Category Archives: Global Change & Long-Term Ecology

Slideshow: Sparkling Lake Rebounds from Invasion

A recent study authored by our former postdoc and PhD student, Gretchen Hansen, reports that an intensive invasive-species trapping experiment had paid off for Sparkling Lake in northern Wisconsin. Not only did our researchers put a big dent in the rusty crayfish population but, four years later, they’re still being kept in check naturally.

Click on the picture below to launch a slideshow of life in the lake today.

After an invasion nearly wiped bluegill and their preferred habitat out, Sparkling Lake now boasts a booming population of the fish. Photo: Gretchen Hansen.All photos by Gretchen Hansen, Adam Hinterthuer and Lindsey Sargent.

The Sparkling Lake crayfish experiment was a project of Jake Vander Zanden’s lab at the CFL and the North Temperate Lakes Long-Term Ecological Research program.

 

CFL in Africa: Fish Pee and After Hours Fieldwork

The CFL’s Ellen Hamann, lab manager for Pete McIntyre’s lab, has been back in Africa this summer, helping continue research on Lake Tanganyika. She sent in this note from the field before returning to Madison for fall semester.
By Ellen Hamann

For the past 48 hours, Benja (Ben Kraemer from Pete McIntyre’s lab) and I have been finishing up the ongoing fish excretion component to our Lake Tanganyika project. It’s pretty similar to last year’s endeavor except that it occurs primarily at NIGHT (in year 3, we seem to be finding creative ways to up the proverbial ante…). At this point, we have a pretty good handle on fish peeing rates during the day, but the suspicion is that things probably tail off at night (which is personally true for me, so it may hold true for the fishes as well).

Two eretmotus, probably peeing, are unaware of their impending capture. Photo: B. Kraemer

Two eretmotus, probably peeing, are unaware of their impending capture. Photo: B. Kraemer

Just to be clear, we’re not interested in peeing for peeing’s sake. As I’ve mentioned before, since Tanganyika is so lacking in nutrients, we suspect the fish themselves facilitate nutrient cycling in the lake (Meaning: algae probably take full advantage of the fact that hundreds of fish pee on them constantly, providing them with nutrients to create biomass that, in turn, feeds the fish) I “heart” cycles.

There’s a fair amount of prep work involved, like filtering 100 liters of water, labeling all the Ziplocs and vials, etc… and the field experience is a bit nuts since a job that was formerly performed by 6 people is now done by 3.

And, like I said, it’s all in the dark. Keep reading at Ellen’s blog, “Ellen At Large” –>

For more on the Lake Tanganyika Ecosystem Project, go here.