Department of Biology, University of Saskatchewan, Saskatoon, S7N 5E2 SK, Canada.
Department of Biomedical Sciences, WCVM, University of Saskatchewan, Saskatoon, S7N 5B4 SK, Canada.
Sci Total Environ. 2014 Aug 15;490:941-6. doi: 10.1016/j.scitotenv.2014.05.102. Epub 2014 Jun 7.
Anthropogenic activities over the past several decades have depleted stratospheric ozone, resulting in a global increase in ultraviolet radiation (UVR). Much of the negative effects of UVR in aquatic systems is minimized by dissolved organic carbon (DOC) which is known to attenuate UVR across the water column. The skin of many fishes contains large epidermal club cells (ECCs) that are known to play a role in innate immune responses and also release chemical alarm cues that warn other fishes of danger. This study investigated the effects of in vivo UVR exposure to fathead minnows (Pimephales promelas), under the influence of two sources of DOC: Sigma Aldrich humic acid, a coal based commercial source of DOC and Luther Marsh natural organic matter, a terrigenous source of DOC. Specifically, we examined ECC investment and physiological stress responses and found that fish exposed to high UVR, in the presence of either source of DOC, had higher ECC investment than fish exposed to high UVR only. Similarly, exposure to high UVR under either source of DOC, reduced cortisol levels relative to that in the high UVR only treatment. This indicates that DOC protects fish from physiological stress associated with UVR exposure and helps maintain production of ECC under conditions of UVR exposure.
在过去几十年中，人为活动消耗了平流层中的臭氧，导致全球紫外线辐射（UVR）增加。水中的溶解有机碳（DOC）可以衰减 UVR，从而在很大程度上减少了 UVR 在水生系统中的负面影响。许多鱼类的皮肤中含有大量的表皮棒状细胞（ECCs），这些细胞已知在先天免疫反应中发挥作用，并且还会释放化学警报信号，警告其他鱼类有危险。本研究调查了活体 UVR 暴露对（褐鳟）的影响，实验中考虑了两种 DOC 来源：Sigma Aldrich 腐殖酸，一种基于煤炭的商业 DOC 来源，以及 Luther Marsh 天然有机物质，一种陆地来源的 DOC。具体来说，我们研究了 ECC 的投资和生理应激反应，发现与仅暴露于高 UVR 的鱼相比，暴露于两种 DOC 来源中的高 UVR 的鱼具有更高的 ECC 投资。同样，与仅高 UVR 处理相比，在两种 DOC 来源中的高 UVR 暴露下，皮质醇水平降低。这表明 DOC 可以保护鱼类免受与 UVR 暴露相关的生理应激，并有助于在 UVR 暴露条件下维持 ECC 的产生。
