Effects of zinc pyrithione (ZnPT) and inorganic Zn (ZnCl₂) were evaluated on a marine polychaete at sublethal concentrations for 14 days. ZnPT decreased the burrowing activity and AChE activity with higher acute toxicities, implying its cholinergic effect. Both ZnPT and ZnCl₂ increased MDA levels at higher concentrations, suggesting lipid peroxidation and oxidative stress. In the ZnPT-treated polychaete, enzymatic activities of CAT and SOD were elevated with an increase in DNA damage, whereas the levels of GSH, GPx, GR, and GST were decreased. However, in the ZnCl₂-treated polychaete, the level of GSH and enzymatic activities of CAT, SOD, GPx, GR, and GST were significantly elevated to resist cellular damage. During 97 days depuration experiment, significant mortality and growth retardation were observed in the ZnPT-exposed polychaete. Overall, ZnPT was found to be more toxic than ZnCl₂ with the harmful impact on antioxidant defense system and DNA stability in marine polychaete.

Microplastics have been found in all environmental compartments investigated so far, even reaching remote areas. However, their presence in Antarctic freshwaters has not been yet reported. Here, we investigated the occurrence of microplastics in a stream from an Antarctic Specially Protected Area (Byers Peninsula, Livingston Island - ASPA No. 126), which is subject to stringent environmental protection measures as a result of which it is considered a pristine international reference site for inland waters research. Our results showed the presence of three types of microplastics in a freshwater seasonal stream, namely four polyester fibers, one black and three transparent; two acrylic fibers, one transparent and one red; and two transparent polytetrafluoroethylene films. The length and width of these fibers and films were in the 400–3546 μm (average 1118 μm), and 10–1026 μm (average 199 μm) ranges respectively. The concentration of MP was 0.95 items/1000 m³ with estimated variability in the 0.47–1.43 items/1000 m³ range. This is the first report of the presence of microplastics in Antarctic freshwater with the uniqueness that it is an Antarctic Specially Protected Area, meaning that plastic pollution reached even the most remote and pristine environments in the planet.

The daily accumulation rates, composition, sizes and potential sources of marine litter collected on a remote island within the Western Indian Ocean were investigated. In total, 9119 items of marine litter were collected during 40 surveys, which equated to 0.0082 items·m⁻¹·d⁻¹. Between 2003 and 2019 there was a significant increase in the amount of litter deposited, with the highest daily accumulation rate recorded in 2019 (0.0255 items·m⁻¹·year⁻¹). All specific litter types increased over time and also differed significantly in their accumulation rates, with polystyrene fragments/pieces (0.00249 items·m⁻¹·d⁻¹), plastic items (0.00135 items·m⁻¹·d⁻¹) and plastic bottles (0.0011 items·m⁻¹·d⁻¹) being the most commonly encountered during this study. The majority of the litter found was ≤5 cm in size. Nearly all (>80%) litter collected was made of or contained some form of plastic. Recommendations for improved management of litter and the importance of establishing regular beach clean-ups within the Seychelles are briefly discussed.

Within Southern California, east Pacific green sea turtles (Chelonia mydas) forage year-round, taking advantage of diverse food resources, including seagrass, marine algae, and invertebrates. Assessing persistent organic pollutants (POP) in green turtle aggregations in the Seal Beach National Wildlife Refuge (SBNWR, n = 17) and San Diego Bay (SDB, n = 25) can help quantify contamination risks for these populations. Blood plasma was analyzed for polychlorinated biphenyls (PCBs), organochlorinated pesticides (OCPs), and polybrominated diphenyl ethers (PBDEs). PCBs and body size explained much of the separation of turtles by foraging aggregation in a principal component analysis. Turtles from SDB had significantly (p < 0.001) higher total PCBs than SBNWR turtles. Most PCBs detected in turtles were non-dioxin-like PCB congeners (153, 138, 99) that are associated with neurotoxicity. Recaptured turtles' POP levels changed significantly over time indicating significant variation in POP levels through time and space, even among adjacent foraging locations.

The Pestalotiopsis sp. genus comprises filamentous fungi whose species present both pathogenic and clinical-industrial importance. The cultivation and production of bivalve molluscs in regions of Rio de Janeiro is lucrative both artisanally and industrially, as the climate, geography and water quality favor the practice of this activity throughout the year at reduced costs, making the region competitive in the national market. The aim of this study was to isolate and identify filamentous fungi associated with the internal tissue anatomy of bivalve molluscs (Perna perna) from mariculture farms. Samples collected from BEMAR marine farms were dissected and transferred to 1% hypochlorite, washed in sterile distilled water and sown on Petri dishes containing potato dextrose agar (BDA). After four days, a white colony, displaying vigorous mycelium, cotton-like with abundant sporulation and black conidia masses was isolated. Observations concerning vegetative and reproductive structures were performed by microcultures stained with Amann's Lactophenol andCotton Blue. Micromorphology analyses indicated spindle and septated conidia, with two to three apical filiform appendages and a short basal pedicel. The result indicates that bivalve mollusks may be bioindicators for the presence of Pestalotiopsis sp; associated with water transport, possibly due to diluted sediments in the medium. No infectious processes or lesions in the processed material were observed. This is, to the best of our knowledge, the first report of Pestalotiopsis sp; in Perna perna mytilids.

Repeated reports of microplastic pollution in the marine pinniped diet have emerged in the last years. However, only few studies address the drivers of microplastics presence and the potential implications for monitoring microplastic pollution in the ocean. This study monitored their in the scats (N = 205) of four pinniped species/subspecies at five different locations in the southern Pacific Ocean (Peru and Chile). Samples from all rookeries contained microplastics, and overall, 68% of the examined scats contained fragments/fibers, mostly blue colored. We confirmed that 81.5% of the fragments/fibers were anthropogenic in origin , but only 30% were polymers. Scats from Juan Fernández Archipelago presented higher microplastic concentrations than continental rookeries. Also, the common diet in each location may influence the levels found in the samples. This study presents a useful non-invasive technique to track plastic pollution in top predator diets as bioindicators for future surveillance/management plans applied to different location.

Titanium (Ti), used in many dailyuse products, such as shampoos and sunscreen filters, in the form of TiO₂ nanoparticles (NPs), may elicit adverse marine biota effects. Marine mammal Ti data is scarce, and subcellular distribution and detoxification information is non-existent. Ti concentrations and metalloprotein detoxification in Pontoporia blainvillei and Steno bredanensis dolphins from Southeastern Brazil were assessed. Metallothionein (MT) concentrations were determined spectrophotometrically, total and subcellular Ti, by ICP-MS and detoxification, by HPLC-ICP-MS. Ti detoxification occurred through MT complexation. Statistical Ti-MT associations were observed in S. bredanensis liver, indicating TiO₂ NPs contamination, as Ti binds to MT only as NPs. MT-Ti correlations were observed for both the coastal (P. blainvillei) and offshore (S. bredanensis) dolphins, evidencing oceanic TiO₂ diffusion. Ti detoxification through binding to reduced glutathione occurred in both species. Thermostable subcellular fractions are a valuable tool for cetacean Ti detoxification assessments and should be applied to conservation efforts.

This paper reported the distribution of phytoplankton biomarkers in surface sediments of Liaodong Bay, Bohai Sea. The primary productivity indicated by biomarkers is consistent with the results from modern water column phytoplankton surveys, indicating that the biomarkers can be used to reconstruct the primary productivity. The productivity in the bay mouth is higher than in the shallow coast area, indicating that the main controlling factor is the turbidity rather than terrestrial nutrients. The high primary productivity near Juhua Island is mainly related to eutrophication caused by human culture and land-based sewage discharge. The relative proportion of biomarkers showed that diatom and dinoflagellate contributed more to the coastal area and were mainly related to the competitive advantage under the condition of high nutrient salts, while a high proportion of haptophytes was found in the middle, which corresponded to the high salinity water.

Baseline characterizations of estuarine sediments in Chukchi and Beaufort Seas, were conducted. Concentrations of 194 organic and elemental chemicals were analyzed in sediment and fish, plus stable isotopes of carbon and nitrogen. The estuaries are shallow embayments, with little shoreline relief. The water columns were turbid, high salinity, and not stratified. Concentrations of arsenic and nickel were elevated throughout the region. Arsenic in fish tissue was elevated. Concentrations of PAHs were relatively high for pristine locations, but did not include petroleum hydrocarbons. Characteristics of PAHs indicate large contributions of terrestrial organic matter. With the exception of Peard Bay, all the estuaries reflected the strong influence of terrestrial plant input with low δₒ/ₒₒ values for carbon and nitrogen. Chlorinated pesticides and PCBs were uniformly low, but detectable in fish tissue. PCB and cyclodiene concentrations were half that seen in southeast Bristol Bay. Hexachlorobenzene was detected in all fish samples.

Hypoxia (O₂ ≤ 2 mg L⁻¹) can severely threaten the survival of marine life and alter the biogeochemical cycles of coastal ecosystems. Its impacts are dependent on its duration. In the present study, hypoxia was observed in autumn at the end of October 2011. It may be one of the latest recorded annual hypoxic events in the East China Sea (ECS). In the hypoxic regions, a large amount of nutrients and dissolved inorganic carbon were observed to regenerate. Also, acidification (low pH) was observed. On the other hand, hypoxic dissipation may be due to the destratification caused by the upwelling of the hypoxic regions in the ECS. These results suggest that hypoxia may occur for longer periods of time than expected and, accordingly, the effects of hypoxia on the ECS ecosystems should be reconsidered and further evaluated.