to identify novel bacterial species with QQ potential. Screening of Palk Bay marine sediment bacteria for QQ activity ended up with the identification of marine bacterial isolate 28 (MSB-28), which exhibited a profound QQ activity against QS biomarker strain Chromobacterium violaceum ATCC 12472. The isolate MSB-28 was identified as Psychrobacter sp. through 16S-rRNA sequencing. Psychrobacter sp. also demonstrated a pronounced activity in controlling the biofilm formation in different bacteria and biofilm-associated virulence factors’ production in P. aeruginosa PAO1. Solvent extraction, heat inactivation, and proteinase K treatment assays clearly evidence the enzymatic nature of the bioactive lead. Furthermore, AHL’s lactone ring cleavage was confirmed with experiments including ring closure assay and chromatographic analysis, and thus the AHL-lactonase enzyme production in Psychrobacter sp. To conclude, this is the first report stating the AHL-lactonase mediated QQ activity from marine sediment bacteria Psychrobacter sp. Future work deals with the characterization, purification, and mass cultivation of the purified protein and should pave the way to assessing the feasibility of the identified protein in controlling QS and biofilm-mediated multidrug resistant bacterial infections in mono or multi-species conditions.