Early Lake Ontogeny Following Neoglacial Ice Recession at Glacier Bay, Alaska

点击翻译按钮获取中文摘要

Drs. Daniel Engstrom and Herbert Wright of the University of Minnesota propose a study of lake ecology following the glacial recession of 10,000 years ago in Glacier Bay, Alaska. This investigation will explore the earliest stages of lake development in relation to primary succession in vegetation and soils along a 120-year deglaciation chronosequence. Emphasis will be placed on changes in water chemistry, primary production and phytoplankton composition, and the influence of catchment geology and hydrology in regulating material flow from watershed to lake. The problem of early lake ontogeny will be attacked with two complementary research strategies. (1) Limnological conditions will be compared among lakes of known age and in different stages of primary catchment succession, and (2) sediment cores from these same trends in pH, alkalinity, and algal composition at individual sites. Several hypotheses concerning early postglacial land/water interactions will be tested, including (a) the progressive leaching of catchment soils makes lakes more acidic over time, (b) hydrologic and geologic differences among sites act to control the rates and direction of limnological change, (c) increased nutrient flux associated with early soil formation result in an initial increase in lake productivity, and (4) peat growth and regional paludification impede internal soil drainage and cause the dystrophication of surface waters. This work has high interests for students of paleolimnology in particular and paleoecology and ecology in general. It gains in significance when placed in context of current interests and concerns about global climatic change and its influence on ecosystems and man-made systems. How lakes develop and stabilize is also of interest to those studying how contemporary lakes are disturbed by and recover from acidification. The investigators and their institution are world renowed for their work in this area.