An oil platform in the Mississippi Canyon 20 (MC-20) site was damaged by Hurricane Ivan in September 2004. In this study, we use medium- to high-resolution (10–30 m) optical remote sensing imagery to systematically assess oil spills near this site for the period between 2004 and 2016. Image analysis detects no surface oil in 2004, but ~40% of the cloud-free images in 2005 show oil slicks, and this number increases to ~70% in 2006–2011, and >80% since 2012. For all cloud-free images from 2005 through 2016 (including those without oil slicks), delineated oil slicks show an average oil coverage of 14.9 km2/image, with an estimated oil discharge rate of 48 to ~1700 barrels/day, and a cumulative oil-contaminated area of 1900 km2 around the MC-20 site. Additional analysis suggests that the detected oil slick distribution can be largely explained by surface currents, winds, and density fronts.

The relationship between Microcystis abundance and environmental variables was studied during a Microcystis bloom in the summer months of 2016 in an artificial lagoon of Hangzhou Bay, China. It was determined that Microcystis abundance increased from 0.16 × 104 cell/L to 5.8 × 107 cell/L within 17 days from 28 July to 14 August, contributing to 96.84–99.56% of the total phytoplankton abundance. Then, Microcystis gradually disappeared 57 days afterwards. The results showed that the growth of Microcystis, including the stage of recovery, outbreak, subsidence and disappearance, was significantly correlated with water temperature, salinity, soluble reactive phosphorus (PO4-P), dissolved inorganic nutrients (DIN), silicate (SiO4-Si), the ratio of DIN/SiO4-Si and zooplankton abundance, and the key environmental triggers which promoted the outbreak of Microcystis were water temperature, PO4-P concentration and zooplankton abundance in this artificial lagoon.

Sewage pollution is contributing to the global decline of coral reefs. Identifying locations where it is entering waters near reefs is therefore a management priority. Our study documented shoreline sewage pollution hotspots in a coastal community with a fringing coral reef (Puakō, Hawai'i) using dye tracer studies, sewage indicator measurements, and a pollution scoring tool. Sewage reached shoreline waters within 9 h to 3 d. Fecal indicator bacteria concentrations were high and variable, and δ15N macroalgal values were indicative of sewage at many stations. Shoreline nutrient concentrations were two times higher than those in upland groundwater. Pollution hotspots were identified with a scoring tool using three sewage indicators. It confirmed known locations of sewage pollution from dye tracer studies. Our study highlights the need for a multi-indicator approach and scoring tool to identify sewage pollution hotspots. This approach will be useful for other coastal communities grappling with sewage pollution.

Microplastics are small plastic particles, globally distributed throughout the oceans. To properly study them, all the methodologies for their sampling, extraction, and measurement should be standardized. For heterogeneous samples containing sediments, animal tissues and zooplankton, several procedures have been described. However, definitive methodologies for samples, rich in algae and plant material, have not yet been developed. The aim of this study was to find the best extraction protocol for vegetal-rich samples by comparing the efficacies of five previously described digestion methods, and a novel density separation method. A protocol using 96% ethanol for density separation was better than the five digestion methods tested, even better than using H2O2 digestion. As it was the most efficient, simple, safe and inexpensive method for isolating microplastics from vegetal rich samples, we recommend it as a standard separation method.

We report a mortality event of Red Phalaropes (Phalaropus fulicarius) that occurred from October to November 2016 on the north coast of British Columbia, Canada. All individuals were severely underweight and showing signs of physiological stress. The guts of all carcasses contained ingested plastics (100%, n = 9). Distribution modelling from pelagic bird surveys (1990–2010) indicated that Red Phalaropes are not typically found in the study area during fall months. Ocean conditions during fall 2016 were unusually warm, coinciding with reduced upwelling in the study area. eBird records since 1980 indicated Red Phalaropes are observed closer to shore during periods associated with reduced upwelling. These results suggest that distribution shifts of Red Phalaropes closer to shore, where plastic debris occurs in higher concentrations, may lead phalaropes to feed on plastic debris while in a weakened state, resulting in a combination of two adverse circumstances.

Jakarta Bay has become contaminated by both organic and inorganic pollutants, including heavy metals. This study aimed to examine the effect of heavy metal pollution on green mussels cultured in Muara Kamal Waters, Jakarta Bay over seven months. In this research, the water quality was assessed, through measuring the concentrations of the heavy metals, Hg, Pb, Cd, Cr, and Sn in the water, and in the tissue of green mussels that had been cultured there for seven months. The percentage of congenital abnormalities (malformations) in the green mussels was analyzed descriptively and the relationship between the water quality, heavy metals, and green mussel malformation was studied through principal component analysis (PCA). The result showed that the heavy metals concentrations in the water and sediment exceeded the quality standard at Muara Kamal but that in other respects the water quality was quite good. The green mussels cultured there for seven months had accumulated high concentrations of heavy metals, and ±60% of them had malformations of their shells. Based on the heavy metal concentrations in their bodies, the main cause of malformations in green mussels was suspected to be Pb, Hg, and Sn. However, the result of PCA showed it was the interaction between nitrogen compounds, phosphate, turbidity, salinity, pH, as well as the heavy metals in the water that determined the green mussel abnormality.

To understand the influence of river discharge on phytoplankton composition along western coastal Bay of Bengal (BoB), surface water samples were collected during peak discharge period. River discharge from the Ganges influences northwest (NW) coastal BoB whereas peninsular rivers (Godavari and Krishna) discharge to the southwest (SW) coastal Bay. River discharge from the Ganges is an order of magnitude higher than peninsular river resulting in low saline, less suspended matter and lower nutrients concentrations in the NW and contrasting to that was observed in the SW. ~50%of the phytoplankton were composed of Thalassiosira spp., Nitzschia spp., Microcystis spp., Amphiprora spp. and Thalassionema spp. in the SW whereas Thalassiosira spp., Nitzschia spp., Chaetoceros spp., Merismopedia spp. and Peridinium spp. in the NW. Significant variability in phytoplankton composition was observed from coast to offshore. Our study revealed that river discharge and associated physico-chemical characteristics governed the phytoplankton community along western coastal BoB.

Here we investigate microplastics contamination on beaches of four islands of the Lesser Antilles (Anguilla, St. Barthélemy, St. Eustatius and St. Martin/Maarten). These islands are close to the North Atlantic subtropical gyre, which contains high levels of microplastics. On average 261 ± 6 microplastics/kg of dry sand were found, with a maximum of 620 ± 96 microplastics on Grandes Cayes, Saint Martin. The vast majority of these microplastics (>95%) were fibers. Levels of microplastics differed among islands, with significantly lower levels found in St. Eustatius compared to the other Islands. No difference in microplastic levels was found between windward and leeward beaches. Our research provides a detailed study on microplastics on beaches in the Lesser Antilles. These results are important in developing a deeper understanding of the extent of the microplastic challenge within the Caribbean region, a hotspot of biodiversity.

Great Lakes states are increasingly faced with questions regarding how plastic debris is impacting marine and coastal ecosystems. This is especially evident along the southern beaches of Lake Erie, where high population and industrial development have contributed to the plastics problem. In Ohio, the most common items found are cigarettes and other smoking related materials, including plastic cigar tips. Given the growing awareness of the issue, and the impact of plastics on beaches throughout the Great Lakes, a focus group convened to investigate strategies to help address the problem. The group was comprised of individuals with practical knowledge of plastic cigar tip use and disposal issues, including representatives of government agencies, nongovernmental organizations, community groups, and local academic institutions. This report represents the exploratory results of the focus group, complete with information regarding the what, why, and how of plastic cigar tip debris in the region, guidance on the material and social barriers to sustaining desired behaviors (cessation of use by minors and/or proper disposal), strategies to overcome those barriers, and suggestions for management and policy actions moving forward. Group members suggest that a combination of education and government-supported financial incentives may be the most effective approach, with community-based positive messaging backed by local taxes on smoking items that have plastic tips and rebates or other rewards for properly disposing of debris.

There exists limited understanding of the long-term dynamics of the seagrass Zostera noltii and how this is influenced by anthropogenic pressures. Milford Haven is a heavily industrialised estuary and also one of the important sites for Zostera sp. in the UK. In this study we examine all available long-term spatial variability and abundance data of Zostera noltii within Milford Haven using historic datasets. Results show that Z. noltii in all sites have shown meadow expansion when compared to the first obtainable records. Little change in abundance over the past 10–15years for the two sites confirms certain seagrass populations to be robust and thriving. We hypothesise that these populations are showing a level of resilience to the high nutrient levels, disturbance and high turbidity present within the water column of the Haven.