Tuesday, September 2, 2014

Snow Arrives in Barrow...

Although people from the NGEE Arctic project will be coming and going from Barrow throughout the month of September, I leave today on the evening flight for Tennessee. It has been a great trip, first to the Seward Peninsula and then to the North Slope of Alaska. We woke up this morning in Barrow to fresh snow, about an inch. We often comment that “summer” is 90 days in length at this high-latitude location. A quite look back on my notes and albedo records kindly provided by our colleagues at NOAA, suggest that bare ground first appeared this year on June 5 with a snow-free landscape maybe a week later; so just short of a 90 day summer. Hard to believe that biology, at least biology aboveground in the form of vegetation must complete its life cycle in this brief period. Just imagine the challenges of a plant root growing at the permafrost boundary or microbial communities releasing nitrogen through soil organic matter decomposition in this cold, often frozen environment!

As I pack for the trip home, I would like to thank everyone who made this a successful trip. The selection of a series of Phase 2 sites on the Seward Peninsula is a significant milestone for the project, one that will facilitate our modeling objectives into the future, as will the continued science being conducted on the Barrow Environmental Observatory. I would like to thank Cara Mousa who has helped post many of the blogs during this trip. She does a great job of supporting me and the project, and a real lifesaver when I am away from the office.
Also, not too many “Pics of the Week” but here are a few for your enjoyment.  David Graham (ORNL) contributed the photo of the lemming...thanks. And yes, they do play highschool football in Barrow. The season opener pitted the Barrow Whalers against the Homer Mariners. The playing field is easily within sight of the Arctic Ocean.
Be safe, be productive, and enjoy your science! 


Monday, September 1, 2014

NGEE Arctic Scientist Links Plot Scale and Satellite Scale Measurements of Soil Moisture…

Much of what the NGEE Arctic team does is directed at gaining fundamental knowledge of processes that control the water, energy, and carbon cycles in tundra ecosystems. This means that members of the team are in the field and laboratory gathering data and sharing that information with our modeling colleagues. We also have an interest in linking our field studies to larger scale information coming from satellites in what if often referred to as scaling. That is, how do small-scale measurements made in the field relate to larger scale properties and processes estimated from remote sensing platforms?

Go Iwahana, a postdoctoral researcher at the UAF International Arctic Research Center (IARC) is especially interested in this topic and has been working this week to install a network of soil moisture probes across the Barrow Environmental Observatory (BEO). These probes are commercially available and, once connected to a small data logger, can record information on soil temperature and moisture for months at a time. Go plans to use data from this network to evaluate relationships between plot-scale data and that coming from the Soil Moisture Active Passive (SMAP) satellite. The intended goal of SMAP is to provide global measurements of soil moisture and its freeze/thaw state. These measurements will be used to enhance understanding of processes that link the water, energy, and carbon cycles, and to extend the capabilities of weather and climate prediction models. SMAP is a directed mission of NASA (https://smap.jpl.nasa.gov/) and is managed by the Jet Propulsion Laboratory.

Living in Barrow…Herman House

A few people have asked what it’s like to live in Barrow. Being the northernmost city in the United States you can guess that it is different from life in the lower 48. However, we have great logistical support from UMIAQ and as a result we typically have everything we need including vehicles and housing. Our team, especially when we have large field campaigns, is usually distributed between 3 apartments in town; two apartments along Boxer Street and the Herman House. All of these locations are close to the gas station, grocery store, etc. This week Larry, Go, David, Baohua, Ziming, and I stayed at the Herman House; a two bedroom house that sleeps 8; nine if you count the futon in the living room. The two bedrooms have bunk beds and can get a little crowded. Everyone, however, seems to find a spot and can operate pretty effectively despite the close quarters. Internet connections are slow, so it helps that people are patient. It can get a little hectic when everyone returns from the field with boots and jackets, especially after a wet day of research like yesterday, drying in various rooms throughout the house. We have a nice kitchen where we can prepare meals and even a washer and dryer. Most people are finding that thanks to these resources, research trips to Barrow can be enjoyable and everyone seems to like the comradery.

Sunday, August 31, 2014

Water, Water Everywhere…But Where Does It Go?

One of the organizing themes of the NGEE Arctic project is hydrology. It is important both for our field and laboratory measurements and especially for our modeling. We are exploring the question of how water distribution across polygonal landscapes will be impacted as permafrost thaws and topography changes due to melting ground ice and ice wedges underlying polygons. Our hydrologists and their modeling colleagues are finding that a key uncertainty in determining water distribution, in addition to topography in these low gradient environments, is the saturated hydraulic conductivity (Ksat) of soils. Knowing Ksat allows us to better understand the movement of water through saturated media and facilitates accurate modeling of water flow in soils. Modelers on our team need this information for the parameterization of our fine-scale models of low- and high-center polygons and for use in our global land surface models.

Today Cathy, Go, Larry, and I left our apartment and stepped out into the windy, cold, and unusually rainy weather. It was slightly annoying at the time, but surely the weather would get better right? As we pulled sleds full of our equipment to the field we soon realized that the sun was not going to appear, that the winds were not going to subside, and that the rain was not going to stop. On the contrary, this was going to be (not withstanding mosquitos) one of the more miserable days on the tundra that I have experienced in the last three years.
Once at the field site Cathy unpacked our Guelph Permeameter that she had purchased some time ago from Soil Moisture Equipment (Santa Barbara, CA). The equipment can be transported, assembled, and operated presumably by one person. However, we found that in rainy weather with winds upwards to 20 mph that two people were needed to stabilize the unit, position the tripod, and get it ready for operation. Once assembled, the permeameter enabled measurements of Ksat to be determined in 35 minutes to an hour. Although all the calculations still need to be completed, it is clear that Ksat values for the silty soils commonly found across our field sites on the Barrow Environmental Observatory (BEO) are low. This means that water movement, especially lateral movement, is very slow. Our team has noticed this in trying to collect samples for water chemistry, etc. It is simply difficult to get water from these soils. We think that once incorporated into models, the consequences of low Ksat – now that we have direct measurements – will become evident in the distribution of water across the landscape and the cascade of other processes of biogeochemistry and vegetation dynamics. We should know more about this before too much longer… 




Saturday, August 30, 2014

Available Forms of Nitrogen for Tundra Plants and Microbes…

Yesterday was a productive day for all NGEE Arctic teams working on the tundra. Today our group left the Herman House apartment with a couple of goals. One was to complete surface and pore water sampling for geochemistry; another was to continue vegetation resurveys for the purpose of fine-scale mapping of plant functional types (PFTs) across polygons. Mallory and I also wanted to finish sampling of soils that she began two days ago for analysis of nitrogen availability. While Mallory has not yet developed the full scope of her PhD studies, she is interested in better understanding the interplay between soil organic matter decomposition and the forms of nitrogen ultimately made available for plants and microbes. More specifically Mallory would like to combined advanced analytical methods with some aspect of plant and microbial biology, and therein characterize the pool size and diversity of low molecular weight (LMW) nitrogenous compounds in soils. There is a considerable amount of published literature on nitrate and ammonium availability in tundra soils, but LMW compounds that can be used by plants and microbes as a source of nitrogen are also important. However, they have not been fully characterized. Working with Bob Hettich and Rich Norby at ORNL and as a student through the Bredesen Center for Interdisciplinary Studies and Graduate Education, Mallory has the opportunity to merge powerful mass spectroscopic approaches (MALDI and electrospray ionization sources) and field ecology, into a single program of study. But before she can do this, Mallory needed to obtain a range of samples from the Barrow Environmental Observatory (BEO) so she could conduct preliminary studies to refine her techniques and then, equally important, the questions that Mallory would like to tackle will also need to be developed. She identified plots within low- and high-center polygons and excavated a small monolith of soil from the upper active layer. She did this at a number of locations making sure that she had adequate replicates and samples for areas that supported the growth of several different plant species. This way Mallory can assess her early work in terms of variation in nitrogenous compounds due to topographic location and species composition. Once samples were collected they were labeled, placed in plastic bags, packed into a cooler, and will be shipped to ORNL later this evening. Mallory will be busy during the coming months and it will be interesting to see how her research develops both with regards to fundamental science and integration of that knowledge into models.

Friday, August 29, 2014

Geochemistry of Methane Formation in Surface and Pore Water Samples…

Today we had 15 people working on the Barrow Environmental Observatory (BEO). Researchers from three DOE national laboratories, the University of Alaska, and scientists from China, Japan, and Germany were collecting data on various topics; soil carbon dynamics, hydrology, and energy balance. It is always rewarding to see this many people working on so many integrated components of the NGEE Arctic project.

David, Baohua, Mallory, Ziming, and I left our apartment in Barrow shortly before 8:00am and stopped by the Barrow Arctic Research Center (BARC) and our storage room in Building 553 before heading to the field. Once we made the 2 km hike to our field site, Baohua and Ziming got busy collecting surface and pore water samples. They used a combination of techniques to obtain water samples from various depths in the soil using macrorhizons, etc. These were inserted into the soil of low- and high-centered polygons yesterday, placed under modest suction, and by this morning had accumulated 40 to 50 cubic centimeters of water. It was necessary to filter the samples to remove suspended sediments and then Ziming and Baohua analyzed them in the field for electrical conductivity, pH, temperature, and concentration of ferrous iron. One of the primary objectives in collecting these samples is to better understand the process of methanogenesis. Methanogenesis is the formation of methane, a potent greenhouse gas, by microbes known as methanogens. These microbes, under anaerobic conditions, use ferric iron as an electron acceptor. This gives rise to ferrous iron which indicates anoxic conditions that may support methanogenesis. Data from the work of Ziming, Baohua, and David will be integrated with field and laboratory experiments to better understand the geochemical controls on methane formation. Improvements in how models represent this important process are one outcome of this research and an important goal of the NGEE Arctic project.

Thursday, August 28, 2014

Early Career Scientists Contribute to NGEE Arctic…

The NGEE Arctic project has been fortunate over the last three years to host a number of post-docs, and PhD and MS students. These include Heather, Lily, Michael, Lydia, Zach, Baptiste, , Shan, Carolin, Melanie, Ingrid, Ali, Chandana, Mark, Andy, Jonathan, Jenny, Santonu, Xiaofeng, Victoria, Taniya, Elizabeth, Nathan, Biao, Andy, Mark, Andrew, and Ben to name just a few. I want to thank all of them for their dedication and for their field, laboratory, and modeling contributions to the project.

This week we are fortunate to have Mallory Ladd and Ziming Yang join us for this trip  to Barrow as new team members. Mallory is starting her PhD as a student with the Bredesen Center for Interdisciplinary Research and Graduate Education (http://bredesencenter.utk.edu/index.php). This program unites complementary resources at the University of Tennessee and Oak Ridge National Laboratory (ORNL). Mallory is working with both Bob Hettich and Rich Norby to assess forms of organic nitrogen in permafrost. She will be applying various analytical techniques to examine nitrogenous compounds in soil and competition for that nitrogen between plants and microbes. Ziming joined the project as a postdoctoral research associate through ORNL’s Postdoctoral Program (http://www.ornl.gov/connect-with-ornl/for-academia/postdoctoral-programORNL) after a successful PhD program at Arizona State University. While at ASU Ziming obtained his PhD degree in organic chemistry in the Department of Chemistry and Biochemistry. Ziming is working with Baohua Gu and will examine the geochemical controls on methane flux from thawing permafrost. He will have both a field and a laboratory component to his research, as will Mallory. It is hoped that the work of both Mallory and Ziming will allow us to better understand and integrate novel aspects of carbon adn nitrogen biogeochemistry into models.
I will focus on Mallory's and Ziming's specific research later in the week and what they are individually doing while in Barrow while working on the NGEE Arctic project.