How do UV radiation, temperature, and zooplankton influence the dynamics of alpine phytoplankton communities?
How do UV radiation, temperature, and zooplankton influence the dynamics of alpine phytoplankton communities?
复制标题
紫外线辐射、温度和浮游动物如何影响高山浮游植物群落的动态？
DOI：
10.1007/s10750-010-0147-5
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发表时间：
2010
期刊：
影响因子：
2.6
通讯作者：
J. Saros
中科院分区：
文献类型：
--
作者：
C. Williamson;Courtney R. Salm;Sandra L. Cooke;J. Saros
与低海拔湖泊相比，高山湖泊中的浮游生物通常面临更高水平的入射紫外线辐射（UVR）、更低的温度和更短的生长季节。高UVR和低温对山地浮游植物的直接抑制作用已被广泛认识。然而，这两个非生物因素对浮游植物的间接影响知之甚少，更具体地说，它们是否会改变浮游动物的摄食率，进而影响浮游植物。在这里，我们报告的现场微观实验的结果，研究温度和紫外线对浮游植物的生长速度和浮游动物的放牧率（成年女性哲水蚤桡足类）的影响。我们还研究了源湖中四种主要浮游植物（Asterionella福尔摩沙，Dinobryon sp.，星盘藻和巴豆脆杆藻）。所有四个物种在较高的温度下表现出较高的生长速率，四个物种中的三个（除Dinobryon外）在UVR的存在下表现出较低的生长速率。浮游动物的原位摄食率对除海星外的所有种类均有显著影响。较低的温度显着降低放牧率脆杆藻和Discostella，但不Dinobryon。虽然UVR没有影响浮游动物的任何四个物种的放牧，有一个显着的交互作用的温度和UVR对浮游动物的摄食甲藻。在UVR的存在下，Discostella和Dinobryon的丰度相对于其他物种有所增加。较冷的温度，浮游动物的存在，紫外线辐射都有一贯的负面影响，在整体浮游植物生物量的增长率。这些结果表明的重要性，间接和直接影响的气候强迫紫外线辐射和温度对浮游植物群落组成的高山湖泊，并建议，温暖的气候和较高的紫外线辐射水平可能有利于某些物种超过其他。
Plankton in mountain lakes are confronted with generally higher levels of incident ultraviolet radiation (UVR), lower temperatures, and shorter growing seasons than their lower elevation counterparts. The direct inhibitory effects of high UVR and low temperatures on montane phytoplankton are widely recognized. Yet little is known about the indirect effects of these two abiotic factors on phytoplankton, and more specifically whether they alter zooplankton grazing rates which may in turn influence phytoplankton. Here, we report the results of field microcosm experiments that examine the impact of temperature and UVR on phytoplankton growth rates and zooplankton grazing rates (by adult female calanoid copepods). We also examine consequent changes in the absolute and relative abundance of the four dominant phytoplankton species present in the source lake (Asterionella formosa, Dinobryon sp., Discostella stelligera, and Fragilaria crotonensis). All four species exhibited higher growth rates at higher temperatures and three of the four species (all except Dinobryon) exhibited lower growth rates in the presence of UVR versus when shielded from UVR. The in situ grazing rates of zooplankton had significant effects on all species except Asterionella. Lower temperatures significantly reduced grazing rates on Fragilaria and Discostella, but not Dinobryon. While UVR had no effect on zooplankton grazing on any of the four species, there was a significant interaction effect of temperature and UVR on zooplankton grazing on Dinobryon. Discostella and Dinobryon increased in abundance relative to the other species in the presence of UVR. Colder temperatures, the presence of zooplankton, and UVR all had consistently negative effects on rates of increase in overall phytoplankton biomass. These results demonstrate the importance of indirect as well as direct effects of climate forcing by UVR and temperature on phytoplankton community composition in mountain lakes, and suggest that warmer climates and higher UVR levels may favor certain species over others.