In our In Case You Missed It series (also known as ICYMI), student interns from the Office of Sustainability offer reflective reports on sustainability-related events and lectures at UW–Madison. The following entry is by Britta Wellenstein.
On August 31, Charlie Berens interviewed a panel of researchers on phosphorus pollution in Wisconsin’s and the nation’s waterways as a part of Berens’s Cripescast podcast series. He spoke with Randy Jackson, agricultural researcher from the Department of Agronomy; Jake Vander Zanden, director of the Center for Limnology; and Dan Egan, an environmental journalist and the author of The Death and Life of the Great Lakes. This spring, Egan published his second book, The Devil’s Element: Phosphorus and a World Out of Balance, which evaluates the history of phosphorus use and its adverse ecological impacts.
The panel sat on a sunny Memorial Union Terrace stage overlooking Lake Mendota. Behind them, students jumped off the Memorial Union Pier into the very waters that are often made unsafe to swim in from phosphorus pollution.
Phosphorus is a necessary part of all ecosystems, naturally found on many foods, in DNA, bones, and stool. But in the past century, †panelists explained, phosphorus has been mined and imported as an agricultural fertilizer.
“We figured out how to turn a slow trickle of this essential nutrient into a pressure,” Egan said. “It’s allowed the population on earth to go from about a billion to some 9 billion and heading for more. Without phosphorus, we couldn’t do it. The problem is there are finite supplies of these rocks. It’s getting into the water and when it gets into the water, it’s not growing a kernel of corn, it’s going to grow algae, and too often that’s toxic algae.”
Agricultural run-off is the main source of phosphorus pollution, followed by urban run-off. Excess phosphorus in waterways creates cyanobacteria, a toxin known as blue-green algae that causes skin rashes when swum in, creates aerosol particles that can cause respiratory issues, and can be deadly when consumed. In 2002, a Madison teenager died from blue-green algae exposure after swimming in an algae-ridden golf lagoon.
Blue-green algae is harmful to the lake’s health as well. As algae grows, it depletes oxygen in waterways, making them uninhabitable for other wildlife both in Wisconsin and the nation. Phosphorus and other nutrient run-off entering the Mississippi River is creating a “dead zone” in the Gulf of Mexico from algae blooms. Panelists spoke about how preventing these blooms requires a reduction in phosphorus pollution.
“If we can reduce the amount of phosphorus coming into [Lake Mendota] by about half,” from 110,000 pounds of new phosphorus each year, Vander Zanden said, “we would have really darn good water quality. … And then the question is, how do we reduce that phosphorus coming in?”
There are already agricultural practices in place to reduce phosphorus pollution and better steward land, like not tilling the soil, using cover crops, and delaying fertilizer application when the ground is frozen or near a rain. But these practices are not enough to meet the current crisis, and increased rainfall from climate change has worsened run-off.
Berens reflected on his experience talking to farmer friends and family about phosphorus limits.
“They’re saying that they do have regulations,” he said. “There are a lot of steps in place to limit [run-off] … Also the profitability, for at least my buddies, they’re not making a ton of money, and so I wonder if the system in play is not set up for them to succeed all the time.”
This problem poses a daunting challenge for Wisconsinites, pitting two hearts of the state against each other.
“The Wisconsin license plate—it’s got a barn on one end and it’s got a sailboat on the other,” Egan said. “These are two things that define this great state and they should not be working at cross purposes.”
Panelists echoed the need for systematic changes, from agricultural practices to policy implications.
“Our agricultural system is set up to basically extract and squeeze as much as we can out of the land and that is no fault of any farmer,” Jackson said. “The farmers are doing what the system is set up to do and they’re responding to the signals that society sends them. And as a result, the system is inherently leaky.”
As the talk concluded, the audience—peppered with environmental groups attending the talk and unexpecting Terrace-goers alike—watched the sun set over Lake Mendota, a reminder of what brought them all together in the first place.
“Lakes are absolutely part of what makes Wisconsin,” Vander Zanden said. “They’re part of our culture. They’re part of our well-being and they affect every one of us. So we are here right now, each and every one of us because of Lake Mendota.”
Wisconsinites’ pride in their land and waterways brings a glimmer of hope to the daunting problems facing both Wisconsin’s water and farmers. Jackson, and the other panelists, called for collective action.
“We have to find a way for society to signal to farmers, Can we expect a little bit less out of the land and reward you for that?” Jackson said. “We have to come together as a people and figure out how to change the system so that it’s better for all of us.”
The talk is available to view here and or on the Cripescast podcast.