摘要
Coralline algae(CA),a type of primary calcifying producer presented in coastal ecosystems,are considered one of the highly sensitive organisms to marine environmental change.However,experimental studies on coralline algae responses to elevated seawater temperature and reduced pH have documented either contradictory or opposite results.In this study,we analysed the growth and physiological responses of coralline algae Porolithon onkodes to the elevated temperature(30.8°C)and reduced pH(7.8).The aim of this analysis was to observe the direct and combined effects,while elucidating the growth and photosynthesis in this response.It was demonstrated that the algae thallus growth rate and photosynthesis under elevated temperature were depressed by 21.5%and 14.9%respectively.High pCO2 enhanced the growth and photosynthesis of the thallus at ambient temperature,while they were deceased when both temperature and pCO2 were elevated.CA is among the most sensitive organisms to ocean acidification(OA)because of their precipitate high Mg-calcite.We hypothesize that coralline algae could increase their calcification rate in order to counteract the effects of moderate acidification,but offset by the effect of elevated temperature.Accordingly,our results also support the conclusion that global warming(GW)is a stronger threat to algal performance than OA.Our findings are also proposed that coralline algae may be more resilient under OA than GW.
Coralline algae（CA）, a type of primary calcifying producer presented in coastal ecosystems, are considered one of the highly sensitive organisms to marine environmental change. However, experimental studies on coralline algae responses to elevated seawater temperature and reduced p H have documented either contradictory or opposite results. In this study, we analysed the growth and physiological responses of coralline algae Porolithon onkodes to the elevated temperature（30.8°C） and reduced p H（7.8）. The aim of this analysis was to observe the direct and combined effects, while elucidating the growth and photosynthesis in this response. It was demonstrated that the algae thallus growth rate and photosynthesis under elevated temperature were depressed by 21.5% and 14.9%respectively. High pCO2 enhanced the growth and photosynthesis of the thallus at ambient temperature, while they were deceased when both temperature and pCO2 were elevated. CA is among the most sensitive organisms to ocean acidification（OA） because of their precipitate high Mg-calcite. We hypothesize that coralline algae could increase their calcification rate in order to counteract the effects of moderate acidification, but offset by the effect of elevated temperature. Accordingly, our results also support the conclusion that global warming（GW） is a stronger threat to algal performance than OA. Our findings are also proposed that coralline algae may be more resilient under OA than GW.
基金
The National Natural Science Foundation of China(NSFC)under contract Nos 41306144 and 41676150
the National Key Research and Development Plan under contract No.2017YFC0506301
the Strategic Priority Research Program of the Chinese Academy of Sciences under contract No.XDA13020402
the Guangdong Basic and Applied Basic Research Foundation under contract No.2019A1515011532
