Positive effects of UV radiation on a calanoid copepod in a transparent lake: do competition, predation or food availability play a role?
Positive effects of UV radiation on a calanoid copepod in a transparent lake: do competition, predation or food availability play a role?
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DOI：
10.1093/plankt/fbi108
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发表时间：
2006-02-01
影响因子：
2.1
通讯作者：
Williamson, CE
中科院分区：
文献类型：
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作者：
Cooke, SL;Williamson, CE
耐受紫外线辐射 (UVR) 的浮游动物可能会通过与同一生态系统中紫外线敏感物种的相互作用而间接受到紫外线辐射的影响。在美国宾夕法尼亚州贾尔斯湖，桡足类小足纲 Leptodiaptomus minutus 比共生物种卡托巴水蚤 (Daphnia catawba) 和独眼巨人 (Cyclops scutifer) 更能耐受紫外线。我们询问 L. minutus 是否会受到紫外线引起的食物竞争者 (D. catawba) 或其无节幼体 (C. scutifer) 捕食者死亡的影响。我们进行了两次原位封闭实验，共六种处理：仅 L. minutus，L. minutus。在存在和不存在 UVR 的情况下，minutus + 水蚤和 L. minutus + 独眼巨人。实验 1 中的处理组之间的存活率几乎没有差异，实验 1 中增加了食物，累积 UVR (320 nm) 剂量为 9.3 kJ m(-2)。在实验 2 中，有环境食物和 20.0 kJ m(-2) 的 UVR (320 nm) 剂量，与 -UVR 相比，L. minutus 在 +UVR 中的存活率和繁殖率更高，无论竞争对手或捕食者如何。实验 2 中的叶绿素 a (Chl a) 在 +UVR 中高于 -UVR。虽然不同 UVR 耐受性的浮游动物物种之间的相互作用可能很重要，但这些结果反而表明，对 L. minutus 的有益 UVR 影响与同时对竞争者和捕食者产生的有害 UVR 影响无关。有必要对浮游植物群落进行进一步研究，以确定紫外线是否会减轻细菌竞争、增加营养物质可用性或通过其他机制影响浮游植物。
Zooplankton tolerant to ultraviolet radiation (UVR) could be indirectly affected by UVR through interactions with UV-sensitive species in the same ecosystem. In Lake Giles, Pennsylvania, USA, the calanoid copepod Leptodiaptomus minutus is more UVR tolerant than the cohabiting species Daphnia catawba and Cyclops scutifer. We asked whether L. minutus is affected by UV-induced mortality of a food competitor (D. catawba) or a predator of its nauplii (C. scutifer). We conducted two in situ enclosure experiments with six treatments: L. minutus alone, L . minutus + Daphnia and L. minutus + Cyclops in the presence and absence of UVR. There were few differences in survival among treatments in Experiment 1, which had enhanced food and a cumulative UVR (320 nm) dose of 9.3 kJ m(-2). In Experiment 2, which had ambient food and a UVR (320 nm) dose of 20.0 kJ m(-2), L. minutus survival and reproduction were higher in the +UVR compared to -UVR, regardless of competitors or predators. Chlorophyll a (Chl a) in Experiment 2 was higher in the +UVR than -UVR. While interactions between zooplankton species of differing UVR tolerances are potentially important, these results instead demonstrate that the beneficial UVR effect on L. minutus is independent of concurrent detrimental UVR effects on competitors and predators. Further research on the phytoplankton community is necessary to determine whether UVR alleviates bacterial competition, increases nutrient availability or affects phytoplankton by other mechanisms.