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The majority of the analytical methods for steroids in marine sediments are laborious and time consuming and involve the use of large volumes of organic (frequently chlorinated) solvents. A method has been developed utilising ethanol extraction with a rapid alumina-ethanol elution clean up, providing an environmentally friendly and inexpensive alternative. Recoveries of steroids (coprostanol, epicoprostanol, cholesterol, cholestanol, 5alpha-coprostanone and 5beta-coprostanone) ranged from 70 to 93% and compared favourably with more traditional analyses. Analytical performance was tested through analysis of reference material and concentrations recorded for coprostanol, cholesterol and cholestanol were close to the mean certified values and were within acceptable values. Relative standard deviations from triplicate analyses were small (6-12%). These initial tests also indicate that the simplified clean up (without fractionation) is not subject to interference in the quantification of the selected faecal steroids.

The Masked Booby Sula dactylatra is a surface-nesting seabird that breeds on offshore islands across the tropical and subtropical oceans. On inaccessible rocky areas on Trindade Island, located about 1200 km from Espírito Santo, Brazil, the nesting of this species has been poorly studied. To model the species’ nesting habitat suitability at Trindade Island, we mapped active nests during the breeding seasons of 2017 and 2019, from October to November, using a hand-held Global Positioning System receiver and an Unmanned Aerial Vehicle. In order to identify key areas, we created nesting habitat suitability maps using seven different algorithms (Random Forest, Gradient Boosting Machine, Artificial Neural Network, Maximum Entropy, Generalized Additive Model, Generalized Linear Model, and Multiple Adaptive Regression Splines) in response to five topographical variables and one vegetation-related variable. Our sample included 87 active nests. Models generated by all four best algorithms were considered satisfactory. Results indicate that elevation and terrain aspect are the main variables influencing booby selection of nesting sites. We found areas of very high nesting habitat suitability along the southwest and northwest faces of the island, mostly in elevations varying from 150 m to 450 m. [ABSTRACT FROM AUTHOR]

Pollution is a key factor in efforts to conserve seabirds and their habitats. The Marine Biological Reserve of Rocas Atoll hosts the largest population of seabirds (-23000 individuals) breeding in Brazilian waters. In the present study at Rocas Atoll, liver samples were collected from dead individuals of five species (adults and nestlings): Masked Booby Sula dactylatra. Brown Booby Sulci leucogaster, Brown Noddy Anous stolidus, Black Noddy Anous minutus, and Sooty Tern Onychoprion fuscatus. They were analyzed for three persistent organic pollutants (POPs): polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs). and polybrominated diphenyl ethers. Carbon and nitrogen stable isotopes (513C and SI5N) were also analyzed to assess feeding and foraging habits. PCBs (3.37-189 ng-g1), OCPs (DDTs, 0.5-23.1 ng-g'1), and hexachlorobenzene (0.31-12.3 ng-g ') were predominant overall, and results were generally consistent with previous studies. Despite the low levels of contaminants, intraspecific stratification was found, with lower concentrations in nestlings compared to adults, as expected. Stable isotopes revealed that differences in POP levels and PCB profiles were associated with diet and foraging patterns. Low levels of POPs at Rocas Atoll were consistent with patterns observed in studies of other low-latitude and high-latitude seabirds. [ABSTRACT FROM AUTHOR]

Summary: The Trindade Petrel Pterodroma arminjoniana is a vulnerable species that breeds on Trindade Island, 1,100 km away from the Brazilian coast, and on Round Island in the Indian Ocean. Recent population estimates for Trindade Island by nest counts in accessible areas, and extrapolated to the whole island provided a figure of 1,130 breeding pairs. Using topographic variables and Predictive Nest Habitat Modelling from known breeding sites, we estimated the potential area of nesting and estimated the size of the breeding population. Nests were associated with low to intermediate elevations in areas of steep slopes and high runoff, which limited the distribution of potential breeding sites to the edges of the Island. By extrapolating the density of nests in the known breeding sites to the overall potential breeding area, we estimated 1,228 nests. We discuss the potential implications of our findings in relation to the population status based on the scenario of intense habitat modification of the island over the few last centuries. This species may have suffered declines due to habitat alteration by human activities and introduction of exotic species. Furthermore, we generate an overview of potential areas for nesting and establish relationships with habitats that may be useful for the conservation of the Trindade Petrel, and restoration actions for Trindade Island in the future. [ABSTRACT FROM AUTHOR]

Urban sewage is a concerning issue worldwide, threatening both wildlife and human health. The present study investigated protein oxidation in mangrove oysters ( Crassostrea brasiliana) exposed to seawater from Balneário Camboriú, an important tourist destination in Brazil that is affected by urban sewage. Oysters were exposed for 24 h to seawater collected close to the Camboriú River (CAM1) or 1 km away (CAM2). Seawater from an aquaculture laboratory was used as a reference. Local sewage input was marked by higher levels of coliforms, nitrogen, and phosphorus in seawater, as well as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), linear alkylbenzenes (LABs), and fecal steroid in sediments at CAM1. Exposure of oysters to CAM1 caused marked bioaccumulation of LABs and decreased PAH and PCB concentrations after exposure to both CAM1 and CAM2. Protein thiol oxidation in gills, digestive gland, and hemolymph was evaluated. Lower levels of reduced protein thiols were detected in hemolymph from CAM1, and actin, segon, and dominin were identified as targets of protein thiol oxidation. Dominin susceptibility to oxidation was confirmed in vitro by exposure to peroxides and hypochlorous acid, and 2 cysteine residues were identified as potential sites of oxidation. Overall, these data indicate that urban sewage contamination in local waters has a toxic potential and that protein thiol oxidation in hemolymph could be a useful biomarker of oxidative stress in bivalves exposed to contaminants. Environ Toxicol Chem 2017;36:1833-1845. © 2016 SETAC [ABSTRACT FROM AUTHOR]

Lipid biomarkers are potential tools for identifying the sources, diagenesis and reactivity of organic matter (OM) in marine systems, including in Antarctica where the particular environmental characteristics have motivated several studies of organic markers. Sedimentary sterol distributions were determined in two sediment cores (PGI-1 and PGI-2) collected from the marine environment around Penguin Island, Antarctica, during the 2007–08 summer. The cores were sectioned at 1 cm intervals and the sterols were analysed using gas chromatography with flame ionization detection. The results indicate that the sterols were subjected to decades of degradation and transformation with depth in both cores. However, an expected progressive conversion of stenols to stanols (evaluated by 5α-stanols/Δ5-stenols ratio) within the deepest sediment layers was not clear, suggesting low degradation rates. In PGI-1, the deposition of large quantities of penguin guano affected the distribution of sterols and, consequently, primary production was favoured by the ornithogenic soil input. The results contribute to the understanding of the current processes associated with primary sources and transformation of OM in this important region of the Antarctic environment. [ABSTRACT FROM PUBLISHER]