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Challenges to Lake Superior's Condition, Assessment, and Management: A Few Observations Across a Generation of Change
Citation:
KELLY, J. R., P. M. YURISTA, S. E. MILLER, A. M. COTTER, T. D. CORRY, J. V. SCHAROLD, M. E. SIERSZEN, E. J. ISAAC, AND J. STOCKWELL. Challenges to Lake Superior's Condition, Assessment, and Management: A Few Observations Across a Generation of Change. Aquatic Ecosystem Health and Management. Taylor & Francis, Inc., Philadelphia, PA, 14(4):332-344, (2011).
Impact/Purpose:
The overall set of observations are used to argue that we need to increase the degree (the spatial comprehensiveness and frequency) to which we assess the whole lake to enable environmental stewardship. Integrated probability designs such as used in our 2006 studies offer one type of efficient design approach; we need also to advance use of emerging synoptic technologies and models.
Description:
Selected comparisons of water quality and biological properties in lakewide samplings of 1970s and 2005/2006 provide a simple illustration of significant changes within Lake Superior in the last three decades. Observations of warmed surface layers, increased nitrate and increased chloride concentrations are consistent with other recent trend analyses. Our comparisons also depict some spatial patterns, including changes in vertical distribution throughout the water column and as a function of depth from inshore to offshore waters. The selected examples speak to different scales of source drivers for change (local, to basinwide, to airshed, and even global) and highlight a lake in which some fundamental properties have been influenced dramatically in a short period relative to its long flushing time (~170 years); this challenges the notion of Lake Superior as resistant to change due to its vastness. Preliminary observation and comparison of some biological features over these 30+ years suggest stability in some components and changes in others. Biological changes do not necessarily suggest direct responses to observed water quality changes, but do illustrate heterogeneity and variation in patterns of important biological distributions. The overall set of observations are used to argue that we need to increase the degree (the spatial comprehensiveness and frequency) to which we assess the whole lake to enable environmental stewardship. Integrated probability designs such as used in our 2006 studies offer one type of efficient design approach; we need also to advance use of emerging synoptic technologies and models.