Recent studies have demonstrated the negative impacts of microplastics on wildlife. Therefore, the presence of microplastics in marine species for human consumption and the high intake of seafood (fish and shellfish) in some countries cause concern about the potential effects of microplastics on human health. In this brief review, the evidence of seafood contamination by microplastics is reviewed, and the potential consequences of the presence of microplastics in the marine environment for human food security, food safety and health are discussed. Furthermore, challenges and gaps in knowledge are identified. The knowledge on the adverse effects on human health due to the consumption of marine organisms containing microplastics is very limited, difficult to assess and still controversial. Thus, assessment of the risk posed to humans is challenging. Research is urgently needed, especially regarding the potential exposure and associated health risk to micro- and nano-sized plastics.

Anthropogenic CO2 emissions are rapidly changing seawater temperature, pH and carbonate chemistry. This study compares the embryonic development under high pCO2 conditions across the south-north distribution range of the marine clam Limecola balthica in NW Europe. The combined effects of elevated temperature and reduced pH on hatching success and size varied strongly between the three studied populations, with the Gulf of Finland population appearing most endangered under the conditions predicted to occur by 2100. These results demonstrate that the assessment of marine faunal population persistence to future climatic conditions needs to consider the interactive effects of co-occurring physico-chemical alterations in seawater within the local context that determines population fitness, adaptation potential and the system resilience to environmental change.

The current capacity in the Caribbean region to enhance the knowledge about algal blooms and harmful algal blooms has several logistical constraints. This work aimed to explore the detection of possible algal blooms using Moderate Resolution Imaging Spectroradiometer (MODIS) Fluorescence Line Height (FLH) data in the Colombian Caribbean Sea between 2003 and 2013. Monthly FLH images with 4 km of spatial resolution were processed and classified. The relationship between the Sea Surface Temperature (SST) and the FLH were explored using a Geographically Weighted Regression. The results showed three areas identified as having possible persistent blooms: the Urabá Gulf (UG), Magdalena Rivermouth (MRM), and Guajira Peninsula (GP). The SST does not have any considerable influence on the variation in the FLH. The supply of nutrients during the rainy season may be causing the frequent massive algae growth. MODIS fluorescence was useful as a screening tool to identify risk areas for potential algal blooms.

Marine debris is pervasive worldwide, and affects biota negatively. We compared the characteristics of debris incorporated within brown booby (Sula leucogaster) nests throughout their pantropical distribution by assessing the type, colour and mass of debris items within nests and in beach transects at 18 sites, to determine if nests are indicators of the amount of debris in local marine environments. Debris was present in 14.4% of nests surveyed, with the proportion of nests with debris varying among sites (range: 0–100%). There was minimal overlap between the type or colour of debris found in nests and on adjacent beaches at individual sites. This suggests that brown boobies do not select debris uniformly across their distribution. We propose that the nests of brown boobies can be used as a sentinel of marine debris pollution of their local environment.

China's coastal environment has been heavily affected by the loading of terrestrial pollutants in recent decades, and quantitative risk assessment is urgently needed to assess the ecological risks of China's coastal environment. We assessed the ecological risks induced by five heavy metals (including Cu, Zn, Pb, Hg and As) in China's coastal waters for three groups of marine organisms (including crustacean, fish and mollusc) based on data obtained from a nationwide unified coastal environment monitoring program consisting of 301 sampling sites. The results show that higher heavy metal concentrations occurred more frequently in the Bohai Sea and in the estuaries of major sea-going rivers. The ecological risks decreased in the following order: Bohai Sea>Yellow Sea>South China Sea>East China Sea. There was generally low ecological risk, but certain hotspots existed near Tianjin and Jinzhou, which had relatively high ecological risks caused by Cu and Zn.

The recently developed modelling tool MERLIN-Expo was applied to support the exposure assessment of an aquatic food web to trace metals in a coastal environment. The exposure scenario, built on the data from Daliao River estuary in the Liaodong Bay (Bohai Sea, China), affected by long-term and large-scale industrial activities as well as rapid urbanization in Liao River watershed, represents an interesting case-study for ecological exposure modelling due to the availability of local data on metal concentrations in water and sediment. The bioaccumulation of selected trace metals in aquatic organisms was modelled and compared with field data from local aquatic organisms. Both model results and experimental data demonstrated that As, Cd, Cu, Ni, Pb and Zn, out of examined metals, were accumulated most abundantly by invertebrates and less by higher trophic level species. The body parts of the sampled animals with the highest measured concentration of metals were predominantly muscles, intestine and liver and fish skin in the case of Cr.The Morris and extended Fourier Analysis (EFAST) were used to account for variability in selected parameters of the bioaccumulation model. Food assimilation efficiency and slopes and intercepts of two sub-models for calculating metal specific BCFs (BCFmetal-exposure concentration) and fish weight (Weightfish-Lengthfish) were identified as the most influential parameters on ecological exposure to selected metals.

Previous studies have shown that ocean acidification has little effect on adult Tigriopus japonicus copepods, and mainly impairs the early development and reproduction of females. This study investigated the possible interactive effect between CO2-induced seawater acidification and food availability on larval development and reproductive output in T. japonicus. Copepods were exposed to either pH8.1 or pH7.3 under different food concentrations (0.5×104–80.0×104cells/mL). Both the development of nauplii and copepodites was delayed at pH7.3 with a greater effect at lower food concentrations. The reproductive output followed a bell-shaped curve with the highest reproductive output at food concentrations between 30×104 and 40×104cells/mL. As an indicator of oxidative stress, the activity of superoxide dismutase increased at lower pH, with a greater increase at lower food concentrations. Therefore, the effect of elevated pCO2 on T. japonicus was food dependent.

137 coastal sites located along the Caribbean coast of Colombia were surveyed to determine scenic quality, litter content, and typology. Scenic evaluation categorized sites into five classes. 26 appeared in Class I; 18 in Class II; 19 in Class III; 30 in class IV; and 44 in Class V. Beach type was categorized into urban (31), resort (18), rural (46), village (32) and remote (10). Litter gave 17 sites an “A” grade (excellent); 34 sites a “B” grade; 53 sites a “C” grade and 33 locations a “D” grade (poor). Almost all sites surveyed have a low scenic quality and also significant litter content. Currently, litter directly produces aesthetic problems along the study area, and improvements are necessary to favor coastal scenic quality. Stakeholders should make a significant effort to improve the scenic human parameters along the study area, litter removal and prevention being the most important.

The increase of pollutants in coastal seawater could produce several harmful biological effects on marine organisms related to the production of reactive oxygen species (ROS) causing cellular and tissue damages through oxidative stress mechanisms. Common octopuses (Octopus vulgaris) inhabiting coastal areas under high anthropogenic activity of Mallorca (W-Mediterranean Sea) have the ability to control oxidative damage by triggering antioxidant enzyme responses. Analyzing the digestive glands, octopuses from human-altered coastal areas showed higher activity of superoxide dismutase (SOD), catalase (CAT) and glutathione S-transferase (GST) compared to octopuses from non-influenced coastal waters (i.e. marine reserve area). Higher metallothionein (MT) concentrations and lack of malondialdehyde (MDA) variations also reflect adaptations of O. vulgaris to polluted areas. This is the first study assessing the levels of the oxidative stress biomarkers on O. vulgaris in the Mediterranean Sea, revealing their usefulness to assess diverse environmental pollution effects on this relevant ecological and commercial species.

Sexual reproduction in predominantly clonal marine plants increases recombination favoring adaptation and enhancing species resilience to environmental change. Recent studies of the seagrass Posidonia oceanica suggest that flowering intensity and frequency are correlated with warming events associated with global climate change, but these studies have been observational without direct experimental support. We used controlled experiments to test if warming can effectively trigger flowering in P. oceanica. A six-week heat wave was simulated under laboratory mesocosm conditions. Heating negatively impacted leaf growth rates, but by the end of the experiment most of the heated plants flowered, while controls plants did not. Heated and control plants were not genetically distinct and flowering intensity was significantly correlated with allelic richness and heterozygosity. This is an unprecedented finding, showing that the response of seagrasses to warming will be more plastic, more complex and potentially more resilient than previously imagined.