So just what is the Deep Roots team doing while we’re up here (or more scientifically, what is the experimental design)?

    Choosing a representative sample

    The tundra behind the field station represents tundra that is fairly typical of what is found here in the North Slope of Alaska. The land has been approved by the Bureau of Land Management for scientific use, so it’s just a matter of determining what plots are approved by the field station for the team and choosing a representative sample. For this experiment, there were 8 plots of tundra that were used (truly 16, as 8 plots were assessed after 24 hours and the other 8 will be assessed in 2017) – 4 greenhouse plots and 4 control plots (shade houses were not used, as the question is about what could happen in a warmed environment). A quadrat is placed over an area of land that is considered “standard” and flags are placed in areas that will receive an injection of Nitrogen-15 which will later be identified in different parts of the plant.

    Quadrat 1
    Drs. Hewitt and Genet lay down a quadrat on a control plot.

    Thaw Depth
    After a quadrat is placed in a greenhouse plot, the thaw depth is measured.

    Quadrat 2
    Colored flags are placed within the quadrat to mark the injection points.

    Colored Flags
    Colored flags are placed within the quadrat to mark the injection points.

    Qualitative and Quantitative Data

    Any good scientist knows that keeping track of all observations is vital to the analysis of your data. Each plot has a unique location, a community of plants, thaw depths, and (at the time of harvest) size and dimensions of the soil cores removed. In a previous post I profiled some of the plants that are found here and posted a picture of me taking a thaw depths.

    Data Sheets
    Qualitative data about the plant species observed in each plot and quantitative data about the thaw depths at each injection point is recorded while in the field.

    Each of the data sheets is identified by plot name (Control 1 vs. Greenhouse 1, etc) and year collected (2016 vs. 2017). When the plots are harvested, each sample is given a unique code – one for the active layer retrieval, one for the soil core retrieval and one for the ice core retrieval. These samples are then further broken down based on the type of analysis they will receive.

    Below ground sample
    A below ground sample undergoing the first level of root identification. Note the number in the upper left hand corner to keep track of its plot location.

    Isotope Analysis

    The day after all of the plots were identified and flagged, we headed back out into the field to inject Ammonium Chloride (NH4Cl) into the soil for isotope analysis. The 15N isotope has a special “signature” which can be identified with complex scientific equipment to determine how far the Nitrogen has traveled throughout the roots and other parts of the plant in a 24 hour period (8 other plots were also injected and will be harvested 1 year from now for analysis).

    Nitrogen Tubes
    Metal tubes are inserted to the depth of the permafrost layer so that the isotope can penetrate deep into the soil and be taken up by plant roots.

    Filling Syringe
    Dr. Hewitt prepares a syringe of Ammonium Chloride is for the soil injection.

    Injecting N
    Dr. Hewitt injects the Ammonium Chloride into one of the tubes. Dr. Taylor steadies the tube as sometimes the soil is waterlogged and the isotope can bubble back up into the tube.
    Mind the shrubs
    I have to hold back any foliage to prevent any isotope ending up on the leaves of the plants so as not to cross contaminate the sample.

    Check out the video below of how Nitrogen is injected into the TundraA treeless area between the icecap and the tree line of arctic regions, having a permanently frozen subsoil and supporting low-growing vegetation such as lichens, mosses, and stunted shrubs. Soil.

    Why Inject Labeled Nitrogen?

    You’ll find that out in my next journal post – stay tuned!

    Toolik Field Station
    Weather Summary
    Sunny and bright


    Aqera akhan

    Which tundra ended up growing the fastest, greenhouse or control plots?
    What was the purpose in using this specific plant?

    justin atoyebi

    i never heard of isotope analysis but when i looked it up i learned that it is checkin the changes in atoms with variations.
    is the quadrat actually necessary for this experiment?

    How do you think the results will change when check the other 8 in 2017? What is your hypothesis?

    Rachel Johnson

    What would happen to the leaves if the isotope would fall on it


    1. Why do you use nitrogen to travel through the roots?2. How deep does the isotope usually travel into the soil?

    Iyana Shelley

    How come the nitrogen has to travel through the roots ? Why is it a 24 hour period and then a 1 year harvest after injection ?

    Susan Steiner

    I really like the manipulative part of the experiment of injecting the ammonium chloride. I wonder if your team developed the technique in the lab and at field sites in the lower 48 before they came, and how long it took to perfect the method? Very cool science!

    Brian Pugh

    I have never heard of ammonium chloride before. I looked it up and I see that it is soluble in water and is mildly acidic.

    Jovie Reyes

    Do believe that the research you are doing will help?Why do you think that when researchers and scientists discover something new, that impacts humans why does it take people time to believe in something like climate change when there has already been evidence that proves that it is real?


    Why the Arctic?What is a quadrat?

    Nell Kemp

    Hi Susan,

    It's my understanding that this approach is completely novel – traditional N labeling involve soaking the soil with the label, but since the team wanted to test the uptake from the permafrost/active layer horizon, they had to develop these injection probes. I know that a local machine shop in Fairbanks made them based on the team’s specifications, but I don’t know exactly how they developed the model – I’ll have to find out!

    Nell Kemp

    Glad that you learned something new :) See you in a week!

    Nell Kemp

    Thanks for reading :) I just realized I cross contaminated...I thought Susan Steiner was the one who asked about Karen's entry...she's probably so confused by my response to her! We are heading down to Healy on Th and then again Sat/Sun so I'll get to experience her site!

    Nell Kemp

    Hi LePra,
    If you click on the word "quadrat" in the journal, it should be hyperlinked to the wikipedia entry with a definition and description - you know that I would never directly give you the answer ;)

    Also, remember that the Arctic is warming faster than any region on the planet, which is problematic since it helps to regulate the climate all over the world.

    Nell Kemp

    Hi Jovie,
    I think that’s such a great but hard question to answer. The research we are doing will definitely help the scientific community to understand this ecosystem better and to make better predictions/models. As far as why people refuse to believe this is happening…I’m not really sure. I think a lot of people understand that climate change is a reality, but maybe those other people who don’t haven’t had good science courses or are afraid of the reality? Hard to say…

    Jamelya Simmons

    I wonder how come the plants cant use the adaptation process and get use to the cold weather just like humans and animals do without having to check the plants to find out what is the reason behind the way that they are forming.

    Susan Steiner

    That is so cool that this technique is unique to this team. I love that you are getting to do such cutting edge science! Polar research is good for so many things polar, of course, but also for developing new techniques and equipment for studying unique problems!

    Nell Kemp

    Hi Jamelya,
    I'm glad that you asked about adaptations, as this is something that we will be discussing during our first unit in Biology this year. Adaptations don't happen overnight or to one organism (i.e. you can't just grow fur on your body because you move to Antarctica), they can take hundreds to thousands of years to show up in populations. Adaptations are all about what genetic traits can get passed down to the next generation, and sometimes it can take a long time for all members of that population to share that trait.

    Dorian Moody

    Ms. Kemp,
    With all of your obversations/data recorded will it be kept as apart of a further research investigation?

    Nell Kemp

    Absolutely! All of this data is important and must be recorded for this experiment and potentially others in the future.

    Zora Beaty

    Have you ever tried this experiment before in recent years, if so were there any changes you noticed between the control house and greenhouse? Also, I am a little confused, what question are you trying to experiment here?

    Eghonghon Eromosele

    In this research specifically, what do you think is more important, qualitative or quantitative date? These are both very important in science in general, but what is your opinion?

    Nell Kemp

    Hi Eghonhon,
    In science, we generally prefer to use quantitative ("hard") data rather than qualitative ("soft") data to draw our conclusions. Qualitative data is still extremely important, however. Sometimes you really need to know if it was raining, or the soil extracted was slippery and muddy rather than dry and compact. So ... I guess they are both pretty important :)

    Nell Kemp

    Hi Zora,
    We will spend class time reviewing the experiment in detail, so hopefully you won't be confused after that!

    Kevin A.

    Do you find that qualitative and quantitative work together or against each other in data analysis? If you had to choose between one over the other, which one do you think would get you farther in the experiment or can you not work with one without the other?
    If some disaster or some extreme climate shift happened next year, how do you predict the experiment data would look?

    Alaina Grason

    If you could what about this would you do differently to maybe get different results?

    Janet Warburton

    This is a great journal Nell! I've learned so much. Thanks for sharing. Did you see the journal from Karen that she posted about Deep Roots? I'll have to find and link it for you :)
    Looking forward to your event on Wednesday!