The distribution characteristics, correlation, and bioavailability of 14 trace elements in different fishes and corals collected from the coral-reef systems of the Xisha Islands, China were systematic studied for the first time. All detected elements were measured using inductively coupled plasma mass spectrometry after pretreatment by microwave digestion. The fishes had slight differences in element enrichment selectivity and bioavailability with average levels as follows: V, 0.100 mg·kg⁻¹; Cr, 0.683 mg·kg⁻¹; Mn, 1.178 mg·kg⁻¹; Fe, 51.806 mg·kg⁻¹; Co, 0.072 mg·kg⁻¹; Ni, 1.286 mg·kg⁻¹; Cu, 1.428 mg·kg⁻¹; Zn, 10.384 mg·kg⁻¹; As, 6.437 mg·kg⁻¹; Se, 0.830 mg·kg⁻¹; Mo, 0.101 mg·kg⁻¹; Cd, 0.051 mg·kg⁻¹; Pb, 0.308 mg·kg⁻¹; and U, 0.008 mg·kg⁻¹. Trace element contents in corals were higher than those in fishes. The distribution characteristics of trace elements in fishes and corals presented a significant correlation in North Reef and Yongle Atoll, thereby indicating an evident effect on living areas compared with trace elements in fishes from the Spratly Islands. Cluster analysis of fishes and corals based on trace elements showed that they had different selectivities and bioavailabilities to trace elements. The EDI and THQ ratios of Cu, As, Cd, Cr, and Pb demonstrated that fishes were unlikely to experience serious adverse effects, except for As in Chaetodon auriga, Myripristis kuntee, Gnathodentex aureolineatus, and Hemigymnus melapterus in Xisha Islands.

The occurrence and composition of meso (5–25 mm) and microplastics (1–5 mm) in Playa Grande beach (Tenerife, Canary Islands, Spain) was monitored during a complete moon cycle on the different moon phases between 17ᵗʰ June and 16ᵗʰJuly 2019. A total of 10 points were sampled each day finding an average content of mesoplastics of 18 g/m² (0.36 g/L) and of microplastics of 13 g/m² (1277 items/m² or 1.6 g/L). Polypropylene and polyethylene accounted for 19% and 76% of the total, respectively. Tar was also found in the 1–5 mm fraction (2% of the total). Among the particles found, 83% were fragments, 11% pellets, 4% fibres and 2% films. The obtained results revealed that microplastic presence could not be related in this case with the tides but with the orientation and strength/speed of the wind.

PURPOSE OF REVIEW: Different selenium species released into the environment by anthropogenic activities pollute surface and ground water resources and can cause severe damage to the environment and ecosystems due to bio-accumulation. Though several physico-chemical methods are available to treat selenium oxyanion-containing wastewater, biological methods have gained significant importance due to their capability to convert selenium oxyanions to elemental selenium nanoparticles. The purpose of this review is to summarize the literature available on biological removal of selenium oxyanions and their recovery as elemental selenium nanoparticles. RECENT FINDINGS: In recent times, the capability of several bacterial and fungal strains to reduce selenate and selenite to form elemental selenium nanoparticles has been reported. The shape, size and location of these selenium nanoparticles along with the selenium oxyanion removal efficiency depend on the operating parameters. Moreover, bioreactor configurations and operation strategies greatly influence the selenium removal and recovery efficiency. Several conventional bioreactor systems can be used to remove selenate and selenite from wastewater and form selenium nanoparticles. However, the selenium nanoparticles are mostly entrapped in the biomass and require a secondary treatment to recover them. On the other hand, some novel bioreactors, viz. inverse fluidized bed bioreactor, rotating biological contractor, horizontal rotating packed bed bioreactor, moving bed biofilm reactor, and hybrid bioreactor, can possibly recover selenium nanoparticles following bioreduction of selenium oxyanions in a single stage system. Thus, this review will help in finding research gaps in this area and providing solutions for resource recovery from selenium oxyanion-containing wastewater.

The Ganga-Brahmaputra delta is among the largest river systems in terms of sediment discharge and the amount of arsenic present in the groundwater. Any slim possibility of arsenic intrusion in the coastal estuaries on account of active submarine groundwater discharge (SGD) can prove fatal to the biotic population at large. In the present study, a working hypothesis for the probable intrusion of arsenic through SGD has been postulated by re-analyzing the data of river discharge, sediment load, and arsenic concentration in the Bengal delta. Our study puts forward a strong argument for the coastal vulnerabilities of Bay of Bengal as the arsenic flux has reached at 1275 × 10³ kg/year and 865.8 × 10³ kg/year in the suspended and the dissolved form respectively. The enriched arsenic adsorbed on the surface of the Cenozoic sediments (dissolved and suspended) is contributing to the majority of arsenic flux to the Bay of Bengal. Furthermore, the flux resulting due to SGD contributes roughly 1% of the total flux, which if unregulated can prove catastrophic to the primary autotrophs. More so, the existence of flood-like conditions, as well as the region susceptibility to the fast-changing climatic trends, significantly increases the risk for the region in the near future. Therefore, ignoring the contributions of SGD in aiding the arsenic carcinogenicity in the coastal region of Bengal cannot continue for long and the time has come when a strong framework for SGD monitoring should be put in place, especially for regions falling under the purview of arsenic hazard zones.

Sea-level rise and overfishing could enhance the strength of hydrological connectivity and the presence of herbivores, resulting in salt marsh loss through physical stress and trophic cascade effects. Our aim was to estimate the effects of these two stresses on autochthonous producers. Survivorship and biomass of Suaeda salsa (S. salsa) were the lowest in areas with high hydrological connectivity, whereas the highest biomass was observed in the areas with moderate connectivity. The biomass of benthic microalgae was higher under low hydrological connectivity and no herbivores. The interactive effects between hydrological connectivity and herbivores on S. salsa but not on benthic microalgae were observed. Herbivores were somewhat (28%) important for the survival of initial S. salsa seedlings, while hydrological connectivity controlled (50%) the biomass of benthic microalgae. Our study highlights that, the autochthonous producers in coastal salt marshes may disappear due to strong hydrological connectivity and the excessive presence of herbivores.

Plastic pollution in mangroves located in small islands was not well documented. This study found that mangrove ecosystem in small island was polluted by plastic debris (mainly film: 63% and fiber: 31%). Density of plastic debris in mangrove area was ranging from 10 ± 4 items m⁻² to 230 ± 75 items m⁻², mean density was 92 ± 28 items m⁻². Landward was the most polluted zone mangrove (mean density: 155 ± 58 items m⁻²) or about 61% of plastic debris was distributed in this zone. This is corresponds to the sources of plastic waste was from land such as households and markets. Mean density of plastic debris was significantly correlated with mangrove health (r² = 0.59, p = 0.00). This indicated that plastic debris negatively affected mangrove ecosystem directly and indirectly. Effective land-based plastic waste management and actions such as regular beach cleanup are essential to reduce plastic pollution and to ensure mangrove conservation.

A fuzzy decision tree (FDT) based framework was developed to facilitate the selection of suitable oil spill response methods in the Arctic. Hypothetical oil spill cases were developed based on six identified attributes, while the suitability of three spill response methods (mechanical containment and recovery, use of chemical dispersants, and in-situ burning) for each spill case was obtained based on expert judgments. Fuzzy sets were used to address the associated uncertainties, and FDTs were then developed through generating: i) one decision tree for all three response methods (FDT-AP1) and ii) one decision tree for each response method and the development of linear regression models at terminal nodes (FDT-LR). The FDT-LR approach exhibited higher prediction accuracy than the FDT-AP1 approach. A maximum of 100% accurate predictions could be achieved for testing cases using it. On average, 75% of suitable oil spill response methods out of 10,000 performed iterations were predicted correctly.

Peripheral marine ecosystems can harbor endemic diversity and attract tourism attention, yet are generally not included in conservation management plans due to their remoteness or inland positioning. A case study in Raja Ampat of seven landlocked marine lakes containing golden jellyfish (Mastigias spp.) was conducted to address the lack of fundamental insights into evolutionary, ecological and social contexts of these ecosystems. An interdisciplinary approach was taken towards identifying the jellyfish lakes as distinct management units in order to incorporate them into existing Marine Protected Areas. Mastigias papua populations showed strong genetic (ϕ_ST: 0.30–0.86) and morphological (F = 28.62, p-value = 0.001) structure among lakes, with putative new subspecies. Risks arising from rapid increase in tourism to Raja Ampat (30-fold since 2007) warrant restrictions on jellyfish lake use. Recommendations are provided for adaptive management and science-based conservation policies for jellyfish lakes across Indonesia.

This review quantifies plastic interaction in marine biota. Firstly, entanglement and ingestion records for all marine birds, mammals, turtles, fish, and invertebrate species, are summarized from 747 studies. Marine debris affected 914 species through entanglement and/or ingestion. Ingestion was recorded for 701 species, entanglement was documented for 354 species. Secondly, the frequency of occurrence of ingestion per species (Sp-%FO) was extracted for marine birds, mammals and turtles. Thirdly, for seabird species, average numbers of plastics ingested per individual were determined. Highest Sp-%FO and average number of plastics were found in tubenosed seabirds with 41% of all birds analysed having plastics, on average 9.9 particles per bird. The Sp-%FO and average number of ingested particles is lower for most other species. However, for certain species, ingestion rates of litter are reason for serious concern. Standardized methods are crucial for future studies, to generate datasets that allow higher level ecosystem analyses.