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.

We investigated an unexpected microplastic (MP) leakage event that occurred along the coastline of Yantai in January 2021. Sediment samples were collected from three zones on 9 beaches. MPs were identified with an average abundance of 247.6 ± 125.6 items/m² on 7 beaches. The total amount of MPs from the leak accident was estimated to be 1.50 × 10⁷ items (514.67 kg). The MPs were identified as polyethylene (PE), polypropylene (PP), and PP/PE blends using μ-FT-IR analysis. By utilizing a numerical model, the transmission process and potential source of MPs were demonstrated. The modeling results showed that the MPs might originate from the central and western part of the Bohai Sea and be driven to the beaches of Yantai by northwest wind and wind-induced surface current. However, due to the absence of direct evidence, the simulation results might only indicate the range of the leaking source, which was the movement trajectory of MPs.

Since 1990s, harmful algal blooms (HABs) of Kareniaceae, primarily caused by species of Karenia and Karlodinium and rarely by Takayama species, have been substantially increasing in frequency and duration in the coastal waters of China. In this study, we recorded a bloom of high abundance of T. acrotrocha in the Haizhou Bay, the Yellow Sea in September 2020, which is the first record of a Takayama bloom in the temperate coastal waters of China. We found that high concentrations of DON and DOP accelerated the proliferation of T. acrotrocha in the Haizhou Bay. Intensive mariculture, and terrestrial nitrogen and phosphorus input may be responsible for the eutrophication in the Haizhou Bay featuring high concentrations of DON and DOP, and high DIN/DIP ratios. The results suggested that, under ocean warming, the HABs of Kareniaceae are becoming increasingly dominant in eutrophic temperate coasts with intensive mariculture activities.

Setting appropriate reference conditions (RCs) is critical for classifying the Ecological Quality Status (EcoQS) which is extremely challenging, considering the present-day estuaries. The EcoQS of three tropical estuaries was assessed by applying five different RCs to identify the best applicable method for the area. The AZTI's indices (AMBI and M-AMBI) categorised areas with sharper pollution gradient with ease, while classification of moderate-low polluted areas was ambiguous. Indices responded to chemical stressors more clearly in the impacted estuary compared to the less polluted estuaries. Ecological status assigned by the default RC (lowest AMBI and highest diversity and richness values) were more accurate than those obtained on application of other four types of RCs, owing to various estuarine constraints that are discussed herewith. Thus, prior to application, caution should be exercised while setting area-specific RCs. The inclusion of combination of AZTI's indices with professional judgment for successful appraisal of ecosystem is recommended.