Andrew Borner, Julia Boyke, Howie Epstein, Bill Gould, Jiong Jia, Anja Kade, Alexia Kelley, Bill Krantz, Hilmar Maier, Christine Martin, Gary Michaelson, Tako Raynolds, Vlad Romanovsky, Dmitri Sergeev, Yuri Shur, Gennady Tipienko, Lee Turner, Skip Walker, and six students from the University of Minnesota
The Biocomplexity group met together for the first time in the field. The goals of the meeting were: (1) Review and reevaluate the project goals, (2) visit all of the sites that were established in 2000 and 2001 along the Dalton Highway, (3) review the progress to date, (4) help the two graduate students, Anja Kade and Alexia Kelley, get their project started, (5) interact with the undergraduate field ecology course of Bill Gould. A summary of the agenda provides the highlights of the meeting
Coordinate future research and discuss possible new proposals. Breakout session addressed each of three core biocomplexity topics:
How do the insulative properties of the vegetation and the self-organizing properties of frost heave interact to create the various forms and patterns of frost boil systems along the arctic climate gradient?
1. Run Differential Frost Heave (DFH) model across temperature gradients
2. Run DFH model for Vlad’s sites
3. Run Vlad’s one-dimensional thermal model for thermal properties of vegetation
4. Run DFH model for Anja’s sites
5. Develop time evolution model
6. Run laboratory simulations to create frost boils
7. Get DFH model on website
Umbrella question: What is the relationship between boil and interboil vegetation, temperature and moisture regimes and the ice-lens morphology, distribution and chemistry?
1. Characterize needle ice formation
2 Ice lenses in active layer
How do ice lenses in active layer reflect temperature and hydrology in freezing system? Shape of ice lenses replicate freezing front in soils
Physical: Study of 3-D aspect to understand spatial aspect of frost heave and to understand sources of water brought into frost boils
Chemical: How do ice lenses and frost heave affect the redistribution of solutes and solids within the frost boil system?
Study: morphology of lenses to understand cryoturbation
Permafrost table shape
Ice-soil interface (liquid water, biological processes)
3. Intermediate Layer
Shape of permafrost table in frost boil system
Morphology of ice content
Physical effects
Chemical effects
Cryptogamic crusts
Tasks:
Ecology of crusts:
Succession
Purpose:
ArcVeg Model
Overview
Goals:
Interactions between physical and biological components of the sytem
Use models individually
ArcVeg – incorporate frost boil density and 1-3 (above)
DFH – incorporate vegetation insulative layer (homogeneous, heterogeneous, transient?)
Link ArcVeg and DFH model
Seasons alternate, so they could be linked sequentially (ArcVeg- summer, DFH – winter), using output from one to run the other
Other approach: tables of outputs for range of values, used as input for other
Effects of cryoturbation on nitrogen availability (Alexia)
This summer we compared soil biogeochemistry of frost boils and inter-boil areas at three sites along the Dalton Highway: Happy Valley, Sagwon Nonacidic and Franklin Bluffs. From three representative frost boils and inter-boil areas at each site, we took multiple samples from the top 5 cm of soil in order to measure total carbon and nitrogen, ammonium, and nitrate. We also used buried bags of soil and resin bags to determine the rates of net nitrogen mineralization. The buried bags were sampled at two week intervals to determine changes in net nitrogen mineralization throughout the summer growing season. In order to characterize the plant communities at our sites and to compare frost boils and inter-boil areas, we took measurements of the Normalized Difference Vegetation Index (NDVI) and Leaf Area Index (LAI). Biomass samples were also taken from each of the boils and inter-boil areas at all three sites. Buried bags of soil were place in frost boils and inter-boil areas at the three study sites and at Howe Island in order to determine the rates of net nitrogen mineralization over the winter. The samples collected will be processed this winter at the University of Virginia.
Anja’s experiment – effect of 4 cover types on soil temperature and heave.
A) Vegetation and Cryoturbation Interactions
A field site along the Dalton Highway in the Sagwon Hills (Sagwon MNT) was chosen to experimentally manipulate the vegetation on frost boils. Twenty-eight well-vegetated frost boils in close proximity were selected, and an area of 0.5 m2 at each frost boil was marked to receive one out of four treatments.
The experimental plots were revisited several times throughout the summer, and following cryoturbation and soil properties were monitored. A metal pole was anchored into the permafrost at each experimental plot to measure vertical movement of the ground (frost heave). A probe was pushed through the active layer to determine thaw depth. Soil moisture was recorded with a ThetaProbe several times throughout the summer and fall. Data loggers were installed at all the plots to measure soil and air temperature close to the soil surface. Toothpicks were inserted halfway into the soil, and the movement of the picks will serve as an indicator for soil-surface stability. The experimental plots will be revisited through the course of two years to study the interaction between vegetation parameters and cryoturbation.
B) Vegetation and Soil Properties along a Toposequence
Vegetation and soil data along a topographic gradient at Franklin Bluffs were collected to give insight as to how plant and soil attributes change with different moisture regimes. Vegetation cover of plant functional types and individual species were identified in 1 m2 relevé plots. Five relevé plots for each community type were sampled to derive an adequate description. Soil sampling was conducted at the same sites where plant communities were studied. The thickness of O-, A- and B-horizons were recorded and samples of each horizon were taken for analysis of soil physical and chemical properties. In addition, the depth of the active soil layer was recorded for each relevé and metal rods were anchored into the permafrost to record frost heave for each relevé.
Three dry vegetated frost boils were selected to receive periodic water additions of 7 gallons per plot throughout the summer. Frost heave and thaw depth will be monitored to study a possible change in cryoturbation due to increased soil moisture.
C) Vegetation and Soil Properties along a Climate Gradient
Soil samples of approximately 100 relevés were taken from the upper 5 cm of the mineral soil to be related to vegetation characteristics along a climate gradient in the Alaskan arctic tundra. In addition, thaw depth of all relevés was recorded.
The most important parameters are climate (air temperature, precipitation, snow, wind), vegetation. Air temperature and vegetation are the two most important drivers. Need to establish past temporal changes in air temperature and vegetation. The future can only be predicted based upon the past.
Students will examine changes in climate, substrate and beta diversity. They will run 3 transects at each site through 5 frost boil and inter-boil areas. They will collect data on vascular plants, bryophytes, lichens and soil insects, and soil data (temperature, texture, pH, thaw depth). The goal will be to differentiate between the effects on beta diversity (difference between boils and inter-boils) of climate and substrate. Beta diversity is expected to decrease with latitude due to the restrictive effects of climate. Beta diversity is expected to increase with frost boil activity, peaking in Subzone C-D. The project is set up to accept additional data from future years, and from additional Subzones (A, B, and C in Canada).
Overview of temperature and hydrology within nonsorted circles on Svalbard.
Our objectives are to examine differences in seasonal hydrologic and thermal dynamic across this gradient of cryoturbation, i.e. the region below the organic border and the mud center.
We installed instruments in a mud boil at a site close to Ny-Ålesund, Spitsbergen, in September 1998. The bare soil circle center ranges about 1 m in diameter and is surrounded by a vegetated border consisting of a mixture of low vascular plants, mosses and lichens.Temperature and moisture sensors were installed over a vertical 1 x 1 m profile and hourly data recording started in September 1998. Surface irregularities, as well as variations of grain size and moisture, create a non-uniform thermal and hydrologic dynamic.