Sunday, March 29, 2009

Invasive Species: Yesterday and Today

It was flattering to be asked to write on the Great Lakes Town Hall website last week, but I am glad to be back to my own spot again. I have no idea whether anyone read my postings there, although the truth is I often don’t know if they read them here either (except I have this little meter that tells me here when someone signs on). But that’s okay, because this whole thing is part of a learning process for me. If someone else learns something along with me, that’s great. If not, I am still smarter and wiser.

I got smarter and wiser yesterday, as did many others including my husband. We went to a lecture given by scientists from the UWM Great Lakes Water Institute. I had mentioned this one day last week in my posting, but I am pretty sure none of the 50 or 60 people in the audience were there because of me.

The topic yesterday in a presentation by Drs. Carmen Aguilar and Russell Cuhel was Great Lakes invasive mussel species. You’ve probably heard about zebra mussels, but we learned that zebra mussels are, as Dr. Aguilar told us, “so yesterday”. Now scientists are studying quagga mussels. The two are similar but quagga mussels can survive in deeper, colder water and so present a new set of problems.

Both mussels affect the lakes ecosystem by filtering out the phytoplankton from the water. In case you don’t know, plankton are microorganisms on which fish feed. These mussels can clear a beaker of murky water in about 15 minutes, as was demonstrated to us during the lecture.

Clearer lake water might seem like a good thing, but the fish don’t think so because of the effect on their food supply. Clear water means more sunlight, which means more plants grow in the water. The small fish may like that because they can hide in the plants from their predators, but the big fish don’t think that’s a good thing. In addition, the mussels also collect on beaches, in storm sewers and can clog up water intake pipes. They have a huge economic impact. And by attaching themselves to recreational boats can affect inland lakes as far from the upper Midwest as Lake Mead Nevada. Amazing.

It’s not all bad news. Some species, such as birds and some fish eat the mussels and do better when they are around, but mostly the invasive species, which come into the come into the Great Lakes with ocean going ships, cause problems. Zebra and quagga mussels are not the only invasive species, just the ones that were discussed in yesterday’s talk.

If you think you know something about native species, or you want to learn what you don’t know, take a quiz I found. I know it says Invasive Species in Pennsylvania in the title, but it is a general quiz. Besides, you may have forgotten that Pennsylvania is a Great Lakes state. Not one of the major ones to most of us but ask the people of Erie PA if think it is an important one. I think they do.

I learned a lot yesterday. I am still thinking about it today and I plan to attend more of this series of lectures to learn even more. Not tomorrow but in two weeks.

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