You reached this page through the archive. Click here to return to the archive.

Note: This article is over a year old and information contained in it may no longer be accurate. Please use the contact information in the lower-left corner to verify any information in this article.

Researchers examine impact of climate change on lakes, wetlands

By Kari VanDerVeen
June 18, 2009

To determine how lakes and wetlands are impacted by global climate change, it's important to understand what's happening in the ecosystems surrounding these bodies of water.

Professor of Biology Charles Umbanhowar Jr. measures a sediment core taken from a lake in northern Manitoba, Canada, as part of a research project examining how interactions among ecosystems affect their response to global climate change.
"Lake responses to climate change are in part controlled by what runs into the lake, either over the ground or through the groundwater," St. Olaf Professor of Biology Charles Umbanhowar Jr. says. "So in looking at past -- or anticipating future -- responses to climate, one needs to understand what is happening in the surrounding area."

Umbanhowar and colleagues from three other institutions are in the midst of a three-year research project examining how interactions among ecosystems affect their response to global climate change. The research is funded by the National Science Foundation, which provided Umbanhowar with a $101,000 grant for the project. He is working on this research with Bowdoin College Associate Professor of Environmental Studies and Biology Phil Camill (formerly at Carleton College), Trinity College Associate Professor of Physics Christoph E. Geiss, and Science Museum of Minnesota Senior Scientist Mark B. Edlund.

By teaming together, the researchers are able to apply their various areas of expertise -- which range from the magnetic properties of soils to using charcoal to determine fire history -- in analyzing the different samples they collect. Researchers at St. Olaf will focus mainly on performing biochemical analyses of the water, soil, and sediment collected. More than 15 St. Olaf students are participating in the research, with a half-dozen of them helping collect samples in the field. Umbanhowar's Geographic Information Systems class has also worked on the project.

The team's research is focusing on the forest-tundra region of northern Manitoba, Canada, which is experiencing some of the fastest rates of warming in the world. It's also a largely unstudied region and is one of the southernmost locations of tundra in the world, Umbanhowar notes.

An aerial view of lakes and wetlands in northern Manitoba, where Professor of Biology Charles Umbanhowar Jr. and a team of researchers are gathering samples of sediment deposited over the past 8,000 years.
This summer the research group is beginning the second of its two field seasons. In the first field season researchers sampled sediment deposited over the past 8,000 years from six lakes as well as water and surface mud from more than 30 lakes and a variety of peat and soil.

Working from the surface of a small raft, Umbanhowar and other researchers obtain samples by coring lake sediments using what is called a piston-corer -- a 1-meter long steel tube that is pushed into the mud using long rods. In gathering these sediment cores from connected lakes, wetlands, and upland tundra and forests, they will be able to examine how interactions between these ecosystems have affected their responses to global climate change.

One example of these interactions is the effect that climate change has had on peatlands, an important source of dissolved organic compound that colors the water brown. This dissolved organic compound provides a food source for bacteria and can limit the amount of light available for photosynthesis in a lake.

"Evidence from Alaska and elsewhere shows that these peatlands are thawing out now and releasing much more dissolved organic compound as they thaw," Umbanhowar says. This means that lakes with peatlands surrounding them will have more dissolved organic compound and, thus, respond differently to climate change than lakes with fewer surrounding wetlands.

The research group expects to release its initial findings this year, with final reports likely completed in 2010 or later.

Contact Kari VanDerVeen at 507-786-3970 or