PURPOSE OF REVIEW: The direct radiative effect of brown carbon (BrC) absorption predicated by climate-modeling studies is highly uncertain, with values ranging between +0.03 W/m² and + 0.57 W/m². This review strives to identify sources of this uncertainty stemming from challenges in translating measurements into model inputs and to draw lessons from recent advances that lead to improved BrC representation in models. RECENT FINDINGS: Previously thought to absorb only short-visible and UV light, BrC was recently shown to comprise components that are strongly absorptive in the mid- and long-visible wavelengths, with light-absorption efficiencies approaching that of black carbon. The classic picture of biomass and biofuel combustion being the major sources of atmospheric BrC still holds, with recent measurements indicating a strong correlation between BrC optical properties and combustion conditions. Other combustion sources of BrC, currently not accounted for in models, include low-efficiency coal combustion and ship engines utilizing heavy fuel oil. Gas-phase, aqueous, and particle-phase reactions in the atmosphere produce secondary BrC and bleach/darken the primary BrC. Climate-modeling studies revealed that predicted BrC radiative effects are sensitive to the assumed optical properties and atmospheric aging mechanisms. BrC can be grouped into four optical classes, each separated by an order of magnitude in mid-visible light absorption. The classes are approximately mapped to BrC sources, with secondary BrC being the least absorbing and BrC from high-temperature combustion the most absorbing. There is evidence that each class exhibits characteristic physicochemical properties (molecular size, volatility, and solubility), which can be leveraged to design measurements that quantify distributions of BrC across classes as well as rates of photobleaching/darkening for each class. Utilizing this framework to develop BrC parameterizations promises to enhance its representation in climate models.

Benthic foraminifera can be used as an environmental bioindicator, especially in the polluted environment where their sensitivity to pollutants may be expressed by a modification in the assemblage. Based on the quantitative and qualitative analysis of 189 surface sediment samples in Liaodong Bay, 76 benthic foraminifera species which belong to 40 genera were recognized. Q-mode factor analysis was made for the 32 benthic foraminifera species, and three assemblages are recognized: Ammonia aomoriensis- Cribroelphidium magellanicum- Protelphidium tuberculatum; Textularia foliacea- Polskiammina asiatica; and Rotalidium annectens- Buccella frigida. To study the effects of heavy metal elements on benthic foraminifera fauna, seven heavy metals elements have been analyzed in all the surface sediment samples, the results show that the heavy metal elements in Liaodong Bay are mainly distributed in Jinzhou Port, and that the overall characteristics are high in northwest and low in southeast. The distribution of foraminifera and heavy metals elements reveals that there is a significant correlation between them. Cribroelphidium magellanicum and Protelphidium tuberculatum have maintained a high level in heavy metal enrichment areas, and may be used as an indicator of heavy metal contamination along the coast of Liaodong Bay.

The Indian Ocean hosts a wide range of living resources including fish stocks. Marine resources contribute significantly to economies and livelihoods, and seafood is a major source of protein in Indian Ocean nations. Fisheries resources in the Indian Ocean have started showing symptoms of depletion. Several regional fisheries management organisations (RFMOs) have been established for sustainable management of the fisheries resources in the Indian Ocean region. These RFMOs were created at different times with various particular mandates, and in some cases prior to the emergence of contemporary scientific concepts and legal approaches to marine environmental governance. In this article, eight such RFMOs are studied to determine the implementation of ecosystem-based fisheries management (EBFM) and the precautionary approach (PA), which are now widely accepted norms of fisheries management and international law. This article argues that there is a mismatch between the legal and governance frameworks, and the fisheries science and management.

The Integrated Nitrogen CAtchments (INCA-N) model was applied to identify the sources and processes controlling riverine nitrogen (N) export in the Jiulong River watershed, coastal China. Future riverine N exports were simulated under various scenarios of climate and land-use changes. The modeling results showed good agreement between the observed and simulated values of streamflow, N concentrations, and loads. It was revealed that fertilizer application, atmospheric N deposition, and sewage discharges were the main N sources, while the primary N cycling processes included soil nitrification, soil denitrification, and N leaching. Nitrate-N exports were predominantly impacted by climate change, whereas ammonium-N exports were more affected by land-use change. The coupled effects of climate and land-use changes were projected to amplify nitrogen export by 30%, 36%, and 36% for nitrate-N and 32%, 48%, and 71% for ammonium-N during the years for 2030s, 2050s, and 2080s, respectively.

Plastics and synthetic materials are polluting the world's oceans. In this study we exposed juvenile mussels, Mytilus edulis, to glass reinforced plastic (GRP) dust, under laboratory conditions. The study ran for a period of 7 days, to test for the morphological and potential physiological impacts of GRP. Infrared spectroscopy has revealed that the GRP resin material is poly diallyl phthalate. In mussels, particulate glass and plastics were detected in the digestive tubules and gills, with a suite of inflammatory features observed in all examined organs. In parallel, we observed the effect of powdered GRP on swimming behaviour and survival of water fleas, Daphnia magna. Polymer particles and fibreglass adhered to the filament hairs on appendages, including the caudal spine, in exposed organisms. Most importantly, swimming impairment and sinking of the animals were recorded shortly after exposure. The potential implications for severe localized impact of GRP on aquatic environment are discussed.

Element concentration (Fe, Mn, Pb, Zn, Cu, Cr, Ni and Co) in the surface sediments of Ashtamudi estuary, Southwest coast of India, has been analyzed to understand the spatial variation and potential ecological risk status. The sediment pollution index and Potential Ecological Risk index suggest that the northeastern part of the estuary exhibits low to moderate polluted sediments with moderate ecological risk. The results of correlation analysis indicate that the natural weathering process and river input play an important role in the distribution of the elements in the surface sediments of the estuary. The extracted factor results indicate that the fine sediment fractions supporting for accumulation of the trace elements, whereas the enriched level of Fe and Mn is chiefly controlled by the riverine process, and other elements are contributed by anthropogenic influences.

The Conwy estuary was evaluated for sediment quality. Microtox bioassay revealed 38 of 39 sites were non-toxic. Hg ranged from 0.001 to 0.153 μg kg⁻¹, mean 0.026 mg kg⁻¹, Σ16 PAH from 18 to 1578 μg kg⁻¹, mean 269 μg kg⁻¹, Σ22 PAH, 18 to 1871 μg kg⁻¹ mean to 312 μg kg⁻¹, two sites had high perylene relative to ΣPAH. Σ22PAH correlated positively with TOC, clay and silt (R² 0.89, 0.92, 0.90) and negatively with sand. Multivariate statistics, delineated four spatial (site) and five variable (measurements) clusters. Spatial clustering relates to sediment grain size, in response to hydrodynamic processes in estuary; fine (clay to silt) sized sediments exhibit the highest Hg and PAH content, because these components partitioned into the fine fraction. Comparison to national and international environmental standards suggests Hg and PAH content of Conwy sediments are unlikely to harm ecology or transfer up into the human food chain.

The Arctic is an ecologically diverse area that is increasingly vulnerable to damages from oil spills associated with commercial vessels traversing newly open shipping lanes. The significance of such accidents on Arctic marine habitats and the potential for recovery can be examined using ecological risk assessment (ERA) coupled with a dynamic object-oriented Bayesian network (DOOBN). A DOOBN approach is useful to represent the probabilistic relationships inherent in the interactions between key events associated with an oil spill, including oil dispersion from the source, ice-oil slick interactions, seawater-oil slick formation, sedimentation, and exposures to different aquatic life. From such analysis, a probabilistic cost analysis can be performed to examine the theoretical cost of habitat services lost and restored. The application of an ERA-DOOBN model to assess oil spills in the Arctic is demonstrated using a case study. The utility of the model output for determining habitat restoration costs and developing policy guidelines for ecological response measures in the Arctic is also discussed.

Fifty years ago, the tanker SS Arrow ran aground in Chedabucto Bay on the east coast of Canada, causing a massive spill of Bunker C oil in winter conditions. This article reflects on this anniversary, briefly describing the spill response and the considerable follow-up research over five decades on the fate and effects of oils spilled in northern cold marine waters. Importantly, the spill led to considerable work in Canada on spill control and bioremediation measures, and advice about oil spills as a marine pollutant of global importance.

The distribution and sources of PAHs in jinga shrimp (Metapenaeus affinis), and human health risks due to consumption was evaluated in collected samples from the Musa Bay, Persian Gulf. The total concentration of PAHs (∑16PAHs) ranged from 10 to 144 μg kg⁻¹ dry weight, indicating low to moderate level of pollution. The PAHs were dominated by three- (41%) and two-ring (38%) compounds. Source identification analyses indicated the PAH pollution mostly originated from petroleum inputs. A preliminary evaluation of human health risk using chronic daily intake, hazard index, benzo[a]pyrene-equivalent (BaPₑq) concentration (PEC) as well as the incremental life cancer risk and non-cancer risk assessment suggest low potential health risk for consumers of the Metapenaeus affinis. However, the results indicate minimal risks associated with the intake of PAHs via shrimp consumption, but long-term monitoring is required to evaluate the changes in ecological and human health impacts of contaminants in the region.PAHs in Metapenaeus affinis from Musa bay, which influenced by anthropogenic activities were low to moderate level of pollution. Human health risk indicates low potential health risk for consumers.