Science

The Polaris Project team works on collaborative projects during the field course in Siberia. Traditional research experiences for undergraduates involve student helpers working on an established research project under a scientist. The Polaris Project takes a different approach by crafting small teams of undergraduates to work on projects they conceive and then refine with the help of the faculty. Some of our research projects are below and many have multimedia pieces that tell the research stories through still images and narration by the students working on the projects.

Uplands
The role of the boreal forest, or Taiga, in the global carbon cycle is hard to understand. The boreal forest is the world’s largest biome on land and plays an important part in the annual fluctuation of carbon dioxide in the atmosphere. The boreal region contains something like 30% of all the Earth’s terrestrial carbon. The ways that carbon might start to exchange with the atmosphere as the planet warms is extremely important to get right. We are trying to understand the role of forest fires in northeastern Siberia and the ways changes in fire frequency and abundance might lead to increased respiration in the soils. We are also interested in measuring the uptake of carbon by trees in the boreal region. For instance, have boreal trees been growing faster? If so, is it because of the increasing levels of carbon dioxide in the atmosphere or because of the increased temperatures?

Permafrost
The entire Kolyma River basin is underlain by permafrost, soil that is perennially frozen. Permafrost in this basin can be categorized into three layers: the active layer, the transitional layer, and the yedoma layer.  The active layer is a thin layer of soils between the surface and the top of the permafrost which thaws and refreezes.  The transitional layer is an old active layer that dates back to the Holocene optimum, a warm period some 5,000 years ago.  This layer has now become re-frozen.  The lowermost layer, yedoma, represents ancient soil deposits dating from the late Pleistocene era, over 10,000 years ago. 

Part of our work focused on how permafrost qualities change over both space and time.  First, we are comparing how the active layer differs across different landscapes, including lowlands, ridges, and tundra.  Second, we are comparing the composition of the three permafrost layers to determine if there have been changes in organic matter over time.  Finally, we are examining a potential connection between the active layer and water by testing what and how many nutrients are “picked up” by water passing through the active layer.

Wetlands

Soil is made up of old stuff. The carbon in arctic soils comes from the bodies of dead plants and animals. These organisms could have died yesterday or thousands of years ago. Arctic wetlands store large amounts of carbon because the high water content and low temperatures in the soil slow or halt the breakdown of this carbon. Frozen soil, or permafrost, thaws as the temperature increases. This triggers the decay of this previously frozen carbon, releasing CO2, which further contributes to climate warming and more permafrost thaw.
Students on the Polaris Project are measuring the carbon in soils and waters in wetlands at the bottom of drained lakes.  Although wetlands contain a relatively small proportion of a watershed’s soil, their slow decomposition rates and large amounts of soil carbon make them an important piece of the carbon puzzle. We are comparing wetland carbon numbers to the data collected in other parts of of the Kolyma system. Through this, we will gain an understanding of how much carbon that wetlands release into lakes and streams and how this will change as the arctic climate warms.

Lakes
Thermokarst lakes appear when ice-filled frozen soil thaws. These lakes have a strong influence on the environment through the release of greenhouse gases (like methane and carbon dioxide) to the atmosphere. One of the things we are looking at it is whether upland thermokarst lakes have different water properties than lowland floodplain lakes. Organisms in the lakes, mainly bacteria, may be found in different numbers depending on the chemistry of the lake water.  The amount of oxygen and basic nutrients controls the amount of life the lake can support.

Streams
Arctic streams carry water, soil, and decaying plants from forests and lakes to larger rivers and the Arctic Ocean. Plants and fallen trees restrict the flow of water through these small streams. Because the flow is sluggish, organisms in the stream—mainly bacteria—have time to eat the carbon in the soils and decaying plants. When organisms eat carbon, it is exhaled as carbon dioxide. Currently, no one understands how much carbon passes through streams and how much escapes to the atmosphere. We also don’t understand the role that nitrogen and phosphorous play in this process. Like a garden, these essential nutrients are required for the organisms to thrive.

We are performing experiments on six arctic streams to answer a few different important questions. Is energy for organisms in the stream provided by photosynthesis in the stream, or from plants that are deposited into the stream from the land? How much do barriers like plants and shrubs in the stream slow down the water? Are the organisms in the stream unable to break down dissolved energy sources because they are lacking nutrients like nitrogen and phosphorous? Understanding the answers to these three questions will allow us to better understand how arctic streams move carbon to the Arctic Ocean.

Invertebrates
Benthic macroinvertebrates are animals without a backbone large enough to be seen without a microscope that are found in the bottom of lakes or streams. They include insects, worms, snails, and spiders, and can act as indicators of freshwater ecosystem health.  The greater the population and diversity of critters, the healthier the ecosystem.  Habitats that are constantly changing or have an unfavorable environment might not contain many animals, or may have only a few species.

In the case of the flat Northeast Siberian landscape, many of the lakes are growing or shrinking depending on the state of the permafrost (frozen soil) underneath them. One of the things we are interested in is looking at how the animals differ from lake to lake.  To do so, we take samples of the top layer of sediment from each lake and sift through our sediment to find, collect, and identify each critter that we can see.  We also take water samples at each site in order to understand the water quality. Little prior research has been done about benthic macroinvertebrates in this region, and our data will provide a first snapshot against which future changes can be gauged.

Rivers
Water from uplands, streams, and rivers in the Kolyma River basin ultimately flows into the Arctic Ocean.  The path that the water takes is important. For instance, water that travels through a small meandering stream will take longer to get to the ocean compared to a large river. In addition, the composition of the water, such as the amount of organic matter it is carrying, varies depending on the length and type of the path.

We are studying the origin and change in carbon as it follows these pathways to the ocean. Living tissue is made up mainly of carbon. For example, a leaf from a tree falls into the water. When the leaf enters the water, bacteria and other small bugs begin to eat the carbon to get energy. The carbon can be exhaled as gas (carbon dioxide) or degraded into a different form of carbon that is harder for other organisms to eat. By the time carbon reaches the ocean, it is usually in a different form than when it first entered the water. The amount and type of carbon entering the ocean is important because it affects life from microscopic plants to bowhead whales.

Satellites

Lakes, streams and rivers cover much of the Arctic, making a landscape that is heavily influenced by water. The characteristics of these waters are largely unknown, leaving major gaps in our knowledge of the regional environment.
With the advent of satellites, we can look at lakes and rivers that have never been directly observed. However, before looking at unknown water bodies, we need ground measurements to interpret the satellite signals.We are measuring things like the clarity, color, and chemistry of lakes and streams in the Kolyma River basin. These properties are linked to the amount of carbon in the water that could eventually be released to the atmosphere as carbon dioxide, a greenhouse gas. If clarity, color, and chemistry of water bodies can be seen from space, we will be able to study much larger areas than could ever be sampled on the ground. This could lead us to a better understanding of how the entire landscape functions and how it is responding to climate change.