Water, water everywhere
- Dec 29, 2016
- Faculty & Staff, Research, EES
As a graduate student, Jay Zarnetske spent two years doing research on the North Slope of Alaska, the last strip of land before reaching the Arctic Ocean.
This past fall, Zarnetske, MSU assistant professor in the Department of Earth and Environmental Sciences, had the opportunity to reengage with the Arctic community through the Arctic Long-Term Ecological Research (LTER) project, part of a network of sites established by the National Science Foundation to support long-term ecological research in the United States.
Zarnetske’s research focuses on the interfaces between ground and surface waters—an integral part of the emerging field of hydroecology, which seeks to understand the influence of hydrology on ecosystems and biogeochemical cycles.
“I often say, ‘Physics sets the limit and the biology gets it done,’” Zarnetske said. “That’s our approach to science—how does the physics of the movement of water dictate or set the template for biological systems.”
Zarnetske’s Arctic LTER team performed exploratory research in three areas—much of it work that had never been attempted before.
MSU research associate Ben Abbott collects data from a mountain stream, Trevor Creek, to understand how different landscapes affect stream network structure and water chemistry.
First, they collected water chemistry samples from three different watersheds—one in the mountains, one in the foothills and one with a series of tundra lakes—to determine how the vegetation, topography and hydrology affect the coupling of terrestrial and aquatic ecosystems.
“Studying the coupling of terrestrial and aquatic ecosystems is so exciting because you absolutely need to understand how water moves, and when it moves and what flow path it takes in order to understand the chemistry and how organisms arrange themselves,” Zarnetske said.
Next, the team explored what happens to carbon that’s melting out of the permafrost.
“Most carbon is bound in ice right now, but the Arctic is warming, and that ice is thawing. How does the hydrology play a role in the fate of that carbon that’s coming out of the permafrost? That’s an enormous question that researchers around the world are trying to tackle,” Zarnetske said.
“The carbon that melts out of the permafrost ends up in the river network as dissolved organic matter," he continued. "Some components of the organic matter are highly desirable for microbial organisms, and some of it is susceptible to physical degradation, when light hits it, for example, and breaks apart the molecules. So finding out what’s in that organic matter is really important to figuring out its fate.”
The third project entailed using new high-frequency water sensors to “take the pulse of the river” without having to collect samples for analysis in the lab.
“We can measure the dissolved carbon and nitrogen directly in the river—as frequently as every minute," Zarnetske said. "This resolution had never been collected before in the Arctic.”
The team deployed two sensors, for the duration of the trip, in a mountain and a tundra watershed, to see how differences in the day and night and during storms affects the carbon and nitrogen moving through the river.
Now back on campus, Zarnetske and his entire group are working as a team to analyze the data they collected.
“Water is our study organism. Water is our expertise. It’s what we look at to bring understanding to other disciplines,” he said.
For a longer version of this story, visit http://pubs.natsci.msu.edu/publication/?i=367552&p=&pn=.