Shrinking the Phosphorus Cycle: Lake Champlain, Phosphorus, and Time (and Patience)

This interesting article from

Anytime I hear about, read about, overhear, or talk about algae blooms in Lake Champlain an image like this one surfaces in my brain:

Shrinking the Phosphorus Cycle
from: St. Francis University (

This graphic representation of the phosphorus cycle, is at the heart of water quality concerns in our Basin and a huge number of basins around the world.  If you follow the arrows which show where the essential nutrient phosphorus flows on the earth to support life as we know it.  Nearly every arrow leads to a living thing, with a few having one step in-between (like the link between the fish and the bacteria and fungi decomposers).  You can follow the arrows of flowing phosphorus for quite a while before reaching a dead end, where phosphorus no longer “feeds” some living things but actually leaves the cycle.  Where does this happen?  At the lake bottom:

Phosphorus only leaves the cycle when either dead organisms get buried in the lake bottom deep enough that decomposers (which actually lie on the lake bottom) do not break them down, or as precipitated phosphorus that settles to the bottom.
Who cares?  Why does this matter?
Getting rid of phosphorus doesn’t happen quickly and because it feeds the growth of organisms that we don’t care for, we struggle about what to do.  In other words, our desire to “clean-up the lake” depends upon changing how much phosphorus flows in the cycle.

I recently attended an informative presentation of the Lake Champlain Basin Program’s State of the Lake and Ecosystem Indicators Report by Bill Howland, the Program Manager for our partner organization.  At the outset, Mr. Howland set the stage for his talk by clarifying that the report is about the status of the lake as shown by the data chosen as indicators since the last report in 2008.  As such, he did not cover what management responses are being implemented in the Basin.  Much of the data he presented centered around phosphorus in the Lake and the Basin’s waters that feed it.  The reports section on phosphorus addresses three questions: How are phosphorous levels in Lake Champlain?  Where does the phosphorus come from?  What is being done to reduce phosphorus concentrations?  Given the media, political, environmental, and regulatory attention that phosphorus gets in our Basin, it makes a lot of sense to pay attention to phosphorus.  Despite the wealth of data about phosphorus entering the lake, its role in producing nuisance algae blooms, and the human desire to reduce the amount of phosphorus in our waterways, I rarely see the questions– “Where does phosphorus go?” and “How long will it take to get there?” — being addressed anywhere.  The answers are important, because without knowing when and how phosphorus may decline in Lake Champlain we cannot know when to see the effects of our collective efforts to “clean up the lake.”