A mangrove sediment core was studied to evaluate possible pollution of an urban estuary in Coffs Harbour, Australia. The heavy metal and nutrient profiles revealed a ~2.5-fold enrichment in more recent sediments. Lead-210 dating showed increasing phosphorous (P) and copper (Cu) accumulation following agricultural activity and population growth in the catchment after 1950. In contrast, nitrogen (N) did not show enrichment suggesting no external sources. Mercury (Hg) depositional fluxes and recent enrichment may be associated to an increase in fossil fuel emissions in the region. Down-core lead (Pb) profiles reflect an increase in leaded gasoline in the 1950s, then a decrease as a result of phasing out leaded gasoline in 1986. The heavy metal and nutrient depositional fluxes are well preserved in mangrove sediments and were related to historical events in the catchment.

The loss of coastal wetlands in Hong Kong Mai Po Nature Reserve adversely affected wetland-depended species. To mitigate this impact, gei wai ponds were reconstructed according to a set of biodiversity management zones (BMZs). This study, based on Canonical Correspondence Analysis (CCA), investigated if waterbird distribution was related to BMZ characteristics. Based on habitat characteristics, ponds in the same BMZ generally clumped in the same quadrant or within a short distance on CCA scatter plots, indicating that a BMZ zone produced common habitat traits. Ponds in a close distance on the plot had similar bird abundance or community structure. Significant correlations were noted between the abundance of cormorants and tall tree, and between waders and bare ground areas within study ponds. This study indicated that the control of key habitat factors was important for the success of reconstruction of gei wais and management of waterbirds in Mai Po.

In the present study, we investigated the influence of phenanthrene (PHE), a three-ring polycyclic aromatic hydrocarbon (PAH) compound, on nitrate (NO3−) reduction processes in mangrove sediments using microcosms. After 10days, nitrate/nitrite reductase activity and abundance of narG and nirS significantly decreased in the bulk sediment at both 10/50mgPHEkg−1 contamination groups. In the rhizosphere, abundance of narG, nirS and nirK markedly declined at PHE treated sediments, while the drop in reductase activity at 10mgkg−1 PHE treatment was insignificant. After 50days, apart from 10mgPhekg−1 treated bulk sediment, abundance of denitrifiers and reductase activity in all PHE spiked sediment samples significantly dropped. Therefore, the influence of PAHs on NO3− reduction capability in mangrove sediments is dependent on spiked concentration, temporal scale of exposure and interaction with roots. Generally, PAHs play an inhibitor role, slowing NO3− turnover rates, which warrant attention from coastal managers.

This study is an attempt to explore the effectiveness of satellite data in predicting hourly PM2.5 (Respirable particulate matter with aerodynamic diameter below 2.5 μm) concentrations for a chosen number of forward time steps over eastern China. MODIS (Moderate Resolution Imaging Spectroradiometer) aerosol optical depth (AOD), hourly forecasted meteorological variables, along with respective pollutant predictors from 2013 to 2015 were used as input to a multi-layer perceptron (MLP) type of back-propagation neural network. A novel approach, based on the correlation coefficients between surface PM2.5 and meteorological variables, was employed in selecting the averaging periods for meteorological input. Backward air mass trajectory was combined with AOD so as to explicitly measure the contribution of regional transport. Owing to the spatial variability of the AOD-PM2.5 relationship, each grid cell on the AOD retrievals was assigned to a prediction model trained by the nearest monitoring station from them. The proposed model seems to perform better in southern China. Also predictions incorporating transport predictor tend to have higher rates of detecting PM2.5 exceedance hours. We further introduced a sensitive analysis in Beijing by testing a model with surface PM2.5 input, evaluated versus the AOD input one. The two models were evaluated on the perturbed test set with input values ranging from 10 to 40%. It is found that PM model significantly outperforms the AOD one when the prediction horizon is longer than 36 h. This approach shows potential to be adapted for other regions, but will be most useful for areas without access to sophisticated deterministic models.

Over the last several decades, concerns in the Northwest Arabian Gulf have risen regarding water quality and ecological conditions, particularly near Kuwait. This interest is mainly attributed to the reduction of freshwater discharge and its associated constituents from the Shatt Al Arab as a result of human activities at diverse scales. From the hydrological perspective, the reduction has also resulted in alteration to the dynamic regime and related residence time and transport conditions. Using a previously well-validated three-dimensional numerical model of the Northern Arabian Gulf (NAG) (Alosairi and Pokavanich, 2017), the residence and transport conditions of numerical tracers have been assessed through a series of numerical tests. The results indicate that density-driven circulations have played a key role in reducing the residence time in the Northwest Gulf by approximately 15% to 20% compared to tidal forces only. The transport conditions correlated well with the Shatt Al Arab discharges, but they were only significant along the Kuwait coast due to counter-clockwise circulations and alongshore currents. Arrival times and mixing processes varied reasonably with the Shatt Al Arab discharges; the results exhibited the enhancement in mixing and transport with increases in discharge. Residence times in the NAG associated with Shatt Al Arab discharge displayed spatial variations, particularly in Kuwait Bay, where the residence time increased by 60days during low discharge compared to high discharge.

Concern is growing that marine fauna can be affected by noise such as naval sonar, pile driving or geophysical surveys, among others. Literature reports a variety of animal reactions to human noise (from apparently null or negligible to strong). However, conclusive results on its effects on marine mammals at individual and population level are still lacking. In 2015, the Italian Environmental Impact Assessment Commission mandated seismic operators apply a standard scientific protocol comparing marine mammal presence before, during, and after offshore seismic survey. For 60days before and after the survey, marine mammals are monitored using visual and acoustic methods. One or more acoustic autonomous recorders, depending on area size, must also be deployed throughout the three phases for continuous monitoring. Consistent data gathered from many surveys will enable robust statistical analysis of results. Diffusion of this monitoring method internationally would improve the study of far-reaching, intense, low frequency noise.

Coastal and estuarine environments are characterised by acute changes in temperature and salinity. Organisms living within these environments are adapted to withstand such changes, yet near-future ocean acidification (OA) may challenge their physiological capacity to respond. We tested the impact of CO2-induced OA on the acute thermal and salinity tolerance, energy metabolism and acid-base regulation capacity of the oyster Saccostrea glomerata. Adult S. glomerata were acclimated to three CO2 levels (ambient 380μatm, moderate 856μatm, high 1500μatm) for 5weeks (24°C, salinity 34.6) before being exposed to a series of acute temperature (15–33°C) and salinity (34.2–20) treatments. Oysters acclimated to elevated CO2 showed a significant metabolic depression and extracellular acidosis with acute exposure to elevated temperature and reduced salinity, especially at the highest CO2 of 1500μatm. Our results suggest that the acute thermal and salinity tolerance of S. glomerata and thus its distribution will reduce as OA continues to worsen.

The spatial distribution and seasonal variation of 16 phthalate esters (PAEs) in water, suspended particulate matter (SPM) and sediment were investigated in the Jiulong River estuary, Fujian, Southeast China. Of the 16 PAE congeners analyzed, only six PAEs, including dimethyl phthalate (DMP), diethyl phthalate (DEP), diisobutyl phthalate (DIBP), di-n-butyl phthalate (DBP), di(2-ethylhexyl) phthalate (DEHP) and diisononyl phthalate (DINP), were identified and quantified. The total concentrations of the six PAEs (∑6PAEs) detected for all seasons ranged from 3.01 to 26.4μg/L in water, 1.56 to 48.7mg/kg in SPM, and 0.037 to 0.443μg/kg in sediment. DEHP, DIBP and DBP were the most abundant PAE congeners in all of the water, SPM and sediment phases. The spatial distributions of PAEs in the estuary were controlled not only by the riverine runoff, seasons, hydrodynamic condition and human activities but also the physicochemical properties of PAEs.

This study was carried out in a popular tourist destination located in Italy, where short-term pollution posed the problem of low quality status of bathing waters (according to European Directive) owing to the fecal contamination caused by drainage ditches. Our goal was to understand the role of meteorological conditions on freshwater and seawater bacterial indicator levels, and the impact of polluted streams on seawater contamination. To this aim, results from surface waters were analyzed during five bathing seasons, from 2011 to 2015. Our results demonstrated a relationship between bacterial densities and rainfall amount and a time-dependent dilution effect of the sea between the two halves of each bathing season. This analytical survey confirmed the strategic role of meteorological variables in bathing waters quality, and it could be a support for generation and development of predicting models of indicator levels for bathing area.