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.

This paper analyzed the long-term variations in nutrients in Liaodong Bay and their potential influencing factors based on historical data from 1978 to 2019. Under the influence of both human activities and natural changes, the concentration of DIN increased approximately 4-fold from the end of the 1990s to the mid-2010s, while DIP and DSi concentrations decreased from the beginning to the end of the 1980s and have since increased again. Asynchronous changes in nutrient levels have led to changes in the nutrient composition, which has caused a series of ecological effects. The total phytoplankton abundance decreased from the 1980s to the end of the 1990s and then increased again. Additionally, the phytoplankton composition shifted from a diatom-dominated to a dinoflagellate-dominated system, and the dominant species of zooplankton changed. Harmful algal blooms (HABs) rarely occurred before the 1980s but have frequently occurred since the end of the 1990s.

Anthropogenic pressures such as the introduction of non-indigenous species (NIS) have impacted global biodiversity and ecosystems. Most marine species spreading outside their natural biogeographical limits are promoted and facilitated by maritime traffic through ballast water and hull biofouling. Propagule pressure plays a primary role in invasion success mixed with environmental conditions of the arrival port. Moreover, with the current ocean sprawl, new substrates are offered for potential NIS recruits. Here, differences in the fouling assemblages thriving inside three different ports/marinas facilities in Madeira Island were assessed for comparison. The locations showed significant differences concerning assemblage structure. Most NIS were detected in plastic floating pontoons. Funchal harbour receives most of the marine traffic in Madeira, acting as the main hub for primary NIS introductions, being recreational boating involved in NIS secondary transfers. Our results highlight the need for future management actions in island ecosystems, particularly monitoring and sampling of recreational boating.

This paper presents experimental results on the cross-shore distribution of non-buoyant microplastic particles under irregular waves propagating, shoaling and breaking on live sediment sloping beds. Eighteen microplastic particle groups having various shapes, densities, and sizes are tested. The experiments consider two initial bottom configurations corresponding to a (i) plane bed and (ii) pre-developed singly-barred profile (more representative of field conditions). Four different microplastic accumulation hotspots are identified: offshore of the breaker bar, at the breaker bar, the plateau region between the breaker bar and beach, and the beach. It is found that the accumulation patterns primarily fall within three different particle Dean number regimes. The importance of plunger-type breaking waves for both on and offshore transport of microplastic particles is highlighted.