My Alaska Research Adventure

This is the first of a series of blog posts I hope to post throughout the summer describing my research experiences at my field site in Alaska. I’m going to try and post once a week throughout the field season (June-August) about my experiences and experiments. Stay tuned, and follow along on either this blog, or Twitter, or Google+.

I flew up to Fairbanks, Alaska on June 2 to spend the field season (June-August) working on the field component of my postdoctoral researcher project. We (the “principle investigator” (PI), Dr. Rebecca Neumann and I) are studying methane oxidation in boreal forest bog and fen wetlands. I’ll start with some background information on what we’re studying and why, then I’ll talk a little bit about my experiences from this week.

Overlooking the Tanana River Valley

Overlooking the Tanana River Valley

Methane is a potent greenhouse gas which is approximately 20 times more effective at trapping heat in the earth’s atmosphere than carbon dioxide. One of the major sources of methane is natural wetlands. Because wetlands in the boreal forest regions of the world are going through such rapid changes do to climate change, we’re focusing on these wetlands for our research. These wetlands are changing quickly due to the melting of permafrost – a layer of frozen water and soil below the surface that remains frozen throughout the year. As areas underlain by permafrost melt, the ecosystem changes from a black spruce forest (dark parts of the forest in the picture above) to a bog dominated by sphagnum moss and/or sedges (light colored parts of the forest where the trees are thinned out). These bogs can be significant sources of methane, but the magnitude of methane flux (losses to the atmosphere) depends on a lot of factors – methane oxidation in particular. Methane oxidation is a process that’s mediated largely by aerobic bacteria which consume organic matter, methane, and oxygen, and release carbon dioxide. They depend on oxygen, and exist either near the soil surface, or in the volume of soil immediately surround plant roots called the rhizosphere.

Because plant roots require oxygen, plants have developed methods to allow the diffusion of oxygen down into the soil. Some of this oxygen diffuses into the rhizosphere where it can be used by the microbes to “oxidize” the methane into carbon dioxide. Our goal is to figure out what factors control the amount of oxygen that is delivered to the rhizospheres of these wetland plants, and just how much methane is oxidized as a result. What we learn from these field studies will help Dr. Neumann, her grad students, and some collaborators refine climate change models so scientists can better predict if the warming of these wetlands (and melting of permafrost) will contribute to additional global warming.

The picture above gives you a pretty cool view of what the boreal ecosystem looks like. The field site is the Bonanza Creek Long Term Ecological Research Station (LTER) which is about a half hour west of Fairbanks, Alaska. The wetlands are down in the floodplain of the Tanana River. It’s very flat in the floodplain, but there’s significant microtopography due to the permafrost. The hills and mountains around the Tanana are very large. You can get a sense for the topography of the area in the picture below. The annual average temperature in the area is right around 0 degrees Fahrenheit, but it can get well below -40 degrees in the winter, and above 80 degrees in the summer. The mosquitoes are pretty bad at the site, but nothing I’m not used to as a wetland soil scientist. There are bears and moose in the area, but there aren’t any poisonous snakes or spiders – which I could get used to after working in wetlands in North Carolina for the last five years (which also had bears but not moose). In addition, the ticks do not carry Lyme’s disease here either! Surprisingly, the black spruce trees in this area are very slow growing due to the extreme conditions in which they’re trying to survive. The tallest trees in the picture below (about 15 feet [5 m] tall) are over 300 years old!

The Beta (bog) site of the Bonanza Creek LTER "APEX" Wetlands

The Beta (bog) site of the Bonanza Creek LTER “APEX” wetlands

I spent the last week meeting some of our collaborators, touring the field site, testing some soil coring methods, and just prepping for the rest of the field season. Walking on the sphagnum moss can actually kill the moss, so there has been a network of boardwalks constructed in the site. I worked on improving some sections of boardwalks this week, and repairing some sections. We’ve had some delays in getting our supplies up here, including lost luggage, shipments that were rejected by Fedex, and more, but I think everything is moving now so hopefully we’ll be installing instruments in no time. Stay tuned for more pictures and stories from the field.

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Officially a Doctor

2014-05-10 14.37.16As of May 10, 2014 I am officially a doctor. After ten years of college I’m finally officially finished and now am a doctor of philosophy in soil science. It feels great to be finished. I want to give a special thanks to all of my family and friends that have supported me through grad school, especially my beautiful wife, Stacy. I couldn’t have done it without her. Another big thanks goes to my adviser, Dr. Mike Vepraskas. I learned a lot from that guy on both a professional and personal level. Thanks to Chris Niewoehner for all of his help with my research projects. Thanks to my Ph.D. and M.S. committee members for all of their help and guidance. Thanks to the soil science professors at Iowa State University for inspiring me to pursue this career path. Lastly, thanks to all of the faculty, staff, and students in the North Carolina State University Department of Soil Science. I couldn’t imagine doing my graduate work anywhere else.

Some of you may be wondering what my plans are now. As many of you know, I’m currently working as a postdoctoral researcher in the University of Washington Department of Civil & Environmental Engineering. I’ll continue in this position for the foreseeable future. I really like the project, and I’m learning a lot about new root and rhizosphere research methods, and wetland methane biogeochemistry. I also get paid to hang out in Alaska during the summers! Eventually I hope begin a career in a soil science or Agronomy department where I can teach soil science, and continue my research. This has been my dream job since I was a sophomore in college sitting in my first soil science class with Dr. Lee Burras at Iowa State. It’s still my dream job, so I hope it works out. Wish me luck!

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Container Garden Water-Saving Tips From a Soil Scientist

Over the last year or so I’ve noticed a lot of websites, blogs, etc. offering water-saving techniques for container gardening. Some tips are useful and scientifically sound, but some are just plain wrong. As a person with a Ph.D. in soil science (and a minor in water resources), this drives me crazy. Because of that, I wanted to put some tips out there that will actually work!

If you’re reading this blog post, it’s likely that you are a gardener that, like me, is either lazy or forgetful when it comes to watering. Despite my lack of a rigorous watering regime for my container plants, I still have a wide variety of beautiful specimens, mainly because I’ve found that these simple tips just plain work.

1. Pick the right plant

This is the biggest decision you’ll face for container gardening, and the best way to make it easy on yourself. Get to know your local landscape and floral supply store (a real one, not a department store gardening section). Workers there will likely have some good advice on what plants do well with very little water. I highly recommend sticking to “succulents“, which are generally adapted to dry climates with little rain. Some great examples are Aloe vera, Crassula ovata (Jade plant), Euphorbias,Schlumbergeras (Christmas cactus) and any other cactus species.

Schlumbergera, Source: Wikipedia Commons

Succulents are generally “CAM” plants, meaning that they open their “stomata” (pores) at night instead of the day so that they can adsorb CO2 with minimal water loss (as opposed to opening stomata during the day like most other plants). Succulents also tend to have waxy skins that further limit water loss, and store lots of water inside their stout leaves or stems. Be sure to investigate the plant thoroughly before you buy it to see what it’s lighting, watering, and space needs are or might be once it matures.

2. Choose the right container

When it comes to containers you generally have two choices – terracotta (clay) pots and plastic containers. Both have advantages and disadvantages when it comes to limiting how frequently you will need to water your container plants.

Source: Wikipedia Commons

The traditional terracotta clay pots are porous, meaning that water can, and does evaporate through the side of the pot, and not just through evaporation at the soil surface, or transpiration through the plant. This can be desirable for a few reasons. For one, the color of the pot will actually tell you how wet or dry the potting soil is, at that moment. The wetter the soil is, the darker the clay pot will be.  Some plants (succulent plants in particular) prefer moist but not wet conditions. Terracotta pots do a great job of preventing saturated soil in the bottom of the pot, which may damage plant roots. The downside of terracotta pots is that the plants will need to be watered more frequently than with plastic pots.

Plastic pots are not porous, so no evaporation occurs along the side of the pot. If you have plants that can tolerate wet conditions reasonably well, then using plastic pots is a great way to limit how frequently you need to water. If you don’t like the look of plastic pots, try placing the plastic pot on the inside of your container of choice.

3. Pick the right location for your pot

The less sun your plant is exposed to, the less water it will use. Shade reduces the temperature of the plant and soil, and thus the transpiration rates. Find out what sun/shade tolerances are of your plant of choice, and aim for something on the shadier side. Your plant may not grow as fast, but at least you won’t have to water it as much.

Source: Wikipedia Commons

Also, try to place the plant in a location where you will see it everyday. This will make it more likely that you will notice that the plant(s) needs watering. More than once I’ve forgotten to water a plant that I don’t see everyday. Picking the right location is a great way to make sure that won’t happen.

4. Use mulch


Every single drop of water that you add to your container goes one of three places. It can be transpired through the plant, evaporated from the soil, or drained out the bottom of the pot. Adding mulch to the soil surface reduces how much water is evaporated from the soil. This is because the mulch shades the soil from the sun, which keeps the temperature down, and in turn reduces evaporation from the soil. One thing to keep in mind is that adding mulch is equivalent to adding a carbon-rich, nutrient-poor substance to the soil. This isn’t a problem, but be sure to add some fertilizer at the same time that you add mulch so that the plants don’t become nutrient-limited.

5. Don’t worry about the potting soil

There are a lot of gimmicky potting soils out there claiming to work miracles in terms of retaining water. Honestly, there’s not much difference between potting soils. I’d recommend just buying the potting soil that is the cheapest. If you follow the first four tips, then the type of potting soil you buy won’t make much of a difference. If you really want to go cheap, use topsoil from a corner of your back yard. It will work the same, as long as you lime and fertilize as needed.



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Soil Science in the News: Eating Dirt

I came across an interesting story from NPR today, entitled “The Old And Mysterious Practice Of Eating Dirt, Revealed“. It’s about the ancient practice of eating soil (or mineral deposits), often called Geophagy. I’ve heard about this practice in a few of the soil science classes I’ve taken over the years, and in a “World Food Issues” class I took as an undergrad. It’s an interesting phenomenon, and from what I understand the cravings to eat soil, or kaolinite specifically (a phyllosilicate clay mineral) occur mostly in expecting mothers.

Source: The Augusta Chronicle

There is a documentary coming out soon that highlights this normally under-the-radar practice entitled “Eat White Dirt“. Here is the trailer for the film:

I’m looking forward to the documentary. If I ever see this Kaolin sold in a store, I just might have to try it out (for purely scientific purposes of course). Have you ever eaten “white dirt”? Tell me about your experiences in the comments.

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Top-Ranked Priority Research Questions for Soil Science in the 21st Century

In 2012 and 2013 I had the privilege to work with a fantastic group of graduate students on a project focused on identifying the top-ranked priority research questions for soil science in the 21st century. It was a great learning experience, and an opportunity for me to collaborate with fellow graduate students from all around the USA – most of which I had never met. The results from our work are now available to the public in the Soil Science Society of America Journal. Please follow that link and read it. I’m interested to know what you think. Let me know either in the comments section here, or tweet at my @ColbyDigsSoil.

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Citizen Soil Science: Cropland Capture

If you’re looking for a fun game for your mobile device but want to help science at the same time, then I know the app for you. “Cropland Capture” is a fun game designed to help classify areas of land on our planet as either cropland or not cropland. With over 7 billion people on the planet it is important that we accurately assess the resources available to feed a growing population. Even with the fanciest computer software, sometimes it’s difficult to accurately identify land uses without the human brain. The makers of Cropland Capture took this daunting task and made a great game out of it, as shown in this video:

The Cropland Capture app contributes data to the Geo-Wiki project, which has the following description on it’s website:

The Geo-Wiki Project is a global network of volunteers who wish to help improve the quality of global land cover maps. Since large differences occur between existing global land cover maps, current ecosystem and land-use science lacks crucial accurate data (e.g. to determine the potential of additional agricultural land available to grow crops in Africa). Volunteers are asked to review hotspot maps of global land cover disagreement and determine, based on what they actually see in Google Earth and their local knowledge, if the land cover maps are correct or incorrect. Their input is recorded in a database, along with uploaded photos, to be used in the future for the creation of a new and improved global land cover map.

The app is available in Google Play for Android devices, and iTunes for Apple devices. I’ve been playing with the Android app for a while now. It’s a lot of fun, and a great way to kill time. Try it out, and save the world!

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New Job!

Source: Wikipedia (c) University of Washington

Hello everyone,

As many of the followers of know, I’ve been working on my PhD in soil science at NC State for a while now. I’ll be finishing up in December, so I’ve been in the midst a thorough job search over the summer and the beginning of the fall semester. That job search is officially over now as I have accepted a position as a postdoctoral researcher in the University of Washington Civil and Environmental Engineering Department. I will be working with Dr. Rebecca “Becca” Neumann. I will be working on a project studying methane oxidation in the rhizosphere of wetland plants.

Methane is a greenhouse gas that is 20 times more effective at trapping heat in the atmosphere than CO2. Methane is produced in wetland soils. Plants can act as both a route for methane to move from the soil into the atmosphere, and as a way for oxygen to enter the soil and oxidize the methane in the rhizosphere (the zone of soil immediately surrounding roots). The objective is to put a solid number on the percentage of methane that’s oxidized in the rhizosphere in order to refine climate change models. We also want to predict how that number changes with different plant communities, and how those communities might change as the climate warms. The field site is about 40 minutes west of Fairbanks, Alaska. The field site has two types of wetlands – a bog and a fen. It is called the Bonanza Creek Long Term Ecological Research Station. I’ll be in Alaska for their growing season (June-September), and in Seattle the rest of the time working on laboratory experiments. 

The position is exactly the type of postdoctoral research position I was looking for in my job search, so I’m really happy I got it. My wife and I are both excited to see what the West Coast is like, and we now have an excuse to visit Alaska.

My start date is January 6, so my wife and I will be moving over the holidays. This new stage of my career will affect this blog a little bit. My first priority is to finish and defend my dissertation on time in December, so I won’t be able to add many blog posts between now and the end of the year. However, once I make the move I should have all sorts of interesting material and pictures from Alaska to post on this blog.

Thanks for stopping by,


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