To date there is no gold standard for sampling microplastics. Zooplankton sampling methods, such as plankton and Neuston nets, are commonly used to estimate the concentrations of microplastics in seawater, but their ability to detect microplastics is limited by their mesh size. We compared different net-based sampling methods with different mesh sizes including bongo nets (>500 μm), manta nets (>300 μm) and plankton nets (>200 μm and >400 μm) to 1 litre bottle grabbed, filtered (0.45 μm) samples. Concentrations of microplastics estimated using net-based methods were ~3 orders of magnitude less than those estimated by 1 litre grab samples. Some parts of the world with low human populations, such as Ascension Island and the Falkland Islands, lack baseline data on microplastics. Using the bottle grab sampling method we found that microplastic litter was present at these remote locations and was comparable to levels of contamination in more populated coastal regions, such as the United Kingdom.

Antarctica and surrounding waters are often considered pristine, but may be subject to local pollution from tourism, fishing and governmental research programme activities. In particular, the quantification of microplastic pollution within the Antarctic Treaty area (south of latitude 60°S) has received little attention. We examined microplastic particle concentrations in sediment samples from 20 locations up to 7 km from Rothera Research Station. The highest concentrations of microplastic (<5 particles 10 ml⁻¹) were recorded in sediment collected near the station sewage treatment plant outfall. The concentrations were similar to levels recorded in shallow and deep sea marine sediments outside Antarctica. The detected microplastics had characteristics similar to those commonly produced by clothes washing. We recommend further research on microplastics around Antarctic stations to inform policy discussions and the development of appropriate management responses.

PURPOSE OF REVIEW: This article reviews the literature and presents the current status of the use of socio-acoustic surveys in soundscape studies, through the indication of appropriate question formats, types, and topics for each data collection method (soundwalks, interviews, listening tests, and focus group) for the involved public and acoustic stimuli. RECENT FINDINGS: The ISO 12913-2 establishes ways of data collection and reporting requirements for soundscape studies (International Organization for Standartization 2017), including the triangulation technique. This standard recommends some data collection methods, like soundwalks and interviews. Even so, some authors are using different methods to collect data, such as focus group and listening tests. This study investigated through 52 peer-reviewed papers published on the last 20 years the current status of socio-acoustic studies regarding question topics and types, used stimuli, and characteristics about the participants, using the four major adopted data collection methods in soundscape studies: soundwalks, interviews, listening tests, and focus group. Some topics like “soundscape quality” and “sound sources identification and evaluation” are common in the recent studies, as well as the adoption of some question types such as semantic differential scale, the staple scale, and ranking order scale.

The effects of simulated electromagnetic fields (EMF), emitted from sub-sea power cables, on the commercially important decapod, edible crab (Cancer pagurus), were assessed. Stress related parameters were measured (l-Lactate, d-Glucose, Haemocyanin and respiration rate) along with behavioural and response parameters (antennular flicking, activity level, attraction/avoidance, shelter preference and time spent resting/roaming) during 24-h periods. Exposure to EMF had no effect on Haemocyanin concentrations, respiration rate, activity level or antennular flicking rate. EMF exposure significantly disrupted haemolymph l-Lactate and d-Glucose natural circadian rhythms. Crabs showed a clear attraction to EMF exposed shelter (69%) compared to control shelter (9%) and significantly reduced their time spent roaming by 21%. Consequently, EMF emitted from Marine Renewable Energy Devices (MREDs) will likely affect edible crabs both behaviourally and physiologically, suggesting that the impact of EMF on crustaceans must be considered when planning MREDs.

Bivalves are commonly used as biomonitors for heavy metal pollution in marine environments because they accumulate heavy metal ions quickly, are sessile, abundant, and widely dispersed, and adult mortality from contamination is rare. However, the breadth of experiments used to measure the effect of heavy metal contamination can obscure general trends. It is unclear which heavy metals cause the most severe effects, how severity varies with exposure concentration and duration, and whether effects vary with level of biological organization. I conducted a meta-analysis of 48 mesocosm studies on the effects of heavy metal ions – silver, cadmium, copper, mercury, lead, and zinc – on marine bivalves. The ordering of effect sizes was Pb > Hg > Cu > Zn > Cd > Ag. The significance and direction of concentration and duration as moderators depended on the metal and the biological level. Future studies should consider non-linear effects over time and concentration, and measure both bioaccumulation and effect of the metals being studies.

Particulate phosphorus was the dominant phosphorus species and accounted for 72 ± 5% of total phosphorus in coastal habitats, 63 ± 4% in estuaries, 58 ± 6% in lakes and 80 ± 7% in aquaculture farms whereas dissolved inorganic phosphorus (DIP) and dissolved organic phosphorus (DOP) were minor components. Correlation analyses (DIP vs Chl a; R2 = 0.407, df = 31, p < 0.001) suggested phosphorus limiting conditions in lakes, which was corroborated with the highest alkaline phosphatase activity (APA) that fluctuated from 0.38 to 41.14 nmol L−1 min−1. In contrast, APA was elevated in coastal habitats and estuaries only when DIP concentration decreased below 0.9 μM. Moreover size-fractionation experiment showed that the highest APA was detected in the 0.2–2 μm pico-size fraction. Our results suggested that the main APA in coastal habitats and estuaries was from phototrophic pico-eukaryotes and heterotrophic bacteria, and regulated largely by DIP availability.

Heavy metals cannot be biodegraded and they remain in the environment until being removed. Thus, the removal of heavy metals from contaminated water is of special concern for the protection of human and aquatic lives. Studies on polymer inclusion membranes (PIMs) started more than 50 years ago and have shown outstanding separation performance of metal ions. The potential and capabilities of PIMs have made it more favorable than ion exchange and liquid-liquid extraction process. To achieve efficient transport of metal ions, different types of extractant with compatible base polymer have been successfully used along with suitable targeted metal ions. However, selectivity of metal ion is only limited to one type of metal ion based on the extractant used in PIMs. The present review describes the current literature on heavy metal removal using PIMs for the past 3 years. The compatibility of extractant with base polymer and plasticizer is discussed. Most of PIM studies used cellulose triacetate (CTA) and polyvinyl chloride (PVC) as the base polymer, and only a few studies have used other base polymers. These new base polymers have shown better PIMs in terms of stability and separation performance compared to the CTA- and PVC-based PIMs. Moreover, a new invention of dual PIM separation system has allowed simultaneous separation of multiple metal ions. Such improvement in PIM technology can speed up commercialization process and make it viable for large scale and industrial use especially in hydrometallurgy and wastewater treatment.

Marine renewable energy (MRE) developments often coincide with sites frequented by small cetaceans. To understand habitat use and assess potential impact from development, echolocation clicks were recorded with acoustic click loggers (C-PODs) in Swansea Bay, Wales (UK). General Additive Models (GAMs) were applied to assess the effects of covariates including month, hour, tidal range and temperature. Analysis of inter-click intervals allowed the identification of potential foraging events as well as patterns of presence and absence. Data revealed year-round presence of porpoise, with distinct seasonal and diel patterns. Occasional acoustic encounters of dolphins were also recorded. This study provides further evidence of the need for assessing temporal trends in cetacean presence and habitat use in areas considered for development. These findings could assist MRE companies to monitor and mitigate against disturbance from construction, operation and decommissioning activities by avoiding times when porpoise presence and foraging activity is highest in the area.

Sediment traps were deployed in the Tema Harbour to estimate the settling fluxes of silt-clay particles and associated metals (Fe, Mn, Pb, Cr, Cu, Zn, Ni, Hg, Sn and As) and characterise their potential ecotoxicological risks. The mean daily settling fluxes of the silt-clay particles and associated metals ranged from 42.7 to 85.0gm−2d−1 and 1.3×10−2 to 49.4mgm−2d−1, respectively, and were characterised by large fluctuations at each station. The silt-clay and metal fluxes strongly correlated, indicating the important role of the silt-clay particles in metal transport and distribution in the harbour. Geochemical indices indicated anthropogenic influences on the harbour as the Pb, Cr, Zn, Hg, Sn and As content in the settling silt-clay particles exceeded their average crustal concentrations. Sediment quality guidelines indicated these metals pose appreciable ecotoxicological risks, particularly As. Increasing temporal trends in As necessitates increased pollution control efforts at the harbour.

This study was designed to investigate the characteristics of bacterial communities in intertidal sediments along the Yangtze Estuary and their responses to environmental factors. The results showed that bacterial abundance was significantly correlated with salinity, SO42− and total organic carbon, while bacterial diversity was significantly correlated with SO42− and total nitrogen. At different taxonomic levels, both the dominant taxa and their abundances varied among the eight samples, with Proteobacteria being the most dominant phylum in general. Cluster analysis revealed that the bacterial community structure was influenced by river runoff and sewerage discharge. Moreover, SO42−, salinity and total phosphorus were the vital environmental factors that influenced the bacterial community structure. Quantitative PCR and sequencing of sulphate-reducing bacteria indicated that the sulphate reduction process occurs frequently in intertidal sediments. These findings are important to understand the microbial ecology and biogeochemical cycles in estuarine environments.