Ecological recovery of Merrymeeting Bay : changing sediment chemistry and wild rice dynamics

by Timothy Stephen Pasakarnis

Merrymetting Bay was identified as a study site both for its unique status as a large freshwater bay that experiences tidal flow, and the critical role it plays as a habitat for migratory birds, anadromous fish, as well as common and rare plant species. There is a history of pollutant and municipal waste input to the bay prior to the 1972 Clean Water Act, which stems from upstream paper and tannery industries and nearby towns. Mr. Pasakarnis quantified the ecological recovery of Merrymeeting Bay from this pollution through a battery of physical and chemical assessments of sediment cores, including an assay of current sediment toxicity. He also used scientific and anecdotal data regarding the wild rice colonies within Merrymeeting Bay as a gauge for the changing conditions, finding important correlations between the density of wild rice stands and the abundance of plant nutrients in the sediment. Levels of organic carbon and phosphorus have dropped since 1967, and pH levels have risen significantly. These results indicate that the general health of Merrymeeting Bay has been restored, though a great deal of local variation exists. The toxicity results indicated three sites that were significantly more toxic than the rest of the sampling areas, highlighting the potential for certain problem areas to remain.