The distribution and bioconcentration of polycyclic aromatic hydrocarbons (PAHs) in water, suspended particulate material (SPM), algae, and zooplankton samples from the Pearl River Delta (PRD), South China, were investigated. The PAHs in the water and SPM samples is significantly associated with chlorophyll a (Chl a), implying the important role of the aquatic productivity on PAH distribution. PAHs in the water or SPM samples were strongly correlated to dissolved organic carbon (DOC) or algal particulate organic carbon (A-POC). Moreover, the log bioconcentration factor (BCF) values (mL g⁻¹) of PAHs in both the algae and zooplankton samples were linearly related to their log octanol-water coefficient (Kow) values. However, the slopes of these relationships were negatively correlated with Chl a, attributing to the difference in the dominant plankton species or the non-equilibrium exchange between air-water-biota. The above results indicate the important role of trophic levels on the distribution and bioaccumulation of PAHs.

A total of 23 beaches were surveyed between July and September 2019. Meso-litter was collected by sieving sediment collected from 0.25 m² quadrats laid along perpendicular transects through 5 mm mesh size sieves. The results showed that plastics were the most abundant litter encountered on all the beaches. Beaches close to urban areas had a higher number of litter categories (i.e. plastic, metal, foam, and paper) compared to the remote beaches that only had plastics. In conclusion, the lack of statistically significant evidence of the influence of proximity to urban centers, the predominant activity in the beaches, and exposure to wave action on the amount of meso-litter attest to the fact that marine litter pollution is a geographical spread problem that will require national, regional, and global action and approach to address. The intervention efforts (including beach clean-ups) should preferably target beaches that have back vegetation compared to those with seawalls.

PURPOSE OF REVIEW: Membrane techniques have been employed to concentrate livestock manure effluent from anaerobic digestion to produce highly concentrated liquid organic fertilizer. This review aims to provide a comprehensive understanding on the opportunities and challenges of membrane processes in the concentration of digested effluent for their further implementation. RECENT FINDINGS: Anaerobic digestion has been deployed to convert livestock manure into biogas (energy) and digestate with high potential as biofertilizer. Digestate can be separated into a solid and liquid fraction to reduce required capacity for onsite storage. The liquid fraction, known as digested effluent, remains a vexing challenge to digestate management due to the contradiction between its continuous production and seasonal application to farmlands, particularly in developing countries. Recent investigation has demonstrated the promise of membrane techniques for the concentration of digested effluent to recover recycling water and produce nutrient-rich liquid fertilizer. These techniques mainly include hydraulically driven membrane processes (from microfiltration to reverse osmosis), forward osmosis, membrane distillation, and electrodialysis. In most cases, these membrane techniques are hybridized to enhance the concentration efficiency. Nevertheless, the practical application of these membrane processes is hindered by several technical challenges, which mainly include membrane fouling, contaminant enrichment, ammonia volatilization, and high economic input. In this paper, we critically reviewed the performance of different membrane processes in the concentration of digested livestock manure effluent. Key technical challenges and their potential countermeasures were elucidated. Furthermore, future perspectives were provided to shed light on further development of membrane concentration techniques in the field.

Flood debris associated with Typhoon Lionrock from the Tumen River at the border between Russia and North Korea was traced using ocean color and a Lagrangian particle-tracking model. As debris is transported along with discharged water during floods, a means of tracing floodwater should also allow any associated debris to be tracked. By analyzing the anomalous distribution of colored dissolved organic matter (CDOM) and total suspended sediments (TSS) from the Geostationary Ocean Color Imager (GOCI), the southward movement of the floodwater was tracked along the eastern coast of the Korean Peninsula. This movement was driven by the North Korean Cold Current and was consistent with model results. The similarity between the satellite-derived and modeled datasets shows that CDOM and TSS can be used to track flood-derived debris for several hundreds of kilometers and locate hotspots of debris accumulation.

Oil weathering is often described subjectively after a spill. Adjectives like “moderate” and “severe” help define the extent of oil loss but fail to communicate quantitatively and reproducibly the degree of weathering. The use of subjective weathering terms often leads to misperceptions about persistence and toxicity of oil residues in the environment. The weathering of MC252 oil from the Deepwater Horizon spill started immediately after release during the 1500-m ascent to the sea surface and continued as it was transported on the surface and reached the shoreline. Weathering processes included evaporation, dissolution, photo-degradation, and biodegradation, among others. With extensive sample collection and detailed chemistry and source fingerprinting analyses, the Deepwater Horizon data provide a unique opportunity to evaluate weathering processes semi-quantitatively. An objective method of defining the degree of oil weathering is developed based on the detailed chemical results for over 700 MC252 oil samples from the environment.

The level of contamination of selected priority pollutants consisting of polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) were investigated from the tissues of stranded green sea turtles, Chelonia mydas, from the Gulf of Oman coast of the United Arab Emirates. Tissue samples - muscle and liver - were collected from 22 stranded green sea turtles from the coasts of Kalba and Khorfakkan from 2016 to 2018. Overall, we detected persistent organic pollutants (POPs) in 77% of the turtles. PAH's were the most frequently detected followed by high concentrations of OCP's (71% and 25% of the turtles, respectively). PCB's were not detected in any samples. Factors such as specimen size, mass of debris ingested and toxin hydrophobicity were not important factors affecting the concentrations of these compounds.

A comprehensive, high resolution, ground truthed benthic habitat map has been completed for Qatar's coastal zone and Halul Island. The objectives of this research were to; 1. Systematically compare and contrast pixel- and object-based classifiers for benthic mapping in a limited focus area and then to, 2. Apply these learnings to develop an accurate high resolution benthic habitat map for the entirety of the Qatari coastal zone. Results indicate object-based methods proved more efficient and accurate when compared to pixel based classifiers. The developed country-wide map covers 4500 km² and underscores the complex interplay of seagrass, macroalgal, and reefal habitats, as well as areas of expansive mangrove forests and microbial mats. The map developed here is a first of its kind in the region. Many potential applications exist for the datasets collected to provide fundamental information that can be used for ecosystem-based management decision making.

Based on field survey in the southwestern Yellow Sea (SWYS) during April–September 2017, the spatiotemporal variations in the hydrological characteristics and nutrient conditions were coupled and analyzed; the intra-seasonal variations in the upwelling in the front of the Yellow Sea Cold Water Mass (YSCWM) and impacts on nutrient transport were explored. The coastal area was controlled by the low-salinity high-nutrient Lubei Coastal Current, Subei Coastal Current, and Yangtze River Diluted Water from north to south; at bottom, the northeastern SWYS was controlled by the low-temperature high-salinity high-nutrient YSCWM. Temperature, salinity and nutrient fronts formed around YSCWM. The upwelling velocity in the front increased during April to late June and decreased in early September; the upwelled fluxes of dissolved inorganic nitrogen (0.29×10³-7.77×10³ μmol·m⁻²d⁻¹), phosphate (0.02×10³-0.27×10³ μmol·m⁻²d⁻¹) and silicate (0.98×10³-8.75×10³ μmol·m⁻²d⁻¹) showed similar variations during April–September. The upwelled nutrients could potentially contribute to local green tide development and phytoplankton growth during spring–summer.

Surficial marine sediments were sampled along the south-east coast and in Discover Bay Jamaica. Total elemental composition was determined for the sediments using three techniques. Total mass fractions of Al, As, Br, Ce, Co, Cr, Cs, Eu, Fe, La, Mn, Sb, Sc, Th, U, V, and Zn were determined using instrumental neutron activation analysis; Cu, Ni, Pb, Sr and Zr using energy dispersive X-ray fluorescence; and Hg using a direct mercury analyser. Potential anthropogenic hotspots were assessed using indices including enrichment factor (EF), geoaccumulation index (Igₑₒ), ecological risk (Eᵣ) and potential ecological risk index (Rᵢ). The quality of the sediments was also assessed using the sediment quality guidelines (SQGs). Temperature, pH, salinity, dissolved oxygen and organic carbon content (OC) were determined to assess variation across sample sites. Results indicated moderate to severe ecological risk at sites in Port Royal and Discovery Bay with ecological risk values as high as 381.9.

Global declines in live coral cover and the proliferation of macroalgae on coral reefs is leading to increased coral-macroalgal interactions that impact reef recovery. However, the effects of macroalgae on coral sexual reproduction—a fundamental life-history process for maintaining population abundances—have rarely been quantified. Here, we examined the direct effects of macroalgae contact on the fecundity (eggs mesentery⁻¹) of two coral species, Echinopora lamellosa and Merulina ampliata, across three degraded reefs in Singapore. Increasing macroalgae contact from 5% to 25% significantly reduced fecundity in colonies of both species by 67–82%, and also reduced M. ampliata egg sizes by 11.4%. These results suggest the diversion of energy from reproduction towards other processes such as repair and defence, and also reveal potential differential energy allocation strategies among coral taxa. While corals on Singapore's impacted reefs continue to produce eggs, increasing macroalgae that suppresses coral fecundity may constrain future reef recovery.