Coupling Between Primary Terrestrial Succession and the Trophic Development of Lakes at Glacier Bay

We use sediment cores from lakes in Glacier Bay National Park to examine the relationship between successional changes in catchment vegetation and trends in water-column nitrogen (a limiting nutrient) and lake primary production. Terrestrial succession at Glacier Bay follows several different pathways, with older sites in the lower bay being colonized directly by spruce (Picea) and by-passing a prolonged alder (Alnus) stage that characterizes younger upper-bay sites. Sediment cores from three sites spanning this successional gradient demonstrate that the variability in trophic development among lakes is a consequence of the establishment and duration of N-fixing alder in the lake catchment. 1 St. Croix Watershed Research Station, Science Museum of Minnesota, 16910 152 North, Marine-on-St. Croix, MN 55047 2 Department of Geosciences and School of Biological Sciences, University of Nebraska, 214 Bessey Hall, Lincoln, NE 68588 ([email protected],