pdf WQ5 Multi-year TP SRP Chl-a Ratios for LCI 2020

Author: R.A. Smith

Author Affiliation: LCWC

Journal: Unpublished Report



A primary nutrient for algae and weed growth has remained within a limited range during the past seven years.

Abstract: Three variables monitored during annual LCWC sampling of Les Cheneaux waters include Total Phosphorus (TP), Soluble Reactive Phosphorus (SRP) and Chlorophyll-a (Chl-a). Phosphorus is a growth limiting nutrient for phytoplankton (free-floating algae). Therefore, the availability of phosphorus is a primary factor in determining how much algae is present during any given year. SRP is a readily used form of phosphorus and can be quickly depleted during times of rapid algae growth. The relationship of these variables is an indicator of Les Cheneaux water chemistry stability. Observed values for these variables each year remain within the upper oligotrophic index signaling the nutrient fluctuation to be within normal Les Cheneaux variation. The stability of TP, SRP and Chl-a demonstrates the resiliency of our wetland ecology, even during years of continued increase in the Lake Huron level of 63 inches ( 160 cm) during this reporting period.
A follow-up paper will be developed to compare SRP/TP ratios of Les Cheneaux waters those of L Huron open waters to deter-mine if the seven-year rise in lake level impacted LCI ratios.