RESUMEN

A wide spectrum of algal-bacterial-viral relationships in aquatic ecosystems provide a complex matrix of interactions with abiotic factors such as temperature, pH and total solids concentrations in water. These relationships are quite reflective of the summative status of changes undergone by the lacustrine environments. However, the environmental risks and vulnerability of aquatic ecosystems in the regions of Global South including India, owing to the increase in sewage and domestic discharges with high loads of viral particles in the post-COVID-19 times have only been sparsely reported. Collective scenarios emerging from the influential factors such as the increase in salinity and total solids need to be explored for scientific significance and understanding. The present article opines that while the changes in the biotic and abiotic factors can enhance or alleviate these risks, identification of the stable and alternate states of the ecosystems make excellent ecosystem level proxies for pandemic-related disturbances at a macro-scale. Further, the need to plan Nature based Solutions to counter these risks under pandemic-like scenarios is discussed.

RESUMEN

Monitoring frameworks under a non-disaster scenario can be helpful to identify the various socio-technical constraints of local and regional origin which influence the economics and resources management of marine fisheries. However, local-scale manifestations of regional/global changes due to the rapid onset of a disaster scenario may lead to unprecedented distortion of the market demand-supply value chains for the fisheries sector at shorter temporal scales. The global pandemic of COronaVIrus Disease (COVID-19) provided a unique short, temporal window to study the evolution of socio-economic challenges to sustainable fishing in the Bay of Bengal (BoB), India. The present study provides a detailed multi-source assessment of the factors that lead to massive complications of market disruption beginning with a public curfew on 22nd March 2020, followed by a nationwide complete lockdown of 54 days beginning from 25th March 2020, indicating an "all-pain no-gain" scenario for the fishers. Aggravating factors as a cessation of food services, and the restriction of exports of perishable commodities indicated negative spin-offs for allied activities sectors such as food processing due to low or negligible demand. The present investigation also indicated that as part of rehabilitation, policies related to overfishing are necessary to promote sustainable fishing practices in the BoB region in a post-pandemic period. New policy frameworks must consider the community-centric factors which facilitated the alleviation of the impacts of anthropogenic activities related to fishing and the slow restoration of the demand-supply chain, with long-term benefits for natural resources sustenance and to aid marine conservation efforts.

RESUMEN

Pulicat lagoon in the south-east coast of India is recharged with the highest fresh water influx annually during north-east winter monsoon. An abrupt heavy rainfall in November-December 2015 was a flood calamity in the region that inundated the lagoon. We investigated the physico-chemical characteristics and palynological profile of the surface sediments from the lagoon at water depth between 0.5 and 2 m to understand the impact of the 2015 event. On the basis of a 'marine index', three zones were demarcated, the 'LC zone' (Araniar river-lagoon confluence, south), the 'LM zone' and the 'LL zone' (Kalangi river confluence, north) showing values of 4.55, 1.25 and 0.25, respectively, indicating the extent of tidal influence. The dissolved oxygen, pH and salinity ranged between 6.4 and 9.6 mg/L, 7.96-9.23 and average ~ 12.3 ppt at different sites, respectively. The highest salinity (31 and 31.8 ppt) was in the LC zone along with the highest dissolved inorganic nitrogen (DIN) concentrations (275-288 mmol/m3) too. The dissolved inorganic phosphates (DIP) ranged between 8.5 and 29.5 mmol/m3, which was relatively high. Sandy sediment, high sodium (Na+) and chloride (Cl-) ions too indicate the landward extension of seawater influx. Forsterite (Mg2SiO4) and beta-uranophane (Ca[(UO2)SiO3(OH)]2.(H2O) minerals show higher values with the dominance of olivine (MgFe)2SiO4) and quartz (SiO2) in this zone indicating magnitude of fresh water influx too through Araniar river. The highest calcium, magnesium and potassium ions were also observed in LC zone. Fe-rich goethite, calcite and aragonite were recorded at all sites but with dominance of illite in LL zone. Halite, an evaporite recorded from all sites shows inundation of the entire lagoon during flooding event. Results show a bloom of Biddulphia pulchella, B. biddulphiana and B. laevis in association with Cladophora in LC zone which serves as potential indicators of physico-chemical characteristics of the lagoon showing intense response to catastrophic events of floods due to above normal monsoon variability.

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RESUMEN

In the recent years, several indices of trophic status of coastal ecosytems are being used worldwide. However, not all of them can be applied successfully to depict the true trophic status of shallow coastal ecosystems due to their inherent complexities in nutrient circulation and interactions between biotic organisms. The most widely used index is Carlson's Trophic State Index (TSI), while more recently, several environmental indices have been constructed using soft computing techniques such as fuzzy logic. In the present investigation, a comparison of the performances of a conventional trophic state index and a newly developed fuzzy-based trophic state index has been presented in detail. The aim of the work was to highlight the advantages of the newer technique over the existing techniques in light of the inherent variability of both data as well as the sampling procedures undertaken for studying a coastal lagoon ecosystem called Pulicat lagoon in the southeast coast of India. The results of the study have shown that while there are discrepancies in depicting the trophic status of the lagoon using Carlson's index, the newer logic-based index predicted the trophic status accurately which was verified by field assessments. Thus the successful application of a more reliable index to estimate trophic status has been presented.

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RESUMEN

Distillery spentwash, owing to its high COD, BOD along with obnoxious odour and dark colour presents several operational challenges when applying biological treatment technologies. Conventional treatment techniques achieve only about 70% COD removal, with the treated effluent still exceeding the limits prescribed by the Pollution Control Board. Hence, the need of the hour is an efficient technology to reduce the polluting capacity of the distillery wastes. Keeping this in mind, an investigation using a laboratory-scale upflow anaerobic filter (UAF) to study carbonaceous removal of distillery spentwash under mesophilic conditions has been attempted. The effect of hydraulic loadings on COD removal has been evaluated at different COD concentrations ranging from 2000 to 13000 mg/L. The COD removal percentage during the period of investigation was found to be in the range of 54.8% to 88.7%. The biogas yield was observed to be in the range of 0.33-0.45 m3/kg of COD destroyed.

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