Toxicity Effects Of Tralopyril On Crassostrea Gigas In The Context Of Ocean Acidification

In recent years,tralopyril has been introduced into the antifouling market as an antifouling biocide to control biofouling by barnacles,hydroids,mussels,oysters and polychaetes,and its toxicity to aquatic organisms has attracted more and more attention.However,the toxic effects of pollutants on aquatic organisms usually do not exist independently,and are often closely related to the surrounding environment.Ocean acidification is considered to be one of the serious threats to marine life and marine ecosystems in the near future,so it is necessary to investigate the toxic effects of tralopyril on aquatic organisms in the context of ocean acidification.Tralopyril(40 μg/L,80 μg/L and 160 μg/L)were used as pollutants to expose Crassostrea gigas for a short period of time.After exposure,the toxicity of tralopyril to Crassostrea gigas were investigated comprehensively by alcian blue staining and biochemical measurements.Long-term exposure of Crassostrea gigas was performed with tralopyril(1 μg/L)as contaminant,combined with ocean acidification(pH=7.7).After exposure,alcian blue staining,transcriptome sequencing,biochemical measurements and quantitative real-time polymerase chain reaction were performed to investigate the toxic effects of tralopyril on mantle of Crassostrea gigas in the context of ocean acidification and the intertissue differences of energy metabolic responses of Crassostrea gigas to tralopyril exposure in the context of ocean acidification.The result shows:(1)Tralopyril short-term exposure increased the mucus secretion coverage ratio of Crassostrea gigas,enhanced the activity of catalase(CAT)and decreased the activity of amylase(AMS)in digestive gland,decreased the activity of acid phosphatase(ACP)and calcium ion(Ca2+)concentration in mantle,and the integreted biomarker responses index increased with the increase of exposure concentration.(2)The toxicity of tralopyril to the mantle of Crassostrea gigas was enhanced in the context of ocean acidification.Both single and combined exposure increased the mucus secretion coverage ratio,activated stress defense responses of Crassostrea gigas,affected energy metabolism by interfering with carbohydrate metabolism,lipid metabolism and amino acid metabolism,and affect the biomineralization ability of Crassostrea gigas.(3)Single and combined exposure activated the energy metabolism sensor of Crassostrea gigas,and the response of Crassostrea gigas to energy metabolism showed tissue differences.The main manifestations were increased glycolysis and decreased aerobic metabolism in gill and muscle tissues.The digestive gland tissue showed increased aerobic metabolism.In conclusion,tralopyril and ocean acidification exposure affected stress defense,energy metabolism and biomineralization ability of Crassostrea gigas,and tissue differences in energy metabolic response to single or combined exposure to tralopyril and ocean acidification.This study can provide a reference for environmental ecological risk assessment of tralopyril,and to fill the gap in the study of tralopyril toxicity to aquatic organisms in the context of ocean acidification.In the future,the metabolic process of tralopyril in vivo can be further explored with the combination of toxicity kinetics,so as to provide a reference for the comprehensive evaluation of the toxic effects of tralopyril.