Coral diseases acting synergistically with other environmental stressors are a growing problem for Caribbean reefs. Hard coral cover, coral traits, and coral diseases were examined from 1999 to 2021 for Akumal reef, located in the Northern Mexican Caribbean. The 45 recorded coral species were classified into life-history strategies: competitive, stress-tolerant, and weedy, associated with different framework-building capacities. Results indicate that cumulative impacts of coral diseases outbreaks in the last two decades, in synergy with the effects of coastal development and thermal stressors, have decreased significantly cover and abundance of major reef-building corals, shifting the dominance of the coral assemblage to species belonging to non-framework weedy life history strategy, corresponding to a low Reef Functional Index. Due to the relevant role of coral diseases in shaping coral assemblages, addressing current, and preventing future coral disease outbreaks through integrated management strategies, will be paramount to preserving physical functionality in Caribbean reefs.

Haze is a well-known air pollution phenomenon linked to the severe and persistent particulate matter (PM) episodes in Southeast Asia (SEA), which significantly impacts the environment, health, and economy. This work reviewed for the first time the characteristics of haze episodes in terms of PM concentrations, chemical compositions, and the causes of haze in both Lower (Maritime) and Upper (Mainland) SEA. In addition, we carried out a systematic comparison of the frequency and intensity of haze events through SEA regions in recent years. Our finding indicated that the different trend of haze frequency and intensity between SEA cities are not only due to local air pollution sources such as biomass burning (BB) but also meteorology and long-range transport. Other sources such as secondary aerosols also play an important role in haze formation, but they have not been comprehensively investigated in previous studies. Due to the complicated formation mechanisms and the transportations of haze and its impacts on SEA’s human health and economy, more sophisticated and specific policies are needed to deal with haze issues not only for individual countries but also on a regional scale.

Coral reefs across the southern Arabian Gulf have declined in the past two decades, with extensive loss of formerly Acropora table corals, which are now functionally extinct in nearshore reefs. This study documents the coral community at Sir Bu Nair (SBN), an offshore island buffered by less extreme environmental conditions, which contains the last remaining large stands of Acropora in the southern Gulf. We found that Acropora is a major reef-building coral throughout SBN. Mean coral cover was 27% (range: 6%–49%) across all sites and depths, of which more than half was comprised by Acropora. This varied around the island, with the highest densities to the south and southwest in shallow waters. Our study provides essential information for the management and conservation of these highly valuable and vulnerable corals.

Marinas have been shown to contribute elevated concentrations of copper (Cu) to marine waters. The Cu can come primarily from antifouling paints which are designed to discourage biofouling of boat hulls. Legislation in Washington State, USA is being developed to limit or regulate the amount and rate of diffusion of Cu from antifouling paints. This study provides baseline data for Cu in five marinas of different configuration and size within Puget Sound, a large fjord estuary. Samples were collected over a year from multiple environmental media. We find strong evidence that Cu accumulates inside marinas to higher concentrations than outside marinas. Marinas that are more enclosed accumulated higher concentrations of Cu than more open marinas. Using a power analysis, we assessed the adequacy of the baseline dataset to measure progress as a result of future legislation towards the reduction of Cu to Puget Sound from marinas.

The pollution characteristics, potential sources, and potential ecological risk of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were investigated in the Hangzhou Bay (HZB) and East China Sea (ECS). Total OCPs concentration ranged from 2.62 to 102.07 ng/L and 4.41 to 75.79 μg/kg in the seawater and sediment samples, with PCBs concentration in the range of 0.40–51.75 ng/L and 0.80–45.54 μg/kg, respectively. The OCPs were positively correlated with nutrients, whereas PCBs presented a negative correlation. The newly imported dichlorodiphenyltrichloroethane (DDT) in HZB is mainly the mixing of technical DDT and dicofol sources. The PCB source composition is more likely related to the mixture of Kanechlor 300, 400, Aroclor 1016, 1242, and Aroclor 1248. Risk assessment results indicate that OCPs posed low risk in seawater. The potential risk of DDTs in the sediments is a cause of concern.

Assessing mercury (Hg) biomagnification requires the description of prey-predator relationships, for each species and ecosystem, usually based on carbon and nitrogen isotope analyses. Here, we analyzed two seabirds from the Humboldt Current ecosystem, the Guanay cormorant (Phalacrocorax bougainvillii) and the Peruvian booby (Sula variegata), as well as their main prey, the Peruvian anchovy (Engraulis ringens). We reported Hg concentrations, Hg biomagnification (BMF) and isotopic discrimination factors (Δ¹³C and Δ¹⁵N) in seabird whole blood. BMFs and Δ¹³C in our study (on wild birds where diet was not controlled) were similar to other piscivorous seabirds previously studied in captive settings, but Δ¹⁵N were lower than most captive experiments. We observed lower Hg concentrations in Humboldt seabirds compared to other oligotrophic ecosystems, possibly due to Hg biodilution in the high biomass of the first trophic levels. This work calls for a better characterization of Hg trophic dynamics in productive upwelling ecosystems.

Continuous measurements of hydrographic, hydrodynamic, and water quality showed marked diurnal, tidal, and seasonal variabilities in Kuwait Bay, a stressed coastal system in the northwestern Arabian/Persian Gulf. Advection of water masses and seasonality in vertical mixing regulated the Bay's hydrographic and water quality properties. Intensive stratification in summer had substantial implications on the Bay environment. Kuwait Bay constantly exports dense bottom water laden with dissolved inorganic nutrients and organic matter to the central basin of the Gulf. The export was largest in August under strong water column stratification. These in-situ findings agreed well with earlier studies that corroborated Kuwait Bay as an important area where the phenomenon of reverse estuarine circulation originates in the Gulf. Thus, Kuwait Bay is a significant source of nutrients and organic matter to the Gulf Deep Water that flows into the core of the oxygen minimum zone in the northwestern Indian Ocean.

The Marine Monitoring Program (MMP) was established in 2005 to monitor the inshore health of the Great Barrier Reef (GBR) and evaluate progress towards water quality objectives in Reef Water Quality Improvement Plans. The MMP provides information on the magnitude and spatial extent of pesticide contamination, reports on temporal variability, and provides a risk assessment for the biota in the GBR lagoon. However, long-term trends in pesticide contamination of inshore marine waters over the entire monitoring period (2005–2018) have not been assessed. We used up to 14 years of monitoring data for five PSII herbicides (ametryn, atrazine, diuron, tebuthiuron, and hexazinone) to conduct temporal trend analyses at 11 inshore monitoring sites. The trend analyses suggested increasing significant trends (p < 0.05) for the five PSII herbicides concentrations at several monitoring sites. Power analysis indicated that monitoring sites with over 10 years of monitoring data had convincing results with 80% power.

Seagrass carbon emission is mainly due to the land-use change; therefore, conservation will be an approach required for carbon offset. A method for estimating carbon offset from conservation activities has been developed. This study aims to evaluate the carbon-offset potential of the seagrass ecosystem by applying this method to five provinces in Indonesia. North Maluku has the widest seagrass area, but only 5% of this is the conserved area. Meanwhile, Jakarta has the highest percentage of its conserved seagrass within the area. Emission reduction at the year 2020 ranged 0.03–1.02 tC/year (with leakage) or 0.05–2.04 tC/year (without leakage). The percentage of emission reduction among the five provinces ranged from 0.75% to 11.3%. About 9.03 tC/year emission from seagrass ecosystems in Jakarta will decrease by up to 8.01 tC/year. Further assessment shows a positive correlation between the percentage of the conserved area and the percentage of emission reduction.