South African Research Chairs Initiative, Shallow Water Ecosystems, Nelson Mandela University, P.O. Box 77000, Port Elizabeth, 6031, South Africa.
Africa Earth Observatory Network, Nelson Mandela University, P.O. Box 77000, Port Elizabeth, 6031, South Africa.
Sci Rep. 2018 Apr 13;8(1):5983. doi: 10.1038/s41598-018-24137-0.
Salinity is an important factor affecting freshwater aquatic species distribution and diversity. The semi-arid Eastern Cape Karoo region of South Africa has been earmarked for shale gas development through hydraulic fracturing. The process uses large amounts of water and produces briny wastewater. When not managed properly, these wastewaters may lead to salinisation of surface freshwater bodies in the region. Therefore, the effect of salinity on the hatching success of crustacean resting eggs was examined using sediments from four depression wetlands found in the region. The sediments were exposed for 28 days to salinity levels of 0.5 g L, 2.5 g L, 5 g L and 10 g L. Control aquaria in which no salt was added were also set up. There was a significant decrease in the emerged taxa richness and abundances at salinities of 2.5 g L and above. Anostraca, Notostraca and Spinicaudata hatchlings were abundant at salinities of 0.5 g L and below, while Copepoda, Daphniidae (Cladocera) and Ostracoda were observed in the highest salinity, but their densities were still lower with increased salinities. Given the importance of large branchiopods in the trophic balance of depression wetlands, their loss may alter the ecological balance and function of these ecosystems.
盐度是影响淡水水生物种分布和多样性的一个重要因素。南非东部干旱的卡卡鲁地区已被指定用于通过水力压裂进行页岩气开发。该过程使用大量的水，并产生盐水废水。如果管理不当，这些废水可能会导致该地区地表水的盐化。因此，使用该地区四个洼地湿地的沉积物，研究了盐度对甲壳类休眠卵孵化成功率的影响。沉积物在 0.5 g/L、2.5 g/L、5 g/L 和 10 g/L 的盐度下暴露 28 天。还设置了没有添加盐分的对照水族箱。在盐度为 2.5 g/L 及以上时，出现的分类群丰富度和丰度显著下降。在盐度为 0.5 g/L 及以下时，丰年虫、无甲目和旋尾目幼虫大量出现，而桡足类、枝角类（桡足纲）和介形纲则在最高盐度下观察到，但随着盐度的增加，它们的密度仍然较低。鉴于大型鳃足类在洼地湿地的营养平衡中的重要性，它们的丧失可能会改变这些生态系统的生态平衡和功能。
