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Sun on Odesa

   Lakes and Reservoirs as Sentinels, Integrators,
    and Regulators of Climate Change

   AGU Chapman Conference: Special Issue of Limnology &

   Lake Tahoe, Incline Village, Nevada, USA 8–10 September 2008

Conveners (AKA Scientific Committee)

Craig Williamson, Miami University, Oxford, Ohio, USA
Web site
Jasmine Saros, University of Maine Climate Change Institute, Orono, Maine, USA
Web site

Conference Organizing Committee (area of contribution)


National Science Foundation Miami University University of Maine Climate Change Institute Tahoe Environmental Research Center Hydro-Québec

Conference Objectives and General Description

The final conference program is now available.

Lakes and reservoirs comprise a small portion of the Earth's total surface area, yet they are likely to play a substantial role both as regulators of future climate change, and as integrators of the present and past effects of climate change on terrestrial and aquatic ecosystems. Lentic ecosystems are the lowest point in the surrounding landscape and as such can provide information on how climate change alters not only aquatic ecosystems, but also the terrestrial ecosystems in the surrounding watershed. Alterations in seasonal temperature and precipitation patterns as well as climate control of carbon flux into and out of lakes may play a central role in both the ecology of aquatic and terrestrial communities and ecosystems, and in global biogeochemical cycles. For example, long-term trends of changes in dissolved organic matter (DOM) have been observed in several regions around the world. The chromophoric component of DOM (CDOM) is a major mediator of climate variability through its influence on ultraviolet (UV) and photosynthetically active radiation (PAR), carbon cycling, energy flow, and aquatic food-web structure. Similar climate effects can be recognized for changes in the flux of energy, water and other dissolved substances that act as ecological subsidies among terrestrial, aquatic and atmospheric domains. The purpose of this Chapman Conference is to synthesize and advance our understanding of the mechanisms by which lakes record, integrate, respond and regulate climate variability.

This conference will examine the potentially important roles of lakes and reservoirs in global climate change, particularly as regards changes in the flux of energy, water and carbon into, within, and out of lake basins and the consequences for aquatic and terrestrial communities and ecosystems. While the conference will focus squarely on science, the intention is to have the product be of substantial value to environmental managers and policy-makers dealing with climate change issues. We plan to assemble four working groups, each of which will be composed of several break-out groups for discussion. The goal of the working groups will be to come to a consensus on the major issues in the respective topical area and write a paper to be submitted for publication in the special issue of Limnology and Oceanography. The four working groups are as follows:

1)   Lakes and reservoirs as sentinels of present climate change
Working Group Chair: Rita Adrian IGB, Berlin, Germany
Co-chair and Rapporteur: Horacio Zagarese, Instituto Tecnológico de Chascomús, Provincia de Buenos Aires, Argentina
Co-chair and Rapporteur: Catherine O'Reilly, Bard College, Annandale-on-Hudson, NY, USA.

As the lowest points in the landscape, lakes and reservoirs are highly responsive to the effects of climate forcing. Physical, chemical, and biological processes in lakes and reservoirs respond to changes in energy, water (including ice development) and dissolved substances over time scales ranging from short-term oscillations to multi-decadal trends. Papers are encouraged that demonstrate the mechanisms by which climate affects lakes, as well as the consequences of these mechanisms for the structure and function of ecological, chemical or physical components of lakes.

2)   Lakes and reservoirs as integrators of past climate change
Working Group Chair: Peter Leavitt, University of Regina, Canada
Rapporteur: Sheri Fritz, University of Nebraska, USA

The sediments of lakes and reservoirs integrate effects of climate variability on terrestrial and aquatic ecosystems over decades to millennia through the deposition and preservation of diverse materials derived from land, lake and atmosphere. This theme will feature papers that quantify how climate has influenced lakes in the past, demonstrate how climate interacts with natural or human disturbance, or which use historical insights to model or forecast climate effects. Any retrospective approach is suitable (microfossils, geochemistry, physical stratigraphy), although preference will be given to studies that advance our insights into the mechanisms of lake response to climate variability.

3)   Lakes and reservoirs as regulators of future climate change
Working Group Chair: Lars Tranvik, Uppsala University, Sweden
Rapporteur: John Downing, Iowa State University, USA

This working group will examine the effects of lakes and reservoirs on modulating regional climate but also the global carbon cycle. Recent estimates suggest that the rate of deposition of fixed organic carbon in lakes and reservoirs exceeds that being deposited in the world's oceans. As such, lakes and reservoirs may account for a substantial portion of the “missing carbon” sink resulting from anthropogenic fossil fuel burning and hence contribute to the regulation of climate change. Lakes are often observed to contain CO2 and other greenhouse gases at concentrations above air-equilibrium, and in some environments such as the arctic tundra aquatic ecosystems may act as major conduits for the transfer of terrestrial carbon to the atmosphere. One portion of the carbon cycle in lakes and reservoirs that remains poorly understood in this respect is the role of photobleaching by UV and longer wavelengths and how it influences the production and processing of organic matter by microbial autotrophs, heterotrophs, and mixotrophs.

4)   Scaling and modeling the role of lakes and reservoirs in climate change
Working Group Chair: Murray MacKay, Environment Canada
Rapporteur: Patrick Neale, Smithsonian Environmental Research Center, USA

Climate effects on aquatic ecosystems range from the molecular level response of UV-induced DNA damage and temperature dependent enzyme kinetics to direct and indirect food web responses at the population, community, and ecosystem levels. The timing of the response of lakes to climate change ranges over time scales of days (thermal stratification in response to storm events) to millennia (sediment records). On a regional scale great lakes play an important role in modulating regional climate patterns, which influence terrestrial ecosystems as well. Tools for examining these responses may range from the use of the ways that stable isotope ratios are altered by climate effects on biochemical pathways to remote sensing and satellite imagery approaches to quantifying the distribution and abundance of lakes and large scale regional or global responses such as the drying of the Aral Sea. Sophisticated scaling and modeling approaches are required to integrate these disparate levels of response of lakes to climate change at local, regional, and global scales.


The conference will be three full days, with arrivals and an evening reception preceding, and morning departures following the last day. The conference's basic format will include six keynote lectures: three by senior scientists, and three by early career scientists. The working group chairs will provide syntheses, and breakout sessions will be held in a workshop setting. There may be an afternoon or post-conference field trip added.


The results of the conference will be published as a special issue (SI) of Limnology and Oceanography. The SI has already been unanimously approved by the ASLO Board. Funding is available for 20–25 papers in the SI, assuming average printed paper length is 10 pages, figures and equations are not excessive, and authors pay for free access and for any color plates. The format of the SI will follow the general format of the conference as outlined here. The SI will include an opening overview entitled “Lakes as sentinels, integrators, and regulators of climate change”. Williamson will be the lead author on this overview and Saros, Vincent, and Smol will be co-authors. In addition to contributed papers solicited through an open call on the ASLO and AGU websites, there will be four synthesis papers, one by each working group. The chair and rapporteur of each working group will be the lead authors and discussion participants whose input is substantial enough to warrant will be included as co-authors. Criteria for accepting papers for submission will be established through an abstract vetting process carried out by the conference organizers and editors in consultation with the Editor-in-Chief of L&O as outlined on the SI portion of the L&O web site. Submitted papers must be directly relevant to the core questions that are developed by the working group leaders, conference co-organizers, and program committee.

Guest Editors of Special Issue of Limnology and Oceanography

Warwick Vincent: Web site
John Smol: Web site

Keynote Speakers

Three senior scientists and three early-career scientists have been chosen to provide both context and insight into the role of lakes as sentinels, integrators, and regulators of climate change.

Further Information

For questions on abstract submissions by students and young investigators (< 5 years since PhD to 10 September 2008), or if you have questions or would like to be placed on a mailing list (be sure to include the name of the meeting you are interested in), E-mail or call the AGU Meetings Department at +1 202-777-7332.