The prediction models of MWQI in mangrove and estuarine zones were constructed. The 2011–2015 data employed in this study entailed 13 parameters from six monitoring stations in West Malaysia. Spatial discriminant analysis (SDA) had recommended seven significant parameters to develop the MWQI which were DO, TSS, O&G, PO4, Cd, Cr and Zn. These selected parameters were then used to develop prediction models for the MWQI using artificial neural network (ANN) and multiple linear regressions (MLR). The SDA-ANN model had higher R2 value for training (0.9044) and validation (0.7113) results than SDA-MLR model and was chosen as the best model in mangrove estuarine zone. The SDA-ANN model had also demonstrated lower RMSE (5.224) than the SDA-MLR (12.7755). In summary, this work suggested that ANN was an effective tool to compute the MWQ in mangrove estuarine zone and a powerful alternative prediction model as compared to the other modelling methods.

Increased sediment loads within algal turfs, can be highly detrimental to coral reef systems. However, significant knowledge gaps remain in relation to sediment dynamics, especially linking suspended sediments, sedimentation and turf-bound sediments. To examine these links, a series of different methods for quantifying suspended sediments, sedimentation and the accumulation of turf sediments were compared, simultaneously, on an inner-shelf reef. We revealed that the amount and composition of sediment quantified using different methods varied markedly, with commonly employed measures of sedimentation failing to accurately reflect patterns of sediment accumulation in turfs. Our results highlighted the propensity for turfs to trap and retain sediments, with turfs accumulating approximately 2.6 times more sediment than traps, and 6 times more sediment than SedPods, over a seven-day period. This study highlights the major, but often overlooked, role that algal turfs can play in sediment dynamics on coral reefs.

The European oyster Ostrea edulis is a keystone species that is internationally recognised as ‘threatened and declining’ in the NE Atlantic by OSPAR and several nations have consequently adopted strategies for its conservation and restoration. Understanding the settlement behaviour of O. edulis larvae is crucial to inform these strategies. We compared the efficiency of several treatments in triggering settlement. The most effective settlement occurred with the presence of conspecifics: 100% settled in <23 h. Marine stones with habitat-associated biofilms induced 81% settlement that started after a 45 h delay. Sterile shells and terrestrial stones did not induce more settlement than control treatments. These results indicate that O. edulis larvae are gregarious and finely-tuned to settle in response to cues which are indicative of their adult habitat requirements. The role of chemical cues in mediating settlement, and the importance of this to restoration, are discussed.

Soundscapes are vital to acoustically specialized animals. Using passive acoustic monitoring data, the temporal and spectral variations in the soundscape of a Chinese white dolphin hotspot were analyzed. By cluster analysis, the 1/3 octave band power spectrum can be grouped into three bands with median overall contribution rates of 35.24, 14.14 and 30.61%. Significant diel and tidal soundscape variations were observed with a generalized linear model. Temporal patterns and frequency ranges of middle frequency band sound matched well with those of fish vocalization, indicating that fish might serve as a signal source. Dolphin sounds were mainly detected in periods involving low levels of ambient sound and without fish vocalization, which could reflect noise avoidance and passive eavesdropping behaviors engaged in by the predator. Pre-construction data can be used to assess the effects of offshore windfarms on acoustic environments and aquatic animals by comparing them with the soundscape of postconstruction and/or postmitigation.

The Arabian Gulf is a warm (summer SST > 30 °C) and hypersaline (salinity > 40 psu at any time) marginal sea of the Indian Ocean. This paper reports on a 3-year study of seasonal and spatial changes of primary production and associated physico-chemical and biological parameters in the coastal waters of Saudi Arabia in the western Arabian Gulf. The primary production rates were low and yet showed a seasonality, with a major spring peak and a minor autumn peak, and a possible significant role for heterotrophs. While the strong relationships between the net changes of carbon uptake and nutrients between seasons showed a control of primary production by the availability of nutrients, the decrease in primary production between spring and summer when nutrients continued to increase suggests that the primary production at this time could have been controlled by higher ambient temperatures and intensities of incident light.

Marine debris is defined as any manmade item, commonly plastics, which ends up in the ocean regardless of the source. Debris found along coastlines can cause harm or even death to nesting and hatchling sea turtles through ingestion, entrapment, or entanglement. Jekyll Island is a prominent nesting beach for loggerhead sea turtles with over 1700 emergences from 2012 to 2017. This study uses debris logged through NOAA's Marine Debris Tracker and loggerhead sea turtle nesting activity on Jekyll Island to generate density maps and evaluate possible interactions. These maps provide valuable information on portions of the coast most at risk for debris and sea turtle interactions. Using these maps help the GSTC Marine Debris Initiative focus citizen science efforts in high overlap areas of the beach. With marine debris being a global issue that impacts all sea turtle and beach nesting species, lessons learned can be applied across a wide range of taxa and management strategies.

Plastic pollution in oceans is a global problem, with growing research efforts focusing on the threat of microplastics (<5 mm fractions). A source of microplastics pollution is derived from personal care products that contain polyethylene micro-spheres which are not captured by wastewater plants. In this work, ten personal care products (mainly scrubs) containing microplastics and marketed in Spain, were physico-chemically characterized. The obtained results proved that those microplastics had different particle size and are presented in high percentages in some cases, between 6 and 7% of the total product. Products with smaller particles usually showed higher concentrations than products with larger particles. Although all the microplastics were shown to be polyethylene, some impurities were observed that demonstrated the presence of silicates and oxides in the microplastics. Regards to morphology, the shape of the particles was irregular in general, although some completely spherical particles can be observed.

In this study we report silica rich anthropogenic spherules from the marine environment. We found spherical, dumbbell, teardrop and fused spherules in Zuari estuary (near the Dona paula jetty), south west coast of India. The spherules were composed of SiO2 (69.8%), Na2O (13.2%), CaO (8.8%), MgO (3.8%), and traces of Al2O3, and FeO. Their high Na and Ca contents rules out the possibility of being an impact spherule or microtektite, or anthropogenic spherules coming from fly ash. Their elemental composition suggests that these are glass micro beads that have many applications including production of road and pavement marking materials, such as traffic paints. Considering that the glass micro beads are known to have high concentrations of Pb, As, and Sb that can leach into the marine environment, this study also raises questions regarding the impact of such spherules on marine biota, and highlights the need for further detailed study.

Oxidant treatment of ballast water (BW) is commonly used in BW systems in order to minimize the transport of alien species. The release of disinfection by-products (DBPs) associated to the treatment of BW and cross-contamination of butyltin (BT) compounds through BW discharge is a topic of environmental concern. A chemical port baseline survey has been conducted in seven ports of the Adriatic Sea. Analysis have been performed on transplanted mussels, surface sediment, seawater, BW. Results showed an evidence of BT contamination, particularly in sediments, probably related to their illegal usage or to intensive shipping activities. Therefore, BW may act as a vector and contribute to re-buildup of BT contamination in the coastal regions.A baseline set of data concerning DBPs is provided, showing the preferential distribution of these compounds in the marine environment that will be useful for future considerations on monitoring and assessment of chemical contamination associated with BW.

A suite of eight polyhalogenated carbazole (PHCZ) congeners were detected in sediments of the Jiaozhou Bay wetland. 3,6-dichlorocarbazole (36-CCZ), and 3,6-dibromocarbazole (36-BCZ) were detected in all samples. The concentrations of ΣPHCZs ranged from 6.9 to 33.4 ng/g dry weight (dw). The recovery of surrogate standard ranged from 85 to 109%. Significant relationships were found between the concentrations of 36-CCZ and those of the other three detected compounds (36-BCZ, 36-ICZ, and 1368-BCZ). However, with regard to the other chemicals, only 1368-BCZ was related to 36-ICZ. The toxic equivalent (TEQ) was used to assess the relative toxicity of PHCZs, which ranged within 0.1–3.9 pg TEQ/g dw in sediment. The inventory of ΣPHCZs was 58.9 kg. These results indicate that PHCZs are widely distributed in the Jiaozhou wetland and the dyeing and finishing industries may be important contamination sources of PHCZs.