“Farm Tech Days” Exhibit Will Focus on Phosphorus Problems and Solutions

by Jenny Seifert

Why is phosphorus in the lakes a long-term problem, why do we care and how could we fix it?


The UW-Madison’s Water Sustainability and Climate Project (WSC) and Center for Limnology will address these questions at their exhibit at the upcoming Wisconsin Farm Technology Days, which will take place Tuesday, August 25 through Thursday, August 27th at Statz Brothers, Inc. Farm in Sun Prairie, WI.

Entitled “Wisconsin’s phosphorus legacy and the long road ahead,” the exhibit will be part of the Education Station Tent and will allow attendees to explore the science behind phosphorus pollution, which degrades water quality in many of Wisconsin’s lakes.

A mid-October algae (or phytoplankton) bloom shows up on the Lake Mendota shoreline. Photo: Sam Oliver
A mid-October algae (or phytoplankton) bloom shows up on the Lake Mendota shoreline. Photo: Sam Oliver

The exhibit will include participatory elements, such as interactive computer graphics explaining challenges to improving water quality in Wisconsin’s lakes and an opportunity to offer your ideas for how to create a future with clean lakes, vibrant cities and thriving farmland.

Several faculty members from the WSC project and the Center for Limnology will also be on hand for “office hours” to chat with folks about the lakes and how our practices on land affect them. Their schedule is as follows:

Tuesday, August 25th

10:00-1:00pm – Chris Kucharik, a professor of agronomy and environmental studies, will be available to chat about the impacts of climate change, weather variability and land management decision-making.

1:00pm-2:00pm – Monica Turner, a professor of ecology, will be available to chat about the ecological effects of land-use change, nature’s benefits and land-water interactions.

Wednesday, August 26th

10:00am-12:00pm – Paul Hanson, a professor from the Center for Limnology, will be available to chat about water quality, lake modeling and sensor networks.

12:00pm-2:00pm – Stephen Carpenter, the director of the Center for Limnology, will be available to chat about phosphorus and lakes.

Thursday, August 27th

12:00pm-1:00pm – Steven Loheide, an associate professor of civil and environmental engineering, will be available to chat about groundwater effects on corn yields.

1:00pm-2:00pm – Adena Rissman, an associate professor of environmental policy and management, will be available to chat about natural resource policy, land management and land conservation.

Visit us at the Education Station Tent to learn the science behind this important issue affecting the health of our lakes and communities.

Video: Up-Close Look at Lake Mendota Water Clarity

On June 4th, after a week of clear-water conditions in Lake Mendota, some of us here at Hasler Lab decided that our window for swimming in clear water was closing. So we decided to take an up-close and personal reading of conditions.

It turns out that our timing was perfect for a refreshing (read: cold) dip. After peaking at a Secchi depth of more than 7 meters (meaning that’s how far down you could see into the lake from the surface), things started getting a little murkier on Lake Mendota yesterday. A reading from the middle of the lake came back at right around 5 meters. That still put the lake in “clear-water” phase, as any reading  deeper than 4 meters qualifies.

But, today, June 5th, after a full week of clear conditions, the Secchi couldn’t even make it 3 meters off of our pier before disappearing from view. Official reading? 2.75 meters. Official verdict? 2015 clear-water phase has come to a close.

But that doesn’t mean you still can’t help us #monitormendota! Send Secchi readings, pictures, videos, anything showing us the current state of the lake to media@limnology.wisc.edu, or on Twitter or Instagram @WiscLimnology. Bonus points if you choose the “full immersion” option like we did!

Happy Friday! (We’ll get fish back on the menu next week!)

A Look at Our Lakes on Earth Day

Happy Earth Day!

Wisconsin, of course, is where it all began, thanks to former U.S. senator Gaylord Nelson’s vision. As we here at the blog mulled over an appropriate topic for an Earth Day post, we kept seeing local media coverage about Madison’s lakes. And that had us returning to one thought – April rains bring July pains.

Satellite view of phosphorous-driven algal blooms. Phosphorus carried into Lake Mendota via the Yahara River fertilizes algal growth. Photo: UW SSEC and WisconsinView
Satellite view of phosphorous-driven algal blooms. Phosphorus carried into Lake Mendota via the Yahara River fertilizes algal growth. Photo: UW SSEC and WisconsinView

While the entire Midwest has been waiting for spring to finally fight off winter (sorry, Minnesotans) and get some of those May flowers out of the ground, our daily deluges also have a longer-lasting impact. We asked Center for Limnology director, Steve Carpenter to comment on this soggy spring and here was his reply: Continue reading “A Look at Our Lakes on Earth Day”

Madison Lakes Have an Early “Spring Cleaning”

The view along the Mendota shoreline shows the lake in its Spring "clear water" phase Photo: Adam Hinterthuer

If you head down to the shore of Lake Mendota today, you’ll notice you can see right down to the bottom. In fact, the current Secchi reading is seven meters, meaning you can get a clear view of Lake Mendota’s depths more than 20 feet down.

At first glance, it might seem that there’s just not much going on down there, but Lake Mendota is actually teeming with life and right in the middle of an algae bloom.

So what gives on the clear water?

The secret to our currently crystal-clear lake is a tiny zooplankton called Daphnia pulicaria.

While conditions are ideal for some species of algae, like fast-growing diatoms, to thrive, the current cool, highly-oxygenated water is also perfect for Daphnia pulicaria, which are voracious grazers of these kinds of algae.

Daphnia pulicaria Photo: The Wilson Lab at Auburn University

According to CFL research specialist, Ted Bier,  this kind of algae means good eats for daphnia and, right now, “they’re gobbling it up as fast as it’s growing.”

Bier says that, in its current state, the lake’s food web is humming right along. Nutrients in the water are consumed by the algae, which are then eaten by Daphnia that then become food for fish, efficiently passing nutrients right up the chain.

But, Bier says, there’s no way to know how long it’ll last. “Two years ago clear water only lasted 36 hours,” he says, thanks to a big rainstorm followed by baking temperatures. “Last year it was two weeks. We’ve had it last as long as two months.”

From left to right: water samples from March 15, April 1 and April 15 show the spring daphnia pulicaria population bloom in Lake Mendota Photo: Adam Hinterthuer

The current clear-water state is happening a bit earlier than average. Bier’s been taking samples each spring for ten years and the first big lake clearing is usually sometime around mid May.

Thanks to this year’s early lake warming and the last couple of weeks of cool, windy, dry weather – conditions are perfect for the annual early algae bloom and subsequent daphnia pulicaria feast. But, if we have a week of high temperatures or a big rain event that flushes a lot of nutrients into the lakes, a different kind of algae, called blue green or cyanobacteria, will begin to take over and we can kiss the clear water phase goodbye. Daphnia just don’t graze on blue green algae with the same relish and head to cooler, deeper waters once the lake warms.

Whatever window of clear water we do get this year, we can thank a little tiny zooplankton that’s a crucial component to our lakes’ water quality and is currently teeming right before our eyes – even if we can’t quite see it.