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Abstract Accounting for temporal changes in carbon dioxide (CO2) effluxes from freshwaters remains a challenge for global and regional carbon budgets. Here, we synthesize 171 site-months of flux measurements of CO2based on the eddy covariance method from 13 lakes and reservoirs in the Northern Hemisphere, and quantify dynamics at multiple temporal scales. We found pronounced sub-annual variability in CO2flux at all sites. By accounting for diel variation, only 11% of site-months were net daily sinks of CO2. Annual CO2emissions had an average of 25% (range 3%–58%) interannual variation. Similar to studies on streams, nighttime emissions regularly exceeded daytime emissions. Biophysical regulations of CO2flux variability were delineated through mutual information analysis. Sample analysis of CO2fluxes indicate the importance of continuous measurements. Better characterization of short- and long-term variability is necessary to understand and improve detection of temporal changes of CO2fluxes in response to natural and anthropogenic drivers. Our results indicate that existing global lake carbon budgets relying primarily on daytime measurements yield underestimates of net emissions.
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This content will become publicly available on July 28, 2026
Multi‐Millennial Context for Post‐Colonial Hydroecological Change in Great Salt Lake
Abstract Terminal saline lakes are environmentally sensitive systems that are sentinels for anthropogenic change. Understanding recent changes in these systems is complicated, however, by a lack of data documenting their natural variability and past response to human disturbance. Isotopic data from shallow sediments of Great Salt Lake (GSL), UT, demonstrate a two‐phase shift in lake water and carbon budgets during the past 200 years. I suggest that these changes are associated with regional colonial settlement, which altered carbon budgets beginning in the mid‐19th century, and the hydrographic effects of a railroad causeway built in 1959. The post‐colonial isotope changes are unprecedented in the preceding ∼2,000 years and unusual in the context of an 8,000‐year record of natural variability. This work illustrates the utility of proxy data in identifying past human impacts on saline lake systems and documenting background states that can serve as targets for management.
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- Award ID(s):
- 2202880
- PAR ID:
- 10617618
- Publisher / Repository:
- American Geophysical Union
- Date Published:
- Journal Name:
- Geophysical Research Letters
- Volume:
- 52
- Issue:
- 14
- ISSN:
- 0094-8276
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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