By identifying the main sources of nitrate (NO3−) can obtain useful information to support the management of NO3− pollution, particularly in subtropical catchments with shallow drinking water wells. This study used water chemistry and dual stable isotopes δ15N and δ18O methods to assess seasonal and spatial variations of NO3− in precipitation, surface water, and groundwater in an agricultural and forest subtropical catchment in Jiangxi Province, China. The maximum concentrations of nitrate-nitrogen (NO3−-N) and ammonium-nitrogen (NH4+-N) were 10.4 and 10.8 mg L−1in samples collected from 221 rainfall events from 2011 to 2013. About 4.4% and 12.3% NH4+-N concentrations of surface water and groundwater exceeded the thresholds of 1.0 and 0.2 mg L−1. The NO3−-N concentrations in surface water were closely correlated with NH4+-N concentrations in surface water and groundwater (r = −0.71 and r = −0.71, P < 0.05). The concentrations of NH4+-N and NO3−-N were significantly higher in a fishery pond and nearby drinking wells than in other monitoring points. Annual exports of NO3−-N and NH4+-N were 4.06 × 104 and 8.14 × 103 kg yr−1, respectively and NO3−-N is the main form of N loss. The δ15N values ranged from 0‰ to 20‰ in surface water and groundwater, and the δ18O values ranged from 0‰ to 15‰ and 1‰–13‰, respectively. Dual stable isotope natural abundance distribution and water chemistry [NO3−]/[Cl−] molar ratio information suggested that manure and sewage and soil N were the main sources of NO3− in surface water and manure and sewage in groundwater in summer and winter. In spring, water occurred denitrification and ammonium fertilizer, manure and sewage were the main sources of NO3− in surface water and groundwater which sampling points were closer residential area and fish ponds than paddy field and local farmers used more Manure. Manure applications should be reasonable around drinking water wells to protect the drinking water quality.

Micro-plastic particles in the world's oceans represent a serious threat to both human health and marine ecosystems. Once released into the aquatic environment plastic litter is broken down to smaller pieces through photo-degradation and the physical actions of waves, wind, etc. The resulting particles may become so small that they are readily taken up by fish, crustaceans and mollusks. There is mounting evidence for the uptake of plastic particles by marine organisms that form part of the human food chain and this is driving urgent calls for further and deeper investigations into this pollution issue.The present study aimed at investigating for the first time the occurrence, amount, typology of microplastic litter in the gastrointestinal tract of Solea solea and its spatial distribution in the northern and central Adriatic Sea. This benthic flatfish was selected as it is a species of high commercial interest within the FAO GFCM (General Fisheries Commission for the Mediterranean) area 37 (Mediterranean and Black Sea) where around 15% of the overall global Solea solea production originates.The digestive tract contents of 533 individuals collected in fall during 2014 and 2015 from 60 sampling sites were examined for microplastics. These were recorded in 95% of sampled fish, with more than one microplastic item found in around 80% of the examined specimens. The most commonly found polymers were polyvinyl chloride, polypropylene, polyethylene, polyester, and polyamide, 72% as fragments and 28% as fibers. The mean number of ingested microplastics was 1.73 ± 0.05 items per fish in 2014 and 1.64 ± 0.1 in 2015. PVC and PA showed the highest densities in the northern Adriatic Sea, both inshore and off-shore while PE, PP and PET were more concentrated in coastal areas with the highest values offshore from the port of Rimini.

Ecological quality objectives (EcoQOs), as tools for implementing ecosystem approach, have long been acknowledged to protect the marine ecosystems and fisheries in regional seas through joint efforts by surrounding countries over the past decade. The present review analyzed the best available meta-data relating to the five ecosystem elements that were recently proposed by the Northwest Pacific Action Plan to evaluate the current status of coastal ecosystem health in marine environment of the Yellow Sea. We suggested the six tentative EcoQOs among five ecological quality elements including: 1) biological and habitat diversity; 2) invasive species; 3) eutrophication; 4) pollutants; and 5) marine litters. Environmental status was assessed, depending on the EcoQOs targets, by comparison to the world average values, existing environmental standards, or reported values of other regional seas. Results of analysis revealed that among the six tentative EcoQOs, two target objectives to marine biodiversity and concentrations of nutrients (viz., DIN and DIP) were met towards good environmental status. Whilst, three EcoQOs relating to hypoxia and red-tide, pollutants (persistent toxic substances and metals), and marine litters (including microplastics) did not meet and one relating to invasive species could not be judged due to insufficient data sets. The biggest weak point for developing suitable EcoQOs and assessing status of ecosystem health could be insufficient meta-data sets available and/or discrepancy in methodological details cross the data-sets or between the two targeted countries. Thus, the cooperation of neighboring countries, viz., Korea and China for the Yellow Sea, is necessary for the ecosystem based management of our regional sea in the future. Overall, this first time review for the assessment of target tentative EcoQOs in the Yellow Sea region encompassing coasts of Korea and China would provide a better understanding of the current status of environmental pollution and ecosystem health.

Climate change and anthropogenic nutrient enrichment are driving rapid increases in ocean deoxygenation. These changes cause biodiversity loss and have severe consequences for marine ecosystem functioning and in turn the delivery of ecosystem services upon which humanity depends (e.g. fisheries). We seek to understand how such changes will impact seafloor functioning using biological traits analysis. Results from a sewage-sludge disposal site in the Firth of Clyde, UK spanning 26 years of monitoring showed that substantial changes in macrobenthic nutrient cycling and the provision of food for predators occurred, with elevated functioning on the margins 1–2 km from the centre of the disposal grounds. Thus, changes in food-web dynamics are expected, that weaken benthic pelagic coupling and lower secondary production (such as fisheries). Generally, functioning was conserved, but declined below a ~6% total organic carbon threshold. Similar to other severely deoxygenated systems, the recovery was slow and hysteresis was apparent.

This paper reviews the recent environmental deterioration in Ariake Sea, Japan, including an increased frequency of red tides and hypoxic waters and decreased fishery production. Analysis of the mechanisms of environmental deterioration suggests that it is possibly induced by the decrease in tidal flat area, decreases in the tide and tidal current and changes in the sediment environment. The Isahaya Bay reclamation project resulted in the loss of 1550 ha of tidal flats, and is one of the possible reasons for the decreases in the tide and tidal current. Therefore, some fishermen and researchers believe that opening the reclamation project dike's floodgates is an effective environmental restoration countermeasure for Ariake Sea. However, the central government decided not to open the floodgates at present due to strong opposition from local farmers, and some researchers believe that the influences of the Isahaya Bay reclamation project on the environmental changes outside of Isahaya Bay are minor. Several lawsuits regarding these relationships and the opening of the dike's floodgates are currently under dispute. To revive Ariake Sea as a sustainable ecosystem, other countermeasures for environmental restoration are suggested and discussed in this paper.

The spatial extent of human activities must be understood for consistent and proportionate regulation, and effective marine planning. Redundant offshore pipelines can be removed or left in situ, but data on the footprint of these options are not readily available. The extents of three North Sea in situ decommissioning scenarios are presented. Leaving pipelines in situ would occupy <0.01% (12.3 km2) of UK waters, and this was similar to, or smaller than, other regulated activities (e.g. aggregate extraction). Adding armouring to large pipelines occupied up to 95 km2, while creating fisheries exclusion zones occupied up to 1119 km2. Removal of pipelines >30″ would be required to regain 50% or more of the seabed currently occupied. At present, the technology to remove pipelines >16″ safely and cost-efficiently is untested for large-scale decommissioning projects. The summaries presented inform the debate over the significance of decommissioning, and the regional consequences of different options.

The presence of toxic elements in fish represents a hazard for human health, especially in Mediterranean countries and other regions with high per-capita fish consumption. The present research, carried out along the northern Catalan coast (NW Mediterranean), aimed to determine the levels of trace metals and arsenic in the muscle of white seabream Diplodus sargus (L.), a common demersal species of growing interest for fisheries and aquaculture. Average mercury concentrations widely exceeded the limits imposed by EU despite the low contamination levels previously reported for the study area, stressing the potential risk associated to the consumption of medium-sized, non-predatory fishes. The other analyzed elements fell within the recommended limits. Preliminary results about the feeding habits of D. sargus are reported, in order to determine feeding habitat and items of the analyzed specimens.

A tropical coastal power plant with a once-through cooling system that pumped sea water along with tiny marine phytoplankton and zooplankton for waste heat discharge recorded reduction in the population density of these organisms by 64% and 93%, respectively, at the discharge site. The depletion of organic carbon is 0.69 tons per annum with loss of 20 to 24 lakhs fish fecundity. The synergistic effect of tropical summer ambiance and waste heat discharge from the power plant considerably reduced the phytoplankton population in the coolant water discharge point during April, June, and July. This resulted in changes in the phytoplankton community structure from Bacillariophyceae > Dyanophyceae > Cyanophyceae to Bacillariophyceae > Cyanophyceae > Dyanophyceae in the Ennore creek system. A unique epibiotic assemblage of the diatoms Licmophora juergensii and Licmophora flabellata was observed on Phormidium sp., a mat-forming Cyanobacterium preharbored along the 4.5-km-long transport channel of the cooling tower blow out of the thermal power plant. These pedunculate fouling diatoms have a symbiotic association with Phormidium sp., which grows few microns high above the substrate, thus creating obstructive flow in cooling water channels of the power plant. Further, loss of fish larvae during zooplankton population reduction creates an impact on the local fishery. However, the emerging scenario of global warming predicts that the migration of fish population toward cooler regions shall further aggravate the fishery reduction near the power plant cooling operation along the tropical coasts. The marine organisms living in tropical coastal waters operated at upper limits of thermal tolerance produce a demand for the regulatory bodies in India to enforce a drop in discharge criteria for coolant water, with the pre-existing power stations permitted to discharge up to 10 °C above the ambient temperature and newer power stations permitted to discharge a maximum of 7 °C. It becomes a requisite for power stations to draw additional seawater along with the plankton. Therefore, an emerging technology of subsurface intake systems called beachwell that resolves the issue of coolant water intake without biota was advocated.

Tropical sea cucumber fisheries are generally traditional, small-scale, multispecies and poorly managed. Many recent studies have improved our knowledge on the biology and ecology of the commercially important species; the main results are analysed and the remaining gaps discussed. The fisheries and the patterns of trade changes during the last decade are presented from the data available and confirm overexploitation in the traditional Indian Ocean and West Pacific countries and territories. Several Latino-American countries now have active fisheries. Despite the management and conservation issues which have recently received more attention at international, regional and national levels, more measures are still needed at all these levels, to ensure sustainable exploitations of these resources.

We simulate oil spills of 1500 and 4500m3/day lasting 14, 45, and 90days in the spawning grounds of the commercial fish species, Northeast Arctic cod. Modeling the life history of individual fish eggs and larvae, we predict deviations from the historical pattern of recruitment to the adult population due to toxic oil exposures. Reductions in survival for pelagic stages of cod were 0–10%, up to a maximum of 43%. These reductions resulted in a decrease in adult cod biomass of <3% for most scenarios, up to a maximum of 12%. In all simulations, the adult population remained at full reproductive potential with a sufficient number of juveniles surviving to replenish the population. The diverse age distribution helps protect the adult cod population from reductions in a single year's recruitment after a major oil spill. These results provide insights to assist in managing oil spill impacts on fisheries.