Estuarine ecosystems are considered hotspots for productivity, biogeochemical cycling and biodiversity, however, their functions and services are threatened by several anthropogenic pressures. We investigated how abundance and diversity of benthic macrofauna, and their functional traits, correlate to sediment biogeochemistry and nutrient concentrations throughout an estuarine-to-hypersaline lagoon. Benthic communities and functional traits were significantly different across the sites analysed, with higher abundance and more traits expressed in the estuarine region. The results revealed that the benthic trait differences correlated with sediment biogeochemistry and nutrient concentrations in the system. The estuarine regions were dominated by high abundance of large burrowing and bioturbating macrofauna, promoting nutrient cycling and organic matter mineralisation, while these organisms were absent in the hypersaline lagoon, favouring accumulation of organic matter and nutrients in the sediment. The results highlight the importance of preserving healthy benthic communities to maintain ecosystem functioning and mitigate the potential impacts of eutrophication in estuarine ecosystems.

In this study, the abundance, and characteristics of the microplastics on the southern coast of the Black Sea were assessed. More than 70% of the detected microplastics were smaller than 2.5 mm and mostly consisted of fibers and fragments. The average microplastic abundance in the beach sediment and seawater were 64.06 ± 8.95 particles/kg and 18.68 ± 3.01 particles/m³, respectively. The western coast of the study area (Marmara region) was the most polluted area, and a spatially significant difference was determined in terms of abundance. The composition in the beach sediment (particles/kg) was dominated by styrene acrylonitrile copolymer (SAC) (40.53%), polyethylene terephthalate (PET) (38.75%), and polyethylene (PE) (6.91%), whereas the seawater (particles/m³) was dominated by PET (57.26%), PE (13.52%), and polypropylene PP (11.24%). The results of our study can be a baseline for environmental modeling studies and experimental studies on the marine organisms inhabiting the Black Sea.

Global plastics production is increasing exponentially and contributing to significant pollution of the marine environment. Of particular concern is ingestion and entanglement risks for marine wildlife, including when items such as rope are incorporated into nest structures. These events are commonly documented using photographic and visual surveys, and each presents a number of challenges and benefits for species conservation and monitoring. Here we compare an invasive (i.e., removing debris from nests) and non-invasive (i.e., photographs) sampling method for quantifying nest debris using the silver gull (Chroicocephalus novahollandiae) as a case study. Overall, 17 debris items were detected in 9% of gull nests. While the use of photographs to monitor nest debris is increasingly popular, the invasive method detected one additional debris item not identified using photography. We therefore recommend caution for nest debris and other monitoring programs where identifying small or cryptic items may require a high level of skill.

We conducted field sampling over 19 months to investigate eelgrass population reproduction status and ecological interactions in a large seagrass meadow in a eutrophic bay in northern China. The results showed asexual growth played an important role in the maintenance of existing meadows, and sexual reproduction played a critical role in the colonization of new areas. We conclude that adult eelgrass shoots do rule the fate of seedlings in the large seagrass meadow. Additionally, nutrient resources (N and P) at this location were found to meet eelgrass growth demand. The N/P ratios of seawater and seagrass indicated N limitation relative to P in the eutrophic bay based on the seagrass Redfield ratio (25–30). Nutrient uptake by seagrass might be an important factor in reducing the probability of a red tide in the study area. The results of this study provide fundamental information for eelgrass restoration and conservation.

Beach litter represents a worldwide problem impacting both terrestrial and aquatic environments. In the present study, we assessed beach litter pollution in a prominent touristic site in Brazil, the Jericoacoara National Park. In particular, we applied a delta-generalized additive modeling (GAM) approach in order to investigate pollution hotspots and to provide better guidelines for coastal environmental managers. A total of 7549 litter items were collected, resulting hard and flexible plastics the most abundant type. Our GAM analysis revealed that the distribution of each type of litter was affected by distinct drivers in the protected area, with the extension of the beach, tourist attractions, wind angle, and the distance to water bodies and villages as the most significant explanatory variables. Our model is suitable in predicting litter pollution hotspots on beaches, which is a valuable tool for future guidelines and effective management strategies to prevent beach pollution worldwide.

To determine the ecological effects of atmospheric wet deposition of dissolved nutrients on the coastal waters around the Yangma Island, rain and snow samples were collected and analyzed at a shore-based site for one year. The wet deposition fluxes of dissolved inorganic nitrogen and phosphorus (DIN and DIP) and dissolved organic nitrogen and phosphorus were 69.2, 0.136, 13.3 and 0.143 mmol m⁻² a⁻¹, respectively. In summer, the new production fueled by wet deposition accounted for 19.3 % of that in seawater and 16.4 % of the amount of particulate organic carbon ingested by the scallops cultivated in the study area, indicating the potential contribution of wet deposition to fishery resources. Meanwhile, precipitation increased the seasonal average DIN/DIP ratios in surface seawater by 17.7 %, 16.3 %, 23.4 % and 6.5 % in spring, summer, autumn and winter, respectively, which could change the composition of ecological community and cause obvious negative impact on the ecosystem and mariculture.

This study focused on marine sediments from the Black Sea, mainly due to bacterial diversity-induced public health / biotechnology application value. Sediment samples were gathered from 14 locations at differing depths across Turkish shores on a seasonal basis over 10 months, with bacterial identifications performed through using multimodal analytical platforms. Overall, 26 differing, predominantly Gram-positive (57.5 %) bacterial species were identified for this region, including Bacillaceae (50.0 %) and Pseudomonadaceae (15.0 %). The most dominant classes were identified as Bacilli (52.5 %) and Gammaproteobacteria (40.0 %). Ten isolates (25 %) to the species level and thirty-six isolates (90 %) to the genus level were identified using VITEK® MS and Bruker Microflex® LT/SH, in comparison to 16S rRNA sequencing results. Identified species – particularly, novel reported species – can contribute to the knowledge of microbial life dwelling upon sediments of the south-eastern regions of the Black Sea.

Potassium hydroxide (KOH) digestion protocols are currently applied to separate microplastics from biological samples, allowing efficient digestion with minor degradation of polymers in a time- and cost-effective way. For biota samples with high-fat content, KOH reacts with triglycerides generating an overlying soap layer, making difficult the digestion and solubilization and subsequent microplastics extraction. Here we studied the addition of Tween-20 in different concentrations to evaluate the effect on the soap layer of post-digested samples. Addition of 10 % of Tween-20 presented higher flow rate during filtration, being set as optimal value. Incorporation of Tween-20 in the extraction procedure increased recovery rates of LDPE, PC and PET and appears to have a protective effect on PC and PET degradation. Tween-20 did not interfere in FTIR spectrum of polymers available in the marine environment. Being low-toxic, makes addition of Tween-20 a simple and economical way to optimize KOH digestion protocols for microplastics extraction.

Marine mammals can serve as an indicator of ecosystem health, and are likely exposed to significant amounts of microplastics (MPs). In this study we estimated the MP uptake of two odontocetes, the short-beaked common dolphin (Delphinus delphis) and the common bottlenose dolphin (Tursiops truncatus), in the Mediterranean Sea and the Northeast Atlantic. These two species are expected to primarily ingest MPs through trophic transfer. To this end, data was collected on their diet, which was subsequently linked to MP occurrence and abundance in prey families. We estimated that D. delphis ingests 76 MPs/day in the Northeast Atlantic and 164 MPs/day in the Mediterranean, and T. truncatus ingests 36 MPs/day in the Northeast Atlantic and 179 MPs/day in the Mediterranean. This study provides important new predictions on MP exposure in two odontocetes, and opens up new research opportunities on the effect of this exposure on the health of organisms.

Trace metals in sediments from the Chester River, a tidal tributary of the upper Chesapeake Bay with a predominantly rural, agricultural watershed, were investigated to better understand distributions and potential sources of metals. Sediments were analyzed for Al, Fe, Ni, Cr, Cu, Zn, As, Ag, Cd and organic C. Concentrations exceeded sediment toxicity guidelines in 44% of samples for Pb, and >20% for As, Ni, Cr, and Cu. Median enrichment factors (EF) for Cd, Ag, Pb, As and Zn were elevated above natural background levels. Nickel, Cu, Zn, and Cd exhibited significant differences in EF medians between the upper, middle, and lower segments of the river. Cadmium and As enrichments are presumably from application of inorganic and organic fertilizers in the watershed. Active marinas are likely an important source of metal enrichment, especially for Cu. The data underscore how land use in rural watersheds contributes to metals loading in aquatic systems.