One of the fundamental sustainable development goals has been recognized as having access to clean water for drinking purposes. In the Anthropocene era, rapid urbanization put further stress on water resources, and associated groundwater contamination expanded into a significant global environmental issue. Natural arsenic and related water pollution have already caused a burden issue on groundwater vulnerability and corresponding health hazard in and around the Ganges delta. A field based hydrogeochemical analysis has been carried out in the elevated arsenic prone areas of moribund Ganges delta, West Bengal, a part of western Ganga- Brahmaputra delta (GBD). New data driven heuristic algorithms are rarely used in groundwater vulnerability studies, specifically not yet used in the elevated arsenic prone areas of Ganges delta, India. Therefore, in the current study, emphasis has been given on integration of heuristic algorithms and random forest (RF) i.e., “RF-particle swarm optimization (PSO)”, “RF-grey wolf optimizer (GWO)” and “RF-grasshopper optimization algorithm (GOA)”, to identify groundwater vulnerable zones on the basis of field based hydrogeochemical parameters. In addition, correspondence health hazard of this area was assessed through human health hazard index. The spatial distribution of groundwater vulnerability revealed that middle-eastern and north-western part of the study area covered by very high and high, whereas central, western and south-western part are covered by very low and low vulnerability zones in outcomes of all the applied models. The evaluation result indicates that RF-GOA (AUC = 0.911) model performed the best considering testing dataset, and thereafter RF-GWO, RF-PSO and RF with AUC value is 0.901, 0.892 and 0.812 respectively. Findings also revealed the groundwater in this study region is quite unfavorable for drinking and irrigation purposes. The suggested models demonstrate their usefulness in foretelling sustainable groundwater resource management in various deltaic regions of the world through taking appropriate measures by policy-makers.

The concept of thresholds shows important implications for environmental and resource management. Here we derived potential landscape thresholds which indicated abrupt changes in water quality or the dividing points between exceeding and failing to meet national surface water quality standards for a rapidly urbanizing city on the Eastern Coast in China. The analysis of landscape thresholds was based on regression models linking each of the seven water quality variables to each of the six landscape metrics for this coupled land-water system. We found substantial and accelerating urban sprawl at the suburban areas between 2000 and 2008, and detected significant nonlinear relations between water quality and landscape pattern. This research demonstrated that a simple modeling technique could provide insights on environmental thresholds to support more-informed decision making in land use, water environmental and resilience management.

Fifty-six groundwater samples were taken from the island of Favignana to evaluate the interaction between the groundwater and seawater, as well as the deterioration factors for the aquifers, using the combined hydrogeochemical and multivariate statistical approaches. Results show that the order of the groundwater chemistry in the study area was Na+> Ca2+>Mg2+>K+ and Cl->HCO3−>SO42->NO3−. The groundwater samples were in the moderate saline zone to highly saline zone and indicate that the groundwater of the island of Favignana was recharged with seawater. The spatial distribution maps of Cl− and NO3− show that most of the groundwater samples had high concentrations of Cl− and NO3− in the study area. The ionic ratio diagrams, such as Na+/Cl− versus Cl−, Mg2+/Ca2+ versus Cl− and Ca2+/HCO3− versus Cl−, and other hydrogeochemical plots reveal that the groundwater chemistry of the study was primarily controlled by the seawater intrusion and reverse ion exchange process, with a small contribution from carbonate dissolution. Additionally, the NO3−/Cl− versus Cl− diagram and principal component analysis (PCA) show that the contamination of nitrate in the study area was due to human activities (i.e. agriculture and domestic sewage disposal). The outcome of the present research could be helpful for groundwater resource management in coastal environments.

Most reef building corals rely on symbiotic microalgae (genus Symbiodinium) to supply a substantial proportion of their energy requirements. Functional diversity of different Symbiodinium genotypes, endorsing the host with physiological advantages, has been widely reported. Yet, the influence of genotypic specificity on the symbiont's susceptibility to contaminants or cumulative stressors is unknown. Cultured Symbiodinium of presumed thermal-tolerant clade D tested especially vulnerable to the widespread herbicide diuron, suggesting important free-living populations may be at risk in areas subjected to terrestrial runoff. Co-exposure experiments where cultured Symbiodinium were exposed to diuron over a thermal stress gradient demonstrated how fast-growing clade C1 better maintained photosynthetic capability than clade D. The mixture toxicity model of Independent Action, considering combined thermal stress and herbicide contamination, revealed response additivity for inhibition of photosynthetic yield in both tested cultures, emphasizing the need to account for cumulative stressor impacts in ecological risk assessment and resource management.

Nurdles, the pre-production plastic pellets, are a major source of plastic pollution in marine environments due to unregulated spills during production and transportation. We analyzed the types of plastics and associated organic pollutants on nurdles collected along the shoreline of Gulf of Mexico in Texas. Our results showed that the nurdles were made from polyethylene (81.9%) and polypropylene (18.1%). Polycyclic aromatic hydrocarbons (PAHs, 16 US EPA priority) and polychlorinated biphenyls (PCBs, 7 commercial congeners) sorbed to the nurdles were in concentration ranges of 1.6–14,700 ng/ g and 0–642 ng/ g, respectively. Heavily weathered nurdles tended to have higher concentrations of PAHs and PCBs than lightly weathered ones. The bioaccessibility of sorbed contaminants was evaluated using a simulated intestinal fluid. The results showed that the associated PAHs were more bioaccessible in lightly weathered nurdles (13.1 ± 2.3%) than heavily weathered one (5.3 ± 0.1%), and that no PCBs were bioaccessible. These findings are informative for toxicity evaluation and resource management of plastic debris in coastal environments.

Mangrove sediment harbors a unique microbiome and is a hospitable environment for a diverse group of bacteria capable of oil biodegradation. Our goal was to understand bacterial community dynamics from mangrove sediments contaminated with heavy-oil and to evaluate patterns potentially associated with oil biodegradation is such environments. We tested the previously proposed hypothesis of a two-phase pattern of petroleum biodegradation, under which key events in the degradation process take place in the first three weeks after contamination. Two sample sites with different oil pollution histories were compared through T-RFLP analyses and using a pragmatic approach based on the Microbial Resource Management Framework. Our data corroborated the already reported two-phase pattern of oil biodegradation, although the original proposed explanation related to the biophysical properties of the soil is questioned, opening the possibility to consider other plausible hypotheses of microbial interactions as the main drivers of this pattern.

The use of shellfish aquaculture for nutrient removal and reduction of coastal eutrophication has been proposed. Published literature has indicated that nitrogen contained in harvested shellfish can be accurately estimated from shell length:nitrogen content ratios. The range of nitrogen that could be removed by a typical farm in a specific estuarine or coastal setting is also of interest to regulators and planners. Farm Aquaculture Resource Management (FARM) model outputs of nitrogen removal at the shellfish farm scale have been summarized here, from 14 locations in 9 countries across 4 continents. Modeled nitrogen removal ranged from 105lbsacre−1year−1 (12gm−2year−1) to 1356lbsacre−1year−1 (152gm−2year−1). Mean nitrogen removal was 520lbsacre−1year−1 (58gm−2year−1). These model results are site-specific in nature, but compare favorably to reported nitrogen removal effectiveness of agricultural best management practices and stormwater control measures.

Water quality monitoring programs (WQMPs) are crucial for assessment of water quality in river basins where agricultural intensification and development raise concerns in freshwater and marine environments. WQMPs if supported by scientists and local communities, and if based on the knowledge needs of all stakeholders, can provide vital information supporting resource management actions.Our paper focuses on the transdisciplinary development and implementation of a community-led pilot WQMP for the Tully River basin, adjacent to the Great Barrier Reef (GBR). The community-led pilot WQMP was established to fill some knowledge gaps identified during development of the Tully Water Quality Improvement Plan (WQIP) and to provide opportunities for active stakeholder participation in the monitoring. Results indicated some water quality parameters (i.e. nitrates and total phosphorus) had higher than expected values and exceeded state water quality guidelines. Hence, the results provided an evidence base for freshwater quality objective development to conserve, protect and improve water quality conditions in this basin and GBR. Leadership of Indigenous people in the pilot WQMP recognizes their deep desire to improve water resources outcomes and to care for country and people.

In the Pacific region, community engagement, participation and empowerment are key to effective and sustainable marine resource management at the local level. With the prevalence of a local marine tenure systems and the widespread decline of coastal resources, communities need to be part of the solution to facilitate recovery. A novel marine monitoring toolkit was developed in Vanuatu with the participation of community resource monitors to inform local management actions. The Toolkit includes simplified versions of established monitoring methods for marine habitats and resources to achieve a balance between robust science and methods appropriate for communities. Key to its success is that it was developed in response to community needs using a participatory approach and implemented through a series of training workshops with local environmental leaders. Of particular note, the Toolkit includes a standardised process for communities to use monitoring results instantly, without the need for complex data analyses or external support. Using the Toolkit, communities are able to adapt their traditional management to address immediate and medium-term issues in their local marine environment. The observed benefits of the Toolkit include increased local awareness through community-led environmental outreach, increased ownership of and motivation for local monitoring and management, implementation of local management actions, expansion of traditional marine managed areas, and new local ecotourism initiatives to generate revenue to support environmental stewardship.

Horse mussel reefs (Modiolus modiolus) are biodiversity hotspots afforded protection by Marine Protected Areas (MPAs) in the NE Atlantic. In this study, horse mussel reefs, cobble habitats and sandy habitats were assessed using underwater visual census and drop-down video techniques in three UK regions. Megafauna were enumerated, differences in community composition and individual species abundances were analysed. Samples of conspicuous megafauna were also collected from horse mussel reefs in Orkney for stable isotope analysis.Communities of conspicuous megafauna were different between horse mussel habitats and other habitats throughout their range. Three commercially important species: whelks (Buccinum undatum), queen scallops (Aequipecten opercularis) and spider crabs (Maja brachydactyla) were significantly more abundant (by as much as 20 times) on horse mussel reefs than elsewhere. Isotopic analysis provided insights into their trophic relationship with the horse mussel reef. Protection of M. modiolus habitat can achieve biodiversity conservation objectives whilst benefiting fisheries also.