Sswat Michael, Stiasny Martina H, Jutfelt Fredrik, Riebesell Ulf, Clemmesen Catriona
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany.
University of Kiel, Department of Economics, Kiel, Germany.
PLoS One. 2018 Jan 25;13(1):e0191947. doi: 10.1371/journal.pone.0191947. eCollection 2018.
In the coming decades, environmental change like warming and acidification will affect life in the ocean. While data on single stressor effects on fish are accumulating rapidly, we still know relatively little about interactive effects of multiple drivers. Of particular concern in this context are the early life stages of fish, for which direct effects of increased CO2 on growth and development have been observed. Whether these effects are further modified by elevated temperature was investigated here for the larvae of Atlantic herring (Clupea harengus), a commercially important fish species. Over a period of 32 days, larval survival, growth in size and weight, and instantaneous growth rate were assessed in a crossed experimental design of two temperatures (10°C and 12°C) with two CO2 levels (400 μatm and 900 μatm CO2) at food levels mimicking natural levels using natural prey. Elevated temperature alone led to increased swimming activity, as well as decreased survival and instantaneous growth rate (Gi). The comparatively high sensitivity to elevated temperature in this study may have been influenced by low food levels offered to the larvae. Larval size, Gi and swimming activity were not affected by CO2, indicating tolerance of this species to projected "end of the century" CO2 levels. A synergistic effect of elevated temperature and CO2 was found for larval weight, where no effect of elevated CO2 concentrations was detected in the 12°C treatment, but a negative CO2 effect was found in the 10°C treatment. Contrasting CO2 effects were found for survival between the two temperatures. Under ambient CO2 conditions survival was increased at 12°C compared to 10°C. In general, CO2 effects were minor and considered negligible compared to the effect of temperature under these mimicked natural food conditions. These findings emphasize the need to include biotic factors such as energy supply via prey availability in future studies on interactive effects of multiple stressors.
在未来几十年里，诸如变暖和酸化等环境变化将影响海洋生物。虽然关于单一应激源对鱼类影响的数据正在迅速积累，但我们对多种驱动因素的交互作用仍然知之甚少。在这种情况下，特别值得关注的是鱼类的早期生命阶段，已经观察到二氧化碳增加对其生长和发育有直接影响。本文研究了大西洋鲱鱼（Clupea harengus）幼体，这种具有重要商业价值的鱼类，其早期生命阶段是否会因温度升高而使这些影响进一步改变。在为期32天的时间里，采用交叉实验设计，在两个温度（10°C和12°C）与两个二氧化碳水平（400微大气压和900微大气压二氧化碳）下，使用天然猎物模拟自然食物水平，评估幼体的存活率、大小和重量的增长以及瞬时生长率。仅温度升高就导致游泳活动增加，以及存活率和瞬时生长率（Gi）下降。本研究中对温度升高相对较高的敏感性可能受到幼体所提供食物水平较低的影响。幼体大小、Gi和游泳活动不受二氧化碳影响，表明该物种对预计的“本世纪末”二氧化碳水平具有耐受性。在幼体重量方面发现了温度升高和二氧化碳的协同效应，在12°C处理中未检测到二氧化碳浓度升高的影响，但在10°C处理中发现了二氧化碳的负面影响。在两个温度下，二氧化碳对存活率的影响存在差异。在环境二氧化碳条件下，12°C时的存活率比10°C时有所提高。总体而言，在这些模拟自然食物条件下，与温度的影响相比，二氧化碳的影响较小且可忽略不计。这些发现强调，在未来关于多种应激源交互作用的研究中，需要纳入生物因素，如通过猎物可获得性提供的能量供应。
