Dr. Craig Williamson
The questions that we ask in our Global Change Limnology Lab deal with how solar ultraviolet radiation, climate change, predation risk, and trophic interactions influence community structure in pelagic ecosystems. We view lakes as integrators, regulators, and sentinels of environmental change. Projects take us all over the world from regions in the U.S. such as northeastern Pennsylvania, Alaska, Lake Tahoe, and the Beartooth Mountains, to the Canadian Rockies, Argentina, and New Zealand. Our questions are field based, but our approaches range from small scale laboratory experiments to the ecosystem level and involve comparative as well as experimental studies. View Publications or Education and Professional Employment.
| From the Field | GLEON Climate Sentinels Working Group | About the Laboratory | Ozone Depletion Update |
From the Field
Transported by backpack and assembled on site, this portable buoy enabled scientists to collect high resolution data on a remote alpine lake. Deployed in alpine Heart Lake, the buoy collected data on ten water and six weather variables at 15 minute intervals. Visit our Current Research page to learn more.
Learn more about our research by visiting the Current Research page and viewing images and video from our field sites using the links below.
Images |
Videos |
|---|---|
| Mobile Buoy | UV in Lakes |
| Canadian Rockies | Invasive Species in Tahoe |
| Lake Tahoe | Undergrads doing Research |
| Beartooth Mountains | High School Teachers doing Research |
| Chile | |
| Poconos | |
| IGERT |
GLEON Climate Sentinels Working Group
Members of our Global Change Limnology Lab work closely with the Global Lake Ecological Observatory Network (GLEON) in a variety of ways including attending and helping to organize meetings and workshops, deploying GLEON buoys, and participating in the GLEON "Climate Sentinels" working group as well as in GLEON site exchanges.
About the Global Change Limnology Lab
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 regional and global environmental changes are altering aquatic communities and ecosystems. Our primary interest and expertise is in lakes, but research has also been conducted in rivers and streams as well as marine systems. In all these systems, the water column 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. Our focus is primarily on the role of zooplankton and larval fish in the structure and function of aquatic ecosystems. The questions that we ask deal with
- how solar ultraviolet radiation (UV), climate change, predation risk, and trophic relationships involving zooplankton and early life stages of fish influence the structure and function of pelagic communities and ecosystems, and
- how water transparency to UV and visible light can be used as an indicator of local, regional, and global environmental change.
Currently, our work is centered on alpine and subalpine lakes in the Beartooth Mountains of Montana and Wyoming, the Canadian Rocky Mountains, and Lake Tahoe in California/Nevada, high elevation lakes in Chile, as well as lower elevation lakes in Pennsylvania and reservoirs in Ohio. 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 and streams 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).
A predatory copepod, Epischura nevadensis (photo credit: R. Moeller).
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).
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.
Update on Ozone Depletion
As part of his service to the scientific and global community, Craig serves on the United Nations Environment Programme Environmental Effects Assessment Panel on ozone depletion (http://ozone.unep.org). The purpose of this panel is to keep the Parties to the Montreal Protocol and the global community informed about the current status of ozone depletion and climate change. The latest UNEP EEAP reports are available at the website above. While the Montreal protocol helped us to avoid potentially catastrophically high UV conditions on Earth (see NASA site), there are still adequate concentrations of ozone-depleting compounds in the atmosphere to lead to an almost total depletion of the ozone in the critical 14-21 km portion of the stratosphere (2006 WMO Ozone Bulletin #4). This has resulted in three of the largest Antarctic ozone holes (in area and mass deficit) occurring since the year 2000 (see File: oz_hole_avg_area_v8.jpg 01-Apr-2008 18:16 106K). The 2006 ozone hole was the largest on record, while the 2009 ozone hole was average for recent years.
Nitrous Oxide - Greatest Ozone Depleting Potential
While the Montreal Protocol has led to substantial decreases in ozone depleting substances like the CFCs, recent findings indicate that nitrous oxide (N2O) now has the greatest ozone depleting potential of any atmospheric compounds (Ravishankara et al. 2009 Science 326:123). The challenge in dealing with N2O is that unlike CFCs, N2O production is tied to the human food supply because it is largely a byproduct of agricultural fertilizers. This will make the control of N2O much more difficult in comparison to CFCs.
For more information
NASA Ozone Hole Watch: This site has images, archives, and educational information on the Antarctic ozone hole.
World Meteorological Organization (WMO) Ozone: This site has information on ozone, educational materials, and the WMO ozone bulletins- current and archives.
Total Ozone Mapping Spectrometer (TOMS): This site has information on monitoring and mapping of both current and historical global ozone. This resource is useful for estimating UV exposure at different locations on Earth.
UV Disaster avoided - what if there were no Montreal Protocol? This site has images and graphs of projected ozone and UV exposure on Earth with and without the reduction of ozone-depleting substances according to the Montreal Protocol.