1. Lakes and Carbon or Why is lake metabolism interesting? Tim Kratz Center for Limnology University of Wisconsin-Madison

2. Outline Brief introduction to GLEON What is lake metabolism? Why is it interesting? How is it measured? What questions remain?

3. The Global Lake Ecological Observatory Network (GLEON) A grassroots network of – lake scientists, ecologists, engineers, information technology experts – institutions and programs – instruments – data Linked by a common cyberinfrastructure With a goal of understanding lake dynamics at local, regional, continental, and global scales Yuan Yang Lake, Taiwan ; photo by Matt Van de Bogert gleon.org

4. GLEON Sites September 2008 Lake Observatory + IT Development 138 individual members --25 countries 21 site members – 11 countries

5. 56 participants 10 First Time 15 students 19 female, 37 male 5 continents Asia Europe North America Oceania South America Australia Brazil China Estonia Finland Germany Hungary Ireland Israel Japan New Zealand Poland Sweden Taiwan United Kingdom United States GLEON 8, Hamilton, New Zealand February 2-6, 2009

6. Lake Sunapee, USA Lake Erken, Sweden Yuan Yang Lake, Taiwan Torrens Lake, Australia Ormajärven, Finland Lake Annie, USA Lake Rotorua, New Zealand Crystal Bog, USA Lake Mangueira, Brazil Typical Instrumentation Weather Thermistor chain Dissolved Oxygen sensor Chlorophyll/phycocyanin fluorometer CDOM fluorometer Turbidity pH CO2 PAR penetration ADCP etc Lake Kinneret, Israel

7. GLEON’s Mission Facilitate interaction and build collaborations among an international, multidisciplinary community of researchers focused on understanding, predicting, and communicating the impact of natural and anthropogenic influences on lake ecosystems by developing, deploying, and using networks of emerging observational system technologies and associated cyberinfrastructure. http://gleon.org

8. GLEON: Shared Vision* Participation: contribute to GLEON mission Openness: share experience and expertise Data: share data as openly as possible Informal: “flat” organization – “grassroots” Transparent: open decision-making Training: integration of students Diversity: gender, geography, discipline *Abstracted from: GLEON Operating Principles and Procedures, Aug 2007

9. GLEON Activities Share experience, expertise, and data Catalyze joint projects Develop tools Conduct multi-site training Create opportunities for students Meet and communicate regularly

10. GLEON and Students

11. GLEON Working Groups Lake Metabolism/DOC Domains of Control Information technology Microbes Climate/Lake Physics Next GLEON meeting: Wisconsin, Oct 2009

12. Lake Metabolism Gross Primary Production (GPP) Ecosystem Respiration (ER) Net Ecosystem Production (NEP) NEP = GPP - ER

13. From Cole, J. J., N. F. Caraco, G. W. Kling, and T. K. Kratz. 1994. Carbon dioxide supersaturation in the surface waters of lakes. Science 265:1568-1570 Mirror Lake, New Hampshire Lake Air Many lakes are supersaturated in CO 2 Lake metabolism and the role of aquatic systems in local to global carbon budgets

14. From Cole, J. J., N. F. Caraco, G. W. Kling, and T. K. Kratz. 1994. Carbon dioxide supersaturation in the surface waters of lakes. Science 265:1568-1570 Of 4665 samples from 1835 lakes worldwide, 87% were supersaturated Why?

15. From Hope, D., T. K. Kratz, and J. L. Riera. 1996. The relationship between P CO 2 and dissolved organic carbon in the surface waters of 27 northern Wisconsin lakes. Journal of Environmental Quality 49:1442-1445. Lakes high in dissolved organic carbon are often high in pCO 2

16. Bog Lakes Clearwater Lakes Surface CO 2 concentrations in 2 brownwater and 2 clearwater Wisconsin lakes From Riera, J. L., J. E. Schindler, and T. K. Kratz. 1999. Seasonal dynamics of carbon dioxide and methane in two clear- water and two bog lakes in northern Wisconsin, USA. Canadian Journal of Fisheries and Aquatic Sciences 56:265-274.

17. CO 2 flux across lake/atmosphere boundary 6.7 mol. m -2 0.09 mol. m -2 1.2 mol. m -2 10.0 mol. m -2 } } bog lakes clearwater lakes From Riera, J. L., J. E. Schindler, and T. K. Kratz. 1999. Seasonal dynamics of carbon dioxide and methane in two clear- water and two bog lakes in northern Wisconsin, USA. Canadian Journal of Fisheries and Aquatic Sciences 56:265-274. to lake to atmosphere open water season totals

18. Atmospheric Flux Allochthonous Inputs Outflow Burial/Resuspension in Sediments Production Respiration Lake Metabolism Carbon dynamics and lakes

19. Autotrophy vs Heterotrophy Autotrophy: GPP>ER; lake makes sufficient reduced carbon in situ Heterotrophy: GPP<ER; lake requires subsidy of organic carbon from outside of lake Autotrophic–Heterotrophic balance is a function of nutrient and dissolved organic carbon concentrations

20. From Hanson, P. C., D. L. Bade, S. R. Carpenter, and T. K. Kratz. 2003. Lake metabolism: relationships with dissolved organic carbon and phosphorus. Limnology and Oceanography 48:1112-1119. Metabolism in 25 Wisconsin Lakes

21. Atmospheric Flux Allochthonous Inputs Outflow Burial in Sediments Production Respiration Carbon Dynamics in Lakes Lake Metabolism

22. From Cole, J. J., Y. T. Prairie, N. F. Caraco, W. H. McDowell, L. J. Tranvik, R. G. Striegl, C. M. Duarte, P. Kortelainen, J. A. Downing, J. J. Middleburg, and J. Melack. 2007. Plumbing the global carbon cycle: Integrating inland waters into the terrestrial carbon budget. Ecosystems 10: 171-184. Global Estimates (Pg C. y -1 )

23. From Tranvik et al. (in review) Limnology and Oceanography

24. Most lakes are small From Downing, J. A., Y. T. Prairie, J. J. Cole, C. M. Duarte, L. J. Tranvik, R. G. Striegl, W. H. McDowell, P. Kortelainen, N. F. Caraco, J. M. Melack, and J. J. Middleburg. 2006. The global abundance and size distribution of lakes, ponds, and impoundments. Limnology and Oceanography 51: 2388-2397.

25. From Downing, J. A., J. J. Cole, J. J. Middelburg, R. G. Striegl, C. M. Duarte, P. Kortelainen, Y. T. Prairie, and K. A. Laube. 2008. Sediment organic carbon burial in agriculturally eutrophic impoundments over the last century. Global Biogeochemical Cycles 22: GB1018, doi:10.1029/2006GB002854

26. Using Sensors to Estimate Lake Metabolism: Diel O2 Dynamics

27. Also seen in Australia, New Zealand, China, etc.

28. LakeTotal DaysDays Detected% Days Crystal Bog, WI, USA432456 Trout Lake, WI, USA32413 Sparkling Lake, WI, USA2136028 Trout Bog, WI, USA27711843 Sunapee, NH, USA601423 Taihu, China321547 Rotorua, New Zealand10014 Kinneret, Israel221150 TOTAL77926033 Slide courtesy of Laurence Choi Nighttime peaks occur on about 1/3 of lake-days

29. Sensors, Lake Metabolism and Water Quality Can we use sensors to predict onsets of algal blooms? UW- Madison ERSC Chris Solomon Lake Mendota, WI, USA

30. Lake Mendota – chl and phycocyanin

32. Lots of remaining questions What controls daily, seasonal, interannual or longer scale variation in lake metabolism? How significant is within lake variability in lake metabolism? Can we predict it with physical models? What are the linkages between carbon dynamics and microbial community structure in freshwater lakes?

33. Lots of remaining questions (cont.) What role does disturbance (e.g. mixing events, typhoons) play? What are the direction and rates of change of metabolism at local, regional, continental, and global scales? What are the reciprocal interactions between human uses of lakes and lake metabolism?

34. From Prairie, Y. T. 2008. Carbocentric limnology: looking back, looking forward. Can. J. Fish. Aq. Sci. 65: 545-548

35. Gross primary production (GPP) Ecosystem Respiration [ER] Net Ecosystem Production = GPP - ER heterotrophic, -NEP autotrophic, +NEP