Limnology in Action: Taking Crayfish for a Walk

Hilts and Caldeira working together to collect crayfish traps.

It is not every day that you get to take a crayfish for a walk on a leash. Well, unless you are part of Alex Latzka’s research team.

“This is going to be the best field day of your life!” promised Emily Hilts, his incredibly enthusiastic undergraduate assistant. And so far, it was true.

I was tagging along with Latzka and his two assistants, Hilts and Yuri Caldeira; spending the day studying how invasive rusty crayfish are affected by fish predation in various habitats. This particular morning started by pulling up crayfish traps (which are modified minnow traps baited with beef liver) all around Sparkling Lake. Continue reading

CFL in Africa – Not Your “Typical” Day at the Lake

“Team” McIntyre gets ready for another summer of fieldwork on Lake Tanganyika.

In the summer of 2012, a team of researchers from the University of Wisconsin-Madison’s Center for Limnology and Wright State University in Ohio, will call the shores of Africa’s Lake Tanganyika home.

The oldest and deepest of the African rift lakes, Tanganyika is a natural wonder under severe threat. What’s more, it’s near-shore ecosystem contains a paradoxical combination of scarce nutrients but globally-high primary productivity, animal biomass and a diversity of grazing fish and invertebrates. What supports such a thriving ecosystem when there’s little nutrient input to the lake? Our sleuths have set out to Tanzania to find out.

Understanding how “Lake T” works is imperative in order to protect its remarkable biodiversity ( there are more than 700 endemic animal species) and the essential services (fisheries, clean water, transportation) it provides to the citizens of the four countries lining its shores.

Our own Ellen Hamann, lab manager for Professor Pete McIntyre, is currently with Pete and the rest of the crew in Africa. She recently recapped a day in the field…

There is no typical day in the field, I guess…but what we do on any given day depends on a few things:

1.       Which project goal we’re trying to accomplish
2.       If our gear is cooperating
3.       If the weather is cooperating
4.       If our guts are cooperating
So here it is…one random field day during the Mahale excursion:
Monday, 2 July 2012
7:30am – Wake up. Head to breakfast and see what Hassan has cooked up.

Team McIntyre heads out into Lake Tanganyika for a day of snail collecting, fish id’ing and sonde deployment.

8:30am – Start packing up the gear we’ll need for the day (snail quadrats, fish quadrats, plum lines, whirl pacs, dive tanks, BCD’s, regs, snorkel stuff, wetsuits-that-reek-of-urine, our lunch!) into the smallest space possible and walk it down to the water.

8:45am – Head down the beach to boat storage with Pete. Watch in horror as Dakota (one of our trusty park staff) mouth-siphons fuel from the 200L barrel into our 25L tank. Mix in the 2-stroke oil and haul it and our motor down to the Zodiac. Pump up the keel of the Zodiac again because it’s always flat (must find mysterious small leak…). Guts feel…off. Take 2 Pepto and pack 2 more into dry bag – Just In Case. – Continue Reading at the Lake Tanganyika Ecosystem Project blog

Limnology in Action: Like Baking a Cake in a Lake

Besides the rowboat being pulled across a grid of buoys, the surface of Peter Lake is calm. But, just 5 meters below the surface, a full experiment is under way.

“Annndddd…. There is C-13 spilling out down there!” shouts Grace Wilkinson. Looking into the water doesn’t do any good, the carbon-isotope tracer that Wilkinson and her assistant, Carol Yang, have just released is sitting well down in the middle strata of the lake.

Grace and Carol put the isotope label in the WILCs before they are deployed.

“Basically, we are putting really expensive baking soda in the lake,” explains Wilkinson. Yang laughs, “Like baking a cake in the lake!”

Continue reading