Marine pollution bulletin最新文献

Saipan, the largest and most populated island of the Commonwealth of the Northern Mariana Islands, has coastal areas with high submarine groundwater discharge (SGD) and heavy metal pollution of sediments. Here, we measured metal concentrations in coastal Saipan groundwater and surface water and explored spatial correlations with pollution sources. Concentrations of Cd, Pb, Cu, and Zn were highest in inland wells, with 3 wells exceeding USEPA guidelines for Cu or Pb. Concentrations tended to be highest in well groundwater, intermediate in beach groundwater and surface water, and lowest in offshore reef areas, suggesting that SGD could transport metals to coastal waters, although surface water dissolved metal concentrations were not elevated in high-SGD areas. High Cu and Cd in Laolao Bay suggested a possible threat to aquatic life. More research is needed on metal concentrations in water supply wells, including the possible influences of dumpsites and other pollution sources.

Microplastic pollution has become a global environmental issue, severely impacting marine ecosystems. In Colombia, understanding of marine microplastic pollution remains limited, necessitating targeted efforts for prevention and conservation. This study presents the first assessment of microplastics along 125 km of the Caribbean coast of La Guajira region in Colombia. Sediment samples from seven beaches (Palomino, Dibulla, Camarones, Riohacha, Valle de los Cangrejos, Mayapo, and Jimatsu) were analyzed for microplastic during two sampling periods, encompassing color, morphology, and polymer composition determined by Fourier transform infrared spectroscopy. Microplastics were found at Dibulla, Camarones, Riohacha, and Mayapo beaches during the two sampling periods (2.4 ± 0.6 to 12 ± 2 particles/m² in one period, and 3.2 ± 0.8 to 22 ± 7 particles/m² in the other). Filaments from fishing activities predominated, with microplastics mostly light-colored and composed of polypropylene, polyethylene, and polystyrene. While microplastic concentrations varied among beach use, differences between the two sampling periods were not statistically significant.

Marine forests support coastal biodiversity and ecosystem functioning. Nonetheless, how their productivity and carbon uptake might be affected by extreme events, such as marine heatwaves (MHWs), is yet to be explored. We experimentally evaluated the changes in oxygen and carbon budgets of the benthic community formed by the fucoid Ericaria brachycarpa induced by the exposure to a MHW. Rocks colonized by E. brachycarpa and associated macroalgal and invertebrate assemblages were collected at Capraia Island (NW Mediterranean) and put into six 500 L tanks at 23 °C. After 10 days of acclimation, the seawater temperature in three randomly chosen tanks was gradually elevated to 30.5 °C and maintained for 5 days, to simulate a MHW predicted by the end of the century under the RCP 8.5 scenario. Oxygen and carbon metabolic rates of the whole community were evaluated under light and dark conditions, using transparent and black incubation chambers, respectively. The exposure to the MHW caused a reduction in Net Community Productivity (NCP) and increased Community Respiration (CR). There was a trend for MHW to enhance total DIC release through the reduction of calcification and the increase of respiration rates, thus shifting the community metabolism to net heterotrophic. Lower net productivity and carbon uptake suggest that the role of these forests in sustaining coastal food webs and mitigating CO₂ emissions could be reduced under future climates. These results have implications for devising climate-proof strategies of conservation and restoration of macroalgal forests.

This study assessed effectiveness of regulations reducing environmental butyltin concentrations in Southern Chesapeake Bay over the 1999-2021 period. Water column monitoring of the Elizabeth River from 1999 to 2006 demonstrated decreasing TBT from 2003 to 2006 (average >1 ng/L at most stations) to <1 ng L^-1 by 2019 but with higher concentrations of degradation products DBT and MBT. TBT degrades to DBT and MBT within sediments, and releases degradation products over time. TBT induces imposex in exposed gastropods. Collections of the rapa whelk in 1999-2001 found TBT levels in female, imposex, and male whelks with median TBT concentrations of 10.5, 11.5, and 70 ng/g respectively. Collections in 2021 were below the TBT detection limit (<4.7 ng/g) and showed reduced incidence of imposex. The decrease of both TBT to below EPA water quality standard (7.4 ng/g) and observed gastropod imposex over the 1999-2021 period provides evidence that regulations limiting TBT use have been successful.

Microplastic pollution poses a significant threat to coastal ecosystems worldwide. Despite its widespread occurrence, knowledge on the prevalence and fate of microplastics across food webs is limited. To bridge this gap, we conducted an extensive study on microplastic contamination in mudflats, mangroves, and sand beaches being key habitats for wintering shorebirds on the west coast of India. Using a comprehensive multi-matrix approach covering water, sediment, biofilm, plankton, benthic macroinvertebrates, and migratory shorebird droppings, we analysed microplastic contamination across ten coastal sites from 2020 to 2022. Our findings show spatial and temporal variations in microplastics widespread in water and sediments, influenced by human activities. Notably, an increase in microplastics within prey and shorebird droppings coincide with a decline in prey abundance and shorebird populations. The prevalence of fibre-shaped microplastics indicates that common sources include discarded fishing gear and domestic sewage. The types of microplastics ingested by shorebirds varied depending on their feeding strategies, with biofilms serving as significant reservoirs of microplastics, facilitating their transfer to shorebirds. Epibenthic feeders, with a more limited foraging range, displayed the lowest levels of microplastics, while species foraging through multiple sediment layers exhibited higher concentrations. These findings underscore the urgent need for stricter conservation measures to tackle plastic pollution at its source. The study raises concerns about the potential harmful effects of microplastic contamination on the population of migratory shorebirds along the west coast of India. Continued research is crucial to understand the ecological impacts of microplastics on wintering shorebirds and to develop effective conservation strategies.

Rare earth elements (REE) are emerging aquatic trace pollutants. A total of 191 sediment samples were analyzed from the Yellow River estuary to study the REE geochemical behavior and environmental impact. The results showed that the samples contained high REE levels, and the average total amount of REE was 195.28 μg/g. REE enrichment was prominent in northern and northeastern fine-grained sediment zones, less near the coast, and the enrichment level was correlated with sediment grain size and land-based influences. Although the REE content varied greatly among the sampling stations, the distribution patterns were similar. They all had a right-dipping negative slope pattern, were relatively enriched in the light rare earth elements (LREE), and were characterized by a V-type REE distribution pattern with an Eu deficit. Evaluation using Geoaccumulation Index (I_geo), Contamination Factor (CF) and Pollution Load Index (PLI) showed that the sediments in the Yellow River estuary were generally in a state of slight REE pollution.