Reviewing the effects of contamination on the biota of Brazilian coastal ecosystems: Scientific challenges for a developing country in a changing world

Metal(loid) contamination in tiger sharks (Galeocerdo cuvier) from a remote oceanic island in the Equatorial Atlantic Ocean and potential impacts on physiological parameters

We investigated the relationship between blood metal(loid) concentrations and plasma levels of glucose, proteins, triglycerides, cholesterol, lactate, urea, and polyunsaturated fatty acids in tiger sharks (Galeocerdo cuvier) sampled off the Fernando de Noronha Archipelago, a remote oceanic marine protected area in the Equatorial Atlantic Ocean. Results revealed that Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn were detected in the whole blood of tiger sharks and no sexual differences in blood metal(loid) concentrations were observed. Females had higher concentrations of plasma proteins and docosahexaenoic acid. In females, all analyzed elements were positively correlated with each other, except As. Only As was positively correlated with triglycerides, suggesting a potential impact of As exposure on the nutritional condition of this species. The results presented herein reinforce that sharks, even from remote sites, are exposed to metal(loid)s and that such exposure might elicit physiological responses.

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.

Tamoxifen induces biochemical responses in Pacific oysters Magallana gigas (Thunberg, 1793) at environmentally relevant concentrations

The activities of catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), glucose-6-phosphate dehydrogenase (G6PDH), and glutathione-S-transferase (GST) were evaluated in the gills (GI) and digestive gland (DG) of Magallana gigas oysters exposed to tamoxifen (TAM) at environmental concentrations of 10 and 100 ng L-1 for 1 and 4 days. A higher CAT activity in the GI and DG and higher GPx activity only in the DG was observed of oysters exposed to both concentrations after 1 day. Furthermore, a significant increase in GR and G6PDH, was detected in the DG after 1 day of exposure to 10 ng L-1 and only G6PDH activity increase after 1 day of exposure to 10 ng L-1 in the GI. This suggests that the DG is a tissue more sensitive to TAM exposure and was confirmed with the individual Integrated Biomarker Response version 2 index (IBRv2i), highlighting the acute stress caused by TAM and a cellular adaptation.

Motility of Mytilus galloprovincialis hemocytes: Sensitivity to paracetamol in vitro exposure

Pharmaceuticals released into the environment (PiEs) represent an environmental problem of growing concern for the health of ecosystems and humans. An increasing number of studies show that PiEs pose a risk to aquatic organisms. The aim of the present work was to contribute to increasing the knowledge of the effects of PiE on marine biota focusing on the effect of paracetamol on the motility of hemocytes in Mytilus galloprovincialis, a bivalve mollusk species widely utilized as bioindicator organism. Hemocytes are the immunocompetent cells of bivalve mollusks. An early and key stage of mollusk immune response is represented by the recruitment and migration of these cells to the site of infection. Therefore, motility is an intrinsic characteristic of these cells. Here, we first characterized the spontaneous cell movement of M. galloprovincialis hemocytes when plated in a TC-treated polystyrene 96-well microplate. Two different cellular morphotypes were distinguished based on their appearance and motility behavior: spread cells and round-star-shaped cells. The two motility morphotypes were characterized by different velocities as well as movement directness, which were significantly lower in round-star-shaped cells with respect to spread cells. The sensitivity of the motility of M. galloprovincialis hemocytes to paracetamol at different concentrations (0.02, 0.2 and 2 mg/L) was investigated in vitro after 1h and 24h exposure. Paracetamol induced alterations in the motility behavior (both velocity and trajectories) of the hemocytes and the effects were cell-type specific. The study of hemocyte movements at the single cell level by cell tracking and velocimetric parameters analysis provides new sensitive tools for assessing the effects of emerging pollutants at the cellular levels in non-target organisms.

Long-term impacts on estuarine benthic assemblages (2015-2020) after a mine tailing spill in SE Brazil

The Rio Doce estuary was critically impacted in 2015 by the world's largest mining tailing spill, with still unclear long-term effects on the aquatic biota. Here we present a long-term (2015 to 2020) assessment of estuarine benthic assemblages, where we demonstrate that despite a decline in the absolute concentrations of potentially toxic elements; sediment contamination is still above pre-impact conditions. The presence of these contaminants is likely responsible for a continued low habitat quality for the benthic fauna, characterized by a reduction of 96 % of the macroinvertebrate density and persistent change in the benthic assemblage composition. Our study supports previous work indicating the long-term nature of pollution impacts in estuaries, and demonstrate that although water quality levels were quickly adequate under regulatory terms, they largely lack significance to the overall ecosystem health assessment, as they are not related to the recovery of bottom- dwelling assemblages in estuarine ecosystems.

Macroecology of rocky intertidal benthic communities along the southwestern Atlantic: Patterns of spatial variation and associations with natural and anthropogenic variables

Assessing spatial variability in biodiversity and its relationships with potential drivers is necessary for understanding and predicting changes in ecosystems. Here, we evaluated spatial patterns in sessile macrobenthic communities in rocky intertidal habitats along the southwestern Atlantic (SE Brazil), spanning over 500 km of coastline. We applied a rapid-survey approach focusing on the main space occupiers and habitat-forming taxa. We partitioned community variance into spatial scales ranging from metres to hundreds of kilometres and assessed whether community patterns were associated with variation in shore topography, nearshore ocean, and human influence. The communities from the mid-midlittoral level exhibited equivalent variation (31-35%) at the scales of quadrats (metres), sites (kilometres), and sub-regions (tens of kilometres). For the communities from the low-midlittoral and infralittoral fringe levels, most variability occurred at the scales of quadrats and sites (30-42%), followed by sub-regions (22%). Wave fetch, sea surface temperature (SST), and shore inclination were the variables that best explained community structure at the mid-midlittoral. At the low-midlittoral and infralittoral fringe, the most influential variables were related to oceanic forcing (SST, total suspended solids, particulate organic carbon, chlorophyll-a concentration) and human influence. Univariate analyses also revealed strong associations between the abundance of the main components of the communities and the predictor variables evaluated. Our results suggest that urbanised estuarine bays and coastal upwelling regimes have a strong influence on adjacent benthic communities, driving macroecological patterns in the study area. This study advances the knowledge in macroecology and biogeography of rocky shores in an understudied coastline and globally and provides valuable insights for future assessments of ecological changes resulting from unfolding human impacts.

Marine shrimps as biomonitors of the Fundão (Brazil) mine dam disaster: A multi-biomarker approach

The disruption of the Fundão dam released 43 million m³ of mine tailings into the Doce River until it flowed into the ocean through the estuary. The mine tailing changed the composition of metals in water and sediment, creating a challenging scenario for the local biota. We used multivariate analyzes and the integrated biomarker response index (IBR) to assess the impact of mine tailings on the bioaccumulation profile (As, Cd, Cr, Cu, Fe, Mn, Pb and Zn) as well as the biomarkers response in gills, hepatopancreas and muscle of shrimps sampled from different sectors during two dry seasons (dry1 and dry2) (Sep/Oct 2018; 2019) and two wet seasons (wet1 and wet2) (Jan/feb 2019; 2020). There was seasonal and local effect under bioaccumulation and biomarker response revealing that the pattern responses seen in each sector sampled changed according to the season. The greater IBR added to the strong association among the most metals tissue content (Cd, Cr, Cu and Mn) and sectors sampled during dry 1 suggests greater bioavailability of these metals to the environment in this period. Estuarine sectors stand out for high Fe bioavailability, especially during wet1, which seems to be associated with greater metallothionein content in hepatopancreas of shrimps. Native species of marine shrimps proved to be successful indicators of sediment quality besides being sensitive to water contamination by metals. The multi-biomarkers approach added to multivariate analysis supports the temporal and seasonal effects, signalizing the importance of continuous monitoring of the estuarine region to better know about the bioavailability of these metals, mainly Fe, and their long-term effects on the local biota.

When One Health Meets the United Nations Ocean Decade: Global Agendas as a Pathway to Promote Collaborative Interdisciplinary Research on Human-Nature Relationships

Strong evidence shows that exposure and engagement with the natural world not only improve human wellbeing but can also help promote environmentally friendly behaviors. Human-nature relationships are at the heart of global agendas promoted by international organizations including the World Health Organization’s (WHO) “One Health” and the United Nations (UN) “Ocean Decade.” These agendas demand collaborative multisector interdisciplinary efforts at local, national, and global levels. However, while global agendas highlight global goals for a sustainable world, developing science that directly addresses these agendas from design through to delivery and outputs does not come without its challenges. In this article, we present the outcomes of international meetings between researchers, stakeholders, and policymakers from the United Kingdom and Brazil. We propose a model for interdisciplinary work under such global agendas, particularly the interface between One Health and the UN Ocean Decade and identify three priority research areas closely linked to each other: human-nature connection, conservation-human behavior, and implementation strategies (bringing stakeholders together). We also discuss a number of recommendations for moving forward.