The Physiological Response of Picophytoplankton to Temperature and Its Model Representation
The Physiological Response of Picophytoplankton to Temperature and Its Model Representation
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DOI：
10.3389/fmars.2016.00164
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发表时间：
2016-09
影响因子：
3.7
通讯作者：
Beate Stawiarski;E. Buitenhuis;Corinne Le Quéré
中科院分区：
文献类型：
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作者：
Beate Stawiarski;E. Buitenhuis;Corinne Le Quéré
浮游植物占海洋（亚）热带浮游植物生物量和初级生产力的大部分。浮游生物功能类型（pft）对生物量的贡献可能随着气候变暖而变化，部分原因是对温度的不同生理反应。为了模拟这些反应，埃普利的经验关系已经建立得很好。然而，它们尚未在统计上对个体pft进行验证。在这里，我们研究了9株浮游植物对温度的生理反应；3株微原核生物和6株微真核生物。我们在-0.5°C和33°C之间的13个温度下进行了实验室实验，并测量了最大生长速率和叶绿素a与碳的比率。然后统计验证了Eppley（1972）提出的两个假设：单个菌株的最大生长速率对温度的响应(1)可以用最优函数表示，(2)整个浮游植物群的最大生长速率可以用指数函数表示。我们还量化了与温度相关的参数。我们发现，皮原核生物（13.7 - 27°C）比皮真核生物（2.8 - 32.4°C）的生长温度范围更受限制。然而，模拟的温度耐受性范围（ΔT）遵循这里检查的菌株的细胞大小的单峰函数。因此，温度耐受范围与最大生长率可以共同解释浮游植物群落规模结构与海洋温度的关系。通过99分位回归得到的浮游植物或微原核生物群的最大生长速率通常低于Eppley估计的速率。然而，我们发现两组的温度依赖性（Q10）分别为2.3和4.9。这两个值都高于Eppley估计的1.88的Q10，并可能对模型中的生物量分布产生重大影响，特别是如果将微原核生物视为独立的PFT。我们还量化了由于驯化导致的叶绿素a碳比随温度升高而增加。这些参数为利用海洋生物地球化学模型探索海洋生态系统对气候变暖的响应提供了必要和有效的生理信息。
Picophytoplankton account for most of the marine (sub-)tropical phytoplankton biomass and primary productivity. The contribution to biomass among plankton functional types (PFTs) could shift with climate warming, in part as a result of different physiological responses to temperature. To model these responses, Eppley's empirical relationships have been well established. However, they have not yet been statistically validated for individual PFTs. Here, we examine the physiological response of nine strains of picophytoplankton to temperature; three strains of picoprokaryotes and six strains of picoeukaryotes. We conduct laboratory experiments at 13 temperatures between -0.5°C and 33°C and measure the maximum growth rates and the chlorophyll a to carbon ratios. We then statistically validate two hypotheses formulated by Eppley in 1972: the response of maximum growth rates to temperature (1) of individual strains can be represented by an optimum function, and (2) of the whole phytoplankton group can be represented by an exponential function. We also quantify the temperature-related parameters. We find that the temperature span at which growth is positive is more constrained for picoprokaryotes (13.7 - 27°C), than for picoeukaryotes (2.8 - 32.4°C). However, the modelled temperature tolerance range (ΔT) follows an unimodal function of cell size for the strains examined here. Thus, the temperature tolerance range may act in conjunction with the maximum growth rate to explain the picophytoplankton community size structure in correlation with ocean temperature. The maximum growth rates obtained by a 99th quantile regression for the group of picophytoplankton or picoprokaryotes are generally lower than the rates estimated by Eppley. However, we find temperature-dependencies (Q10) of 2.3 and of 4.9 for the two groups, respectively. Both of these values are higher than the Q10 of 1.88 estimated by Eppley and could have substantial influence on the biomass distribution in models, in particular if picoprokaryotes were considered an independent PFT. We also quantify the increase of the chlorophyll a to carbon ratios with increasing temperature due to acclimation. These parameters provide essential and validated physiological information to explore the response of marine ecosystems to a warming climate using ocean biogeochemistry models.