Located within the subtropical convergence zone, the Hawaiian archipelago is subject to high debris loads. This paper represents the first study to determine the spatial and temporal trends of floating macro debris quantities and polymer composition within Maui County waters. Ocean surveys were conducted from 2013 to 2017 and collected 2095 debris items of which 90% were plastic. Attempts to categorize items by source resulted in only 6% likely from land, 12% from ocean-based sources, 50% from either land or ocean, and 32% from unknown sources. Results found a multi-step process for debris accumulation, with temporal trends linked to survey day and year and spatial trends linked to ocean processes. High- and low-density polyethylene and polypropylene accounted for the majority of polymer types. The results of this study demonstrate minimal debris in Maui originates from land/local sources, and the importance of baseline data to guide further research and mitigation measures.

This study estimates levels of marine litter including plastics (macro-, meso- and microplastics) in sediments collected in shallow marine water from Croatia (Central Adriatic Sea). Selected sampling areas are characterized by different human pressure: Silba is highly stressed by tourism while Grebena is listed as marine protected area (MPA) of future institution. Obtained results on marine litter in sediments are correlated to ecological features recorded in each sampling site. Marine litter in collected sediments ranged within 180–528 items/kg d.w. Macroplastics were not recorded while mesoplastics were 1.3–4.8%. On a general basis, fibres are higher than microplastics. In Južni Greben, level of fragments higher than fibres was recorded. A slight significance of the factor “water depth” was evidenced by the statistical analyses exploring relationships among marine litter and ecological features. Furthermore, Silba and Grebena Islands showed a significant different assessment of size, shape and colour features. These results suggest different sources/dynamics affecting marine litter recorded in marine areas stressed by tourism compared to MPA.

Based on field observations in the summer of 2006 and long-term series data, this paper investigates the spatiotemporal variations of hypoxia and associated physical-biogeochemical driving mechanisms in the Bohai Sea (BS), China. Results show that the benthic hypoxic zone is mainly distributed in the “V”-shaped trough region in the western BS, and it tends to form two hypoxic centers which generally correspond to the bottom cold-water core. The regional difference in the intensity of stratification has a significant impact on the spatial distribution of hypoxia. The relatively weak stratification and the mesoscale anticyclonic eddy in the central shoal of the BS weaken the connectivity between the southern and northern hypoxic zones. Organic matter decomposition contributes to hypoxia and results in corresponding nutrient pool with a “dual (southern and northern)-core” structure. Intensified eutrophication is the main drive for decreasing in bottom dissolved oxygen and expansion of hypoxic zone in the BS.

The frequency of disease within coral communities was evaluated using an 18-month series of coral photographs taken before, during, and after a major dredging program at Barrow Island, off Australia's northwest coast. Up to 60 corals were assessed repeatedly at each of four dredging ‘impact’ sites (<1 km from dredging), and four ‘reference’ sites (>20 km from dredging). Contrary to an earlier report, the frequency of occurrence of coral disease (usually <5% of corals) was not significantly altered by dredging. The pattern of occurrence of coral disease does not constitute a suitable early warning bioindicator of dredging impacts on coral. This study suggests that disease is difficult to measure and evaluate, and is not a key indicator in the potential impacts of dredging on coral health. We propose that environmental monitoring during dredging should continue to focus on known impact indicators.

Metals are subject to internal subcellular compartmentalization, altering their bioavailability. Thus, subcellular metal assessments are crucial in biomonitoring efforts. Metal distribution in three subcellular fractions (insoluble - ISF, thermolabile - TLF and thermostable - TSF) were determined by ICP-MS in Steno bredanensis specimens from Southeastern Brazil. Associations between metals, metallothionein (MT) and reduced glutathione (GSH) were also investigated. Differential metal-detoxification mechanisms were observed. MT detoxification was mostly noted for As, Cd, and Pb, while Cu, Cr, Hg, Ni, Se and Ti displayed lower MT-associations. Fe, Zn and Se, on the other hand, were poorly associated to MT, and mostly present in the ISF, indicating low bioavailability. This is the first report on subcellular Sn and Ti distribution in cetaceans and the first in this species in Brazil. Potential protective roles of essential metals against toxic elements are postulated. This study indicates that important biochemical detoxification information is obtained through subcellular fraction analyses in marine mammals.

Drill cuttings (DC) are produced during hydrocarbon drilling operations and are composed of subsurface rock coated with hydrocarbons and drilling fluids. Historic disposal of DC at sea has resulted in the formation of large piles on the seabed that may be left in situ following infrastructure decommissioning. This study provides a first insight into the microbial abundance, diversity and community structure of two DC piles from North Sea oil and gas installations. The abundance of both bacteria and archaea was lower in DC than in surrounding natural sediments. Microbial diversity and richness within DC were low but increased with distance from the piles. Microbial community structure was significantly different in DC piles compared to nearby natural sediments. DC bacterial communities were dominated by Halomonas, Dietzia and Dethiobacter. The presence of such organisms suggests a potential function of hydrocarbon degradation ability and may play an active role in DC pile remediation.

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.

We report the occurrence of macroplastic debris in the stomach of a common dolphinfish (Coryphaena hippurus) caught in the Western Equatorial Atlantic. On the deck, we noticed that the fish was remarkably undernourished and decided to remove its stomach for laboratory analysis. A large part of a plastic bowl and a tuna pectoral fin were the only items recorded in the fish stomach. The plastic measured 99.57 cm2 and weighed 12.77 g, likely blocking the digestive tract and reducing food intake by the fish, as supported by signs of starvation. This is the record of the largest plastic debris ingested by a dolphinfish to date. As the source of the plastic container was probably a tuna fishing boat, we suggest strengthening environmental education programs to enhance the awareness of fishermen and mitigate the impacts of plastic pollution on the pelagic ecosystem and associated organisms, such as C. hippurus.

The annual sea surface temperature increased at a rate of 0.038 to 0.074 °C/year in recent decade, and pH decreased at a rate of 0.012–0.014/year in two coastal waters of the South China Sea. Therefore, a culture experiment was conducted to study the effects of acidification and warming on coral calcification rates. The calcification of three coral species were significantly reduced during the exposure to elevated CO₂, while other three coral species were not significantly affected. The reef coral Pocillopora damicornis was resistant to high CO₂, but was not able to survive during the exposure to 33 °C in our culture experiments. Our findings suggested that some corals might not survive in tropical areas if coral could not adapt to warming rapidly, and subtropical coastal waters with temperature of <30 °C will serve as refugia for the corals resistant to high CO₂ at the end of this century.

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.