-
Outdoors
Outdoors
By V. Browne
Iron County Lakes & Streams Partnership
IRON COUNTY – The first of several registration deadlines for participation in the Cooperative Lakes Monitoring Program is March 1. The parameter is spring phosphorus. According to the protocol, citizen scientist volunteers need to get to the deepest basin of the lake within two weeks after ice out, submerge the bottle they were sent upside down to a depth of one foot, then turn the bottle upright to collect the sample. Once frozen, the sample is sent to EGLE for analysis.
According to Mike Golas, one of the CLMP volunteers on Sunset Lake, most folks don’t have a boat in the water within two weeks of ice out, so gathering the data sometimes requires a canoe or kayak trip through pretty chilly waters and then a quick paddle home to warm up.
A phosphorus sample is gathered as part of CLMP twice during the year –within two weeks of ice out and then again during late summer. According to the MiCorps Fact Sheet on phosphorus, the spring sample gives a reading of the total phosphorus present when the lake is well mixed from top to bottom. The late summer sample, which is also collected at the deepest basin at a depth of one foot, gives a reading of total phosphorus for the upper layer of the lake where algal productivity occurs. In late summer deep lakes are stratified with the warmest temperatures in the top layer (the epilimnion).
Monitoring phosphorus is important because phosphorus is an essential nutrient for algae and aquatic plants which are the start of the food web. Phosphorus is a ‘limiting factor’ meaning that even if there are other nutrients, the amount of phosphorus will determine productivity. Of the three important nutrients (carbon, nitrogen and phosphorus), phosphorus is the one organisms needed for growth. This is similar to the phosphates in garden fertilizers which encourage root development and blooms.
Recall that some productivity is good, but too much leads to ‘weedy’ lakes and algal blooms. Also, phosphorus encourages all growth, so invasive species will take advantage of elevated phosphorus levels. Invasives are the bullies of the aquatic community. They should not be encouraged!
The phosphorus in a lake comes from many sources. Sedimentary rocks made of calcium phosphate leach phosphorus. Sediment on the lake bottom holds and releases phosphorus under various conditions. When aquatic plants die and decompose, nutrients are released back into the lake. These are natural sources.
Other sources are man-made. As soil erodes from runoff or landscape alterations, phosphorus washes into lakes. Livestock manure, wastewater, bone meal and some fertilizers contain phosphorus. Improperly maintained septic systems can be culprits. Laundry detergents, dish soaps and other cleaning products often contain phosphates which are anions of phosphorus combined with oxygen. Even matches and fireworks may contain phosphorus. These are sources to watch for and prevent.
According to Erick Elgin, water resources educator with Michigan State University Extension and coordinator for CLMP, collecting baseline data about total phosphorus in a lake and then monitoring annually for changes is important. “Small increases in total phosphorus may lead to excess plant growth. Reversing upward trends in total phosphorus is costly.”
Anyone can help monitor Iron County lakes. So if your interest has been piqued, consider joining the intrepid CLMP volunteers who venture onto lakes in Iron County just after ice out. For more information, contact Iron County Lakes & Streams Partnership by email: ICLakesandStreamsPartnership@Gmail.com or visit the CLMP website: https://micorps.net/lake-monitoring ICLakesandStreamsPartnership@Gmail.com or visit the CLMP website: https://micorps.net/lake-monitoring