Contrasting tourism regimes due to the COVID-19 lockdown reveal varied genomic toxicity in a tropical beach in the Southern Atlantic

Weekly variation of seawater ecotoxicity on marine sandy beaches in relation to coliform densities

The hypothesis tested here is a direct relationship between microbiological and ecotoxicological quality on beaches. Seawater was collected weekly for one year in Northeast Brazil. The quantification of thermotolerant coliforms was obtained using the multiple tube technique. The ecotoxicological bioassay utilized the nauplii of the copepod Tisbe biminiensis. The percentage of development and survival was estimated after 72 h. Rainfall, salinity, tidal height and amplitude were analyzed. The results didn't demonstrate a relationship between the density of coliforms and lethal effects, thus rejecting the proposed hypothesis. This result suggested that sewage contamination passed through riverine plumes before arrives the beaches and coliforms died in this long way. Higher toxicity was observed during dry periods, probably due to high contaminant concentration due to lower river discharge. Other hypotheses are proposed to explain the data as higher rainfall observed in 2022 and the negative effect of population use.

Comparative genomic damage among three shark species with different habits: Sublethal impacts of human origin in a protected island environment in the South Atlantic

Elasmobranchs can bioaccumulate and biomagnify pollutants. However, few studies are directed to the effects of pollutants on the health of these animals, and in most cases, are limited to the analysis of biochemical markers. Thus, the incidence of genomic damage among shark species inhabiting a protected ocean island in the South Atlantic was investigated in association with the analysis of pollutants in seawater sample. High levels of genomic damage were identified, especially in Negaprion brevirostris and Galeocerdo cuvier, in addition to interspecific variations that may be related to characteristics such as animal size, metabolism and habits. High concentrations of Surfactants were observed in seawater sample, in addition to low concentrations of Cadmium, Lead, Copper, Chromium, Zinc, Manganese, and Mercury. The results evidenced the potential of shark species as a bioindicator of environmental quality and allowed assessing the anthropic impact on the archipelago, which currently drives its economy through tourism.