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Paul Hanson

Distinguished Research Professor
UW Center for Limnology
CV as of March 2013

Research Interests

Carbon cycling: Lakes play important roles in carbon cycling at the watershed, regional, and even global scales. The balance between carbon sequestration and storage versus mineralization in lakes depends on how ecosystem boundaries are drawn, the nature of the lake and the load, and the time scale of interest. My research in carbon cycling focuses on how ecosystem processes alter these balances across different space and time scales in different ways among lakes of the world. Carbon cycling theme pervades work in a number of funded research projects in which I’m the lead PI or a co-PI, including the North Temperate Lakes LTER, a Wisconsin Focus on Energy project, and a collaborative project funded by Mellon foundation on regional carbon cycling modeling in Wisconsin.

Ecosystem variability: My general interest in ecological scaling issues underlies recent work in cross-scale analyses of lake data sets. Ecological data are inherently messy and tend to show pattern at multiple scales — a phenomenon especially evident in data from sensor networks. Understanding controls over that variability presents analytical challenges that benefit from signal processing tools, such as wavelet transforms, spectral analysis, and other system identification approaches. The payoff has been a clearer picture of, e.g., how dissolved oxygen in lakes is controlled by internal waves at short time scales, metabolism at days to weeks, and long-term weather oscillations at decades. Such approaches also show promise for developing scaling laws governing, e.g., phytoplankton dynamics.

Microbes, algae, and even fish: Although some of my past work has emphasized fish bioenergetics and fish identification through software and modeling tools, I’ve recently downsized in organisms. The control over microbial (bacteria and phytoplankton) dynamics in real ecosystems remains a mystery under many conditions. Through partnerships with microbial ecologists and physical limnologists at the University of Wisconsin and in the Global Lake Ecological Observatory Network (GLEON), we are using high-tech sensor network measurements, coupled physical-chemical-biological models, and signal processing to study the vagaries of microbial dynamics. Studies of algal blooms, for example, are central to much of the research happening on Lake Mendota in Madison, Wisconsin.


Research Projects

CDI: New knowledge from the Global Lake Ecological Observatory Network (GLEON)

GLEON RCN: Advancing lake ecology by building an international community to exploit innovations in sensor network technology (GLEON)

Wisconsin Focus On Energy: Carbon cycling in Wisconsin Lakes; The Loon Project

Mendota Research Group (MeRG)

North Temperate Lakes Long Term Ecological Research Program (NTL LTER)

WiscFish, a Computer-based fish identification system, and Fish Bioenergetics



Fish Bioenergetics



Harmful Algal Blooms (Erika Phillips)

Lakebase (Luke Winslow)

Mendota Research Group (MeRG)

Water @ UW-Madison



Recent Publications

Kara, E.L., P.C. Hanson, D.P. Hamilton, M. Hipsey, K.D. McMahon, J. Read, L. Winslow, J. Dedrick, K. Rose, C.C. Carey, S. Bertilsson, D. Motta Marques, L. Beversdorf, T. Miller, C. Wu, Y.F. Hsieh, E. Gaiser, and T.K. Kratz. 2012. Time-scale dependence in numerical simulations: Assessment of physical, chemical, and biological predictions in a stratified lake at temporal scales of hours to months. Environmental Modelling & Software, doi: 10.1016/j.envsoft.2012.02.014.

Lottig, N.R., E.H. Stanley, P.C. Hanson, and T.K. Kratz. In press. Comparing lake and stream biogeochemistry accentuates local and regional processes influencing aquatic ecosystems. Limnology and Oceanography.

Davies, N., D. Field, et al. 2012. Sequencing data: A genomic network to monitor Earth. Nature 481: 145  doi:10.1038/481145a.

Carey, C.C., P.C. Hanson, D.A. Bruesewitz, et al. 2012. Organized Oral Session 43. Novel Applications of High-Frequency Sensor Data in Aquatic Ecosystems: Discoveries from GLEON, the Global Lake Ecological Observatory Network. Bulletin of the Ecological Society of America 93:100–105. [doi:]

Porter, J.H., P.C. Hanson, C.C. Lin. 2011.  Staying afloat in the sensor data deluge. TREE 1484:1-9.

Trolle, D., D.P. Hamilton, M.R. Hipsey, K. Bolding, J. Bruggemen, W.M. Mooij, J.H. Janse, A. Nielsen, E. Jeppesen, J.A. Elliot, V. Makler-Pick, T. Petzoldt, K. Rinke, M.R. Flindt, G.B. Arhonditsis, G. Gal, R. Bjerring, K. Tominaga, J. Hoen, A.S. Downing, D. M. Marques, C.R. Fragoso, M. Sondergaard, P.C. Hanson. 2011. A community-based framework for aquatic ecosystem models. Hydrobiologia. DOI 10.1007/s10750-011-0957-0.

Hanson, P.C., D.P. Hamilton, E.H. Stanley, N. Preston, O.C. Langman, E.L. Kara. 2011. Fate of Allochthonous Dissolved Organic Carbon in Lakes: A Quantitative Approach. Plos One. 6:E21884.

Watras, C.J., P.C. Hanson, T.L. Stacey, K.M. Morrison, J. Mather, Y.H. Hu, and P. Milewski. 2011. A temperature compensation method for CDOM fluorescence sensors in freshwater. Limnol. Oceanogr. Methods. 9: 296-301. DOI: 10.4319/lom.2011.9.296

Lottig, N.R., E.H. Stanley, P.C. Hanson, and T.K. Kratz. In press. Comparing lake and stream biogeochemistry accentuates local and regional processes influencing aquatic ecosystems. Limnology and Oceanography.

Tsai, J.W., T.K. Kratz, P.C. Hanson, N. Kimura, W.C. Liu, F.P. Lin, H.M. Chou, J.T. Wu, and C.Y. Chiu. 2011. Metabolic changes and the resistance and resilience of a subtropical heterotrophic lake to typhoon disturbance. Can. J. Fish. Aquat. Sci. 68: 768-780.

Staehr, P.A., D. Bade, M. Van de Bogert, G. Koch, C. Williamson, P.C. Hanson, J. Cole, and T.K. Kratz. 2010. Lake metabolism and the diel oxygen technique: State of the science. Limnol. Oceanogr. Methods. 8: 268-644.

Buffam, I., S.R. Carpenter, W. Yeck, P.C. Hanson, and M.G. Turner. 2010. Filling holes in regional carbon budgets: predicting peat depth in a north-temperate lake district. Journal of Geophysical Research (115), G01005, doi:10.1029/2009JG001034.

Cardille, J.A., S.R. Carpenter, J.A. Foley, P.C. Hanson, M.G. Turner, and J.A. Vano. 2009. Climate changes and lakes: estimating sensitivities of water and carbon budgets. J. Geophys. Res. Biogeosciences, 114, doi:10.1029/2008JG000891.

Kamarainen, A.M., R. Penczykowski, M. Van de Bogert, P.C. Hanson, and S.R. Carpenter. 2009. Phosphorus sources and demand during summer in a eutrophic lake. Aquatic Biology, 71: 214-227.

Porter, J., E. Nagy, P.C. Hanson, T.K. Kratz, S. Collins, and P.A. Arzberger. 2009. New Eyes on the World: Advanced Sensors for Ecology. Bioscience (59): 385-397.

Hanson, P.C., S.R. Carpenter, N. Kimura, C. Wu, S.P. Cornelius, and T.K. Kratz. 2008. Evaluation of metabolism models for free-water dissolved oxygen methods in lakes. Limnol. Oceanagr. Methods. 6:454-465.

Hanson, P.C. 2008. New ecological insights through the Global Lake Ecological Observatory Network (GLEON). Ecological Science. 27(5): 300-302.

Winslow, L.A., B.J. Benson, K.E. Chiu, P.C. Hanson, T.K. Kratz. 2008. Vega: A flexible data model for environmental time series data. Environmental Information Management Conference. Albuquerque, NM.

Coloso, J.J., J.J. Cole, P.C. Hanson, and M.L. Pace. 2008. Depth-integrated, continuous, estimates of metabolism in a clear-water lake. Can. J. Fish. Aquat. Sci. 65:712-722.

Tsai, J.W., T.K. Kratz, P.C. Hanson, J.T. Wu, W.Y.B. Chang, P.W. Arzberger, B.S. Lin, F.P. Lin, H.M. Chou, C.Y. Chiu. 2008. Seasonal dynamics and regulation of lake metabolism in a subtropical humic lake. Freshwater Biology. 53:1929-1941.

Tilak, S., P. Arzberger, B. Benson, R. Bhalerao, K. Chiu, T. Fountain, D. Hamilton, P. Hanson, T.K. Kratz, F.P. Lin, and L. Winslow. 2007. Conceptual Challenges and Practical Issues in Building The Global Lake Ecological Observatory Network. ISSNIP07 conference proceedings.

Hanson, P.C. A grassroots approach to sensor and science networks. 2007. Frontiers in Ecology and the Environment. 5(7): 343.

Hanson, P.C., S.R. Carpenter, J.A. Cardille, M.T. Coe, and L.A. Winslow. 2007. Small lakes dominate a random sample of regional lake characteristics. Freshwater Biology. 52: 814-822.

Carpenter, S.R., B.J. Benson, R. Biggs, J.W. Chipman, J.A. Foley, S.A. Golding, R.B. Hammer, P.C. Hanson, P.T.J. Johnson, A.M. Kamarainen, T.K. Kratz, R.C. Lathrop, K.D. McMahon, B. Provencher, J.A. Rusak, C.T. Solomon, E.H. Stanley, M.G. Turner, M.J. Vander Zanden, C.-H. Wu and H. Yuan. 2007. Understanding regional change: Comparison of two lake districts. BioScience. 57(4): 323-335.

Cardille, J. A., Carpenter, S. R., Coe, M. T., Hanson, P. C., Foley, J. A., Turner, M. G., and J. A. Vano. 2007. Integrating carbon and water cycling in lake-rich landscapes: effects of landscape connections on lake hydrology and biogeochemistry. Journal of Geophysical Research – Biogeosciences. 112, G02031, doi:10.1029/2006JG000200.

Kratz, T.K., P. Arzberger, B.J. Benson, C.Y. Chiu, K. Chiu, L. Ding, T. Fountain, D. Hamilton, P.C. Hanson, Y.H. Hu, F.P. Lin, D.F. McMullen, S. Tilak, C. Wu. 2006. Towards a Global Lake Ecological Observatory Network. Publications of the Karelian Institute 145:51-63. (

Hanson, P.C., S.R. Carpenter, D. Armstrong, E.H. Stanley, and T.K. Kratz. 2006. Lake dissolved inorganic carbon and dissolved oxygen: changing drivers from days to decades. Ecological Monographs. 76(3): 343-363.

Lyons, J., P.C. Hanson, E.A. White. 2006. A photo-based computer system for identifying Wisconsin fishes. Fisheries. 31: 269-275.

Lauster, G. H., P. C. Hanson, and T.K. Kratz. 2006. Gross primary production and respiration differences among littoral and pelagic habitats in North Temperate lakes. Canadian Journal of Fisheries and Aquatic Sciences. 63(5): 1130-1141.

Porter, J., P. Arzberger, P. Hanson, T. Kratz, S. Gage, T. Williams, S. Shapiro, P. Bryant, F. Lin, H. King, T. Hansen, H. Braun, W. Michener. 2005. Wireless sensor networks for ecology. Bioscience. 55: 561-572.

Hanson, P.C., Y.H. Hu, T.K. Kratz, P. Shin. 2005. Lake metabolism variability: Identifying physical and biological events using support vector machine. Departmental report CFL-05-01. (

Benson, B. J., P. C. Hanson, J. W. Chipman, and C. J. Bowser. 2004. Breaking the data barrier: research facilitation through information management. Chapter 13 in Long-Term Ecological Research of North Temperate Lakes: Dynamics of Lakes in the Landscape. J. J. Magnuson, T. K. Kratz, and B. B. Benson, eds. Oxford University Press.

Hanson, P. C., A. Pollard, D. L. Bade, K. Predick, S. R. Carpenter, and J. Foley. 2004. A model of carbon evasion and sedimentation in temperate lakes. Global Change Biology. 10: 1285-1298.

Bade, D. L., S. R. Carpenter, J. J. Cole, P. C. Hanson, and R. H. Hesslein. 2003. Controls of d13C-DIC in lakes: Geochemistry, lake metabolism, and morphometry. Limnol. Oceanogr. 49: 1160-1172.

Hanson, P.C., Bade, D. L., Carpenter, S. R., and T. K. Kratz. 2003. Lake metabolism: Relationships with dissolved organic carbon and phosphorus. Limnol. Oceanogr. 48: 1112-1119.