by izik
Zebra mussels hang on while quagga mussels take over:
[Via Eureka! Science News - Popular science news]
The zebra mussels that have wreaked ecological havoc on the Great Lakes are harder to find these days — not because they are dying off, but because they are being replaced by a cousin, the quagga mussel. But zebra mussels still dominate in fast-moving streams and rivers.
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You have to really enjoy something that comes out of the Center of Rapid Evolution. Much more interesting than the Center of Slow Evolution.
Some very nice work revealed that the ability to generate the threads that hold the mussels to a surface is a major indication of what sort of habitat these cousin species can occupy.
The zebra can generate a lot of threads when water flow is great, meaning it can occupy fast moving rivers where the quagga can not. Both of the mussels have tremendous impacts on the Great Lakes environment, removing the major food sources required by fish. So the fish are disappearing or failing to grow.
In addition, the filtering of the water by the mussels produces much clearer water. It may look nicer but the increased penetration of the water by sunlight results in larger algal blooms which can deplete oxygen from the water and again, harm fish.
It seems to me that studying the environments in the Great Lakes is very similar to studying on an island. The environment is generally closed to outside encroachment and so has developed a well defined, stable ecosystem. Thus, when something is introduced that the ecosystems have no defense against, we can observe the perturbations that result quite easily.
Now if we can just figure out what to do about it without causing greater problems. BUt one can certainly see why evolution might be rapid. The selective pressures on the ecosystem must also be rapidly changing.
Technorati Tags: Environment, Science
