Vibrio species are widely distributed in the estuarine and coastal waters that possess the greatest threat to human health worldwide. In this study it is aimed to isolate and observe the abundance of Vibrio sp. and prevalence of biomarker genes and antibiotic resistance profile of V. cholerae isolated from the Port Blair bays of South Andaman. A total of 56 water samples were collected from the seven sampling stations of Port Blair bays in which maximum number of Vibrio sp. population density (1.78 × 10⁴) was recorded in Phoenix Bay. Among the 786 isolates 57.38% of the isolates were confirmed as Vibrio sp., Vibrio cholerae and Vibrio parahaemolyticus. PCR results revealed that the prevalence of biomarker genes was recorded maximum in the isolates from Phoenix Bay and Junglighat Bay samples. Upon further analysis, it was observed that the prevalence of hlyA gene (215 bp), was found to be the most widespread biomarker determinant in 84.17% of isolates. Major virulence determinants; ctxA, ompU and toxR genes were not detected in V. cholerae isolates from Port Blair bays. Maximum antibiotic resistance pattern was observed in Phoenix Bay isolates and maximum number of V. cholerae isolates was resistance to tetracycline (60.76%). Cluster and Principal Component Analysis were employed to understand the diversity and distribution of Vibrio isolates and its biomarker genes. Upon PCA analysis seasonal influence was not much perceived in Vibrio species diversity in Port Blair bays and the lack of significant difference in the detection of species diversity in this study is due to resemblance in geographical conditions and sources of pollution.

In 2020, the global cap of maximum allowable sulphur content in marine fuel will be reduced from the current 3.5% to 0.5%. Another way to reduce the sulphur emissions is to install a seawater scrubber that cleans exhausts but instead release acidic water containing nutrients and contaminants back to the marine environment. In the current study, scrubber washwater was tested on a Baltic Sea microplankton community. A significant increase in chlorophyll a, particulate organic phosphorus (POP), carbon (POC) and nitrogen (PON) were observed when the community was exposed to 10% scrubber washwater for 13 days as compared to the control. A laboratory experiment with the filamentous cyanobacteria Nodularia spumigena and the chain-forming diatom Melosira cf. arctica showed negative responses in photosynthetic activity (EC10 = 8.6% for N. spumigena) and increased primary productivity (EC10 = 5.5% for M. cf. arctica), implying species-specific responses to scrubber washwater discharge.

Native generalist grazers can control the populations of non-indigenous invasive algae (NIIA). Here, it was found that the simultaneous consumption of two co-occurring NIIA, Caulerpa cylindracea and C. taxifolia var. distichophylla, hinders the grazing ability of the main Mediterranean herbivorous, the native sea urchin Paracentrotus lividus. The ingestion of any of the two NIIA alone did not produce any difference in sea urchin righting time with respect to usual algal diet. In contrast, the simultaneous consumption of both NIIA, which grow intermingled in nature and are consumed by P. lividus, retarded its righting behavior. Such result reveals substantial physiological stress in the sea urchin, which resulted in reduced motility and coordination. The reported findings reveal the potential of NIIA co-occurrence to escape the supposed control exerted by the main native generalist grazer in Mediterranean sublittoral communities, which in turn can be locked in an “invaded” state.

Heavy metal concentrations were investigated in water and sediments of Shadegan Wetland southwest of Iran to assess the fate, partitioning, and risk assessment and also to quantify the sources of heavy metals using MLR-APCS (multiple linear regression of absolute principal component scores) receptor model. The relatively high values of Kd (partition coefficient) for Pb, Zn, Ni, As, and V revealed their affinity for being enriched in sediments while Sb, Mo, and Se exhibited greater partitioning towards water. Enrichment factors of Se, Cd, Pb, Mo, Co, Zn, and Cu revealed significant to moderate contamination and should be of some concern. Application of the modified ecological risk index (MRI) revealed sediments moderate to high risk. Hazard index values for Hg were found less than the safe level. MLR-APCS model indicated that anthropogenic sources in sediments were responsible for 80.9%, 73.2%, 73.1%, 88.6% and 74.2% of Se, Mo, Hg, Pb, and Zn, respectively.

This study undertook to investigate the occurrence of microplastics (MPs) in the high and low-tide sediments of five coastal areas in Tamil Nadu, India. The abundance of microplastics vary from 439 ± 172 to 119 ± 72 (HTL) and 179 ± 68 to 33 ± 30 (LTL) items kg⁻¹ of sediments. The MP polymers found in the study sites are Polyethylene (73.2%), polypropylene (13.8%), nylon (8.2%), polystyrene (2.8%) and polyester (2%). The weathered surfaces might act as high-capacity carriers and this was confirmed by SEM-EDAX. The results of an analysis of the textures of the sediments do not ascribe any influence on microplastic abundance. The recreation, religious and fishing activities are the major contributors to plastic pollution in these beaches, which is borne out by the high abundance of MPs in the study sites. A regular and permanent waste management system should be put in place for the protection of beaches.

This study investigated the removal of microplastics from different treatment stages in three WWTPs and examined the performance of tertiary treatment that was done by coagulation and different technologies such as ozone (WWTP-A), membrane disc-filter (WWTP-B), and rapid sand filtration (WWTP-C). The results showed that the primary and secondary treatment processes effectively remove microplastics from wastewater with efficiencies ranging between 75% and 91.9%. The removal efficiency increased further to >98% after tertiary treatment. Microbeads and fragments were the major types of microplastics found in all wastewater sampling points. Microbeads found in the wastewater samples were classified as primary microplastics, that mainly came from personal care products, whereas secondary microplastics consisted of fragments, fibers, and sheets that were generated mainly due to fragmentation of larger plastics. Microplastics were still found in a high concentration in the final effluent, especially from WWTP-B, which is discharged into the Geumho river.

Thanks to several European directives and conventions there is a general increase of awareness regarding the key ecological role of coralligenous habitats in the Mediterranean Sea, addressing several research projects to standardize protocols for the description of its integrity. Here we surveyed 13 stations along the Italian coasts of the Western Mediterranean Sea, using video-transects technique, comparing the biological structure of coralligenous assemblages and testing the importance of their three-dimensional complexity as a proxy to define their health conditions. We considered the diversity of taxa, fishing impacts and the entity of damage on gorgonian's choenenchyme due to thermal stress, to evidence a gradient in the coralligenous health conditions. Here we developed a method to evaluate coralligenous complexity, selecting categories of taxa particularly sensitive to multiple stressors, named Structural Descriptors to describe the three-dimensional structure of the bioconcretions and to assess a unique Index of 3D - Structural Complexity.

To study the impact of rapid industrialization and urbanization in Guangxi Province on the coastal environment in recent years, seven metals (Hg, Cu, Pb, Cd, Cr, Zn and As) were investigated in the surface seawater and sediments of the northern Beibu Gulf. The levels of the metals were lower than in other regions in China, but Hg, Cu and Cd showed a significant increasing trend in both seawater and sediments over the past 20 years. Higher levels were consistently observed in the nearshore area, particularly in the northwest, which may be related to the rapid industrial development in coastal areas. Correlation and principal component analyses suggested that both terrestrial inputs and biological processes influenced the distribution of metals. In addition, the higher risk observed for Hg and Cu may be largely influenced by the increasing trend in these metals in the Beibu Gulf.

The 90Sr activities of seawater were investigated in the high-latitude region of the Arctic Ocean from August–September 2017. The 90Sr activities in seawater in the Chukchi Sea, central Arctic Ocean and East Greenland Sea were 0.31–2.42, 0.12–1.86 and 0.13–1.20 Bq m−3, respectively. The average 90Sr activity (0.92 Bq m−3) below 500 m in the central Arctic Ocean was higher than those in previous reports. Our study provided high-resolution baseline 90Sr activity data for the whole water column in the high-latitude region of the Arctic Ocean (~85°N). The inventory of 90Sr in the central Arctic Ocean was higher than those in the Chukchi Sea and East Greenland Sea. The results of our study indicated that 90Sr could be transported to the deep seawater and remain in the Arctic Ocean for a long time.