The geochemical characteristics of heavy metals (Cd, Co, Cr, Cu, Ti, Zn) in 61 surface sediments from the Yangtze River Estuary and its adjacent East China Sea were studied. The high values of Cu, Co and Zn are distributed near the mouth of Hangzhou Bay. The high values of Cr appear near Zhoushan Archipelago. The high values of Cd appear in the Yangtze River Estuary, while Ti and Cd have high values in the open sea eastward. The order of pollution degree is Cr > Cd > Co > Zn > Ti > Cu. The enrichment degree is Cd > Cr > Zn > Co > Ti > Cu. Except for some sites, Cd is moderately enriched, but there is no severe enrichment. The main sources of human activities of the six metals include industry and shipping. Agricultural production may be another important source of human activities for Cd.

Climate change will increase energetic demands on marine invertebrate larvae and make planktonic food more unpredictable. This study determined the impact of ocean acidification on larval energetics of the oysters Saccostrea glomerata and Crassostrea gigas. Larvae of both oysters were reared until the 9-day-old, umbonate stage under orthogonal combinations of ambient and elevated p CO ₂ (340 and 856 μatm) and food was limited. Elevated p CO ₂ reduced the survival, size and larval energetics, larvae of C. gigas being more resilient than S. glomerata. When larvae were fed, elevated p CO ₂ reduced lipid levels across all lipid classes. When larvae were unfed elevated p CO ₂ resulted in increased lipid levels and mortality. Ocean acidification and food will interact to limit larval energetics. Larvae of S. glomerata will be more impacted than C. gigas and this is of concern given their aquacultural status and ecological function.

Governments in Australia and internationally are experimenting with policy instruments to facilitate the adoption of farming practices with reduced environmental impacts. The Great Barrier Reef (Australia) is one such case, where sustained efforts over 20 years have yielded insufficient progress towards targets to reduce the impacts of agriculture on water quality in downstream marine ecosystems. We present a critical review of policy instruments as implemented in Great Barrier Reef catchments. We catalogue the evolving mix of policy instruments employed in reef programs, and examine evidence of the effectiveness of agricultural extension, financial incentives, and direct regulation of farming practices. There is little robust evidence to assess instrument effectiveness, in part due to the evolving mix of the instruments employed, weak program evaluation and heterogeneity of agricultural enterprises. We identify the need to improve the understanding of instrument fit to landholders and enterprises. We recommend a modelling approach to clarify pathways to impact and guide improved policy evaluation.

Using structured surveys in 2008 and 2016, change in disease burden and use of chemical treatments in Bangladesh shrimp farm management was examined. Overall, disease burden had increased in all farms and was more polarized, with a fewer number of individual infectious diseases responsible for most disease in ponds. Farmers also reported physical deformities, nutritional deficiencies, and unknown diseases further indicating poor health of their stock. To combat the threat, more chemical treatments were used (5.2 treatments per farm in 2008 versus 28.8 in 2016), resulting in an average increase of 424% in the number of active substances entering shrimp ponds. Although there was a modest reduction in the use of antimicrobials, shrimp was being exposed to a wider range of chemicals during rearing. The subsequent concern for the environment, animal and human health demands further research to identify potential risks from residues of chemical products.

Microplastics (MPs) are ubiquitous in oceans. Their transboundary transport and fate have aroused global attention. Taiwan is located close to the western boundary current-Kuroshio, is an excellent location to study of MP mobility in the global current and Pacific Garbage Patch. This study is the first investigation to understand the microplastic contamination from Taiwan to the Kuroshio. MP concentrations in the area varied from N.D. to 0.15 items m⁻³, with an average concentration of 0.05 ± 0.03 items m⁻³. The majority of MPs were polypropylene, polyethylene, polyethylene and terephthalate. We found two MP hotspots near the coastal zone. One additional hotspot was also identified in the “pristine” Kuroshio suggesting rivers and local currents may play critical roles in transporting or injecting MPs from Taiwan into the North Pacific Gyre. These findings suggest that marine environments are altered by anthropogenic disposal and provide needed data for modelling and prediction of MPs.

South Korea is one of the largest consumers of flame-retardants worldwide. In this study, water, sediment, and biota samples were collected from a highly industrialized lake to investigate contamination, isomeric profiles, source, and the bioaccumulation potential of hexabromocyclododecanes (HBCDDs). Almost all of the sediments were severely contaminated by HBCDDs, which were some of the highest global levels compared to those found in previous studies. The highest concentrations and similar profiles to those of technical mixtures of HBCDDs were observed in creeks passing through industrial complexes, indicating on-going contamination by high consumption of HBCDDs from industrial activities. γ-HBCDD was dominant in water and sediment, whereas α-HBCDD was dominant in fish and shellfish. The diastereoisomeric profiles of HBCDDs in multiple matrices were influenced by proximity to industry and chemical properties. In-situ biota-sediment accumulation factors of α-HBCDDs were > 1 in benthic species, implying that HBCDDs are of great concern in sedimentary environments.

Marine scientists and other experts depend on information found in archival documents and other historical records to investigate underwater munitions. These sources help them locate dumpsites, establish timelines, identify ordnance, and better understand the hazards, chemicals, and degradation products found in their studies. However, historical sources do not always satisfy these needs, and can sometimes lead investigators down convoluted, incomplete, and misleading trails of evidence. This article seeks to provide scientists with some advice about conducting archival research and interpreting meaning from historical sources by recounting the history of a dumping operation that never happened over the summer of 1921. In doing so, this article demonstrates the value of historical perspectives and research methodologies, and encourages scientists to better integrate historical evidence into their work and seek out more collaborative opportunities with historians.

Long-term changes of nutrients, plankton and macrobenthos were studied to research the transformation of ecosystem in Jiaozhou Bay and Daya Bay in the past 30 years. Concentrations of dissolved inorganic nitrogen and phosphate increased with significant changes in nutrient compositions and ratios. Concentrations of Chl a slightly decreased in Jiaozhou Bay but increased in Daya Bay. Phytoplankton abundances increased and diatoms were dominant, however, dinoflagellate gradually had the competitive advantage under high N/P and N/Si in the two bays. Zooplankton biomass significantly increased in Jiaozhou Bay, but only increased slightly in Daya Bay over the past years. Polychaetes were dominant in macrobenthos in the bays, indicating their adaptation to the changing benthic environments. The long-time variations of biocenoses and nutrients reflected that the ecological environments have changed under the influence of anthropogenic activities in the two bays.

High nutrient loading discharge into the oceans is an evolving threat to the marine biota at large, including the Bay of Bengal (BoB) which receives one of the highest inflows of nutrient fluxes from rivers like the Ganga and the Brahmaputra. Further, the complex riverine and deltaic formations are difficult to be quantified, hence satellite-based observation of chlorophyll and phytoplankton species can add more insight in the nutrient aggregation process. We evaluated the spatial sensitive zones in the BoB in terms of anthropogenic nutrients. Our study shows that coccolithophore population and chlorophyll a concentration can be an active indicator of flood mediated nutrient inflow into the oceans. SST illustrated weaker correlation with phytoplankton species during the monsoon owing to prevalence of cyclonic conditions and high nutrient concentration, however, the relationship is relatively stronger during the pre-monsoon when more stable oligotrophic conditions exist. Higher concentration of diatoms, cyanobacteria and chlorophytes in BOB compared to the Pacific Ocean indicates the ecological sensitivity and the resilience of the Bay of Bengal in terms of nutrient cycling.