Craig Williamson
Global Change Limnology Laboratory

About the Global Change Limnology Lab

Oesa Lake in Canadian Rockies
As the lowest point in the watershed, lakes serve as sentinels, integrators and regulators of climate change.

The larger context for our research in the Global Change Limnology Lab lies in understanding how climate change is altering ecosystems. Our focus is primarily on the role of lakes as sentinels, sensors in the landscape that provide sentinel responses that inform us about the response of aquatic ecosystems and their catchments to climate change as well as invasive species and disease ecology. The water column of lakes can be viewed as a vertical habitat gradient along which populations and communities vary as a function of changes in factors such as light, temperature, oxygen, food availability, predators, and anthropogenic disturbance. These physical and chemical characteristics of lakes provide a rich suite of sentinel responses, metrics that can be used to understand the ecological consequences of environmental change - how living organisms are influenced. Our expertise is with the ecology of UV and optical signals, as well as the role of zooplankton and larval fish in the structure and function of aquatic ecosystems. The questions that we ask deal with

Currently, our work is centered on alpine and subalpine lakes in the U.S. and Canadian Rocky Mountains, as well as lower elevation lakes in northeastern Pennsylvania where we have a long-term database on several lakes. Our past work has also included the study of lakes in Glacier Bay, Alaska, the Southern Andes of Argentina, New Zealand, and other regions of the world. While the research questions are field-based, the approaches include laboratory and field experiments as well as comparative limnology. Students in the lab work collaboratively with other investigators at Miami University as well as at other institutions to give them experience with a broader range of skills, expertise, and perspectives on issues in aquatic ecosystems.

Aquatic ecosystems are controlled as much by processes in the surrounding watershed as those within the basin itself. As integrators of ecological processes in the surrounding region, lakes provide information on the impact of environmental change on both terrestrial and aquatic ecosystems. We use environmental gradients in aquatic ecosystems as "natural experiments" to tease out the effects of environmental change, with a particular emphasis on solar ultraviolet radiation (UV) and climate change. The core interest is in the interactions between abiotic and biotic factors and how they influence the distribution and abundance of organisms at higher trophic levels (zooplankton, larval fish and amphibians, and benthic invertebrates).

Epischura nevadensis
A predatory copepod, Epischura nevadensis (photo credit: R. Moeller).

Fish larvae
The redside minnow (top) from Lake Tahoe contain pigments to protect them from UV damage, whereas invasive bluegill (bottom) do not (photo credit: A. Tucker).
Synchaeta spp.
The rotifer Synchaeta pectinata (photo credit: R. Magnien).

In collaboration with many individuals from Miami University and other institutions, we are currently striving to understand the role of UV radiation in aquatic systems at levels ranging from the cell and molecular to the organism, population, community, and ecosystem. These interests are often integrated with our earlier work with vertical habitat gradients in predation risk and food limitation in the water column. Both climate change and stratospheric ozone depletion are changing the nature and timing of the development and breakdown of habitat gradients in aquatic ecosystems. Understanding these habitat gradients is essential if we are to predict how the structure and function of lake ecosystems are likely to respond to future changes in climate and other natural and anthropogenic disturbances. Our work in recent years has been supported by National Science Foundation Grants DEB-9306978, INT-9314421, DEB-9509042, DEB-9740356, and DEB-9973938. However, any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.