Craig Williamson
Global Change Limnology Laboratory

Dr. Craig Williamson

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 sentinels, integrators, and regulators of environmental change, with an emphasis on deciphering the most valuable sentinels of climate 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.

Lake observatory networks play a central role in the broader goals of the Global Change Limnology Laboratory.

  • Lakes serves as sentinels -or sensors- in the landscape, providing signals about changes in the surrounding environment. (Photo: Beauty Lake, MT)
  • Using buoys and sensors, we collect high frequency lake data that interface with lake ecological observatory networks. (Photo: Jennie Brentrup, Lake Lacawac, PA)
  • Field samples help us to better understand a lake's sentinel responses and the resulting biotic consequences. (Photo: Grinnell Lake, MT)
  • Students couple laboratory and field experiments to answer their research questions. (Photo: Matt Meeks, Lake Lacawac, PA)
  • Collaboration with other scientists enables us to answer large-scale ecological questions. (Photo: LEOW Meeting, Lacawac Sanctuary, PA)

Update on UV and 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 ( 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.

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.