Variability in the phytoplankton community of Kavaratti reef ecosystem (northern Indian Ocean) during peak and waning periods of El Niño 2016

El Niño, an interannual climate event characterized by elevated oceanic temperature, is a prime threat for coral reef ecosystems worldwide, owing to their thermal threshold sensitivity. Phytoplankton plays a crucial role in the sustenance of reef trophodynamics. The cell size of the phytoplankton forms the “master morphological trait” with implications for growth, resource acquisition, and adaptability to nutrients. In the context of a strong El Niño prediction for 2015–2016, the present study was undertaken to evaluate the variations in the size-structured phytoplankton of Kavaratti reef waters, a major coral atoll along the southeast coast of India. The present study witnessed a remarkable change in the physicochemical environment of the reef water and massive coral bleaching with the progression of El Niño 2015–2016 from its peak to waning phase. The fluctuations observed in sea surface temperature, pH, and nutrient concentration of the reef water with the El Niño progression resulted in a remarkable shift in phytoplankton size structure, abundance, and community composition of the reef waters. Though low nutrient concentration of the waning phase resulted in lower phytoplankton biomass and abundance, the diazotroph Trichodesmium erythraeum predominated the reef waters, owing to its capability of the atmospheric nitrogen fixation and dissolved organic phosphate utilization.     

Occurrence of Norovirus,Rotavirus, Hepatitis a Virus,and Enterovirus in Berries in Argentina

Food and Environmental Virology - Berries have been implicated as the probable vehicle of infection in multiple outbreaks of norovirus and hepatitis A virus (HAV). These foods often receive minimal...     

Polycyclic aromatic hydrocarbons study in atmospheric fine and coarse particles using diagnostic ratios and receptor model in urban/industrial region

Atmospheric fine and coarse particles were collected in Teflon filters in three cities of the region of the Lower Sinos River Basin of Rio Grande do Sul in the year 2010. The filters were Soxhlet extracted, and 14 priority PAHs were analyzed using a gas chromatograph coupled to a mass spectrometer (GC/MS). The principal emission sources of these compounds were assessed by using diagnostic ratios and receptor model: positive matrix factorization (PMF 3.0) of the US Environmental Protection Agency. The results of PAHs concentration for the studied year showed significant levels of high molecular weight (HMW) PAH, Ind, and BghiP, in PM_2.5 in the winter season, showing the influence of mobile sources. The application of receptor model PMF 3.0 revealed that the main sources of PAHs were vehicle fleet (both diesel and gasoline), followed by coal combustion, wood combustion, and resuspension of dust. The results of the receptor modeling are in agreement with the data obtained by the ratio diagnostic.     

Sub-hourly changes in biogeochemical properties in surface waters of Zuari estuary, Goa

Processes in natural waters are highly variable in time and space. Although changes are expected in short-time scales, how short one could get to measure reliably is subjective to sampling strategies and methodologies. Here, we show that sub-hourly changes in surface waters dissolved oxygen, nutrients, and pigments are measurable and significant in an estuarine system. Tidal circulation has been found to strongly influence the observed changes and has implications to material fluxes in and out of estuaries.     

Input-export fluxes of heavy metals in the Cochin estuary,southwest coast of India

Cochin estuary (CE) is one of the largest tropical estuaries along the southwest coast of India, sustaining rich bio-resources. Several studies enlighten the environmental changes in the CE caused by anthropogenic activities. In the present study, an attempt has been made to quantify the heavy metal (dissolved and particulate) fluxes brought by the six rivers into the CE with their exchange into the coastal ocean through the major inlet at Cochin during a steady flow period (October–November 2015). The water flux across the inlet was quantified using an acoustic doppler current profiler. The measured daily input of dissolved metals from the rivers was 2.43?×?10³ kg Fe, 334 kg Zn, 259 kg Ni, and 83 kg Cr, while that of particulate metals were 85.30?×?10³ kg Fe, 8. 6?×?10³ kg Mn, 236.9 kg Cr, and 111.9 kg Zn. The net export of metals through the Cochin inlet (per tidal cycle) was 3.3?×?10³ kg Fe, 515 kg Cr, 150 kg Zn, and 5 kg Ni in dissolved form and 3.32?×?10⁵ kg Fe, 1747 kg Mn, 1636 kg Cr, 1397 kg Zn, and 586 kg Ni in particulate form. The high concentrations of metals during ebb tides are clear indications of their contribution from the industrial conglomerates (industrial units of metallurgy, catalyst, fertilizer, and pesticides) located in the Periyar River. The significance of this study is that the export fluxes may increase further during the summer monsoon (June to September), which may impact the abundant fishery emanating in the coastal environment during the period due to intense upwelling.

     

Bioaccumulation of butyltins and liver damage in the demersal fish Cathorops spixii (Siluriformes,Ariidae)

The toxicity of butyltin compounds (BTs), mainly tributyltin (TBT), has been reported in different organisms. However, such an analysis in fish after field exposure with reference to the related biomarkers has not been commonly observed in the literature. This study presents the uptake of BTs in the liver of a neotropical marine catfish Cathorops spixii in Paranagua Bay, an important estuarine system located in southern Brazil. Two different areas, close to and distant from the harbor, were used for chemical analysis evaluation of hepatotoxicity through genetic, enzymatic, and histopathological biomarkers. The presence of polycyclic aromatic hydrocarbons in bile was also considered as a biomarker. The results showed a significant relationship between TBT levels and the inhibition of biotransformation enzymes and high occurrence of melanomacrophages in fish collected close to the harbor site. These effects were linked to the absence of TBT metabolites in the liver. In the second site, the presence of DBT was associated with an increase in EROD and GST activity. The larger amount of DNA damage as well as the highest oxidative stress was noted in fish from the less TBT-polluted area, where DBT and bile PAHs occurred. These findings showed different impact levels due to or increased by the chronic exposure of biota to BTs.     

The Potential of Cleaner Fermentation Processes for Bioplastic Production: A Narrative Review of Polyhydroxyalkanoates (PHA) and Polylactic Acid (PLA)

Journal of Polymers and the Environment - Synthetic plastics generate major problems in landfills after their consumption for occupying high volumes and difficult the decomposition of other organic...