We investigated coral bleaching by monitoring colour changes and measuring the delayed fluorescence (DF) of symbiotic dinoflagellates in the hermatypic coral Acropora tenuis, exposed to 1.0 μg/L Irgarol 1051 (photosystem II herbicide) for 14 d. The Irgarol concentration corresponded to those from international port regions of the world. The coral colour and DFs under the control treatment were stable throughout the experiment, whereas under the Irgarol treatment the corals showed gradual bleaching. The Irgarol treatment caused a rapid decrease in the slow decay DF component (10.1–60.0 s), while the fast decay DF component (0.1–10.0 s) decreased significantly after 6 d. The significant correlation between the latter values and the coral colour indicates that if the electron accumulation function of quinones QA and QB is compromised, corals will bleach. The present study will contribute to the understanding of the mechanism involved in bleaching of coral exposed to herbicides.

Although it has previously been shown that bisphenol (BP) analogues may interfere with the normal hormonal regulation by acting as endocrine disrupting chemicals (EDCs), little information is available on effects of BP analogues in invertebrates, particularly on cladocerans. In the present study, we identified estrogen-related receptors (EER), vitellogenin (VTG), and VTG receptor (VtgR) from the brackish water flea Diaphanosoma celebensis, and examined the effects of BPA and the substitutes, BPF and BPS, in different sublethal concentrations. Gene expression varied with time well matched with brooding, suggesting that DcEER, DcVTG, and DcVtgR play a role in reproduction in D. celebensis. qRT-PCR analysis showed that BPA and its substitutes differently modulated mRNA expressions of DcEER, DcVTG, and DcVtgR, indicating that these compounds adversely affect the normal reproduction-related pathway. This study facilitates better understanding of the molecular mode of action of BP analogues on the reproductive system of D. celebensis.

Ten global harbours were assessed for sediment quality by quantifying the magnitude of anthropogenic change and ecological risk. Anthropogenic change (enrichment) was high for Derwent River and Sydney estuary, moderate for Santander Harbour, Rio de Janeiro and Dublin Port, slight for Hong Kong, minimal for Darwin. All 10 enrichment indices used showed similar results. Derwent River sediment was rated at high ecological risk, followed by Sydney and Santander estuaries with moderate risk. Auckland and Darwin sediments exhibited minimal ecological risk and sediment in the remaining harbours (Dublin, Hong Kong, Ravenna, Ria de Vigo and Rio de Janeiro) were assessed at slight ecological risk.The extraordinary variety of environments and types/quantities/qualities of data investigated resulted in as much a critique and development of methodology, as an assessment of human impact, including unique techniques for elemental normalisation and contaminant classification. Recommendations for an improved technical framework for sediment quality assessment are provided.

Field investigations and incubation experiment were carried out in the Dafengjiang River (DFJR) and Sanniang Bay (SNB) surface water from September 2017 to July 2018 to study the composition and spatio-temporal distributions of different nitrogen (N) species, lability of dissolved organic N (DON), and contributions of different N species from the DFJR to the dissolved inorganic N (DIN) level in the SNB. The spatio-temporal distributions of different N species exhibited significant seasonal variation (p < 0.05). The average contribution of DIN, DON, and particulate nitrogen (PN) to TN was 31.91%, 46.57%, and 21.52%, respectively. Comparatively being the dominant form of N in the study area, the average lability of DON across the incubation sites D1, D5 and D7 ranged from 72%–79%. DIN, DON, and PN from the DFJR respectively contributed to 55.95%, 7.03%, and 5.63% of water quality in the SNB.

The significant amount of plastic litter in the form of microplastics (size <5 mm) is garnering attention owing to its potential threat to marine life. Reliable, cost- and time-efficient analysis methods for monitoring microplastic abundance globally are still missing. Several studies proposed a fast detection method by binding the solvatochromic dye Nile Red on the surface of microplastics and using fluorescence microscopy for their detection. All the staining approaches reported so far differ in terms of Nile Red concentration, solvents, and staining procedure. Here, we compare the staining protocols published prior to 2019 and propose an optimized staining protocol. Furthermore, we explore the potential of Nile Red staining in combination with photoluminescence spectroscopy to identify the polymer type and to distinguish plastics from non-plastics.

Constructed wetlands (CWs) have been used for wastewater treatment for decades, but research on microorganisms involved, especially long-term changes, is still limited. In this study, we evaluated changes in the substrate microbial community in a pilot-scale horizontal subsurface-flow constructed mangrove wetland during 10-years operation. In the 3rd year of operation, microbial biomass carbon and phospholipid fatty acids (PLFAs) reached peak values in two vegetated belts planted with Aegiceras corniculatum (Ac) and Kandelia obovata (Ko), respectively, then stabilized or declined in the 9th and 10th years of operation. PLFA profiles reflecting microbial community compositions varied significantly in the Ac belt during the operation period. Principal component (PCA) and redundancy analyses (RDA) revealed that microbial community compositions were significantly correlated with organic matter content, especially in the 9th and 10th years of operation, implying that the substrate microbial community in constructed mangrove wetland is sensitive to substrate characteristics and can be used as an indicator for long-term performance of CWs.

Turkey, with her two important straits, is geographically in the middle of one of the major transportation routes and will continue to face risks the oil tankers pose in those sensitive areas. This paper revisits the site of an oil tanker accident that occurred at the northern entrance of the Istanbul Strait in 1994. The aim of the study was to simulate the same accident in PISCES-II Simulator to compare the response actions of the time with the present capabilities. Effort is also made to understand how the negative impacts of an oil spill accident can be lessened. Therefore, the study is planned to set to cover two separate response scenarios for the identical oil spill incident, actually simulating the 1994 M/T Nassica accident. The results showed that oil pollution response in places with strong currents like Istanbul Strait needs special care to sea conditions as well as related assets.

The visual survey is the most common method to quantify and characterize beach litter. However, it is very labor intensive and difficult to carry out on beaches which are remote or difficult to access. We suggest an alternative approach for assessing beach litter using an unmanned aerial vehicle (UAV), or aerial drone, with automated image requisition and processing. Litter of different sizes, colours, and materials were placed randomly on two beaches. Images of beaches with different substrates were obtained by the drone at different operating heights and light conditions and litter on the beaches was identified from the photos by untrained personnel. The quantification of beach litter using the drone was three times faster than that by visual census. This study has demonstrated the potential of using the drone as a cost-effective and an efficient sampling method in routine beach litter monitoring programs.

To identify the seasonal variability of body-size spectrum for monitoring surveys based on periphytic protozoa, a one-year baseline survey was carried out in a coastal region of Yellow Sea, northern China. A total of 240 glass slides were collected after immersion times of 3, 7, 10, 14, 21 and 28 days in a four season cycle, i.e., winter, spring, summer, and autumn. Body-size ranks S2 and S5 dominated the periphytic protozoan communities from the initial stage (from day 3) to the next periods in spring and autumn, while body-size ranks S7, S8 and S4 showed high variety at the equilibrium stages (from day 10) in summer and winter. The expectation analysis revealed that the samples had different patterns of departure from the anticipated body-size spectrum in each season. This study shows that an ideal sampling approach needs to be established when protozoa is used as bioindicators of marine water quality.

Plastic ingestion by seabirds is an efficient way to monitor marine plastics. We report temporal variation in the characteristics of marine litter regurgitated by albatrosses and giant petrels on sub-Antarctic Marion Island between 1996 and 2018. Both fishery and other litter peaked during the height of the Patagonian toothfish fishery around the island (1997–1999). Comparing the two subsequent decades of reduced fishing effort (1999–2008 and 2009–2018), fishing litter decreased while other litter increased across all species. Litter increased most in grey-headed albatrosses, followed by giant petrels and wandering albatrosses. Similar ranked responses were found in the same species at South Georgia, but non-fishery-related litter has increased faster in the Indian Ocean than the southwest Atlantic, indicating regional changes in litter growth rates. These seabirds' regurgitations provide an easy, non-invasive way to track changes in oceanic litter in a remote area that is otherwise difficult to monitor.