Cetaceans as bio-indicators revealed the increased risks of triclosan exposure and associated thyroid hormone disruption during the COVID-19 pandemic

The global surge in disinfection practices from the COVID-19 response has raised concerns about the marine exposure to the hazardous ingredients in disinfectant products, including triclosan (TCS) and triclocarban (TCC). However, there are very limited studies on the response of marine TCS and TCC (TCs) loading to the COVID-19 pandemic. Here we used cetaceans as bio-indicators for a long-term retrospective analysis of TCs loading to the South China Sea (SCS) between 2004 and 2022. Hepatic TCs was 100% detected in all nine cetacean species (n = 120). Interestingly, TCS concentrations decreased in Indo-Pacific humpback dolphins (IPHD) before the pandemic from 2010 to 2017. However, after 2019, TCS concentrations in IPHD significantly increased several-fold. Similarly, post-pandemic TCS concentrations in Indo-Pacific finless porpoises (IPFP) and two fish species were significantly higher than pre-pandemic levels. There were significant relationships between thyroid hormones (THs) and TCs in IPHD and IPFP, suggesting that increased TCs may worsen the interference of THs homeostasis and nutritional conditions in cetaceans. These findings demonstrate the profound impact of the surging use of TCs-containing products from the COVID-19 response on marine ecosystems.

Bioremediation by oil degrading marine bacteria: An overview of supplements and pathways in key processes

Oil spillage is one of the most common pollutants which brings greater economic loss and damage to the environment. The intensity and amount of the damage may vary depending on factors such as the type of oil, the location of the spill, and the climatic parameters in the area. As for any pollution management, the guidelines are Reduce, Re-use, Recover and Disposal. Amongst the other remediation processes, Bioremediation is amongst the most significant environmentally friendly and cost-effective approaches for marine biological restoration because it allows complex petroleum hydrocarbons in spilt oil to decompose completely into harmless compounds. Mainly, the necessity and essence of bioremediation were talked about. This review discussed the bacteria identified which are capable of degrading various oil related pollutants and their components. Also, it covered the various media components used for screening and growing the oil degrading bacteria and the pathways that are associated with oil degradation. This article also reviewed the recent research carried out related to the oil degrading bacteria.

Omics of the marine medaka (Oryzias melastigma) and its relevance to marine environmental research

In recent years, the marine medaka (Oryzias melastigma), also known as the Indian medaka or brackish medaka, has been recognized as a model fish species for ecotoxicology and environmental research in the Asian region. O. melastigma has several promising features for research, which include a short generation period (3-4 months), daily spawning, small size (3-4 cm), transparent embryos, sexual dimorphism, and ease of mass culture in the laboratory. There have been extensive transcriptome and genome studies on the marine medaka in the past decade. Such omics data can be useful in understanding the signal transduction pathways of small teleosts in response to environmental stressors. An omics-integrated approach in the study of the marine medaka is important for strengthening its role as a small fish model for marine environmental studies. In this review, we present current omics information about the marine medaka and discuss its potential applications in the study of various molecular pathways that can be targets of marine environmental stressors, such as chemical pollutants. We believe that this review will encourage the use of this small fish as a model species in marine environmental research.