In order to fully understand the Deep Roots experiment, there are a few things to review about plants (and how the Arctic places limits on plant growth). Sure, we all know the basic parts of a plant – roots, shoots, leaves – and we also know that plants require sunlight and CO2 to make glucose (photosynthesis). But there’s a little more to it then that.

    Plant growth in the tundra

    The glucose created by photosynthesis is used for building structures like stems, leaves, flowers, and, of course, roots. But just like in other living things, plants need more than just Carbon, Oxygen and Hydrogen to build structures; Nitrogen and Phosphorous are fundamental to the structure of DNA and proteins, which is why a lot of commercially abundant plant fertilizer is saturated with N and P. And if you’ve ever applied fertilizer, you know that you apply it to the soil – because it’s the roots that take up those minerals to promote the plant’s growth.

    Fertilizer ingredients
    A list of ingredients from commercially available organic fertilizer, note that the two main ingredients are Nitrogen and Phosphorous. Source: AGgrand.com

    All organisms build structures as they grow, but plants are limited by the amount sunlight they have access to (just like animals are limited by the amount of food they ingest). In the high Arctic, there is no sunlight for nearly half of the year, so plants must adapt to this limitation accordingly. Common adaptations across the tundra include being fairly low to the ground (it takes a lot of time and energy to grow tall), small waxy leaves (to minimize water loss) and growing close together (to help insulate and offer protection against high winds).

    Tundra flowers
    Bright tundra flowers in the height of summer. Notice how close to the ground the flowers are.

    Tundra carpet
    A fairly typical shot of open tundra. Note how close together the plants are, sort of like a carpet.

    Waxy
    Typical tundra plant leaf, notice how shiny and waxy the outer covering is.

    In addition to the lack of sunlight, these plants also have to deal with a unique soil type – permafrost. PermafrostPermanently frozen ground., commonly called “Earth’s Freezer” is soil (and whatever dead organic material is in that soil) that remains permanently frozen throughout the year – and can remain frozen for thousands of years. This means that the permafrost layer is a storehouse of some of those vital elements to plants – particularly Carbon and Nitrogen.

    The layer of soil above the icy permafrost, the active layer, is the layer where plants can put down roots and grow. The depth of the ice layer can vary along the tundra due to many factors (which scientists are still trying to understand), so the depth of the active layer and plant roots can vary as well.

    Thaw depth
    The thaw depth of soil is measured to see how deep the permafrost is below the active layer.

    Tundra brownie
    A tundra soil monolith showing the dense network of roots in the organic soil layer.

    Deep roots
    An extreme close up of some very fine roots found within a soil monolith.

    Deep Roots

    Since the name of this project is Deep Roots it’s pretty obvious that the team wants to understand the root structure of these tundra ecosystems. To do this, there are several questions that need to be examined. Below are just a few of the questions that the team is investigating:

    1. What types of plants are putting down roots in the tundra?

    2. How deep are different types of roots throughout the active layer?

    3. What microorganisms (fungi) live on the root systems of some of these plants?

    4. How quickly does Nitrogen move through a plant’s system and where does it ultimately “end up?”

    5. How will a warmed environment have an effect on questions 1-4? Will it have an effect at all?

    6. If warmed environments DO show different answers to any of these questions, what predictions could we make in light of our changing climate?

    Keep reading my journals as I attempt to explain how the research team is collecting data to try and answer some of these questions!

    Setting up the experiment
    Just why is this frame being placed over the Alaskan tundra? It’s part of the experiment!

    Author
    Date
    Location
    Toolik Field Station
    Expedition
    Weather Summary
    Foggy and chilly
    Temperature
    50F

    Comments

    sandeep bijoy

    where do the wax of the leafs come from. Do they naturally generate from the organic material they already have or they get the wax coating by collecting the organic matter over time and cover the leaf with.

    Susan Steiner

    great heads up reminder about the essential elements for plants found in fertilizer are super important for DNA and making proteins.I wonder if the plants that have the deeper roots are better at battling permafrost, and if so, they would be adversely affected by a deeper active layer?

    Kylie Malone

    Hi, I'm Kylie and I see that all different plants need the CO2 and all the other things. They have to grow to grow healthy. I want to know if their are certain plants that can defeat or fight the permafrost there? I also want to know do the roots of the plants freeze in the ground?

    Lennox Lyles

    what's the average height for a plant in the arctic and how long does it take to fully grow compared to a plant the has more access to sunlight

    Nell Kemp

    Exactly what the team is trying to find out! We've been plucking leaves & roots for the past 2 days which will eventually get analyzed to see if the labeled 15N made it into the plant (and also how deep the roots penetrate) which will hopefully help climate modelers predict if plants will be able to access the nutrients at the permafrost thaws, which could (potentially) lead to a deceleration of that CO2 feedback loop...

    Nell Kemp

    Hi Kylie,I just wrote a journal about some of the different plants up here, and while none of them can “beat” the permafrost, they definitely have unique adaptations that help them to survive this environment. Remember that the permafrost is about 1-2 feet beneath the layer of soil where the plants grow (the active layer). The roots don’t freeze because the winter snow acts as a layer of insulation on that active layer to keep it warm enough (although still pretty cold) for life to keep going during those cold, dark winter months.

    Nell Kemp

    The plants in the tundra vary in height, but none of them get much taller than a few feet high (some of the shrubs can get to 4-5 feet if they are close to a stream/river or on the side of the road benefiting from run-off). It takes a few years for the shrubs to get that tall, but everything else grows to their maximum height in about 1-2 seasons. I just posted a journal about the tundra plants, so feel free to ask more questions after reading!

    Kevin A.

    1. As a botanical photographer I would really like to go see where you are now because the picture of the flower is just really amazing to me2. If the plants grew a little taller, let's say 5 centimeters or so, would that drastically effect if they survive and/or how they look?

    Nell Kemp

    Hi Kevin,
    Maybe someday you can get up to the tundra - there are lots of ways to get here besides science! I agree that the flowers are amazing, which is why scientists want to understand what could happen to them as our climate changes. This is still a big question that scientists are trying to figure out - I'm not sure that anyone has the answer yet!

    Mark Buesing

    Around Toolik what is the range of depths of the active layer?

    Brian Pugh

    Hello Ms Kemp. Is there a small amount or large amount of sunlight because if I recall the arctic and antarctic have half of the year 24 hrs of sunlight and the other half having 24 hrs of darkness.

    Nell Kemp

    The active layer depths really range around Toolik - we sampled some as shallow as 37cm and some as deep as 83cm, but I'd say a lot fall in the 50-70cm range.

    Nell Kemp

    Hi Brian,
    At this time of the year, the Arctic is receiving close to 24 hours of sunlight. In the last week at the field station, the sun would "set" around 10:30-11pm and it would be dark at midnight - we got to see the moon before we left! I'm not sure what time the sun rises, but I'd say it's probably between 2-4 am.

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