Mallets Creek Marsh, Lake Champlain: A plant-nutrient study

Nitrogen and phosphorus dissolved in the interstitial water of Mallets Creek Marsh sediments supply about 42 percent of the nitrogen and about 9 percent of the phosphorus used by rooted macrophytes within the marsh. These percentages may become larger during middle and late summer, when water inflow to the marsh is reduced and the supply of dissolved nitrogen and phosphorus is diminished. Fluctuations in water-surface level alternately saturate and partially dewater sediments between approximately 98.5 feet and 93.5 feet above mean sea level. Repeated water-level declines to below 98.5 feet through lake-level regulation in spring or early summer could transport interstitial nitrogen and phosphorus from the marshes to Lake Champlain. This would decrease the growth of rooted macrophytes within the marsh and promote eutrophication of the lake.