Thats probably True. But to what extent will nature mitigate this, and offset the negative with positives. For example: 1) Clearer water means that light reach

Thats probably True. But to what extent will nature mitigate this, and offset the negative with positives. For example: 1) Clearer water means that light reaches deeper. Potentially allowing more aquatic plants to grow over huge new areas. Providing new habitat, food sources and shelter for fish. 2) Zebra mussels might trap some chemicals like PCBs. And accumulate them in their shells. Once the mussel dies, they fall to the bottom, and might permanently lock up them up into the sediment.