Data from: Living in flowing water increases resistance to ultraviolet B radiation

Ultraviolet B radiation (UV-B) is an important environmental driver that can affect locomotor performance negatively by inducing production of reactive oxygen species (ROS). Prolonged regular exercise increases antioxidant activities, which may alleviate the negative effects of UV-B-induced ROS. Animals naturally performing exercise, such as humans performing regular exercise or fish living in flowing water, may therefore be more resilient to the negative effects of UV-B. We tested this hypothesis in a fully factorial experiment, where we exposed mosquitofish (Gambusia holbrooki) to UV-B and control (no UV-B) conditions in flowing and still water. We show that fish exposed to UV-B and kept in flowing water had increased sustained swimming performance (Ucrit), increased antioxidant defences (catalase activity and glutathione concentrations) and reduced cellular damage (lipid peroxidation and protein carbonyl concentrations) compared with fish in still water. There was no effect of UV-B or water flow on resting or maximal rates of oxygen consumption. Our results show that environmental water flow can alleviate the negative effects of UV-B-induced ROS by increasing defence mechanisms. The resultant reduction in ROS-induced damage may contribute to maintain locomotor performance. Hence, the benefits of regular exercise are ‘transferred’ to improve resilience to the negative impacts of UV-B. Ecologically, the mechanistic link between responses to different habitat characteristics can determine the success of animals. These dynamics have important ecological connotations when river or stream flow changes as a result of weather patterns, climate or human modifications.紫外线B辐射（Ultraviolet B radiation, UV-B）是一类关键的环境驱动因子，可通过诱导活性氧（reactive oxygen species, ROS）的产生对动物的运动表现产生负面影响。长期规律运动可提升机体抗氧化活性，进而缓解UV-B诱导的ROS所介导的负面效应。因此，自然状态下会进行运动的动物——如坚持规律运动的人类，或是栖息于流水环境中的鱼类——对UV-B的负面影响具备更强的耐受能力。本研究通过完全析因实验对该假说展开验证：将食蚊鱼（Gambusia holbrooki）分别置于流水与静水环境中，同时施加UV-B照射与对照（无UV-B照射）处理。结果显示，相较于静水环境中的个体，经UV-B照射且处于流水环境的食蚊鱼，其持续游泳性能（临界游泳速度Ucrit）、抗氧化防御能力（过氧化氢酶活性与谷胱甘肽浓度）均显著提升，而细胞损伤指标（脂质过氧化与蛋白质羰基浓度）则明显降低。UV-B照射与水流流速均未对静息耗氧率与最大耗氧率产生显著影响。本研究结果表明，环境水流可通过增强机体防御机制，缓解UV-B诱导的ROS所带来的负面影响。ROS诱导的损伤得到有效缓解后，或可维持动物的运动表现。因此，规律运动的益处可被"迁移"，从而提升机体对UV-B负面影响的耐受能力。从生态学视角来看，动物对不同生境特征的响应之间所存在的机制性关联，可决定其生存适配的成功与否。当河流或溪流的水流因气象格局、气候变化或人类活动而发生改变时，这类动态关联具备重要的生态学内涵。