Bear Bog and Gold Mine are two locations of particular interest. Analysis of both areas provides greater insight regarding prior vegetation, climate changes and life after deglaciation of the area. After macrofossil analysis of Bear Bog there is a notable progression in the history of the bog. Through the study of macrofossils, we can clearly see that this area was once a lake as determined from the aquatics. It then became a sedge fen or bog, and finally as trees surrounded the area it became a bog. This transition is indicated by the presence of Andromeda polifolia, a heath, that can only be found in bogs.

Previous studies suggest that the rate of carbon storage in Alaskan peatlands was higher when the bogs were younger. “Between 11,500 and 8,600 years ago, each square meter of peatland accumulated about 20 grams of carbon each year on average, Yu and Jones find. More recently, since 8,600 years ago, the average annual rate of carbon sequestration has been only 5 grams per square meter [Perkins 2010].” Warmer summers and cooler winters actually contribute to and promote carbon accumulation during the earlier times.

Future studies should focus on containing or reversing the loss of peatlands and subsequent damage. There are still several LOI tests to be completed and Gold Mine has yet to be analyzed. The correlation between the Aleutian Low and these specific sites has yet to be defined.

Global warming and the future of the Earth’s carbon cycle are at the forefront of many controversial debates today. Studying carbon accumulation in peatland core samples can help us reconstruct past climate. A four meter core spanning 11,000 years was collected from Bear Bog near Cordova, Alaska in July 2010. This location is of particular interest because it is potentially sensitive to future changes in climate. Another core was collected from Goldmine, near Fairbanks Alaska. The Bear Bog core was analyzed using Loss on Ignition (LOI), a technique used to measure the particular amount of combustible organic material in a given sample and is closely related to the carbon content of the peat, and macrofossils, visible plant remains (seeds, needles, etc) which serve as indicators of changes in vegetation, which are also directly related to climate changes. LOI samples were taken every 2 cm, and macrofossils were analyzed every 10 cm. Through the study of macrofossils and LOI, a record of both climate and carbon sequestration is under development at both sites. We hypothesize that carbon accumulation is strongly controlled by climate, such as abundance of available sunlight and precipitation. The study of this bog and other wetlands throughout Alaska will aid in understanding the Aleutian Low, a semi-permanent low pressure over the North Pacific ocean, which is responsible for the production of most of the precipitation in the Northern Hemisphere, and especially in the western areas. Consideration of carbon accumulation and changes in vegetation will allow for an adequate reconstruction of a climate focused timeline, as well as an understanding environments in Northern and Southern Alaska. Bear Bog and Gold Mine are two sites of three to be used in a study of a south to north transect of Alaskan peatlands.

 Peat is composed of partially

decayed plants that grew on what was once surface. Peatlands provide significant information regarding past climate and they temporarily contain and sequester substantial amounts of carbon [Clymo et al. 1998]. It is believed that peatlands sequester nearly 500 billion metric tons of carbon, keeping harmful greenhouse gas from escaping into the already compromised atmosphere. Annually, compromised and degraded peatlands are responsible for emitting three billion tons of carbon dioxide, globally. This degradation is often a result of human activity. Figure 1:

Fairbanks and Cordova, AK are the sites of Gold Mine and Bear Bog respectfully.

Loss on Ignition (LOI)Loss on Ignition is an analytical chemistry technique primarily used in the analysis of sediment to determine the abundance of organic matter. LOI can be useful in compiling a climate history based in carbon sequestration. The samples were weighed and dried overnight. The mass was then measured a second time after burning for an hour at 550 C. The remaining mass is the inorganic fraction. The organic matter is the portion lost through burning.

1

2

Sponsors:National Aeronautics and Space Administration (NASA)NASA Goddard Space Flight Center (GSFC)NASA Goddard Institute for Space Studies (GISS)NASA New York City Research Initiative (NYCRI)

Contributors:Dorothy Peteet (P.I.)Jonathan Nichols (Post-Doctorate Researcher)Argie Miller (HS Teacher)Alicia McGeachy (NYCRI Undergraduate Research Apprentice)Max Perez ( NYCRI Research Apprentice )

A four-meter core was collected in Bear Bog, a site near Cordova, AK. The cores were designated by drives. The first two drives of the five drives were analyzed using LOI testing and Macrofossil analysis. The total depth of the first two drives is 138 cm. Volumetric samples were taken every 2-cm and used in LOI analysis. For macrofossil analysis, 1-cm samples were taken every 10-cm. These samples were hydrated and refrigerated. Each sample was washed through two screens with openings of 150 and 500 microns.

Macrofossil samples were analyzed in water using a microscope. For each sample we picked identifiable seeds, needles, etc that could later be identified. These sub-samples contained sphagnum moss, seeds, needles and insect remains.

Figure 2: The graph above shows the Loss on Ignition data from the first two drives (138cm total) of the core from Bear Bog near Cordova, Alaska. The graph is skewed to make a visual representation of the makeup of the core; the top of the core is at zero on the X axis while the Y axis shows the amount of organic content lost (%LOI). Although the organic content does not change much in the past few thousand years (The full core is ~5 meters and dated at around 9000 years old at the bottom), there are a few dips in the organic content. This could be caused by a warmer, drier climate where plants could not survive as much, or a sudden influx of inorganic content such as metals and minerals from a dust storm.

Figure 3: Above is a graph created in Tilia. The graph can be divided into three zones. Zone 1 spans a depth of 293.5-344 cm, Zone 2, 157-284.5cm and Zone 3 9-148-cm. Macrofossils from Zone 1 indicate that the site was a lake populated with alder. In Zone 2, there is a progression from a lake to a bog or fen populated with sedges. A fen is usually neutral or alkaline in nature. Zone 3 is indicative of a bog within a forest and this phase persists today. The area is populated with Andromeda polifolia (Bog-rosemary), Vaccinium uliginosum (Bog-Blueberry) and Empetrum nigrum (Black crowberry).

0

50

100

150

200

250

300

350

De

pth

Picea

sitch

ensis

seed

Picea

sitch

ensis

nee

dle

Tsuga

het

erop

hylla

nee

dle

Tsuga

mer

tens

iana

need

le

Alnus s

eed

20

Alnus b

ract

Vaccin

ium u

ligino

sum

leaf

Andro

med

a po

lifolia

leaf

Andro

med

a po

lifolia

seed

Empe

trum

Nigr

um le

af

Carex

trigo

nous

Carex

lent

icular

Viola

seed

Men

yant

hes s

eed

Potam

oget

on se

ed

Nupha

r see

d

Sphag

num

Bryoz

oan

Stato

blast

Mite

sBet

tle P

arts

Other

Mos

s

Lake with Alder

Sedge Fen

Bog with Conifers

Figure 1b (From left to right):1.Sphagnum is a type of moss that makes up a large majority of the mosses found in peat bogs. Sphagnum moss plays an important role in the shape and purpose of peat bogs and marshes by uptaking certain minerals such as calcium and magnesium, as well as preserving the cores; the high amounts of water within the sphagnum itself creates anaerobic environments and therefore retard decay.2.Sedge is a family of grass- like or rush-like herbs. The genus name for the sedges identified is Carex. 3.Andromeda polifolia, or Bog- rosemary is common to acidic habitats, such as bogs, or lake shores in cooler regions.

Carbon Accumulation in Peatland R. S. Clymo, J. Turunen and K. Tolonen OikosVol. 81, No. 2 (Mar., 1998), pp. 368-388Published by: Blackwell Publishing on behalf of Nordic Society OikosArticle Stable URL: http://www.jstor.org/stable/3547057

http://plants.usda.gov/java/