Too Much of a Good Thing

2026 UPDATE: I returned to this page in June 2026, when eutrophication was having a moment because of presidential malfeasance. I updated the link to the 2014 PBS story that discusses eutrophication in a more common sense. First, a little bit about the current debacle.

The desecration of the Reflecting Pool at the Lincoln Memorial is not the most important misdeed of the current administration.It is not as damaging as the needless wars in Iran and elsewhere, the attacks on civil liberties, or even the other architectural disasters he has visited upon my hometown (I happen to have been born in DC).

But it is relevant to environmental geography and I see an important parallel to climate science. The connection is this: the warming of the atmosphere and the fouling of standing water are simple processes.

 

Algae needs a few things to grow: nitrogen, phosphorous, potassium, warm water, and sunlight. All five of these components are readily available in surface waters, especially during warm weather. And all five are what is called limiting factors. If all are abundant, then algae growth will be proportional to any component that increases. Increasing the temperature of water leads to more algae, and a darker bottom increases waster temperature. It really is that simple, though the administration does seem to have found some ways to make the situation even worse. 

At the moment, National Guard troops who were not available during the January 6, 2021 riots are being deployed to prevent people from observing this debacle too closely. 

And now, the original 2014 post:

The Greek word element eu signifies something good -- the good words of a eulogy, the good sound of euphony, the good speech of a euphemism -- but in the case of eutrophication, the nutrients are not just good. They are too good. Excessive nutrients in waterways lead to excessive algae, which in turn depletes oxygen and can also just look and smell nasty.

Those concerned with water quality recognize the seriousness of eutrophication. It is a major reason for the arduous Title V septic-system requirements in Massachusetts, and a major part of the secondary-school outreach of my university's Watershed Access Lab.

Because certain kinds of algae create toxins, though, eutrophication can actually be a matter of life and death, as in the recent contamination of the Toledo, Ohio water supply. On September 4, 2014 the PBS Newshour program included an in-depth discussion of long-term research on algae in Lake Erie. It is a very good introduction to the causes, consequences, and importance of eutrophication; it is for a general audience, though, and does not even use the word.

Algae on The Newshour

The story is from the point of view of experts on water quality itself, but also illustrates the interrelated nature of the environmental challenges we face. Human and physical geography are essential to understanding the linkages among climate change, agricultural practices, urban land use, and environmental regulation that end up determining what comes out of a kitchen faucet.

Lagniappe

The story is also an example of the importance of long-term work in basic science. Consistent monitoring over decades is often tedious, lonely work, and work whose benefits may not be immediately obvious. The work at the center of this story has been conducted for decades at the OSU Stone Laboratory on Gibraltar Island. Zoom in and out of the map below to appreciate this unusual location, which Pam and I had the privilege of visiting when a fellow graduate student from Miami University was spending a summer at the lab. It is an island in a bay of an island in a lake -- and much closer to Canada than I realized. To visit our friend Carol, we had to drive to Port Clinton (near Toledo), take a ferry to South Bass Island, and then take one of the lab's boat from the vacationland of Put-in Bay to the lab itself. The tiny research boat was conspicuous among the gleaming yachts.