Ocean Acidification Affects the Phyto-Zoo Plankton Trophic Transfer Efficiency.
Ocean Acidification Affects the Phyto-Zoo Plankton Trophic Transfer Efficiency.
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DOI：
10.1371/journal.pone.0151739
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发表时间：
2016
期刊：
影响因子：
3.7
通讯作者：
Lindeque PK
中科院分区：
文献类型：
--
作者：
Cripps G;Flynn KJ;Lindeque PK
桡足类动物在海洋生态和生物地球化学中的重要作用，使我们有必要了解这些动物对海洋酸化的反应。由于二氧化碳分压升高，OA对桡足类动物的潜在直接影响的认识正在改善，但对自下而上（食品质量）效应的间接影响知之甚少。我们首次评估了直接和/或间接暴露于升高的二氧化碳分压下对类calanoid桡足动物Acartia tonsa的行为、生命率、化学和生化化学计量学的慢性影响。二氧化碳浓度升高的自下而上效应导致浮游植物饲料发生物种特异性生化变化，对桡足类种群结构产生不利影响，使增殖量减少30%。pCO2升高的直接影响引起了成虫的性别特异性呼吸反应，刺激雄性呼吸速率增加（2倍），而当间接升高的pCO2暴露时，雌性呼吸反应受到抑制。在间接+直接联合暴露条件下，浮游植物向浮游动物的碳营养转移效率下降到对照种群的50%以下，吸收量也相应下降。生物化学计量学首次在塑造桡足动物营养动力学中发挥了明确的作用。暴露于二氧化碳的猎物的生化组成的改变影响了桡足类动物的生化化学计量，这可能对更高热带水平的生产产生影响，特别是渔业。我们的研究表明，在未来的OA情景下，浮游植物的控制和包括桡足类在内的更高营养水平的支持显然有可能受到不利影响。
The critical role played by copepods in ocean ecology and biogeochemistry warrants an understanding of how these animals may respond to ocean acidification (OA). Whilst an appreciation of the potential direct effects of OA, due to elevated pCO2, on copepods is improving, little is known about the indirect impacts acting via bottom-up (food quality) effects. We assessed, for the first time, the chronic effects of direct and/or indirect exposures to elevated pCO2 on the behaviour, vital rates, chemical and biochemical stoichiometry of the calanoid copepod Acartia tonsa. Bottom-up effects of elevated pCO2 caused species-specific biochemical changes to the phytoplanktonic feed, which adversely affected copepod population structure and decreased recruitment by 30%. The direct impact of elevated pCO2 caused gender-specific respiratory responses in A.tonsa adults, stimulating an enhanced respiration rate in males (> 2-fold), and a suppressed respiratory response in females when coupled with indirect elevated pCO2 exposures. Under the combined indirect+direct exposure, carbon trophic transfer efficiency from phytoplankton-to-zooplankton declined to < 50% of control populations, with a commensurate decrease in recruitment. For the first time an explicit role was demonstrated for biochemical stoichiometry in shaping copepod trophic dynamics. The altered biochemical composition of the CO2-exposed prey affected the biochemical stoichiometry of the copepods, which could have ramifications for production of higher tropic levels, notably fisheries. Our work indicates that the control of phytoplankton and the support of higher trophic levels involving copepods have clear potential to be adversely affected under future OA scenarios.