Dissolved inorganic nitrogen (DIN) runoff from Great Barrier Reef (GBR) catchments is a threat to coral reef health. Several initiatives address this threat, including the Australian Government's Reef 2050 Plan. However, environmental decision makers face an unsolved prioritization challenge: determining the exposure of reefs to DIN from individual rivers. Here, we use virtual river tracers embedded within a GBR-wide hydrodynamic model to resolve the spatial and temporal dynamics of 16 individual river plumes during three wet seasons (2011−2013). We then used in-situ DIN observations to calibrate tracer values, allowing us to estimate the contribution of each river to reef-scale DIN exposure during each season. Results indicate that the Burdekin, Fitzroy, Tully and Daintree rivers pose the greatest DIN exposure risk to coral reefs during the three seasons examined. Results were used to demonstrate a decision support framework that combines reef exposure risk with river dominance (threat diversity).

PURPOSE OF REVIEW: Stormwater runoff of nutrients from developed landscapes is recognized as a major threat to water quality degradation through cultural eutrophication, which can lead to ecosystem imbalances and harmful algal growth. This review summarizes the current state-of-knowledge on the occurrence, sources, and transport processes of nitrogen (N) and phosphorus (P) in urban stormwater runoff and describes strategies for nutrient management of urban stormwater runoff. Future research needs identified from this review are provided as well. RECENT FINDINGS: Stormwater runoff of nutrients from urban environments to fresh water is controlled by multiple factors, including type of inputs, land use, development patterns, and management strategies. Recent research on stormwater management strategies has focused on internal nutrient cycling processes, such as microbial transformations of N in conventional wet ponds or bioretention cells, leading to a better understanding of the mechanisms that control the efficacy of stormwater management practices. Mitigating nutrient exports from urban environments will require controlling both quantities and sources of nutrient inputs into water systems, as well as new mechanistic understanding of the biogeochemical processes controlling nutrient treatment in stormwater ponds and low impact design (LID) structures. We need more research on source tracking of P from stormwater runoff as information is still relatively scarce. There is also a need to obtain better understanding of the dynamic interactions among multiple factors (e.g., sources, land use, characteristic of catchment and climate, management strategies) that control fate and transport of nutrients in urban stormwater runoff.

This is the first comprehensive study on the input, occurrence, and distribution of artificial sweeteners (ASs) in coastal wastewater treatment plants (WWTPs) and their receiving coastal waters. Acesulfame (ACE), aspartame (ASP), cyclamate (CYC), saccharine (SAC), and sucralose (SUC) were monitored for 6 months in Cadiz Bay (SW Spain). ASP was always detected at <0.1 μg L−1 and removal efficiencies were >90% for SAC and CYC. Higher ACE removal efficiencies were observed during warmer months. Persistence of ACE and SUC was observed in both WWTPs and their receiving coastal surface waters, where values up to 0.6 and 3 μg L−1 were measured, respectively. The highest concentrations were measured in a sewage-impacted estuary located in the north of the bay, where conservative behavior was confirmed. The source specificity and recalcitrance of ACE and SUC make them suitable for being used as sewage-pollution markers in coastal environments.

The ingestion of plastic debris by marine organisms has been documented across a variety of taxa including; marine mammals, sea birds, sea turtles and some fish species. Fewer reports have described ingestion by sharks, in this study the gastrointestinal tracts of 20 small spotted catsharks (Scyliorhinus canicula) trawl captured in the North Sea were investigated. Macroplastics (>20 mm) were found in 2 individuals and microplastic (<5 mm) was found in one other individual, this is the first time that plastic ingestion has been reported in this species. These observations suggest that gastrointestinal analysis of commonly landed elasmobranch species is worthwhile, to further understanding on the organisms and habitats impacted by plastic pollution.

Cape monkfish (Lophius vomerinus) is one of the long-lived species and top predators in the northern Benguela region. Studies on bioaccumulation of mercury (Hg) in cape monkfish are limited. This study compared the total Hg concentration between monkfish muscle and liver tissue; and related the monkfish total Hg concentrations to fish body size and capture locations (depth and latitude). Monkfish specimens (n = 529) were collected from 2016 to 2018. The mean total Hg concentration was 0.126 ± 0.005 mg/kg in muscle tissues and 0.106 ± 0.005 mg/kg in liver tissues. No significant differences were observed between total Hg concentrations of muscles and liver tissues. Differences in Hg concentrations between monkfish length classes were observed. No significant correlation was found between total Hg concentrations and latitude. A significant increase of total Hg concentration with the depth was observed. The concentrations of Hg were below the World Health Organization (WHO limits for fish (0.5 mg/kg).

This study provides the first evidence of nylon filament occurrence in the stomach of an economically important target shrimp species in the Mediterranean Sea, Plesionika narval (Fabricius, 1787). Samples were collected monthly from November 2014 to October 2015 from shallow (10–30 m) and deeper waters (150–170 m). The occurrence of plastics in the stomachs of the Narwal shrimp was 5.93% and identified as Nylon by FT-IR analysis. Higher percentages of ingested plastics were found in females from shallower depths and in males from deeper waters. The maximum number of plastics was recorded in January and March, possibly related to the higher feeding intensity of females prior to their reproduction period. A total of 10.3% of females and 4.8% of males with ingested plastics had almost empty stomachs. The presence of plastics in the stomach of P. narval is an evidence of passive ingestion which in this study related to fishing activities.

Information is scarce on historical trends of perfluoroalkyl substances (PFASs) in the coastal environment. In this study, four sediment cores were collected from semi-enclosed bays of Korea to investigate the pollution history, contamination profiles, and environmental burden of PFASs. The total PFAS concentrations in sediment cores ranged from 6.61 to 821 pg/g dry weight. The highest concentrations of PFASs were found in surface or sub-surface sediments, indicating on-going contamination by PFASs. Historical trends in PFASs showed a clear increase since the 1980s, which was consistent with the global PFAS consumption pattern. Concentrations of PFASs were dependent on the organic carbon content in sediment cores. PFOS and longer-chain PFASs were predominant in all of the sediment cores. In particular, a large proportion of longer-chain PFASs was observed in the upper layers of the sediment cores from industrialized coastal regions. Inventories and fluxes estimated for PFASs were similar to those for PCDD/Fs.

The current status of the water quality in terms of nutrients and trace elements were assessed in the Uppanar river estuary, Southern India. Twenty-five sampling stations were monitored in the study area, which is dominated by anthropogenic activities such as agriculture, settlements and fishing harbour in the downstream. Whereas, the upstream and midstream is dominated by barren lands and industrial hub respectively. Nutrients and trace elements such as nitrate, phosphate, iron and lead exceed the permissible limit of WHO drinking water guidelines. The water quality index derived from WHO permissible limits reveal that most of the samples fall under fair to good category. The marginal to fair water quality is noticed in the midstream to downstream region, where anthropogenic activities are high. The multivariate statistical analysis divulges that the overall water quality is controlled by two major sources such as natural weathering of soil/bedrock and agricultural and industrial activities.

Ultraviolet (UV) radiation is a primary environmental stressor for marine species inhabiting intertidal pools. Thus, the use of microhabitats as refuges is key to protect organisms against this stressor. In this study, we compared the quality of rocky and algae as refuges for the intertidal fish Girella laevifrons exposed to UV radiation. Refuge quality was studied by evaluating oxygen consumption and weight gain in control and UV-exposed fish. Rocky-refuge fish consumed less oxygen and gained significantly more weight than algal-refuge fish. The obtained results support the importance of refuge quality on energetic balance of intertidal organisms, where energy can be differentially allocated towards key life processes such as protection/repair or growth. Energy trade-offs need to be considered in research concerning animals inhabiting stressful habitats.

The discharge of petroleum hydrocarbons (PHs; ~10,000tons annually) into the Bohai Sea, a shallow inland sea in China, presents a serious threat to the marine environment. To evaluate the effects of PHs pollution and estimate the corresponding environmental capacity, we have developed a genetic algorithm-based coupled hydrodynamic/transport for simulating PHs concentration evolution and distribution from July 2006 to October 2007, with the predicted values being in good agreement with monitoring results. Importantly, the mean PHs concentrations and seasonal concentration variations were primarily determined by external loading, i.e., currents were shown to drive PHs transport, reconfigure local PHs patterns, and increase PHs concentration in water masses, even at large distances from discharge sources. The developed model could realistically simulate PHs distribution and evolution, thus being a useful tool for estimating the seasonal environmental capacity of PHs.