With the objective of characterizing the composition and spatial distribution of plastic fragments in a subtropical lagoon system, five sample areas affected by various anthropogenic impacts were chosen in the southern part of the Estuarine Lagoon System in Laguna, Santa Catarina, Brazil. The total density of the floating meso- and microplastics encountered was 7.32/m³, with the greatest density in the access channel and external area of the lagoon. Plastic filament was the most abundant and mainly comprised polyester (PET), polypropylene (PP) and polyethylene (PE) from 0.05 to 0.71 mm². Fishing and urbanization were the main sources of the meso- and microplastics in the environment. This is the first study to evaluate contamination by meso- and microplastics in the southern part of the Estuarine Lagoon System and provides information about the nature and extent of contamination by plastics in this estuarine ecosystem.

The ongoing reduction in extent and thickness of sea ice in the Arctic might result in an increase of oil spill risk due to the expansion of shipping activity and oil exploration shift towards higher latitudes. This work assessed the response of two oil-in-ice surface drift models implemented in an open-source Lagrangian framework. By considering two numerical modeling experiments, our main finding indicates that the drift models provide fairly similar outputs when forced by the same input. It was also found that using higher resolution ice-ocean model does not imply better results. We highlight the role of sea ice in the spread, direction and distance traveled by the oil. The skill metric seems to be sensitive to the drift location, and drift model re-initialization is required to avoid forecast deterioration and ensure the accurate tracking of oil slicks in real operations.

Green tide has broken out for 15 years in the Yellow Sea, affecting the marine ecological environment. This study extracted green tide information from 2007 to 2021, processed chlorophyll a (Chl-a) concentration data from 1997 to 2021 based on the Google Earth Engifne platform, and examined the relationship between them. Results showed that (1) the green tide had a inhibitory effect on the growth of phytoplankton, and the larger the scale of the green tide was, the stronger the inhibitory effect was and the slower the recovery of phytoplankton had after the green tide dissipated; (2) both the early distribution area of green tide and the Chl-a concentration in spring were correlated with the green tide scale. In addition, the feasibility of Chl-a to predict the scale of the green tide was preliminarily explored. With a view to improving the ability to predict green tide in the long term.

Coastal macrophytes serve as bioindicators of coastal trace metal contamination. In this study, trace metal levels in India's seagrass and saltmarsh ecosystems were assessed for their suitability as bioindicators of metal contamination. Trace metal accumulation and bioindicator potential of both seagrasses and saltmarshes were found to be metal and species-specific. Higher concentrations of Cu, Fe, Mg and Mn were found in the tissues of seagrasses, while saltmarshes showed higher accumulation of Cd, Cr, Hg, Ni, Pb and Zn. The leaves of seagrasses are suitable bioindicator of metals in the water column, while the roots and rhizomes of saltmarshes/seagrasses are suitable bioindicators of metals in the sediment. This study proposes the development of a monitoring network using seagrasses and saltmarss as model organisms for short and long-term monitoring of coastal metal contamination. Determining the phytotoxic levels of trace metals in seagrasses and saltmarsh is important for monitoring plant die-offs and loss.

The consumer preference of bivalves originating from fishery or aquaculture has gained momentum in response to higher nutrition, quality, and market availability. However, potential toxicity caused by plastics, the pollution icons of the current era, could raise concerns for the sources of essential nutrients provided by bivalves. Thus, we investigated the abundance, spatial distribution, polymer composition, size, and the shapes of the microplastics (MPs) in the sediment and Chamelea gallina from 15 sites at gradual depths (10 and 30 m) along the Southwestern Black Sea coast. The abundance of the MPs ranged from 28 to 684 MP kg⁻¹ in the sediments and the amount of 0.22–2.17 MP individual⁻¹ (or 0.20–2.16 MP g⁻¹ fresh weight soft tissue) in C. gallina. Seven types of polymers were detected by FTIR, and the most abundant type was polyethylene terephthalate (34.2–35.1%), polyethylene (28–31.1%), and polypropylene (18.9–21%). MP sizes were ranged from 73 to 4987 μm. 47% and 65% of the MPs in the sediments and C. gallina, respectively, were <1000 μm in size. The most dominant shape of the MPs was found as fibers (56.5% for sediments and 68.9% for C. gallina). The risk data predicted that people are exposed to 304 MPs when consuming a single portion of C. gallina weekly. Hypothetical calculations performed with a chemical additive simulation (bisphenol A) showed that the risk associated with the MP-contaminated C. gallina model is negligible, and the consumption is rather beneficial due to already known positive aspects.

The accumulation of drift organisms (Arribadas, constituted by benthic microalgae, macroalgae and bryozoans) on Central Beach in Balneário Camboriú (SC) has drawn attention since the early 2000s. However, historical surveys suggest an ancient phenomenon that has been increasing in intensity, promoted by urbanization and the eutrophication of the bay in recent years, leading to changes in the taxonomic composition. Previously, these Arribadas were comprised of two species of benthic microalgae (Amphitetras antediluviana and Biddulphia biddulphiana) and the bryozoan Arbocuspis ramosa. However, since 2019, a substantial increase in biomass has been observed on the beach and the dominance of the macroalgae Bryopsis plumosa strongly suggests an increase in the load of organic matter and nutrients in the bay. Recently (2022) the presence of a new invasive bryozoan species (Amathia alternata) was detected, highlighting the need to continue investigating the Arribadas to monitor the ecological evolution of this process.

Estuaries are ecologically valuable ecosystems that process nutrients through complex biogeochemical processes. Here we identify drivers and inhibitors of nitrogen removal in unvegetated intertidal sandflats at six sites in Manukau Harbour (37° 2.00′S 174° 42.00′E) to quantify the exchange of solutes across the sediment-water interface, with nitrogen removal rates (NRR) measured at two contrasting sites (PI and CB) near and far, respectively, from an historical wastewater treatment plant. Solute fluxes were paired with sediment and macrofauna community data to identify drivers of ecosystem function. Fluxes of oxygen, nitrogen and phosphorous were found to vary among sites, with differences attributed to variation in sediment characteristics (grain size, chlorophyll a, organic content) and macrofauna community structure. Mean NRR was found to vary between sites (PI = 32.2 vs CB = 217.9 μmol N₂/m²/h), with bioturbating macrofauna (bivalves Austrovenus stutchburyi and Macomona liliana), microphytobenthic biomass, and exposure to nutrients likely key contributing drivers.

Marine debris, in particular plastic debris and debris related to fishing activities, have an impact on marine mammals and seabirds. In marine-coastal species such as otariids, we can detect the incidence of these interactions through land-based observations. In this study, we recorded and described interactions between marine debris and the otariids Arctocephalus australis and Otaria byronia in a natural protected area in Peru, according to age class categories. Between 2016 and 2020, we recorded 151 animals that were directly impacted and/or were observed interacting with marine debris. Residual collars from fishing gear, ropes, plastic bags and unidentified material were recorded. Direct interactions with debris at colonies (e.g., plastic bags) were also recorded, as well as animals evidenced interacting with hooks. The age class category and species with the highest number of individuals impacted by residual collars were adult female A. australis and subadult male O. byronia. Single-use plastics were the most commonly bitten/moved waste by animals in the reserve. In the case of hooks, these were mostly lodged in the mouths of otariids. Our results highlight the importance of continuing to promote segregation at source, as well as the correct disposal of waste, locally and globally, to mitigate impacts on marine fauna.

This study helps understand the ballast water-mediated species spread risk dynamics in the Mediterranean and examine potential policy options for ballast water management to further reduce species spread risk in the region. Results show that Gibraltar, Suez, and Istanbul remained high-risk ports from 2012 to 2018, and they are hub ports connecting several clusters. We reveal ballast water management implications for both the Mediterranean region and individual hub ports respectively. To further reduce the risks of individual Mediterranean hub ports beyond the IMO standards, the most effective (cost-effective) regulatory method is to set more stringent regulation towards such hub ports besides the IMO regulation. To further reduce the risks of the Mediterranean as a whole, the most effective (cost-effective) regulatory scenario is to set more stringent regulation towards all Mediterranean ports besides the IMO regulation. The barge-based method is the most cost-effective technology to achieve stricter regulations.

Citizen science (CS) can help to tackle the emerging and worldwide problem of marine litter (ML), from collecting data to engaging different stakeholders. We reviewed what and how the scientific literature is reporting CS on ML to identify possible gaps to be improved. The 92 search results (separate occasions when 48 different CS initiatives were discussed across 85 publication records) revealed an under-representation of studies in developing regions. Most search results focused on the science of ML, whilst information regarding citizen scientists was commonly vague or missing, preventing critical analysis of good practices on this aspect. The studies concentrated on the shoreline and did not harmonize types and sizes of items collected, thus precluding data meta-analyses. The standardisation of CS methods and approaches and the detailed report of aspects related to citizen scientists are essential to support the science we need for the advances in CS efforts to face ML.