Morphometric and chemical response of two contrasting lake systems to modern climate change |
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| Authors: | Tamie J Jovanelly Sherilyn C Fritz |
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| Institution: | (1) Berry College, 2277 Martha Berry Hwy, Mount Berry, GA 30149, USA;(2) University of Nebraska, 320 Bessey Hall, Lincoln, NE 68588, USA |
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| Abstract: | Observational data on the response of lakes during modern-day 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 U.S. 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 A.D. |
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