Snow Pond / Messalonskee Lake Association

How’s The Water?
“Come on in, unless you’re a phosphorus molecule!”

If you’ve ever seen someone anchored near the New England Music Camp who seems to be messing with equipment other than fishing rods, that would be me. For the past eight years I’ve been a volunteer water quality monitor for Messalonskee Lake. Every 2 weeks during the summer I drop anchor at station #1, the “deep hole” near the New England Music Camp, to record data and collect water samples for additional testing. I was trained by the Maine Volunteer Lakes Monitoring Program (VLMP), a non-profit citizens group that has partnered with the Maine Department of Environmental Protection to collect water quality data on Maine lakes since 1970. While DEP employees do some of the data-gathering, most of the data has been obtained through the years by VLMP-trained volunteers.

So what are we testing for? With so much attention focused on Milfoil these days, it’s easy to forget about another threat to our continued enjoyment of Messalonskee Lake. “Eutrophication” refers to the increase of plant nutrients (such as phosphorus and nitrogen) in a body of water. Phosphorus is usually a limiting nutrient to plant growth in a lake, meaning that plant growth increases at the same rate as phosphorus is added to the system. And the plants we are most concerned about in this case are not milfoil, but the various species of algae: the source of those notorious algae blooms that cause some otherwise beautiful lakes around here to occasionally turn green and murky during the summer. (I won’t name names. They know who they are.)

Phosphorus content since I began collecting samples in 2001 has been fairly stable, ranging from 10 to 14 parts per billion (ppb). It’s hard to know if this stability is a result of improved landscaping practices and drainage conditions around the lake, but it is encouraging that conditions do not appear to be getting worse, especially given the increased development on the lake during these years.

In addition to phosphorus content, I also measure dissolved oxygen and water transparency. Dissolved oxygen levels in Messalonskee do seem to be worsening over time. During spring overturn, when water is mixing from the top to the bottom of the pond, oxygen levels are high at all depths. In Messalonskee, we see a mid-summer depletion of oxygen in the water between 30 and 40 feet deep because decomposers like fungi and bacteria are feasting on dead algal cells and thriving –- but using up the oxygen in that zone. In other words, we’re back to phosphorus again: increased phosphorus leads to increased algae, which leads to oxygen depletion (as the algae are decomposed).

Decomposition also leads to oxygen depletion in the deepest waters as well. For many years Messalonskee has had higher oxygen levels in the water between 50 and 60 feet deep, which provides a refuge for cold water fish such as salmon and trout. The duration of this refuge over the course of the summer appears to be shrinking, a bad thing for the cold water fish.

Water transparency is what most of us think of when we think about how “clean” or clear the lake is. It is measured using a “Secchi Disk”. Since algae are the most abundant particles in the lake, transparency is an indirect measure of algae growth. Secchi disk readings on Messalonskee range from about 4-7 meters (13-23 ft) through the course of the summer. The best Secchi reading since 1970 was 7.5 meters (24 feet), recorded in 1971, and the worst was 3.9 meters (13 feet), in 1997. The best reading I got last summer was 5.7 meters (19 feet).

You can see all the data that has been collected on Messalonskee Lake since 1970 by going to www.pearl.maine.edu. Messalonskee Lake has had 3 testing stations, but in recent years only station number 1 has been monitored on a regular basis. If you would like to consider becoming a volunteer monitor to collect data at one of the other stations on our lake, please feel free to contact me via the e-mail address in this newsletter, or contact the Maine VLMP through their web site or by phone (783-7733).

If becoming a volunteer lake monitor is not your cup of tea, there are still three things that every landowner can do to prevent phosphorus buildup in the lake: 1) landscape your property to reduce erosion and runoff into the lake, 2) avoid using fertilizer on your lawn, and 3) make sure your septic system is well maintained. There is no successful method for removing phosphorus from a lake once it has entered; the only way to prevent an algae bloom is to decrease phosphorus loading before it is too late. Unlike some other nearby lakes, Messalonskee has not yet had an algae bloom. Let’s do everything we can to keep it that way!

-- Gilliam Johnston
(With thanks to Linda Bacon, Maine DEP employee and lifetime denizen of Messalonskee Lake.)