![]() |
Photo courtesy of Skye Sturm |
Characterized by vast amounts of carbon stored in permafrost and a rapidly evolving landscape, the Arctic is an important focal point for the study of climate change. These are sensitive systems, yet the mechanisms responsible for those sensitivities remain poorly understood and inadequately represented in Earth System Models. The NGEE Arctic project seeks to reduce uncertainty in climate prediction by better understanding critical land-atmosphere feedbacks in terrestrial ecosystems of Alaska.
Monday, July 1, 2013
North Slope students experience science first hand…
Alessio Gusmeroli has a passion for science, and this week
he gets to put that boundless enthusiasm into practice as he interacts with
students on the North Slope of Alaska. I have worked with Alessio now for
several years as part of the NGEE Arctic project and he is not your typical
quiet scientist, he is full of energy and ready to talk to anyone about
the Arctic. Alessio has the experience necessary to discuss the snow science,
glaciology, permafrost dynamics in a changing world, and just about anything
else that just happens to exist at temperatures below the freezing point.
Alessio is a post-doctoral research associate at the
International Arctic Research Center (IARC) at the University of Alaska
Fairbanks. This week he is working in collaboration with the local community college in Barrow (Ilisagvik College) as they host a summer
camp for North Slope Residents, 7th-8th graders. The camp has 10 kids,
from different villages across the North Slope; including Barrow, Point Hope,
Point Lay, Wainwright and White Mountain. The camp is called Nuna, which is the
Inupiat word for Earth. Alessio and others involved in the camp will do
numerous activities in the coming days focused on the Earth as a whole, from
mountains to sea, from glaciers to permafrost, from people to animals and
plants. Day 1 was, according to Alessio, fun and everyone enjoyed
celebrating their success on the gravel beaches of Barrow.
Friday, June 28, 2013
Final thoughts from the tundra...
It has been a long, but productive and enjoyable trip to
Alaska. In the last 10 days, we've landed in Prudhoe Bay and driven south on the
Dalton Highway; we've learned about the Toolik Lake field station in Interior
Alaska and benefited from insights from our NSF-sponsored colleagues; we've
flown beyond the Arctic Circle and worked in Barrow on the North Slope; and
we've conducted field research outside of Nome on the Seward Peninsula. That
covers a tremendous north-south gradient in latitudes and reinforces the great
diversity of terrestrial ecosystems in Alaska.
Experiencing that diversity first-hand and in a timeframe
that spans slightly more than a week emphasizes the many challenges we face in
modeling important feedbacks between Arctic ecosystems and climate. We must
take measurements to inform models of current climates and also do so such that
we can represent model-based predictions of future climates. This is not be
easy undertaking, but it is an important one if we are to improve climate
simulations and potential impacts of future climates on what we believe are
globally important, sensitive, and poorly understood high-latitude ecosystems.
This is both the challenge and the opportunity being tackled by the NGEE Arctic
team.
As we depart Anchorage, bound for Knoxville, I upload the
following pictures for what has been a rewarding trip to Alaska. My thanks to
Rich, Dan, Guido, Victoria, Santonu, and Jenny; we had our share of long days
and late nights. By the way, I'll be back in Barrow in two weeks; keep an eye
out and an ear open for more thoughts from the tundra...
Third day is a charm...
Our first two days in Nome consisted of warm temperatures
and clear skies. Today's forecast shows no change in temperature, but a
possible chance of rain in the afternoon. Weather in Alaska, particularly along
the coast, is hard to predict so we left Nome prepared for whatever conditions
Mother Nature had in store for us. We knew that mosquitoes would be part of the
forecast, that we could definitely count on!
Our group got together last night and looked over a
series of satellite images that Santonu had prepared and brought with him.
After some discussion, it was decided that we would visit a more recent drained
thaw lake basin along the Kougarok Road. The lake basins we worked at earlier
in the week were, according to Guido, several thousand years old. The basin
that we had picked out for today was much younger; in aerial images it showed
up as a wetland in the 1950s, a lake in the 1970's, and then drained just
within the last 5 years. This meant that it was a good analog for what might be
expected in a changing climate. That is, a landscape in transition at time scales
relevant for inclusion in climate models.
We arrived at the site mid-morning and went about our
routine. Jenny and Guido quickly set up the GPS base station, while the rest of
us walked a short distance across the tundra to the basin of interest. What we
found was a basin 150 to 200 meters in diameter. The basin was 5 to 10 meters below
that of the surrounding tundra. Guido mentioned that the lake most likely
drained when the down-slope rim for the basin was breached by high water and
set-up conditions favorable for thermal erosion. Indeed, when we walked down to
that area, there was strong evidence of a deep thermal gully running out into
the tundra. The basin itself was dotted with small ponds several meters in
diameter and large rounded mounds that were rich in peat. These mounds were
exceptionally dry and plant mortality was severe. In some cases, large areas
were completely lacking live vegetation. This was similar to what we see in
terms of vegetation dynamics on high-centered polygons in Barrow.
As we had in previous days ,we laid out transects and
began collecting data. Guido was curious about the ponds within this basin and
started mapping their location. Although polygonal structures within the basin
were only weakly visible, the ponds to my eye were mostly in trough
intersections. Guido probed a little to determine their depth and they were
maybe on average a meter deep. However, in one there was a much deeper area
that ran lengthwise across the pond, leading Guido to speculate that this could
be an area were the underlying ice-wedge had melted. In some cases the water
was actively running through these areas and in others the ponds were static.
In the latter case, the water was 13 to 15C, warm enough to certainly contribute
to a deepening or expansion of these ponds. The surface and subsurface
interactions are undoubtedly strong in these young and changing drained thaw
lake basins. Since our team has such a good geophysical characterization
capability, this is something that we are interested in pursuing further.
Having worked hard, we left the field today very
satisfied with what we had seen and accomplished. It did rain, but not enough
to stop our work for very long. The topic of discussion over dinner was whether
we could locate any more of the young basins along either the Kougarok or
Council Roads out of Nome. Guido, Dan, and Santonu were going to take a more
extensive look at their maps and see. Last year, we saw small drained lake
basins out the road to Council and Larry Hinzman, Chief Scientist for the NGEE
Arctic project, has studied several "disappearing lakes" in this
region over the last decade. Whether these lakes drain due to surface water
drainage in continuous permafrost like the one we saw today or more subtle
connection to groundwater in areas of discontinuous permafrost like Council
would be an interesting research question. If such features become more
prevalent in the future because of regional warming, then they represent
processes that could be incorporated into climate models for improved
predictions. This is, of course, the goal of our project.
Thursday, June 27, 2013
A second day out Kougarok Road...
This morning we drove back out the Kougarok Road to begin
our day. The drive was not as long as yesterday; we reached our destination
after 64 miles. According to Guido, this was his Site 5 and it also represented a
drained lake basin similar to the one we previously worked at further down the road. This
feature, however, was smaller with a more abrupt transition from upland to
basin. The transition area was dense with woody shrubs, while the basin was wet
and contained a variety of sedges and grasses.
Our trips out the Kougarok Road required us to stop this morning at the Bonanza Express for fuel. Because gas is brought in
on barges each year the price of fuel in Nome is generally high. Gas in Barrow
is also expensive; slightly more on average than Nome.
Guido established this site not too long ago and, unlike
the other sites, this one is instrumented with a tripod-mounted weather station
where air and soil temperatures are monitored, along with radiation and
relative humidity. Data is logged, stored, and then uploaded via a satellite
weekly. There is also a 4.5 meter borehole nearby that allows an accurate
record of temperatures below-ground to be obtained. This is important when
working in these environments. In looking at this installation, one cannot help
but see that all wires and cables are housed within flexible conduit. This
protects the cables from being chewed on by rodents and foxes. Damage like this
can be a big problem for remote instrument locations, and we have experienced
instrument failures in Barrow for just this reason.
Once we got our bearings and examined the general area, we
laid out transects like yesterday. We had a good routine and everyone knew
their job. Victoria set up vegetation plots and conducted plant composition
surveys; Jenny and Santonu started gathering data with the ASD
specroradiometer; Guido and Dan marked all locations with dGPS; and Rich and I
harvested the vegetation plots. Harvesting the small plots was a little harder
than it was yesterday thanks in large part to the presence of woody shrubs,
mostly Betula.
One thing that was new today was our goal of inserting
ion exchange resins into the soil to get a sense for nutrient availability in
the various areas along the transect. Rich and Victoria have used a commercial
"Plant Root Simulator" or PRS probe for this purpose last year in
Barrow with good results and wanted to try them at Site 5 as well. The PRS
probes comes with a membrane that contains either an anion or cation exchange
resin. Probes are installed in the ground, you then can come back in several
months and remove them for analysis. You can specify the nutrients to be
analyzed, but we will certainly want estimates of NO3- and NH4+ availability.
We will be back later in the summer to recover these probes.
Wednesday, June 26, 2013
Out of Nome on the Kougarok Road...
Rich, Victoria, Jenny, and I arrived in Nome yesterday
after a short flight from Anchorage. We gathered up our luggage, flagged down a
taxi, and made our way several miles out of town to housing that Rich had
arranged for us at "Dredge No. 7". The name echoes back to the gold
mining days of the early 1990's when miners would use mechanized dredges to
search for gold in the streams and small rivers around this area of the Seward
Peninsula. That gold rush continues today in the Horton Sound (Bering Sea) where
floating "dredges" literally vacuum gold from the sea floor. The
influx of modern-day miners is making it difficult to find housing in Nome.
We had traveled to Nome to work with colleagues from the
Oak Ridge National Laboratory and University of Alaska Fairbanks. Our goal was
to conduct a series of surveys across thermokarst formations, thaw slumps, and
much like we did in Barrow, drained thaw lake basins. We met up with Dan,
Santonu, and Guido shortly after breakfast and made our way out of town on the
Koukarok Road. This is one of three roads leading out of Nome. The road is
dotted with summer cabins and used mostly by bird watchers who frequent this
area throughout the season. It is also a favorite road for scientists like us
who want quick access to the tundra for studies in both continuous and
discontinuous permafrost ecosystems
Once transects were laid out, Santonu and Jenny collected
spectral signatures of several plots of different sizes using a back-pack
mounted ASD spectroradiometer. This instrument collects data across a wide
range of wavelengths and allows researchers to compare ground-based
measurements to remote imagery of the type collected by NASA satellites. By the
end of the day, Jenny and Santonu had worked out a good routine for capturing
spectral information; I look forward to seeing the data, especially how it
varies across species composition.
While Jenny and Santonu collected spectral data with the
ASD system, the rest of us gathered other kinds of data. Victoria determined
species composition for the various plots; Rich measured thaw depth, soil
temperature, and water content; and Dan and I clipped plots for standing
biomass. Guido has a long history of conducting research in drained lake basins
and wanted to know something about permafrost characteristics and depth of
organic matter. He worked hard to obtain one soil core from an upland location
and one from the basin itself. He used a SIPRE coring device and a hand-held
motor. We were able to extract an intact core down to 1.8 meters for the basin
area. This core was rich in peat throughout the entire length of the sample.
It was a good first day and we accomplished a lot. Given
the long drive out the Kougarok Road we were also able to see a lot of scenery
and wildlife; several moose and their calves; a Peregrine falcon and its nest;
fish for various kinds (including Grayling) as we crossed numerous bridges along
the road; and then a diversity of wild flowers.
Tuesday, June 25, 2013
A walk across a drained thaw lake basin...
Participants in the NGEE Arctic project are interested in
better understanding feedbacks between ecosystems and climate. These feedbacks,
both negative and positive, can arise through changes in the flux of CO2 and
methane to and from the atmosphere. One of the factors that drive carbon cycle
processes in the Arctic is the distribution of water across the landscape. Our
team began exploring this dynamic last year across a series of inter-connected
low- and high-centered polygons on the BEO. Those studies are going well and we
have made significant progress in gathering the process knowledge required to
inform a range of models from the individual polygon to climate grid cells.
Another important feature of Arctic landscapes that
drives carbon, water, and energy-related dynamics is the presence of drained
thaw lake basins (DTLBs) across the coastal plain. These occupy a large portion
of the land surface and are known to be of various ages (e.g., young to
ancient), each with unique soil and vegetation characteristics. The NGEE Arctic
project will begin to study these this year in an area just south of the BEO.
We laid out transects using LiDAR data, courtesy of Craig Tweedie, and a site
visit in April. However, we had not seen this area in a snow-free condition. That
was our goal today.
Rich, Victoria, Bryan, Gus, and I drove along the west
edge of the BEO before turning east and then south again on a road that goes to
the gravel pit. We stopped just before the entrance to the gravel pit and
headed across the tundra to our west. Our map, an original product of Ken
Hinkel at the University of Cincinnati and his colleagues, showed that we would
walk first across an old DTLB and then up and over a slight ridge to a DTLB
that was considerably younger. The old DTLB was wetter, polygons were filled
with water, and in some areas were beginning to coalesce into larger bodies of
water. Gus confirmed that this was a feature of the admittedly poorly
understood life cycle of DTLBs. By comparison, the younger DTLB had a quite different
composition of vegetation and lacked any well-define polygonal structure or
ponding water.
Our team will lay out a sampling transect across this area and begin a series of measurement campaigns in early July. Our goal is to assess CO2 and methane exchange, and energy budgets, across the various DTLBs and relate those potential differences to soil water content, degree of inundation, soil temperature, and vegetation. All this information will be useful as we add new insights about landscape feedbacks to climate models.
Monday, June 24, 2013
Friday flashbacks...
One of the unanticipated benefits of having Gus Shaver
visit Barrow and interact with our NGEE Arctic team is the fact that he worked
here in the early- to mid-1970's. Gus has conducted a lot of interesting,
excellent research in his career. He started working in the Arctic as a
young scientist with the International Biological Program (IBP). The IBP was a
large, multi-investigator effort between 1964 and 1974 which coordinated
large-scale ecological and environmental studies. One early aspect of work that
Gus enjoyed as part of the IBP team, and for which he is well known, was his
characterization of roots in various arctic plant species. This research took
place just south of Barrow. Our team has driven past this site many times on
the way to the Barrow Environmental Observatory (BEO) and we had never stopped.
Today, we pulled off the road at a place Gus recommended and walked a short
distance onto the tundra. As Rich, Victoria, Gus, and I walked, Gus talked
about his research. He pointed out the location of several experiments and
mentioned the changes that had taken place in the landscape over the last 45
years. He talked about the stream that ran through this area and how in the
1970's he had examined exposed ice wedges along the stream bank. The stream now
is wider than he remembered with steeper, more degraded embankments.
As we walked, Gus began looking for what he called
"root boxes". These were boxes have wooden sides with plastic front
and backs. Tundra vegetation was excavated, placed carefully into these boxes,
and inserted back into the soil. The idea was that the wooden boxes could be
periodically removed and the growth of roots examined through the clear plastic
windows. After some looking, we found one, then two, and before long we had
located his original plots. The thermocouples that had been inserted into each
box were still visible. Victoria was particularly keen to talk to Gus about
this work. It was agreed that although a simple approach, the data that came
from those wooden boxes is still some of the most complete information on root
growth and structure for plants on the North Slope. Victoria is conducting
research on plant roots in polygonal landscapes as part of the NGEE Arctic
project and plans to revisit these boxes later in the year and see if any roots
can be observed. It is hoped that a better understanding of root traits can
improve our description of plant functional types.
We walked back to the van and drove the remaining
distance to the BEO parking area. As we walked along the boardwalk, Gus was
reminded that the small "greenhouses" in the distance were part of an
educational effort that he and others had initiated several years ago. These
structures were placed over tundra vegetation and essentially raised the air
and soil temperature throughout the season. Teachers from the local elementary,
middle, and high schools would bring students out to the site. They would then
talk about climate, climate change, and how increased temperatures could potentially
impact local vegetation. I participated in one of these tours last fall and
these simple structures are a good "show and tell" opportunity for
educators. It was also a good local outreach activity for participants in the
NGEE Arctic project. Thanks Gus!
Subscribe to:
Posts (Atom)