Coastal pollution levels in Todos Santos Bay (TSB) recreational beaches have increased in recent years due to the uncontrolled disposal of wastewater and pollutants to the coast by human activities (urbanization and tourism). In this work, the concentration of water quality parameters along the coast of TSB was evaluated from February 2012 to January 2013. Sampling was carried out at monthly intervals on 29 beach locations. Results showed that the maximum values of all parameters were always found close to the treated wastewater discharge area at Arroyo El Gallo station. Temporally, both nutrients and biochemical oxygen demand reached notably high levels in winter-spring and close to wastewater discharges. During summer, maximum counts of total coliforms and parasite eggs were detected close to wastewater discharges. Overall, our study provides a diagnostic approach on the spatiotemporal variability of water quality parameters for future studies along the coastal waters of TSB.

Clinus superciliosus was collected for element analysis from six localities along the South African west and south coasts. Concentrations in muscle and liver were determined, considering size and sex. No significant positive correlation between size and concentrations were detected, except for Mn and Sn in liver from Simons Town marina, while no significant differences in sex were detected. The majority of element concentrations were significantly higher in fish from Tsitsikamma in the Garden Route and the small town Chintsa, while some concentrations were significantly higher in muscle at Simons Town marina. Land-use activities had a limited role in element bioaccumulation in klipfish. Element concentrations were influenced by large scale oceanographic processes (currents; upwelling) and localised seasonal geogenic derived run-off. Limited data on element accumulation patterns of intertidal fish species in South Africa, highlights the need for long-term monitoring and further studies on different resident and transient intertidal fish species.

This study evaluates the transcriptional profiles of genes related to physiological responses in digestive glands (DG) of Mytilus galloprovincialis under the influence of seasonal changes of environmental variables, gender bias, and gonadal development. Composition of the DG microbiome was also explored. Mussels were collected across 7 months encompassing 3 seasons from a farm in the Northwestern Adriatic Sea. All gene products showed complex transcriptional patterns across seasons. Salinity, surface oxygen and transparency significantly correlate with transcriptional profiles of males, whereas in females temperature and gonadal maturation mostly explained the observed transcriptional changes. Seasonal variations and gender-specific differences were observed in DG microbiome composition, with variations resembling metabolic accommodations likely facing season progression and reproductive cycle. Results provide baseline information to improve actual monitoring strategies of mussel farming conditions and forecast potential detrimental impacts of climatological/environmental changes in the study area.

Concentrations, sources and interactions between black carbon (BC) and polycyclic aromatic hydrocarbons (PAHs) were investigated in 42 sediment samples collected from riverine, coastal and shelf areas in Peninsular Malaysia. The concentrations of BC measured by benzene polycarboxylic acid (BPCA) method and PAHs showed broad spatial variations between the relatively pristine environment of the East coast and developed environment of the West and South coast ranging from 0.02 to 0.36% dw and 57.7 ng g⁻¹ dw to 19,300 ng g⁻¹ dw, respectively. Among diagnostic ratios of PAHs, the ratios of Ant/(Ant+Phe) and LMW/HMW drew the clearest distinctions between the East coast versus the West and South coast sediments indicating the predominance of petrogenic sources in the former versus pyrogenic sources in the latter. PAHs significantly correlated with BC and total organic carbon (TOC) in the sediments (p < 0.05) having similar correlation coefficients. BC accounted for 6.06 to 30.6% of TOC in sediments.

In recent years, urban and industrial development initiatives at Puducherry and Diu such as tourism, shipping, and fisheries have led to sediment contamination by trace metals, and contributed to this investigation that extended from 2016 to 2017. Strong factor loadings of Cd (0.94), Ni (0.84), Al (0.84), Cr (0.83), Co (0.82), and Fe (0.78) illustrated the variability at Puducherry, whereas Cr (0.88), Cd (0.86), Ni (0.83), Co (0.77), Cu (0.77), and Fe (0.77) showed variability at Diu. The mean rank order distribution of the top three metals in sediment was Fe > Al > Mn, which exhibited higher variability. The highest contamination factor was observed for Cd at Diu, whereas the lowest was observed at Puducherry for Al. Similarly, the risk index also exhibited considerable risk which could be attributed to Cd contamination in the sediment at Diu compared with that at Puducherry. The results obtained are essential to establish a reference for better comparison and management of the tropical environments.

There is a rich literature on coral reef sediments. However, this knowledge is spread among research fields, and the extent to which major sediment reservoirs and reservoir connecting processes have been quantified is unclear. We examined the literature to quantify where and how sediments have been measured on coral reefs and, thereby, identified critical knowledge gaps. In most studies, sediments in one reservoir or one sedimentary process were quantified. The measurement of water column sediments (55% of reservoir measurements) and sediment trapping rates (42% of process measurements) were over-represented. In contrast, sediments on reef substrata, and the transition of sediments from the water column to the benthos, were rarely quantified. Furthermore, only ~20% of sediment measurements were accompanied by the quantification of hydrodynamic drivers. Multidisciplinary collaborative approaches offer great promise for advancing our understanding of the connections between sediment reservoirs, and the sedimentary and hydrodynamic processes that mediate these connections.

A Lagrangian model which describes radionuclide transport in the northern Indian Ocean is described. Water circulation is obtained from HYCOM ocean model for year 2017. The model includes advection by currents, turbulent mixing and radionuclide interactions between water and sediments, described in a dynamic way using kinetic transfer coefficients. Hypothetical releases from five coastal nuclear power plants operating in the northern Indian Ocean were simulated. Releases were supposed to start both during the winter and summer monsoons, to study reversing circulation effects. Age distributions of releases were calculated, which adds information about circulation and radionuclide pathways. It was found that, for some of the NPPs, radionuclide distributions resulting from releases starting in both seasons were not as different as could be expected from the opposed circulation schemes during each monsoon. Effective ¹³⁷Cs half-lives in the ocean surface were calculated and results were two orders of magnitude below previous estimations.

Unlike records of plastic ingestion and entanglement in seabirds which date back to the 1960s, the literature regarding debris in bird nests is comparatively limited. It is important to identify standardised methods early so that data are collected in a consistent manner, ensuring that future studies can be comparable. Here, we outline a method that can be applied to photographs for estimating the proportion of visible debris at the surface of a nest. This method uses ImageJ software to superimpose a grid onto a photograph of a nest/s. The number of cells with and without debris are then counted. Our proposed method is repeatable, straightforward, and accessible. We optimised the method to estimate the level of visible debris in Northern Gannet (Morus bassanus) nests, however, with some modification (i.e., adjustment of grid cell size), it could be applied to other seabird species, and terrestrial birds, that incorporate debris within nests.