decomposition of ancient organic carbon: a scientific
Ning Zeng, Project Scientist, Associate
Jay Gregg, Junior Scientist,
Email contact: email@example.com
expedition to King George Island (KGI),
The expedition was part of a summer school organized in conjunction with the International Polar Year (IPY) 2007-2010. The IPY is a international effort to foster collaborative research in the polar regions of the Earth. The first IPY was from 1882-1883, the second from 1932-1933. This research comes at the tail end of the third IPY, the goal of which was to increase our knowledge of the poles, how they are changing, and to better understand the influence of the poles on the global climate system and vice-versa. The third IPY marks the largest international collaborative science effort since the International Geophysical Year 50 years prior.
project was conducted on
Because of the wildlife and the dynamic geology, many countries have established research stations (most of them operating year-round) on King George Island, including Argentina, Brazil, Chile, China, Ecuador, South Korea, Peru, Poland, Russia, and Uruguay. Research for this project was conducted from the Russian Bellingshausen station, though the field sites were near the edge of the Collins glacier near the glacial moraine.
Trip to/from and around KGI
We spent the first three days on the island conducting reconnaissance hikes with experienced scientists and orienting ourselves with the environment. We learned the safety protocols when doing field research, the hazards of the island (snow swamps, slippery permafrost under a layer of mud, and its unpredictable and quickly changing weather. We also learned about the various wildlife on the island, safe distances to maintain, and sensitivity to the fragile flora in this environment. On these hikes, we discovered areas of particular interest in recently exposed glacial moraines at the edge of the Collins glacier. It is these areas that served as our field sites for this project.
Climate and Ice
three days, scouting hikes were conducted along the edge of
(Collins Glacier), guided by Russian glaciologist Bulat
edge is marked
with glacial moraines and nunataks (rock islands in ice). Over
decades, the edge of the ice cap has been retreating rapidly. A
50 meters away from the edge of the ice cap was under ice 20
consistent with the general warming in the region. The
Collins glacier and Bellingshausen dome in background. Moraine is in front of the glacier and a Nunatuk appears on the left side of dome.
temperature record shows that
the ice retreats, vegetation develops quickly on newly exposed
moss and grass grow on KGI. A transect perpendicular to the ice
Visual inspection showed no visible sign of vegetation in the
nearest to the ice edge. This is supported by a team from the
which measured the photosynthesis and respiration along the edge of the Collins glacier.
Moss vegetation near the coast of the
Sampling of organic carbon and CO2 measurement
one location north of
Jay Gregg set up the LICOR LI-8100 Automated Soil CO2 Flux System near Site 1.
A pile of moss layer (brown) exposed. Organic odor was clear.
Layered moraine outcrop: moss layers are brown, one layer above the spoon, one layer below. Shells (small white pieces) are above the lower moss layer. Exposed ice (permafrost) is white-blue at the lowest level, partly covered by loose fallen soil.
The moraine outcrop from distance; note the spoon as in the above picture.
Glacial outwash deposit, 50m downstream from the outcrop. Organic rich material including dead moss was present inside the deposit.
Results: CO2 measurement
CO2 flux measurements were conducted using the LI-8100 Automated Soil CO2 Flux System at Site 1. Two measurements, both immediately in front of the layered outcrop were conducted: one test spot had visible (dead) moss lumps on the surface, while the other had no visible moss. Tests showed discernable CO2 flux after the standard 3 minute collection time. The collection time was then increased to 30 min afterwards.
the LI-8100 Automated Soil CO2 Flux System were
LICOR File Viewer software, and further analyzed in Microsoft
calibrate the instrument to the background level of atmospheric
concentration (388.6 ppmv), data from the CO2
the King Seong Station (
Site 1, Spot 1, CO2 concentration in the chamber increased by 0.47 ppmv min-1, corresponding to a CO2 flux of 0.09 mmol m-2 sec-1.
Site 1, Spot 2, CO2 concentration in the chamber increased by 0.68 ppmv min-1, corresponding to a soil respiration CO2 flux of 0.15 mmol m-2 sec-1.
amounts of organic carbon in a glacial moraine outcrop and the
outwash were found at the front edge of Collins Glacier,
The measured CO2 flux was significant, indicating the comparatively rapid decomposition once the old carbon is exposed. There was no evidence of new vegetation growth around the outcrop where measurement was done. This indicates a relatively fresh exposure, possibly within last few seasons. These results are intriguing, suggesting that soil organisms (decomposers) are active within newly exposed soil from the glacial moraine. Whether they lie dormant under the ice for millennia, or they are newly transported to the area from somewhere else will be determined by carbon dating the soil. Further work will be undertaken to date the sample to understand the age and developmental history of the organic carbon.
We are most grateful to the financial support from the Wilderness Research Foundation, New York, and its president Sheldon Bart, without whose persistent effort, this work would not have been possible. We also gratefully acknowledge LICOR for supplying us the LICOR-8100 soil CO2 analyzer.
B. L., 2007: Late-Holocene advance of the Collins Ice Cap,
Zeng, N., 2003: Glacial-Interglacial Atmospheric CO2 Change--The Glacial Burial Hypothesis. Adv. Atmos. Sci., 20, 677-693.
Zeng, N., 2007:
Quasi-100ky glacial-interglacial cycles triggered by subglacial
burial carbon release. Climate of the Past, 135-153.
At Punta Arenas, Patagonia, I noticed that many plants, including conifer trees and small shrubs appear to be titled, or more precisely the leaves and branchs tend to be better developed on one side. This is in response to the prevailing winds. Over the growth of a tree, the strong winds in Patagoina forced the tree to grow asymmetrically. To put it another way, the flexible tree adapts itself to the strong wind.
This leads to an interesting possibility: the direction of the trees can be used as an indicator for local prevailing winds. In Patagonia, the strong winter winds mostly comes from the south, i.e., Antarctica. If the trees all tend to 'lean' in one direction, that will prove the above reasoning. A related conjecture is that the direction of tree leaning is not necessarily related to, e.g., annual average wind, but probably more to the strong wind which tends to be in the winter. This is not surprising as weak wind won't really influence the plants, but only really severe condition has impact. This is made clear later after I arrived at KGI, where we stayed in the guesthouse of the Russian Bellingshausen Station. The house is perched up a little hill where the wind is super strong, and we have to walk with our body bent against wind, sometimes at almost a 45 degree angle so that we don't get blown down. Of course, the direction of bending is the opposite of the trees leaning.
I plan to do some measurement with a compass on the way back from Antarctica so as to define the direction of the prevailing strong wind . This could provide an independent direction measure if we are lost in the dark, or we are confused about the direction of the Sun in the southern Hemisphere :-).
Blue vs white iceberg
The day after our arrival, Hans, a German biologist who studies penguins, seals and birds took us for a hike along the west coast of KGI. We saw icebergs floating off the shore. Most icebergs were white, but one or two were blue. Hans said that the blue icebergs are old ice, could be as old as thousands of years. I put on my physicist's hat and offer the following explanation.
White icebergs are relatively fresh snow, and the snow flakes/particles scatter sun light and appears white. Cloud, a collection of many many water droplets appears white for the same reason. Instead, old iceberg is compacted solid ice chunk. Sunlight penetrates into the ice and is reflected back. Light rays of different wavelengths have different refractivity, and blue light is more preferentially reflected back so that old iceberg appears blue. This is the same reason why ocean is blue.