Probing for clues to climate change
On a research trip to Alaska's Toolik Field Station 160 miles north of the Arctic Circle, UT Arlington biology Associate Professor Laura Gough carefully inserts a probe in a small land tract that researchers have been studying for three decades. The probe sinks almost a foot before stopping, as if striking rock. But rock it isn't.
"It's permafrost," she says, making a note: The permafrost level at this particular spot has dropped a centimeter since she began studying the area years ago. Some probes in other areas show more pronounced permafrost melting, some less.
In environmental terms, a centimeter can mark a critical trend. Here, far into the land of the Northern Lights, the frozen permafrost never goes away, though in the throes of a brief summer the depth of soil that thaws can vary from 10 centimeters (about 4 inches) to 30 centimeters (almost a foot).
It's mostly organic matter above the permafrost, carbon-rich topsoil that has been building up slowly for centuries. The permafrost in the Northern Hemisphere can be shallow, but what it lacks in depth it makes up for in area, covering hundreds of thousands of square miles.
This matters, Dr. Gough says, because continued climate warming tends to create a sort of patchy thawing of the permafrost, an indicator that the soil above it is warming up.
"We know that change is happening. It's warmer now than it used to be. There's a dramatic name for what's happening: a biotic awakening."
Gough says that as the soil warms up it tends to promote increased bacteria and fungi growth, a byproduct of which is more production of carbon dioxide and methane gases, as well as nitrogen that plants can use to grow. Some carbon gases end up in the atmosphere and might contribute to the greenhouse effect, and some end up in the soil and air, providing resources for the Toolik area's vegetation, such as shrubs.
Small changes in soil temperature can create significant changes in vegetation, which in turn impacts animal life in the region. Gough has received two National Science Foundation grants to study the impact of these changes. One focuses on the effects of soil nutrients on tundra plants, soil organisms, and soil chemistry. The other examines the effects of increasing shrub density and size on migratory birds. In addition to Gough, five UT Arlington undergraduate and graduate students will work at Toolik on the grants.
"We're seeing something of a greening of the Arctic," Gough says, "with implications for everything from greenhouse gases, to impact on prey species, to breeding patterns for migratory birds."
“IT’S WARMER NOW THAN IT USED TO BE. THERE’S A DRAMATIC NAME FOR WHAT’S HAPPENING: A BIOTIC AWAKENING.”
Though the bird study looks at songbirds in general, it will focus on white-crowned sparrows and Lapland longspurs.
"Life cycles in this part of the world take place quickly, so we'll also be looking to see if the warming trend affects things like insect hatchout or seed production, which are important because the bird migratory pattern timing tends to be very consistent. Longspurs, for instance, arrive in mid-May, and they're gone by the end of July."
Gough says the implications of climate warming in delicate areas like the Arctic amount to a giant puzzle: Each change sets off a potential chain of events that will leave some species as losers and others as winners.