Mei Xueying, Zhang Xiufeng, Kassam Sinan-Saleh, Rudstam Lars G
College of Resources and Environment, Anhui Agricultural University, Hefei, China.
Cornell Biological Field Station, Department of Natural Resources, Cornell University, Bridgeport, New York, United States of America.
PLoS One. 2016 Dec 22;11(12):e0168494. doi: 10.1371/journal.pone.0168494. eCollection 2016.
Zebra mussels (Dreissena polymorpha) are known to increase water clarity and affect ecosystem processes in invaded lakes. During the last decade, the conspecific quagga mussels (D. rostriformis bugensis) have displaced zebra mussels in many ecosystems including shallow lakes such as Oneida Lake, New York. In this study, an eight-week mesocosm experiment was conducted to test the hypothesis that the displacement of zebra mussels by quagga mussels leads to further decreases in phytoplankton and increases in water clarity resulting in increases in benthic algae. We found that the presence of zebra mussels alone (ZM), quagga mussels alone (QM), or an equal number of both species (ZQ) reduced total phosphorus (TP) and phytoplankton Chl a. Total suspended solids (TSS) was reduced in ZM and ZQ treatments. Light intensity at the sediment surface was higher in all three mussel treatments than in the no-mussel controls but there was no difference among the mussel treatments. There was no increase in benthic algae biomass in the mussel treatments compared with the no-mussel controls. Importantly, there was no significant difference in nutrient (TP, soluble reactive phosphorus and NO3-) levels, TSS, phytoplankton Chl a, benthic algal Chl a, or light intensity on the sediment surface between ZM, QM and ZQ treatments. These results confirm the strong effect of both mussel species on water clarity and indicate that the displacement of zebra mussel by an equivalent biomass of quagga mussel is not likely to lead to further increases in water clarity, at least for the limnological conditions, including summer temperature, tested in this experiment.
已知斑马贻贝（多形饰贝）会提高水体透明度，并影响入侵湖泊中的生态系统过程。在过去十年中，同属的魁蚶（罗氏沼贻贝）在包括纽约奥奈达湖等浅水湖泊在内的许多生态系统中取代了斑马贻贝。在本研究中，进行了一项为期八周的中宇宙实验，以检验以下假设：魁蚶取代斑马贻贝会导致浮游植物进一步减少，水体透明度增加，进而导致底栖藻类增加。我们发现，单独存在斑马贻贝（ZM）、单独存在魁蚶（QM）或两种贻贝数量相等（ZQ）的情况下，总磷（TP）和浮游植物叶绿素a均减少。在ZM和ZQ处理中，总悬浮固体（TSS）减少。在所有三种贻贝处理中，沉积物表面的光强度均高于无贻贝对照，但贻贝处理之间没有差异。与无贻贝对照相比，贻贝处理中的底栖藻类生物量没有增加。重要的是，在ZM、QM和ZQ处理之间，营养物质（TP、可溶性活性磷和NO3-）水平、TSS、浮游植物叶绿素a、底栖藻类叶绿素a或沉积物表面的光强度没有显著差异。这些结果证实了两种贻贝对水体透明度都有很强的影响，并表明以等量生物量的魁蚶取代斑马贻贝不太可能导致水体透明度进一步提高，至少对于本实验所测试的湖沼学条件（包括夏季温度）而言是这样。
