Effects Of Ocean Acidification On Fertilization And Embryonic Development Of Abalones And Their Hybrids

Since the industrial revolution,human activities have resulted in a large amount of CO2 emitted into the atmosphere,of which 25?30%was absorbed by seawater,leading to the lower pH and the formation of ocean acidification that threatens to the survival of marine organisms,especially calcareous organisms.Numerous previous studies have shown that ocean acidification can affect the fertilization and early embryonic development of marine invertebrates.But few studies have compared the effect of ocean acidification on abalones and their hybrids,and the synergistic effect of ocean acidification and other environmental factors on marine organisms still need to be explored.In this experiment,I simulated the environmental conditions of ocean acidification in the future by the instruments,and the differences in the effects of ocean acidification on fertilization and embryonic development of Haliotis discus hannai,Haliotis gigantea,Haliotis fulges,SD,DF,SD-D and D-DF were compared;the differences in the effects of ocean acidification and temperature,ocean acidification and heavy metals Cd,Hg,Cr,ocean acidification and persistent organic pollutants PCB1254 on fertilization and embryonic development of H.discus hannai were compared;the effects of ocean acidification on the shell morphology of 3 kinds abalone veliger at 24h after fertilization were compared.The results are as follows:1.Effects of ocean acidification on fertilization and embryonic development of abalones and their hybridsOcean acidification could afifect fertilization and early embryonic development of abalones to a certain extent.Generally,with the increase of pCO2 level,fertilization rate and hatching rate would decrease,and malformation rate would increase.Ocean acidification had a greater impact on the malformation rate of abalone veliger.Almost all of abalone veliger in 3000 ppm treatment group were malformed,which seriously affected the normal development of abalone veliger.However,there were differences in the response to ocean acidification among abalones and their hybrids.Among them,H.discus hannai,SD,DF and SD-D were more tolerant to ocean acidification,while H.gigantea,H.fulgens and D-DF were more sensitive to ocean acidification,which may be related to heterosis and their different living environment.2.Combined effects of ocean acidification and temperature on fertilization and embryonic development of H.discus hannaiOcean acidification and temperature had adverse effects on fertilization and embryonic development of H.discus hannai,and there was an synergistic effect between ocean acidification and temperature,that is,ocean acidification would enhance the adverse effect of temperature on fertilization and embryonic development of H.discus hannai.3.Combined effects of ocean acidification and pollutants on fertilization and embryonic development of H.discus hannaiThe sensitivity of abalone to different pollutants was different,H.discus hannai was not sensitive to the concentration change of Cd,Cr,but was very sensitive to the concentration change of Hg and PCB1254.There was an synergistic effect between ocean acidification and pollutants.Ocean acidification would enhance the adverse effects of Cd,Cr and PCB1254 on H.discus hannai,and alleviate the adverse effect of Hg on the fertilization rate.4.Analysis of shell morphology of abalones and their hybrid under ocean acidificationScanning electron microscope(SEM)and energy disperse spectroscope(EDS)were used to photograph the veliger of DD,SS,SD which were 24h after fertilization under acidification and analyse the Ca element content.The result showed that:ocean acidification could inhibit the calcification of three abalones,reduced the Ca element content in the shell structure,eroded the surface structure of the shell and reduced the surface raised area.At high pCO2 level,the larval shell completely disappeared which seriously affected the normal development of veliger,increased the mortality rate of abalone and threatened the survival of the larvae.The shell surface structures of three abalones differed in response to different levels of pCO2.This result may be consistent with the first part,that was,SD had certain heterosis,DD and SD were more tolerant to ocean acidification,while SS was more sensitive to ocean acidification.