Morphometric and chemical response of two contrast

Authors: Tamie J Jovanelly Sherilyn C Fritz

Publish Date: 2011/05/22

Volume: 46, Issue: 1, Pages: 89-98

PDF Link

Abstract

Observational data on the response of lakes during modernday periods of abundant precipitation and drought may provide analogs for Holocene stratigraphic records and help elucidate the mechanisms that influence how lakes integrate climate This study evaluated the impacts of climatic variation during the past 50 years on the morphometry and salinity of two neighboring lake systems in the central US The two lakes were chosen because paleolimnological reconstructions indicated that they had opposing geochemical responses to climate change at AD1200 This divergence suggested that local differences in hydrological setting had a major impact on the lake response to climate variation Changes in surface area and volume were derived from aerial photographs and historic measurements of lake conductivity to contemporaneous annual precipitation data the Palmer Drought Severity Index and to groundwater table elevation Hypsographic curves help to illustrate changes in lake surface area to depth Both lakes showed predictable changes in surface area volume and salinity in response to precipitation change but the magnitude of change in surface area and volume varied between the two lakes likely because of differences in basin morphometry but mechanisms remain speculative These differences in basin size and shape also affected the salinity response over time In the modern systems the influence of groundwater on the chemical budgets appears to be limited and does not clarify the differential response of the lakes in the past Yet in the past the groundwater connection may have been different in turn changing the way the basins responded to climate Although this study furthers our understanding of differences in the impacts of climate variations on Moon and Coldwater Lakes during recent times it still does not clearly reveal why Moon and Coldwater Lake show opposite patterns of salinity change at 1200 ADWe would like to thank Ed Harvey for critical advice on groundwater sampling and data interpretation Joe Hlady for his expertise in Geographic Information Systems and the University of NebraskaLincoln Department of Geosciences for overall support We also thank J Almendinger for his thorough and thoughtful review which improved the quality of the manuscript This paper was sponsored by the NSF GAIN grant

Keywords: