ABSTRACT: Diel vertical migration is a widespread behaviour amongst zooplankton, yet its effect on the rate at which individuals respire remains poorly understood. To address this, we investigated the effect of short-term temperature change on the respiration rate of Euphausia triacantha, a common component of the Southern Ocean zooplankton and a prominent vertical migrator. We found respiration to vary in response to size, with a value of 0.84 for the scaling coefficient, b. When scaled to b, respiration varied strongly in response to transitory temperature change, ranging from 0.37 to 1.65 µl O₂ mg dry weight (DW)^-b h^-1 between 0.17 and 4.74°C, resulting in a Q₁₀ of 3.6. This Q₁₀ is higher than found by other studies examining the short-term respiration response of euphausiids, including those taking a multi-species perspective. This indicates that E. triacantha shows little compensation during short-term exposure to temperatures normally encountered during migration. Furthermore, it shows a distinct metabolic cost to diel vertical migration (DVM) when substantive changes in temperature are encountered over the course of the transit. This temporal variability in respiration rate has important implications for how community respiration is estimated, and for our understanding of DVM behaviour. Our results also have particular relevance to estimating the flux and sequestration of respiratory products, such as dissolved carbon dioxide, to and within the ocean interior.

中文翻译：

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南方大洋金鱼（Euphausia triacantha）的狄尔垂直迁移及其对短期温度变化的代谢反应

摘要：Diel垂直迁移是浮游动物中的一种普遍行为，但对个体呼吸速率的影响仍然知之甚少。为了解决这个问题，我们研究了短期温度变化对南太平洋细小叶藻（Euphausia triacantha）（南大洋浮游动物的常见组成部分和显着的垂直迁徙者）呼吸速率的影响。我们发现呼吸随大小而变化，缩放系数b值为0.84 。当缩放为b，呼吸响应于瞬时温度变化强烈变化，范围从0.37到1.65微升Ò ₂毫克的干重（DW）^{- b} ħ ^-1 0.17 4.74℃之间，产生了Q ₁₀的3.6。这个Q ₁₀高于其他研究杜鹃花的短期呼吸反应的研究，包括从多物种角度看的那些。这表明E. triacantha在短期接触迁移过程中通常遇到的温度时，显示出很少的补偿。此外，当在运输过程中遇到温度的实质变化时，它显示出降低垂直迁移（DVM）的代谢成本。呼吸速率的这种时间变化对社区呼吸的估计方式以及我们对DVM行为的理解具有重要意义。我们的研究结果还与估计呼吸产品（例如溶解的二氧化碳）流入海洋内部和在海洋内部的通量和封存特别相关。