Search

As an important form of renewable energy, offshore wind power can effectively reduce dependence on traditional energy sources and decrease carbon emissions. However, operation of wind turbines can generate underwater noise that may have negative impacts on marine benthic organisms in the surrounding area. Sea cucumbers are slow-moving invertebrates that inhabit the ocean, relying on their immune system to adapt to their environment. To evaluate the frequency range of characteristic noise produced by offshore wind turbines, we conducted a field survey. Additionally, we utilized sea cucumbers in simulated experiments to assess their response to the noise produced by offshore wind turbines. We established a control group, a low-frequency noise group simulating offshore wind turbine noise at 125 Hz and 250 Hz, and a high-frequency noise group at 2500 Hz, each lasting for 7 days. Results from measuring immune enzyme activity in the coelomic fluid suggest that noise can reduce the activity of superoxide dismutase enzymes, which may make sea cucumbers more susceptible to oxidative damage caused by free radicals. Exposure to low-frequency noise can have the effect of diminishing the activity of catalase, and this decrease in catalase activity could potentially increase the susceptibility of the sea cucumber's coelom to inflammation. In order to elucidate the hypothetical mechanism of immune response, intestinal tissue was extracted for transcriptome sequencing. The results showed that under 125 Hz low-frequency noise stress, the number of differentially expressed genes was the highest, reaching 1764. Under noise stress, sea cucumber's cell apoptosis and cell motility are reduced, interfering with lipid metabolism process and membrane synthesis. This research provides theoretical support for the environmental safety assessment of offshore wind power construction., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

While offshore wind power has support from countries around the world, studies show that offshore wind farms (OWFs) may affect marine organisms. Environmental metabolomics is a high-throughput method that provides a snapshot of an organism's metabolic state. To elucidate the effects of OWFs on aquatic organisms, we studied, in situ, Crassostrea gigas and Mytilus edulis attached within and outside of OWFs and their reef areas. Our results show that epinephrine, sulphaniline, and inosine 5'-monophosphate were significantly increased and L-carnitine was significantly reduced in both Crassostrea and Mytilus species from the OWFs. This may be related to immune response, oxidative stress, energy metabolism and osmotic pressure regulation of aquatic organisms. Our study shows that active selection of biological monitoring methods for risk assessment is necessary and that metabolomics of attached shellfish is useful in elucidating the metabolic pathways of aquatic organisms in OWFs., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Libin Zhang reports financial support was provided by the National Key Research and Development Program of China (2022YFD2401302), China., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Offshore wind power is a typical example of clean energy production and plays a critical role in achieving carbon neutrality. Offshore wind farms can have an impact on the marine environment, especially sedimentary environments, but their influence on sediments remain largely unknown. This study, which uses the control-impact principle to define different areas, investigated the characteristics of marine sediments under the Putidao offshore wind farm in Bohai Bay, China. We used chemical and microbiological observations to evaluate sediment quality and microbial community structure. According to both the geo-accumulation index (I geo ) and contamination factor (CF) indexes, copper, chromium and zinc were the major contaminants in the offshore wind farm sediments. The pollution load index (PLI) index showed that the various sites on the wind farm were only lightly polluted compared with baseline values. Closer to the wind farm's center, the metal concentrations started to rise. The physicochemical features of the sediments could better explain changes in the microorganisms present, and screening the microbiomes showed a correlation with heavy metal levels, linking the relative abundance of microorganisms to the sediment quality index. This comprehensive study fills a knowledge gap in China and adds to our understanding of how to assess the sedimentary environments of offshore wind farms., Competing Interests: Declaration of competing interest The authors declare no competing or financial interests., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Gender differences in physiological characteristics are widespread in animals. Herein, differentially expressed genes (DEGs) in gonads of the sea cucumber Apostichopus japonicus were analysed by transcriptomics, and the results showed that 19,973 genes were commonly expressed in the males and females, 4186 were female-biased, and 2540 were male-biased, 4695 genes were up-regulated in the females and 3436 genes were up-regulated in the males. These DEGs were mainly associated with metabolism, including lipid metabolism, amino acid metabolism, nucleotide metabolism, energy metabolism, and cofactor and vitamin metabolism. 29 Cytochrome P450 (CYP) superfamily genes with gender differential expression were selected, and performed gene identification, phylogenetic, and functional analyses. The results indicated significant roles in multiple metabolic pathways, such as steroid hormone biosynthesis, ovarian steroidogenesis, cortisol synthesis and secretion, arachidonic acid metabolism, linoleic acid metabolism, and retinol metabolism. The findings provide insight into the molecular characteristics of physiological gender differences in sea cucumbers, and will help lay the foundation for the establishment of effective sea cucumber breeding technologies., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Multiple environmental stressors caused by global warming influence the regulation of proteins involved in various biological processes in aquatic organisms. As an important component of the marine ecosystem, sea cucumber is a suitable echinoderm species for researching stress responses. In this study, we have investigated the proteomic response of respiratory trees in the sea cucumber Apostichopus japonicus, challenged with environmental stresses by using the iTRAQ technique. Results showed that 262, 155 and 433 proteins were differentially regulated in response to heat, hypoxia, and heat plus hypoxia, respectively. Expression of key genes and proteins were measured by real-time PCR and western blot to validate the accuracy of the proteome files. Results showed that the interaction between these two stressors has an additive effect at the proteome level. Proteins involved in amino acid and carbohydrate metabolic processes were largely induced by heat while repressed by hypoxia. Exposure to multiple climate change stressors caused several proteins involved in lipid metabolic progress to be down-regulated and lipid catabolic processes were induced. Additionally, hypoxia and the combined stress induced proteins involved in iron homeostasis. ATP synthesis and gluconeogenesis were induced under heat and the combined stress, while ATP and glycogen synthesis were depressed under hypoxia. Proteins related with immune and defense response were largely induced and protein synthesis ability was depressed under all three stresses. Thus, sea cucumber may adopt different strategies to cope with varied environmental stress, and the situation in heat group is more similar with the combined treatment than hypoxia group. These proteomic changes in response to high-temperature and low-oxygen levels may provide insights into the defense strategies of sea cucumber in response to global climate changes. SIGNIFICANCE OF THE STUDY: The study focused on comparative quantitative proteomics on Apostichopus japonicus respiratory tree using iTRAQ in responses to multiple climate change stressors: heat, hypoxia and the combined stress. Data showed that A. japonicus can have an acute reaction in diverse biological pathways to both individual and interacting environmental stress, including substance metabolism, signal transduction, protein synthesis, immune response and energy production. Results indicated that sea cucumber adopted different strategies to cope with varied environmental stress, and the interaction between these two stressors has an additive effect at the proteome level. These results offer insight into the molecular regulation of A. japonicus to multiple environmental stress and reveal possible molecular events in sea cucumber under climate changes. The understanding of adaptive variation under global climate changes in aquatic organisms could be improved., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Economically important marine organisms face severe environmental challenges, such as high temperature and low dissolved oxygen, from global climate change. Adverse environmental factors impact the survival and growth of economically important marine organisms, thereby negatively influencing the aquaculture industry. However, little is known about the responses of sea cucumbers to combined environmental co-stressors till now. In this study, ultra-performance liquid chromatography (UPLC) was utilized to obtain metabolic profiles of sea cucumbers. Changes in the concentrations of 84, 68, and 417 metabolites related to the responses of sea cucumbers to heat (26 °C), hypoxia (2 mg/L) and the combined stress, respectively, were observed and analyzed. Representative biomarkers were discussed in detail, including deltaline, fusarin C, halichondrin B and rapanone. The concentration of metabolites involved in the regulation of energy metabolism, including amino acid, carbohydrate and lipid metabolism were significantly changed, and the tricarboxylic acid (TCA)-cycle was significantly altered under heat plus hypoxia. We interpreted these changes partly as an adaptation mechanism in response to environmental stress. Based on the decreased accumulation of glutamine, we hypothesized that heat stress is the main factor that interferes with the process of glutamic acid-glutamine metabolism. The present study showed that combined environmental stressors have a more extensive impact on the metabolites of the respiratory tree in sea cucumbers than single stress. These results would facilitate further development of the sea cucumber as an echinoderm model to study mechanisms of response to adverse environments, as well as to help advance knowledge of the adaptation of marine organisms to global climate change., (Copyright © 2018 Elsevier Ltd. All rights reserved.)