Ecostatus of Ulhas estuary, one of the most polluted estuaries along the industrialized and urbanized northwest coast of India, was evaluated by six widely accepted benthic indices viz. H′(log2), AMBI, M-AMBI, BENTIX, BOPA and BO2A to test their efficiency in a tropical setting. The mesohaline zone, which presented eutrophic conditions, was classified as ‘bad’ by all indices due to the azoic status. Despite significant correlations obtained between indices, there were discrepancies in the accurate level of EcoQS assigned to each station. AMBI was observed to be most efficient in indicating a clear spatial variability from a ‘poor’ to ‘bad’ ecological quality status in the middle and upstream zones to an improved status in the downstream region. Limitations of all indices are discussed in light of their suitability for assessing the estuarine environmental condition. The present results could provide a fillip to environmental improvement initiatives currently being undertaken in the estuary.

The distribution of metals in surface sediments of Gulf of Pozzuoli (GoP), embedding the former second Italian largest integrated steelworks of Bagnoli, was studied based on sediment dispersal, quality guidelines (SQGs) and quantitative pollution indices of the respective metals. As, Cd, Hg, Pb, Zn largely exceeded the limits. Hg had a mean of 5.8mg/kg, twentyfold higher the rule, accumulating primarily near Bagnoli site. The mean effective range quotient, m-ERM-Q, revealed a high potential for negative biological effects especially in the area nearby the Bagnoli site. The enrichment factor (EF) values were outstandingly high, >1.5 with values which were often ≥100. The geoaccumulation index, Igeo, was very critical for Cr, Cu, Hg and Ni, showing an Igeo in the range of strongly polluted (4<Igeo <5) and very strongly polluted (Igeo>5). The principal component analysis (PCA) and Pearson's correlation matrix (CM), excluded significant contribution from weathering products.

The drivers behind microplastic (up to 5mm in diameter) consumption by animals are uncertain and impacts on foundational species are poorly understood. We investigated consumption of weathered, unfouled, biofouled, pre-production and microbe-free National Institute of Standards plastic by a scleractinian coral that relies on chemosensory cues for feeding. Experiment one found that corals ingested many plastic types while mostly ignoring organic-free sand, suggesting that plastic contains phagostimulents. Experiment two found that corals ingested more plastic that wasn't covered in a microbial biofilm than plastics that were biofilmed. Additionally, corals retained ~8% of ingested plastic for 24h or more and retained particles appeared stuck in corals, with consequences for energetics, pollutant toxicity and trophic transfer. The potential for chemoreception to drive plastic consumption in marine taxa has implications for conservation.

Microplastics (MPs) are prevalent in marine ecosystems. Because toxicants (termed here “co-contaminants”) can sorb to MPs, there is potential for MPs to alter co-contaminant bioavailability. Our objective was to demonstrate sorption of two co-contaminants with different physicochemistries [phenanthrene (Phe), log10Kow=4.57; and 17α-ethinylestradiol (EE2), log10Kow=3.67] to MPs; and assess whether co-contaminant bioavailability was increased after MP settlement. Bioavailability was indicated by gene expression in larval zebrafish. Both Phe and EE2 sorbed to MPs, which reduced bioavailability by a maximum of 33% and 48% respectively. Sorption occurred, but was not consistent with predictions based on co-contaminant physicochemistry (Phe having higher log10Kow was expected to have higher sorption). Contaminated MPs settled to the bottom of the exposures did not lead to increased bioavailability of Phe or EE2. Phe was 48% more bioavailable than predicted by a linear sorption model, organism-based measurements therefore contribute unique insight into MP co-contaminant bioavailability.

Resting stages of plankton were sampled in the surficial sediments in the port of Haifa, Israel, on the eve of a major port enlargement project. We recorded the structure of the assemblages and examined their relationship with different environments within the port. Our findings reveal a remarkably high diversity coupled with low density and the highest number of oligotrich ciliate cyst types recorded from marine sediments. Near the eutrophic and highly polluted zone of the Kishon estuary ciliates were more abundant than elsewhere in the port, whereas dinoflagellates' abundance was reduced, and these trends held true both for full and empty cysts. Some harmful or potentially toxic species, such as Scrippsiella acuminata, were widespread in the port. The toxigenic species include Alexandrium minutum, Gymnodinium uncatenatum and Lingulodinium polyedrum. Active cells of the unarmoured, bloom-forming Akashiwo sanguinea were identified in the cultures obtained from the incubated sediments.

To manage trace metal pollution it is critical to determine how much temporal trends can be attributed to local or large-scale sources. We tracked changes in metal content in the seagrass Posidonia oceanica, along the NW Mediterranean from 2003 to 2010. While Cu, Cd and Ni showed a large inter-site variation, likely due to local factors, Fe, Mn and Pb showed little local variation and synchronous interannual variability across sites, most likely due to large-scale sources. Zn showed equal importance of local and large-scale sources of variation. Temporal trends of Ni, Zn, Cd, Cu remained almost stable. In contrast, Fe, Mn and Pb slightly increased in the last decade. These trends suggest that metals like Cu, Cd, Ni can be effectively managed at local scale. Whereas, elements like Fe, Mn and Pb have an important large-scale component that needs to be managed across the frontiers of national jurisdictions.

We surveyed the abundance and accumulation patterns of mesoplastic marine debris (5–25mm) on 20 beaches in Korea. The mean abundance of it was 13.2items/m2, and the mean weight was 1.5g/m2. Hard plastic and Styrofoam were the dominant types. The proportions of hard plastic and Styrofoam were highly variable among the beaches, each accounting for 0–100% of the total debris on a given beach with 32% and 48.5% (by number) on average, respectively. Relatively lower abundances of mesoplastic marine debris compared with our previous studies were likely due by differences of the sampling areas within the beach. The samples of this research were selected from backshore, middle line, and water edge whereas they were selected from high strandline and backshore in our previous studies. It should be considered when discussing the level of mesoplastic marine debris.

This study was designed to identify in the pearl oyster Pinctada margaritifera, used as a bio-accumulator, molecular biomarkers for the presence of heavy metals in the lagoon environment. Pearl oysters were exposed to 2 concentrations (1 and 10μgL−1) of cadmium (Cd) and chromium (Cr) compared to a control. Twelve target genes encoding proteins potentially involved in the response to heavy metal contamination with antioxidant, detoxification or apoptosis activities were selected. P. margaritifera accumulated Cd but not Cr, and mortality was related to the amount of Cd accumulated in tissues. In response to Cd-Cr contamination, metallothionein (MT) was significantly up-regulated by Cd-Cr at both concentrations, while 7 others (SOD, CAT, GPX, GSTO, GSTM, CASP, MDR) were down-regulated. Based on the development of these molecular tools, we propose that the pearl oyster, P. margaritifera, could be used as a sentinel species for heavy metal contamination in the lagoons of tropical ecosystems.

This study investigated Enterobacteriales and their antimicrobial resistance in green sea turtles captured adjacent to the central Great Barrier Reef (GBR) and proximate to urban development. Cloacal swabs were taken from 73 green turtles between 2015 and 2016. A total of 154 out of 341 Gram-negative bacterial isolates were identified as Enterobacteriales that represent 16 different species from 9 different genera. The dominant isolates were Citrobacter (30.52%), Edwardsiella (21.43%) and Escherichia (12.34%). The resistance against 12 antibiotics belonging to 6 different classes was determined. The isolates showed highest resistance to β-lactam antibiotics (78.57%) followed by quinolone (50%) and tetracycline classes (46.1%). Approximately one-third (37.7%) of the isolates identified exhibited multidrug-resistance. Isolates recovered from rehabilitated turtles were significantly multidrug resistant (p<0.009) compared to isolates from other study sites. These results provide baseline information on antimicrobial resistance while revealing gaps for further research to evaluate the level of pollution in the GBR.

The aerosol color ratio, depolarization ratio and aerosol optical depth (AOD) were measured by a two-wavelength-depolarization lidar at Wuhan, China during the period from May 2015–July 2016. The annual average AOD at Wuhan was about 0.33 during the period 2015–2016. The seasonal average AOD is small (0.26 ± 0.25) during the winter (December–February) season and large (0.4 ± 0.1) during the summer (June–August) season. The monthly average color ratio is small (0.23 ± 0.09) in January and large (0.76 ± 0.21) in August with an annual average value 0.54. The maximum monthly mean depolarization ratio (0.2 ± 0.07) occurred in the month of October, while the minimum (0.06 ± 0.02) occurred in the month of September, and the annual mean depolarization ratio was about 0.17. An analysis of temporal variations of color ratio and depolarization ratio suggests the presence of coarse and non-spherical particles during the autumn. The aerosol color ratio between 0.3 and 2.0 km was large (0.65), suggesting a large number of coarse particles in this range. The vertical distribution of the depolarization ratio is uniform. Finally, the spatial aerosol distribution under different weather conditions and its relationship with the color ratio is investigated in detail. The color ratio value of 0.74 could be used as a threshold for distinguishing polluted weather from clean weather. The aerosol optical and physical properties are investigated to provide a comprehensive understanding of aerosol radiative forcing and environmental problems in this region.