Recording plastic ingestion across various species and spatial scales is key to elucidating the impact of plastic pollution on coastal and marine ecosystems. The effect of plastic ingestion on the diets, physiologies, and behaviors of selected fish species are well documented under laboratory settings. However, prevalence of plastic ingestion in wild fish across latitudinal gradients is yet to be widely documented; with a substantial lack of research in the Southern Hemisphere. We analyzed the gut content of reef fish across ~30ᵒ latitude of the east coast of Australia. Of 876 fish examined from 140 species (83 genera and 37 families), 12 individuals had visible (meso-plastics detectable to the naked eye) plastics present in the gut. Here, we present a first-look at plastic ingestion for coastal species with this region.

Over 5000 tons of spilled oil reached the northeast coast of Brazil in 2019. The Laboratory for Computational Methods in Engineering (LAMCE/COPPE/UFRJ) employed time-reverse modeling and identify multiple potential source areas. As time-reverse modeling has many uncertainties, this article carried out a methodology study to mitigate them. A probabilistic modeling using Monte Carlo approach was developed to test these source areas with the Spill, Transport, and Fate Model (STFM) and a scenario tree methodology was used to select possible spill scenarios. To estimate the performance of Lagrangian models, two new model performance evaluations were added to Chang and Hanna (2004). The combination of probabilistic simulations, scenario tree analysis, and model performance evaluation proved to be a powerful tool for mitigating the uncertainties of time-reverse modeling, yielding good results and simple implementation.

We evaluated the status of anthropogenic marine debris (AMD) in two natural mangrove forests on Mauritius, one of which in proximity to human settlement (Mahebourg) and the other more remote (Ferney). AMD was collected monthly from October to December 2018 in 1500 m² at both sites and classified into material composition and their potential sources. In all, 2127 items (150.07 kg) was sampled at Mahebourg and 1098 items (43.71 kg) at Ferney. In line with global studies, plastic made up most of the debris in terms of both count (42.92%, 43.66%) and total weight (40.65%, 32.08%) at Mahebourg and Ferney respectively. Most debris originated from shoreline and recreational activities. This work sets a baseline to assess impacts of AMD on mangroves, public awareness required and future strategies for waste monitoring and management in mangroves that may be applied both locally and on other small islands.

The study aims to investigate the source and concentration of PAH fractions in the reef sediments of the Vembar group of Islands, Gulf of Mannar, India. The concentration of PAHs ranged from 0.36 to 15.98 ng/g. The reef environment was less contaminated with low-molecular-weight PAH fractions. The accumulation of the LMW-PAH fraction was very less, whereas the HMW fraction was derived from pyrolytic sources. The level of low and high molecular weight PAHs was lower than the level of Effective Range Median (ERM) and Effective Range Low (ERL).The calculated total TEQ value ranged from ND to 10.24 ng/g in the reef sediments.

The evaluation of occurrence, risk quotient (RQ), bioaccumulation factor (BAF), and sources of PAH was conducted in Sergipe-Poxim estuarine system. PAH distribution that ranged from 7.1 to 30.9 ng L⁻¹ (surface water, SW), 5.4 to 19.5 ng g⁻¹ (sediment, S), and 4.3 to 18.1 ng g⁻¹ (oyster, O), characterized the environment with low contamination; 2-3 (SW), 5-6 (S), and 4 (O) PAH rings accounted for 54.5%, 68.7%, and 87.7%, respectively, along with naphthalene (SW), dibenzo(a,h)anthracene (S), and pyrene (O) as the prevailing compounds. PCA suggested the predominance of particular groups related to SW (LMW-PAH), S (HMW-PAH), and O (pyrene and fluoranthene). Furthermore, one sample of O presented a high PAH bioavailability as shown through the BAF, with emphasis on pyrene (BAF = 26.8). The RQ showed a low to moderate range in SW and S; hence, in-depth information about the possible toxic effect in organisms of this region is required.

A 2D-numerical model is used to estimate suspended sediment (SS) transport and residence time (RT) of the Gulf of Khambhat (Gulf). Tidal current, as well as bottom topography, play a key role in sediment entrapment inside the Gulf and hinders the SS exchange between Gulf and Arabian Sea. The northern and central regions of the Gulf experiences high RT throughout the year. RT of more than a month were recorded in the northern region of the Gulf where SS concentration was also high (>500 mg/l). A barrier formed during non-monsoonal months cause distinct RT and SS in the Gulf compared to Arabian Sea. During monsoon, a partial withdrawal of the barrier could be seen leading to lower RT inside the Gulf, especially in the southern region. Whereas, the SS plume resided in the northern region even during the monsoon. Present study infers that particle entrapment occurs inside Gulf for a prolonged period.

The combustion efficiency of simulated at-sea surface oil burns (in situ burns) was determined in a 63 m³ tank while testing varied boom configurations and air-assist nozzles in the presence and absence of waves. Combustion efficiencies of Alaska North Slope oil based on unburned carbon in the plume emissions ranged from 85% to 93% while values based on oil mass loss ranged from 89% to 99%. A four-fold variation in PM₂.₅ emission factors was observed from the test conditions. The most effective burns in terms of reduced emissions and post-burn residue concentration of total petroleum hydrocarbons were those that had high length to width boom ratios resulting in higher flame front surface area exposure to ambient air. The amount of oil mass lost was not related to any combustion efficiency parameters measured in the plume, representing a potential tradeoff between unburnt oil and air pollution.

Phosphorus (P) plays key role in phytoplankton primary production in coastal water. In this study, seawater samples collected within China's Leizhou Peninsula coastal waters from October 2017 to July 2018 were examined to determine the seasonal variation, speciation, and transport flux of total dissolved phosphorus (TDP) linked to hydrographic features. TDP concentration and speciation had significant seasonal variations (P < 0.01), and the annual mean TDP concentration was 0.42 ± 0.25 μmol·L⁻¹. High concentrations of TDP occurred in coastal waters adjacent to Zhanjiang Bay and Jianjiang River estuary, whereas low TDP concentrations were found across large offshore areas. Dissolved inorganic and organic P were the main TDP bulk species in different seasons, comprising up to 55.5 ± 7.9% and 46.5 ± 22.6%, respectively. The Beibu Gulf was annually subjected to 3.5 × 10⁹ mol flux of TDP through the Qiongzhou Strait. Coastal currents, river plumes, and human activities were responsible for the dynamic variations in P species.

Increasing human activities have caused the accumulation of dissolved organic nitrogen (DON) in the ocean, which can alter dominant coastal phytoplankton species. However, insights into DON's effects on marine phytoplankton growth are insufficient compared with those of dissolved inorganic nitrogen (DIN), especially regarding the role of specific DON components. Therefore, in this study, the effects of the hydrophilic (Hic) and low molecular weight (LMW) components of two anthropogenic DON sources on the growth and bioavailable nitrogen uptake of phytoplankton were studied using in situ cultural experiments conducted in Jiaozhou Bay, China. Animal-derived DON from domestic and livestock breeding showed a higher bioavailability compared with that of vegetal DON derived from agricultural sources, with bioavailable component proportions of 76% ± 4% and 66% ± 3%, respectively. Both forms of DON could be absorbed by Skeletonema costatum, stimulating it to become the dominant species in the mesocosm ecosystem; the hydrophilic components of DON contributed approximately 75% of the uptake of DON by S. costatum. The bioavailability of LMW DON was significantly (p < 0.05) lower than that of the Hic DON. The high bioavailability of the Hic DON was mainly associated with its protein-like T1 and T2 components, identified using parallel factor analysis on the excitation-emission-matrix spectra, while the low bioavailability of LMW DON was mainly associated with the humus-like A component. The protein-like T2 components may be directly absorbed by algae, while T1 may be transformed through mineralization and algal absorption. Understanding the impacts of anthropogenic DON and its components on phytoplankton will help improve coastal environmental management. More knowledge of the effect of anthropogenic DON on the phytoplankton community structure in coastal waters should be accumulated in the future.