A look into a climate-altered Alaska

Experiments in the permafrost zone near Denali simulate a warmer North.

 

Struggling to keep my balance, I teeter along a narrow plankway that wends through the rolling foothills near Denali National Park and Preserve. Just ahead, Northern Arizona University ecologist Ted Schuur, a lanky 6-footer, leads the way to Eight Mile Lake, his research field site since 2003. Occasionally I slip off the planks onto the squishy vegetative carpet below. The feathery mosses, sedges and diminutive shrubs that grow here — Labrador tea, low bush cranberry, bog rosemary — are well-adapted to wet, acidic soils.

Rounding the top of a knoll, we look down on an expanse of tundra that bristles with so many sensors and cables that it resembles an outdoor ICU ward. At the center of the site stands a gas-sensing tower that sniffs out the carbon dioxide drifting through the air from as far away as a quarter of a mile. At ground level, polycarbonate chambers placed atop the tundra whoosh as their tops periodically shut, then open, then shut again. Their job, I learn, is to trap the carbon dioxide rising from the surface and shunt it to an instrument that measures the amount.

Ted Schuur with his permafrost research monitoring equipment at Eight Mile Lake study area, near Healey, Alaska. Schuur mimics conditions expected in the future to monitor how much carbon will be released in a warmer future Alaska.
Thomas Nash

The objective is to keep a running tally of CO2 as it’s inhaled and exhaled by plants and soil microbes, but not merely in the here and now. By artificially warming selected patches of tundra, Schuur’s open-air experiment aims to mimic the future, when air temperatures in Alaska are expected to be significantly higher. By 2100, the state is projected to see an additional warming of at least 4 to 5 degrees Fahrenheit over what’s already occurred, and that’s under the most optimistic scenario. Already, the tundra here is leaking carbon dioxide to the atmosphere, according to recent satellite-based measurements. The question Schuur is hoping to answer: As the region continues to warm, just how much more carbon dioxide will it contribute to the global pool?

Along with terrestrial and aquatic plants, the soil microbes that decompose organic matter are major players in the global carbon cycle. In the lingo of climate science, plants are “sinks” for carbon. Through the sunlight-driven process of photosynthesis, they lock up more carbon dioxide than they release, thus keeping it out of the atmosphere. By contrast, soil microbes that decompose organic matter are “sources” that burp out micro-bubbles of CO2 night and day, winter and summer.

Schuur draws my attention to the stack of drift-catching snow fences that, come October, researchers will array around half a dozen experimental plots, then laboriously remove again in April. Snow is an excellent insulator, he explains: “It’s like a giant blanket.” Beneath the drifts, Schuur and his colleagues have found, the ground can stay a good 3 to 4 degrees Fahrenheit warmer than it does in the unfenced control plots, thereby accelerating the warming that occurs in spring.

The impacts of this manipulation are many. Triggered by the extra warmth, subsidence caused by slumping permafrost has lowered the surface of the experimental plots by several feet. The depth to which the soil thaws at the end of summer has likewise increased, indicating that the top layer of what used to be permafrost has added more organic matter to the microbial dining table.

Most dramatic of all is the speed-up in the carbon cycle that Schuur and his colleagues have observed. Plants in the experimental plots grow faster, and sop up more carbon dioxide, than do plants in the cooler control plots. Soil microbes in the experimental plots have likewise increased their metabolic rate. But plants lock up carbon only during the growing season, whereas microbial activity continues year round. On an annual basis, the CO2 microbes release more than offsets the amount removed by plants.

Given the present rate of temperature rise, the imbalance between plant uptake and microbial release of CO2 may well grow. By the end of the century, Schuur says, the amount of carbon the world’s permafrost zone transfers to the atmosphere each year could be in the range of 1 billion tons, comparable to the present-day emissions of Germany or Japan.

Still unaccounted for, though, is the significant amount of carbon that appears to have vanished from underlying soils — about 20 times the amount Schuur and his colleagues have detected in the air. “Wow,” Schuur remembers saying to himself when he realized the size of the discrepancy. “This is a surprise.” Perhaps water seeping downslope is ferrying the missing carbon into streams, rivers and lakes, including Eight Mile Lake, or shunting it to swampy, oxygen-poor pockets of soil ruled by microbes that convert carbon to methane.

How much of the carbon coming out of permafrost will be transformed into methane? That’s another question Schuur is starting to tackle, for while methane is less abundant than CO2, it has 30 times the heat-trapping power over the course of a century. On the way back to the car, Schuur points out a clump of cotton grass whose partly hollow stems pipe methane into the atmosphere. “What matters is not that carbon goes in and out,” he says. “The important question is, what’s the net effect?”  

J. Madeleine Nash is a San Francisco-based science writer who frequently covers climate issues.

NewTowncarShare News Classifieds
  • Position Summary: Western Resource Advocates seeks a passionate Water Policy Analyst with knowledge of western water issues to join our Healthy Rivers Team to strengthen...
  • 9+ acre inholding. Passive solar strawbale off the grid and next to the Continental Divide Trail in ponderosa pine/doug fir forest at 7400.
  • Conservation nonprofit Friends of Cedar Mesa in Bluff, Utah is hiring an Education Center Director to oversee the operation of the Bears Ears Education Center....
  • Friends of the Verde River, Cottonwood, AZ. Apply at https://verderiver.org/employment-opportunities/
  • Verde River Exchange - Friends of the Verde River, Cottonwood, AZ. Apply at https://verderiver.org/employment-opportunities/
  • Teton County Planning & Building is hiring! Our ideal candidate is a team-player, a problem-solver, pays attention to detail, and can clearly communicate technical material...
  • Studio Architects is seeking a full time Architectural drafts-person/project manager with1-3 years of experience to join our firm. At Studio Architects our mission is to...
  • needed for 16,000+ acre conservation property in south central Colorado. Qualified candidate would have experience working on a ranch or wilderness property, general forestry/fire management...
  • Nanny for 18-mnth-old. Yearly salary, vacation, health insurance. Spanish/other foreign-language native spkr prefrrd.
  • Washington Association of Land Trusts seeks an ED to build on WALTs significant success & to lead the association to new levels of achievement. See...
  • Secluded, energy efficient Southwestern home on 40 wooded acres. Broker - Rand Porter - United Country Real Colorado Properties. 970-261-1248, $425K
  • 57 acres in Skull Valley, AZ, 17 miles from Prescott, year-round creek, swimming holes, secluded canyon, hiking/meditation trails, oaks, pines, garden, greenhouse. House, office building,...
  • Title: Public Lands Organizer About the Arizona Wildlife Federation (AWF) The AWF is a non-profit organization dedicated to educating, inspiring, and assisting individuals and organizations...
  • Historic 1893 Ranch Headquarters. 4 Bdrm, 3.5 Ba, 4000 ft2. Remodeled 2002. Includes 2 studio apts, stables, arena, workshop, 5 RV hookups. Chirachua & Peloncillo...
  • The Vice President of Retail Operations will provide overall leadership and accountability for purchasing, product development, merchandising planning, visual merchandising, retail operational excellence, oversight and...
  • Grand Staircase Escalante Partners seeks an experienced fundraiser with excellent communication and organizational skills.
  • position in Phoenix with the Babbitt Center for Land and Water Policy.
  • Vaulted ceilings, two fireplaces, two bedrooms, loft, jetted tub, wifi. Forest, mountain views. Wildlife. [email protected]
  • Our director is seeking to employ the services of an Accounting Clerk to assist with various accounting and administrative tasks. This is a great opportunity...
  • Community Radio Project, Cortez, CO (KSJD & the Sunflower Theatre). Visit ksjd.org and click on the Executive Director search link. CRP is an EOE.


 
также читайте gefest-sv.kiev.ua

наливные полы

у нас www.nl.ua