Kevin Czajkowski, Richard Becker, Changliang Shao Jiquan Chen, Carol Stepien, Thomas Bridgeman, Housen Chu 4/24/2014

Objective - questions gracegreaterthanoursin.wordpress.com What is the role of lakes in regional water cycling? CarbonWater

The Framework

Measurements including: 3-D wind speed and direction CO 2 CH 4 H 2 O and energy Air pressure, temperature and humidity Rainfall PAR Radiation balance, albedo Water surface temperature Water temperature profiles +++ Eddy-covariance system and study site Most direct and defensible way to measure ecosystem gas fluxes 12km N Lake Erie LEC CB LI

Results - Meteorology Data from 2011 up to now In 2012, for the whole year, the daily mean T a was 12.0 and 12.2°C at CB and LI (a) The VPD was higher 11% at CB than LI (c) 2012 August having a greater PPT near 100 mm. 2013, PPT reached a high of 100 mm in June and 150 mm in July (e) Summer raining, 2013 Wind speed&direction

Daily patterns of evaporation (E) and sensible heat (H) Lake LI Grassland Lake Evaporation or H (W m -2 ) Rn E H E H

655 mm 713 mm 642 mm 819 mm 817 mm 671 mm 798 mm 993 mm 706 mm 642 mm 669 mm Month (forest)(crop) (marsh) (lake)

Summer typical day: 0.18 mm (0.07 inches) The Great Lakes total surface area: 94,250 square miles A one-day loss equates to: 120 billion gallons per day 3 times the flow rate of Niagara Falls Regional status of Lake evaporation University of Michigan even reported a 0.5 inches of water to evaporation, 7 times higher than our result.

Results – Daily changes of CO 2 fluxes Western Lake Erie acted as a carbon source in the yearly perspective of 70.8±17.4 and 116.1±37.3 g C m -2 yr -1 in the first and second years, respectively, but as a small carbon sink in the summers of both years.

Lake CH 4 Pulse pattern Release in winter Range -80~300 nmol m -2 s -1 Lake Marsh Chu et al, 2014 One day pattern

Regional comparison CO 2 sequestration among ecosystems Scaling our results across the entire Western Lake Erie Basin releases 4.78×10 5 tons of C per year This carbon loss is equivalent to 1/3 sink of the natural forests or 1/4 of the croplands of western Lake Erie Basin watershed rcs/detail/oh/programs/?cid=nrcs144p 2_029640

Summary From an annual perspective, western Lake Erie acted as a carbon source, but as a small carbon sink in the summers of both years. Although the lake evaporation for this location returns ~90% of annual rainfall to the atmosphere, the turbulent energy accounted for <40% of the input energy. The remaining 60% of the energy was stored in the water body or was undetected. Lake evaporation was obvious lower than other terrestrial ecosystems, lower than what we previously thought.

Publications and presentations Chu, H, J. Chen, J. Gottgens, Z. Ouyang, R. John, K. P. Czajkowski, R. Becker. Net ecosystem CH 4 and CO 2 exchanges in a Lake Erie coastal marsh and a nearby cropland, Journal of Geophysical Research –Biogeosci., DOI: /2013JG Shao, C, J. Chen, C. A. Stepien, H. Chu, T. B. Bridgeman, K. P. Czajkowski, R. Becker, Z. Ouyang, R. John. Diurnal to annual changes in carbon, latent and sensible heat over a Laurentian Great Lake, Limnology and Oceanography (under review) 4 more under preparation via cooperation or data sharing Carol Stepien et al. A New Land-Lake Sensor Network for Measuring Greenhouse Gas, Water, and Energy Exchanges: Use in Education and Outreach JASM meeting in Portland, May Housen Chu et al. Contrasting the interannual variability of evapotranspiration in a temperate Oak woodland, a freshwater marsh, a conventional cropland and Lake Erie International evapotranspiration symposium, NC, April 7-10 Shao, C, J. Chen, C. A. Stepien, H. Chu, T. B. Bridgeman, K. P. Czajkowski, R. Becker, Z. Ouyang, R. John. Eddy covariance measurements of carbon, latent and sensible heat fluxes from western Lake Erie AGU annual meeting (B21A-0443), SF, Dec 10

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