CO_2加富对魁蚶稚贝潜沙能力和3种酶活性的影响

Effects of Elevated Seawater pCO_2 on the Burrowing Ability and Three Enzymes of Scapharca broughtonii(Bivalvia:Arcidae) Juvenile

贝类的生长和代谢过程可能会受到高CO2浓度的影响。潜沙行为和酶活性是贝类响应环境变化的重要指标,但其对海水CO2浓度升高响应的研究鲜有报道。本文采用CO2加富培养实验的方法,研究了高CO2浓度条件对魁蚶(Scapharca broughtonii)稚贝潜沙能力和超氧化物歧化酶(Superoxide dismutase,SOD)、过氧化氢酶(Catalase,CAT)和乙酰胆碱酯酶(Acetylcholinesterase,AChE)3种酶活性的影响。结果表明,CO2组(1 000μatm)培养水体中DIC浓度显著高于对照组,魁蚶稚贝初次潜沙时间((5.73±0.51)min)相比对照组((7.80±1.27)min)明显缩短,潜沙率((69.67±5.13)%)相比对照组((61.33±3.21)%)明显升高。实验开始时魁蚶稚贝壳长为(17.20±0.03)mm,实验结束时CO2组魁蚶稚贝壳未出现明显生长((17.24±0.02)mm),显著低于对照组魁蚶稚贝壳长(17.37±0.07)mm。CO2组魁蚶稚贝SOD活性在培养第2和第4天时显著高于对照组(P<0.01),之后出现下降并与对照组无显著差异;CO2组和对照组魁蚶稚贝CAT活性在前4天均上升,之后CO2组魁蚶稚贝CAT活性基本不变,而对照组出现下降;两实验组魁蚶稚贝AChE活性在培养过程中无明显差异。高CO2浓度条件下魁蚶稚贝壳的生长受到影响,潜沙过程受到促进,3种酶活性在培养过程中的变化趋势存在差异,未来海洋酸化可能会影响魁蚶的养殖。

Growth and metabolism of bivalves will be influenced by the elevated seawater pCO2.To investigate the effects of seawater carbonate chemistry changes caused by elevated seawater pCO2 on the burrowing ability and antioxidant enzymes（superoxide dismutase,catalase and acetylcholinesterase）activity of marine benthic organisms,we exposed juvenile of Scapharca broughtonii in seawater bubbled with CO2-enriched（1 000μatm）gas mixtures.We demonstrated that elevated seawater pCO2 significantly altered seawater carbonate chemistry equilibrium and interfered shell growth of the juveniles.The first burrowing time of S.broughtonii juvenile in CO2 treatments（（5.73±0.51）min）was significantly lower than that in the control treatments（（7.80±1.27）min）,and the burrowing rate in CO2 treatments（（69.67±5.13）%）was significantly higher than that in the control treatments（（61.33±3.21）%）.Simultaneously,shell length of the S.broughtonii juvenile in CO2 treatments（（17.24 ± 0.02）mm）was significantly lower than that in the control treatments（（17.37±0.07）mm）.Activity of SOD enzyme of S.broughtonii juvenile in CO2 treatments was significantly higher than that in the control treatments（p〈0.01）at the2 nd and 4 th day and then decreased.Activity of CAT enzyme of S.broughtonii juvenile in the two treatments increased at the first 4 days,then activity of CAT enzyme in the control treatments decreased.There was no significant difference between the activity of AChE enzyme of S.broughtonii juvenile in the two treatments.Ocean acidification may lead to the loss of break out of aquaculture of S.broughtonii and present challenges to the stability of marine ecosystem and biodiversity.