海洋酸化对刺参碳、氮收支的影响

Impacts of ocean acidification on the carbon and nitrogen budgets of sea cucumber Apostichopus japonicus

以东亚浅海生态系统关键种和重要经济生物——刺参(Apostichopus japonicus)为研究对象,设置380、750和1900 ppm 3个p CO2梯度(实测p H分别为8.06、7.72和7.41),研究CO2驱动的海洋酸化对刺参碳、氮收支的影响。结果显示酸化会抑制刺参对碳、氮生源要素的摄入,p H每降低1个单位,刺参摄取的碳和氮会分别减少40.28 mg/g/d和2.48 mg/g/d;粪便碳、粪便氮、呼吸碳和排泄氮均与p H存在线性正相关关系,而生长碳、氮与p H无线性关系。酸化影响了刺参对碳、氮的分配模式,但用于生长的碳、氮占摄食碳、氮的比例未受影响。研究表明,刺参对海洋酸化具有一定的适应能力,这种适应或许与其较低的钙化程度和在自然条件下p H多变的生境中"提前适应"有关。

Three p CO2 levels of 380 ppm、750 ppm and 1900 ppm（ effective p H being 8. 06、7. 72 and 7. 41,respectively） were set to observe the effects of ocean acidification driven by excessive CO2 on the carbon and nitrogen budgets in sea cucumber Apostichopus japonicus（ Selenka）,which is an ecologically and economically important holothurians in East Asia. Results showed that seawater acidification inhibited ingested carbon and nitrogen in A. japonicus,with40. 28 mg/g/d carbon and 2. 48 mg/g/d nitrogen decreased while p H fell by 1 unit. The impact of p H on carbon and nitrogen budgets were variable： the feces carbon/nitrogen,respiration carbon and excretion nitrogen linearly decreased with decreased p H whereas growth carbon/nitrogen did not. The ocean acidification affected the allocation models of carbon and nitrogen budgets,but the proportion of growth carbon/nitrogen in digested carbon/nitrogen was not affected statistically. These findings indicated that A. japonicus is resilient to ocean acidification,which would be due to its less-calcified feature and the ＂pre-adaptation＂in variable p H environment.