The golden tide, caused by the brown algae Sargassum horneri, exerts severe influences on the Pyropia aquaculture of Jiangsu coast, China. To study the outbreak of the golden tide in response to increasing greenhouse gas emissions, S. horneri was cultured under four conditions: ambient condition (10 °C, 400 μatm), elevated temperature condition (14 °C, 400 μatm), elevated CO₂ level (10 °C, 1000 μatm), and potential greenhouse condition (14 °C, 1000 μatm). The growth, photosynthetic performances, and inorganic carbon affinity of S. horneri were studied. The results showed that elevated temperature exerted a more pronounced positive influence on S. horneri growth, photosynthesis, and carbon assimilation than CO₂ enrichment. The growth of S. horneri was significantly improved by moderately elevated temperatures, especially under concurrently elevated CO₂ levels. This suggests that the greenhouse effect will benefit growth and carbon sequestration of S. horneri, which may enhance the frequency and scale of golden tides.

Knowledge about the occurrence of emerging organic micropollutants in the marine environment is still very limited, especially when focusing on the Belgian Part of the North Sea (BPNS). This study therefore optimized and validated a Speedisk® based SPE and LC-Q-Orbitrap HRMS method to tackle the challenge of measuring the expected ultra-trace concentrations in seawater. This method was applied to 18 samples collected at different locations in the open sea and harbor of the BPNS. Forty-eight compounds, among which several pharmaceuticals, personal care products or pesticides described in the EU Watchlist, were detected – some for the first time in seawater – at concentrations ranging up to 156 ng L⁻¹. Moreover, the untargeted screening potential of the newly developed HRMS method was highlighted by revealing the presence of up to 1300 unknown components in a single sample and by assigning molecular formulae to those components demonstrating high discriminative potential between samples.

The marine macroflora of the ports of Le Havre and Antifer have been studied by citizen scientists since the late 1970s. In addition to analysis of the previous results, the field study was extended from 2010 to 2018. A total of 97 and 62 macroalgae were identified, respectively, including 14 NIS (non-indigenous species), the latter number being certainly an underestimate since microscopic species were not exhaustively sought and given the high number of cryptogenic species encountered. No new primary introduction of NIS for the NE Atlantic has been detected since the late 1970s. The origin of NIS and vector(s) of introduction were investigated. For all NIS, the donor region is the Indo-Pacific. Two likely vectors have been identified: maritime traffic for earlier introductions, and shellfish imports for more recent ones. The role of these ports and maritime traffic in the processes of introduction is discussed.

Heavy metals (HMs) and polychlorobiphenyls (PCBs) enter the Arctic environment through a variety of anthropogenic sources with deleterious effects towards biota and public health. Bacteria first transfer toxic compounds to higher trophic levels and, due to the tight link existing between prokaryotic community functions and the type and concentration of contaminants, they may be useful indicator of pollution events and potential toxicity to other forms of life. The occurrence and abundance of HM-tolerant and PCB-oxidizing bacteria in the sub-Arctic Pasvik river area, heavily impacted by anthropogenic modifications, was related to HM and PCB contamination. This latter more likely derived from local inputs rather than a global contamination with higher PCB and HM amounts (and higher bacterial viable counts) that were determined in inner and middle sections of the River. Finally, a panel of bacteria with potential applications in the bioremediation of cold environments were selected and phylogenetically identified.

The ballast water management convention incorporates principles of risk assessment. A new ballast water management risk assessment model was developed to support the implementation of most efficient management measures, which we also present as a flowchart decision support system model. The risk assessment model was tested using data from port baseline surveys where available, and real shipping and ballast water discharges data. The here presented ballast water management risk assessment and possible management options are applicable elsewhere to support and improve complex decision making in the implementation of management requirements according to the ballast water management convention. If needed, the model may easy be adapted to address local specifics in any other region or area.

The concentrations of some trace metals in the Acropora downingi coral skeleton and sediment samples of Khark Island, Chirouyeh and Hendorabi Island in the northern part of the Persian Gulf were evaluated to determine the ecological risks of trace metal contamination in the sediment. Risk assessment indices revealed that Cd in all of the studied areas as well as Ni and Pb in Chirouyeh site would be expected to cause ecological risk occasionally. Moreover, Chirouyeh site showed a high tendency for trace metal adsorption. Khark and Chirouyeh sites showed higher risk values than the unpopulated Hendorabi, indicating that the anthropogenic activities had a significant impact on the trace metal contamination. Multivariate clustering dendrogram and Pearson's correlation coefficient indicated that Pb originated mainly from anthropogenic sources, Cu originated from both anthropogenic and natural sources, while other metals mainly originated from natural sources. The adsorption rate of trace metals in sediment samples was significantly correlated with the physico-chemical properties of the environment, whereas the uptake of trace metals by the Acropora downingi corals seemed to be dependent on their metabolic factors. Overall, the results showed that coral (Acropora downingi) reef ecosystems of the Persian Gulf are at the low to moderate risk of trace metal contamination of the bottom sediment. Overall, this study provides a 'snapshot' of the status of trace metals pollution in the coral reef ecosystems of the Persian Gulf, and also highlights the need for long-term studies in order to understand, monitor and mitigate further trace metal pollution in the region.

The identification and quantification of ascorbic acid, phenolic acids and flavonoids were carried out simultaneously with a rapid method of reverse-phase high-performance liquid chromatography (RP-HPLC). Total flavonoid contents were being determined by UV–Vis spectrophotometry, and total phenolic contents were determined by UV–Vis spectrophotometry using the Folin-Ciocalteu Reagent (FCR) method.In all of the individual contents and total phenolic content analysis, the best results were obtained with the methanol-water solvent system. The methanol-hexane solvent system was selected as the best for the extraction of total flavonoid contents. The reason for this difference is the flavonoids in the analyzed samples which were the lipophilic character. Examining the algae species, the highest contents were achieved from Ulva lactuca and Ceramium rubrum species. Depending on industrial activity and the population density, regional characteristics have been shown to be effective in the changes of these contents which show antioxidant properties.

Following the Editorial addressing the BALMAS project, we open the ballast water management special issue for the Adriatic Sea by providing background information on non-indigenous species and the mechanisms (vectors) of transport. Problems allocating introduction mechanisms for various species with certainty are described; in general, key introduction mechanisms are shipping, with ballast water and biofouling as dominant vectors, and aquaculture activities. The dominant mechanisms for introduction may differ through time, between regions and across species. We highlight ballast water as the focus of an international convention to prevent future introductions, reviewing management options and suggesting future research needs. This assessment is not restricted in application to the Adriatic Sea, but is applicable to other coastal waters. Results of such future work may contribute to the experience building phase planned by the International Maritime Organization for a harmonised implementation of the Ballast Water Management Convention.

As the production of plastic products continues to increase, determining the fate of plastic waste in the environment is of high importance. Densely populated areas, such as Mediterranean coastlines, represent locations of high pollution risk for surrounding environments. Thus, this study aims to assess the abundance, size, and composition of floating meso- and microplastics collected during four weeks in 2018 in the Ligurian and Tyrrhenian Seas. The results show average meso- and microplastic particle concentrations of 28,376 ± 28,917 particles km⁻², and an average mass of 268.61 ± 421.18 g km⁻². The particle shape ratio was 65% fragments, 19% films, 10% lines, 4% foams, and 2% pellets. Microplastic particles comprised 65% of the sample. Analysis with attenuated total reflection Fourier transform infrared spectroscopy showed predominant polymer types included polyethylene, polypropylene, polystyrene, and polyamide. These data are an important starting point for long-term monitoring of plastic pollution levels within this region.

Pollution by microplastics (MPs) is currently a global problem in the coastal and marine environment. Transfer of MPs from land to sea and their inclusion in the food web has a significant adverse effect on the marine life and human health. The present study was carried out at the fishing harbour of Chennai, southeast coast of India. The possible MPs were isolated from the soft tissues of the commercially important bivalve Perna viridis and examined by microscopic and DXR Raman spectroscopic methods. The MPs were identified as to be polystyrene polymers in the soft tissues. This investigation revealed that size and color are the major factors affecting the bioavailability of MPs to bivalves in the study area. The presence of colorants in organisms revealed an anthropogenic origin through the use of a wide array of applications. Hence, coastal zones are a hotspot for pollution by MPs, and filter feeding bivalves are at the highest risk. Therefore, further studies are required to understand the accumulation rates and residence time of MPs across the food webs.