Effect Of Simulated Ocean Acidification And Temperature On The Development And Reproduction Of Tigriopus Japonicus

The rise of atmospheric CO2concentrations caused by human being triggeredglobal warming as well as ocean acidification, which had been drawing increasingattentions worldwidely. In this study, CO2-induced ocean acidification was combinedwith temperature variation to investigate impacts on reproduction and development ofTigriopus japonicus. The pH values of seawater were set as8.0,7.7,7.3,6.5while thetemperatures were set as10℃、15℃、20℃and25℃respectively. Moreover, asurvey of how T. japonicus responded to seawater acidification in generation serieswas conducted.Copepoda is a key-group in the ocean ecosystem and plays an essential role as aconnecting link among the marine food chains. T. japonicus is a kind of marinebenthic copepods and a good marine ecotoxicity testing organism. The investigationof effects of ocean acidification and temperature variation on reproduction anddevelopment of T. japonicus helped further reveal potential influence on marine lifeand ecosystem.Main results of present study were as follows:1. A96h acute toxicity test on T. japonicus treated with seawater acidificationand temperature variation was conducted. The results showed that acidification didn’thave obvious impact on survival rates. After the combination of temperature, theimpact on survival rate wasn’t conspicuous either.2. A chronic toxicity test was performed on T. japonicus treated with CO2-drivenseawater acidification and temperature variation. The results proved that thedevelopment time of nauplius was prolonged with the declining of pH value inseawater, while the influence on development time of copepodite was not significant.Besides, the decline of pH value in seawater resulted in a low survival rate of T.japonicus, a low ratio of female to male and less numbers of born nauplii. Increasing temperature could shorten development time of both nauplius and copepodite stage,improve the survival rate and increase the ratio of female to male. Combination oftemperature and pH did not show significant cross effects on the survival rate andnumber of born nauplii but did have significant cross effects on the ratio of female tomale. Increasing of temperature may reduce the negative effects of seawateracidification in the experimental temperature range.3. Three generations test showed that from F0to F2, the mortality declined andthe ratio of female to male increased. T. japonicus demonstrated certain extentadaptability to sea water acidification from F0to F2.