title: Long-term experiment on physiological responses to synergetic effects of ocean acidification and photoperiod in the Antarctic sea ice algae Chlamydomonas sp. ICE-L.
abstract: Studies on ocean acidification have mostly been based on short-term experiments of low latitude with few investigations of the long-term influence on sea ice communities. Here, the combined effects of ocean acidification and photoperiod on the physiological response of the Antarctic sea ice microalgae Chlamydomonas sp. ICE-L were examined. There was a general increase in growth, PSII photosynthetic parameters, and N and P uptake in continuous light, compared to those exposed to regular dark and light cycles. Elevated pCO2 showed no consistent effect on growth rate (p=0.8) and N uptake (p=0.38) during exponential phrase, depending on the photoperiod but had a positive effect on PSII photosynthetic capacity and P uptake. Continuous dark reduced growth, photosynthesis, and nutrient uptake. Moreover, intracellular lipid, mainly in the form of PUFA, was consumed at 80% and 63% in low and high pCO2 in darkness. However, long-term culture under high pCO2 gave a more significant inhibition of growth and Fv/Fm to high light stress. In summary, ocean acidification may have significant effects on Chlamydomonas sp. ICE-L survival in polar winter. The current study contributes to an understanding of how a sea ice algae-based community may respond to global climate change at high latitudes.
authors.affiliation: Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China.
authors.forename: Dong
authors.initials: D
authors.lastname: Xu
authors.forename: Yitao
authors.initials: Y
authors.lastname: Wang
authors.forename: Xiao
authors.initials: X
authors.lastname: Fan
authors.forename: Dongsheng
authors.initials: D
authors.lastname: Wang
authors.forename: Naihao
authors.initials: N
authors.lastname: Ye
authors.forename: Xiaowen
authors.initials: X
authors.lastname: Zhang
authors.forename: Shanli
authors.initials: S
authors.lastname: Mou
authors.forename: Zheng
authors.initials: Z
authors.lastname: Guan
authors.forename: Zhimeng
authors.initials: Z
authors.lastname: Zhuang
mesh_terms: D000143:Acids / Q000737:chemistry*; D000864:Antarctic Regions; D002245:Carbon Dioxide / Q000494:pharmacology; D002254:Carbonates / Q000032:analysis; D002696:Chlamydomonas / Q000254:growth & development / Q000502:physiology* / Q000528:radiation effects; D006863:Hydrogen-Ion Concentration; D046448:Ice Cover; D008027:Light; D008055:Lipids / Q000032:analysis; D009792:Oceans and Seas; D017440:Photoperiod; D010788:Photosynthesis / Q000187:drug effects / Q000528:radiation effects; D045332:Photosystem II Protein Complex / Q000378:metabolism; D013997:Time Factors
chemical_list: D000143:Acids; D002254:Carbonates; D008055:Lipids; D045332:Photosystem II Protein Complex; D002245:Carbon Dioxide