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Among the diverse Vibrio spp. autochthonous to coastal ecosystems, V. cholerae, V. fluvialis, V. vulnificus and V. parahaemolyticus are pathogenic to humans. Increasing sea-surface temperature, sea-level rise and water-related disasters associated with climate change have been shown to influence the proliferation of these bacteria and change their geographic distribution. We investigated the spatio-temporal distribution of Vibrio spp. in a tropical lake for 1 year at a 20-day interval. The abundance of Vibrio spp. was much higher during the south-west monsoon in 2018, when the lake experienced a once-in-a-century flood. The distribution of Vibrio spp. was influenced by salinity (r = 0.3, p < 0.001), phosphate (r = 0.18, p < 0.01) and nitrite (r = 0.16, p < 0.02) in the water. We isolated 470 colonies of Vibrio-like organisms and 341 could be revived further and identified using 16S rRNA gene sequencing. Functional annotations showed that all the 16 Vibrio spp. found in the lake could grow in association with animals. More than 60% of the isolates had multiple antibiotic resistance (MAR) index greater than 0.5. All isolates were resistant to erythromycin and cefepime. The proliferation of multiple antibiotic-resistant Vibrio spp. is a threat to human health. Our observations suggest that the presence of a diverse range of Vibrio spp. is favoured by the low-saline conditions brought about by heavy precipitation. Furthermore, infections caused by contact with Vibrio-contaminated waters may be difficult to cure due to their multiple antibiotic resistances. Therefore, continuous monitoring of bacterial pollution in the lakes is essential, as is the generation of risk maps of vibrio-infested waters to avoid public contact with contaminated waters and associated disease outbreaks. [ABSTRACT FROM AUTHOR]

In the absence of an effective vaccine or drug therapy, non-pharmaceutical interventions are the only option for control of the outbreak of the coronavirus disease 2019, a pandemic with global implications. Each of the over 200 countries affected has followed its own path in dealing with the crisis, making it difficult to evaluate the effectiveness of measures implemented, either individually, or collectively. In this paper we analyse the case of the south Indian state of Kerala, which received much attention in the international media for its actions in containing the spread of the disease in the early months of the pandemic, but later succumbed to a second wave. We use a model to study the trajectory of the disease in the state during the first four months of the outbreak. We then use the model for a retrospective analysis of measures taken to combat the spread of the disease, to evaluate their impact. Because of the differences in the trajectory of the outbreak in Kerala, we argue that it is a model worthy of a place in the discussion on how the world might best handle this and other, future, pandemics. [ABSTRACT FROM AUTHOR]

Comparison of chlorophyll data of three sets of CMIP5 models for RCP 4.5 (MPI-ESM-MR, HadGEM2-ES and GFDL-ESM2M) and RCP 6.0 (IPSL-CM5A-LR, HadGEM2-ES and GFDL-ESM2M) were done with satellite derived data (OC-CCI) for the period of 1998–2017 along four Indian coastal regions. The monthly, yearly and zone-wise seasonal comparison between model and satellite data were carried out. Analysis of monthly variations of chlorophyll during 1998–2017 reveals that the satellite data show maximum value of 0.53 mg/m3 in September, whereas all other models show maximum in August. Yearly analysis indicates maximum satellite data in the year 2004, while minimum was observed in 2015. HadGEM2-ES exhibited maximum model value and the lowest was found for IPSL-CM5A-LR. It was observed that the maximum chlorophyll value of 2.56 mg/m3 for satellite data was in the monsoon season and the lowest value of 0.14 mg/m3 was in the pre-monsoon. Seasonal analysis reveals no clear match among model and satellite values in any of the coastal regions. In northwest and northeast regions, the satellite values were found higher than the model values in most of the years, whereas in other regions, the model values were found fluctuating with the satellite values. Owing to the mismatch of the model and the satellite values, the work cautions to apply biases or corrections on usage of RCP model data for regional marine climate change research. Research Highlights: Regional and seasonal chlorophyll variations for Indian coastal regions were elucidated for three decades from CMIP5 models and satellite derived data and compared. The northwest region of India exhibits maximum chlorophyll values and variations compared to the southern coasts. The discrepancies among satellite and model chlorophyll data were evidenced from the respective shift of chlorophyll maximum values from September to August. The research emphasis the need to apply necessary bias corrections in regional marine climate forecasts. [ABSTRACT FROM AUTHOR]

Globally, marine fisheries sector provides livelihood, food security and employment to the fishers engaged in subsistence, artisanal and industrial fishing activities. The dependency on marine fish supplies keeps rising globally leading to intense competition, fishery conflicts and unsustainable fishing practices which threatens the sustainability and leading to the depletion of marine fishery resources. Andaman and Nicobar Islands (ANI) in India is a tropical archipelago cited as an example where marine fishery resources were considered to be highly underutilized vis-a-vis the harvestable potential. Developmental plans often envisage the enormous scope to harness the oceanic fishery resources however, the overriding issues which affect the sustainable fishery management were least understood or addressed. Offshore fisheries were trade and economy based whereas small scale fisheries are livelihood and food security-based, operating with small to medium scale commercial prospects. Radical management approaches in artisanal and industrial fisheries is essential to foster community resilience and sustainable fishery management. The emerging body of evidence suggests the critical need to reliably estimate the fish catches and population dynamics for sustainable fisheries management. Comprehensive opinions on prevailing issues, complexities in governance, challenges faced and the management strategies that need to be adopted were discussed to ensure the robust governance and sustainability of marine fisheries sector. [ABSTRACT FROM AUTHOR]

This study presents the structural characteristics and regeneration potential of mangrove patches in the estuarine and coastal areas of Kerala, a tropical maritime state in India. Field surveys were carried out at 46 selected sites during August 2015 to May 2016. In each site, the vegetative structure and regeneration status were assessed using the quadrat method. Altogether 219 quadrates were laid out and a total of 13 true mangrove species, belonging to 5 families and 8 genera, were recorded. The total tree density and stand basal area of the study region was 1678.08/ha and 20.33 m2/ha respectively. The low basal areas indicate the reduced structural development in mangroves. Of the 13 tree species, Avicennia constitutes 56% of the total Important Value Index (IVI) and Avicennia officinalis represents 41% of the IVI in Kerala, followed by Avicennia marina (15%), Rhizophora mucronata (15%), Sonneratia alba (8%) Rhizophora apiculata (7%) and Excoecaria agallocha (7%). The diameter at breast height (DBH) in the study area revealed that 47% of the tree species came under the 1-10 cm DBH class. Total sapling and seedling density in Kerala was 2238.35 and 3232.42 individuals/ha respectively. Density of young plants (seedlings + saplings) was only 31% greater of tree density and varied from 3-63%, which indicates poor regeneration potential. The Maturity index value (MIV) and complexity index (Ic) value of mangroves were 18.30 and 109.81 respectively. However, the low Ic value (< 10) observed in seven out of ten coastal districts indicated poor structural development of mangroves in Kerala. Therefore, location-specific conservation and management measures, guided by the knowledge on spatial distribution and habitat requirements of mangrove varieties should be taken to preserve the mangrove diversity of Kerala. [ABSTRACT FROM AUTHOR]

The impact of coastal pollution was studied using edible oysters, Crassostrea rivularis as an indicator at two sites viz., North Wandoor (NW) and Phoenix Jetty (PJ) in Port Blair, Andaman. The hydrographic parameters showed that nitrite, nitrate and phosphate concentration were less and dissolved oxygen were more at NW compared to PJ. The oysters were collected from the study sites and biochemical, microbial, mineral profiles and ATPase activities were estimated. ATPase activity was inhibited in the gill tissue of oysters ( p < 0.05) of PJ sample. Total microbial load in the water and oyster, and coliform bacteria (MPN) in the water were significantly ( p < 0.05) higher at PJ compared to the NW. There was no significant difference ( p > 0.05) in the mineral profile of water collected from both the sites. However, calcium and magnesium were more in the oysters collected from NW ( p < 0.05), and Cu, Zn and Cd were more in PJ samples ( p < 0.05). [ABSTRACT FROM AUTHOR]

During the last decade, the Andaman and Nicobar Islands (ANI) have witnessed a marginal population growth with associated variations and degradation in the water quality of the inhabited coastal region. Monthly water quality data collected from six coastal locations in ANI were used to evaluate the anthropogenic influence in an otherwise pristine island environment. Exceptionally low dissolved oxygen (0.7-2.0 mg/L) at the Phoenix Jetty (PJ) and mangrove site indicates hypoxic conditions. Among the nutrients, nitrate shows high values at PJ due to heavy nutrient loading from domestic sewage. The cluster analysis segregated PJ from the remaining sites, indicating deterioration in the water quality. On the other hand, water quality at Sippighat, a low-intensity aquaculture site, does not indicate any deterioration. Apart from the large modulations in the water quality of the study area by the Bay of Bengal waters, the effect of domestic waste discharges significantly affects the coastal waters of Andaman. Though the present water quality at most of the study sites appears acceptable, the increased volume of tourism and allied activities poses a potential threat to the island ecosystem. Besides the anthropogenic influences, the long-term trends in oceanographic factors were analyzed in order to decipher the expected natural effect on future water quality of the region. Based on the increasing sea surface temperature as well as the decreasing chlorophyll-a, eddy kinetic energy, and zonal kinetic energy, we propose that the combined effect of both natural and anthropogenic factors can ultimately distress the present ambient water quality of ANI. [ABSTRACT FROM AUTHOR]

A two-dimensional hydrodynamic and particle tracking model was used to estimate the dispersion and retention of barnacle larvae from their possible spawning sites in a tropical monsoon-influenced estuarine system (central west coast of India). Validation of the hydrodynamic simulations yielded a good match with field measurements. The pattern of larval dispersal in the region varied with the winds and currents. The seasonal changes in abundance could be attributed to physical forcing and weather conditions. The extent of barnacle larval dispersal from spawning sites varied from 10 to 78 km for different sites and seasons. During a 24-h cycle, the larval abundance showed one to two peaks in the estuarine area. The increased larval abundance is favored by the flood currents, pushing the larvae into the estuary. Physical forcing in the region helps in transport of the larvae from their spawning sites hugging to the coast and contributing to the population within the estuary. Field observations and numerical experiments suggest the occurrence of higher larval abundance in the estuary during post-monsoon. The dispersal pattern indicated that the barnacle population present in the estuary is well mixed, and with a seasonally changing pattern. [ABSTRACT FROM AUTHOR]

The reefs in some islands of Andaman and Nicobar suffered severe damage following a tropical storm in the Bay of Bengal off Myanmar coast during 13-17 March 2011. Surveys were conducted at eight sites in Andaman, of which five were located in the Ritchie's Archipelago where maximum wind speeds of 11 m s was observed; and three around Port Blair which lay on the leeward side of the storm and had not experienced wind speeds of more than 9 m s. Corals in the shallow inshore reefs were broken and dislodged by the thrust of the waves. Significant damage in the deeper regions and offshore reefs were caused by the settlement of debris and sand brought down from the shallower regions. The fragile branching corals ( Acropora sp.) were reduced to rubbles and the larger boulder corals ( Porites sp.) were toppled over or scarred by falling debris. The reefs on the windward side and directly in the path of the storm winds were the worst affected. The investigation exposes the vulnerability of the reefs in Andaman to the oceanographic features which generally remain unnoticed unless the damage is caused to the coastal habitats. [ABSTRACT FROM AUTHOR]