From DNA to ecological performance: Effects of anthropogenic noise on a reef-building mussel

Responses of marine invertebrates to anthropogenic noise are insufficiently known, impeding our understanding of ecosystemic impacts of noise and the development of mitigation strategies. We show that the blue mussel, Mytilus edulis, is negatively affected by ship-noise playbacks across different levels of biological organization. We take a novel mechanistic multi-method approach testing and employing established ecotoxicological techniques (i.e. Comet Assay and oxidative stress tests) in combination with behavioral and physiological biomarkers. We evidence, for the first time in marine species, noise-induced changes in DNA integrity (six-fold higher DNA single strand-breaks in haemocytes and gill epithelial cells) and oxidative stress (68% increased TBARS in gill cells). We further identify physiological and behavioral changes (12% reduced oxygen consumption, 60% increase in valve gape, 84% reduced filtration rate) in noise-exposed mussels. By employing established ecotoxicological techniques we highlight impacts not only on the organismal level, but also on ecological performance. When investigating species that produce little visually obvious responses to anthropogenic noise, the above mentioned endpoints are key to revealing sublethal effects of noise and thus enable a better understanding of how this emerging, but often overlooked stressor, affects animals without complex behaviors. Our integrated approach to noise research can be used as a model for other invertebrate species and faunal groups, and inform the development of effective methods for assessing and monitoring noise impacts. Given the observed negative effects, noise should be considered a potential confounding factor in studies involving other stressors

Insights into technical challenges in the field of microplastic pollution through the lens of early career researchers (ECRs) and a proposed pathway forward

Early career researchers (ECR) face a series of challenges related to the inherent difficulties of starting their careers. Microplastic (MP) research is a topical field attracting high numbers of ECRs with diverse backgrounds and expertise from a wealth of disciplines including environmental science, biology, chemistry and ecotoxicology. In this perspective the challenges that could hinder scientific, professional, or personal development are explored, as identified by an international network of ECRs, all employed in MP research, that was formed following a bilateral workshop for scientists based in the UK and China. Discussions amongst the network were grouped into four overarching themes of technical challenges: in the field, in the laboratory, in the post data collection phase, and miscellaneous. The three key areas of representativeness, access to appropriate resources, training, and clean labs, and the use of databases and comparability, as well as the overarching constraint of available time were identified as the source of the majority of challenges. A set of recommendations for pathways forward are proposed based on the principles of research openness, access to information and training, and widening collaborations. ECRs have great capacity to promote research excellence in the field of MPs and elsewhere, when provided with appropriate opportunities and suitable support

Organotin and osmoregulation: quantifying the effects of environmental concentrations of sediment-associated tri-n-butyltin and triphenyltin on osmoregulatory processes in the European flounder Platichthys flesus (L)

The disruption of physiological and morphological aspects of osmoregulatory processes in freshwater-adapted 0-group European flounders, Platichthys flesus (L.), caused by exposure to environmental concentrations (150 ng triorganotin g-1 dry weight sediment) of sediment-associated tri-o-butyltin chloride (TBTCl) and triphenyltin chloride (TPhTCl), was examined and quantified. Radiotracers were used to measure hydromineral fluxes, the water balance and passive sodium efflux of chronically (35 days) exposed fish. The water permeabilities of exposed flounders varied during the course of the experiment and were significantly lower than the corresponding controls, that did not change significantly with time. It was found that the maximum change in water permeability of TBTCl- and TPhTCl exposed fish occurred after 14 days and 21 days, respectively; thereafter there was an increase towards control values, suggesting adaptation to compensate for the effects of the organotin exposure. Drinking rates increased significantly in both organotin groups buturine production rates did not change. The effects of organotin exposure on the passive sodium efflux and Na+/K+-ATPase activity showed an inverted relationship in the TBT group, where the Na7K+-ATPase activity was reduced and the passive sodium efflux was increased. TPhT had no inhibitory effect on Na7K+-ATPase activity and the passive sodium efflux increased only gradually. The overall effect of these changes in these components of hydromineral regulation was to reduce the mean blood osmolalities of the organotin groups compared to the control values.The effects of chronic exposure to sediment-associated triorganotin compounds during sea water adaptation was examined and quantified by measuring the active sodium efflux, Na+/K+-ATPase activity and structural changes to the gill epithelium usually encountered in euryhaline fish during adaptation to sea water. Following the transfer to seawater, the Na+/K+-ATPase activity and the active sodium efflux were decreased in the TBT group but increased significantly in both the TPhT and control groups. Similarly, the morphological changes to the gill epithelium, involving chloride cell distribution, associated with sea water adaptation, took place in the control group and only partially in the TPhT group but were significantly inhibited or delayed in the TBT group. The exposure to organotin caused the mean blood osmolalities in fish of the TBT and TPhT to rise beyond the expected values that were observed in the control group. The results presented in this study lead to the conclusion that tri-tt-butyltin chloride and triphenyltin chloride in sediments are capable of significantly disrupting both the physiological as well as morphological components of osmoregulatory functions of an estuarine fish, at concentrations currently found in local sediments

Climate change: Implications for ecotoxicological environmental impact assessment

As a consequence of increasing atmospheric CO2 and its subsequent sequestration, the oceans are undergoing changes that have not been seen for millennia, including temperature increases, ocean acidification, and localized alterations in salinity. Current methodologies for undertaking environmental-impact assessments may not be suitable for use under near-future (2100) conditions. This paper reviews and analyses what research has presently been undertaken to address these concerns. The authors find that little attention has previously been paid to chronic-exposure conditions that accurately reflect the near future, but the few available studies show that the consequences of oceanic climate change will not only be significant for marine life, but also impact humans who depend on it. The authors suggest that future research should target understanding how climate change will impact the physiological health of a wide array of species, important both economically and ecologically, going beyond the often-chosen model species and standardized testing. This information is necessary to accurately estimate the environmental risk of proposed engineering projects in changing environmental conditions