Noatak National Preserve

Jones Home

Overview:

My research interests focus on two general themes: 1) carbon and nitrogen cycling in streams, rivers and soils (especially in the context of land-water interactions), and 2) watershed-scale carbon cycling and climate change.  I am interested in carbon and nitrogen cycling at a range of scales ranging from the molecular composition and microbial use of dissolved organic molecules, to the biogeochemical cycling in streams and soil, to larger scale fluxes from watersheds and trace gas emissions to the atmosphere.  A central theme of my research is the role of hydrology, both surface and ground water, in linking ecosystems and governing biogeochemical transformations.  A second theme involves the role of permafrost and permafrost thaw in controlling ecosystem structure in boreal forest and arctic ecosystems.

Watershed Hydrobiogeochemistry:

We are investigating how streams are linked to their catchments, and focuses on how permafrost influences groundwater inputs of nutrients and organic matter to streams.  The boreal forest in interior Alaska is underlain with discontinuous permafrost, which has a major affect on watershed hydrology.  Where permafrost is present, groundwater flowpaths through catchments are largely restricted to soils, whereas in the absence of permafrost water can infiltrate into deeper bedrock regions of watersheds.  In addition to affecting hydrology, permafrost stores a lot of soil organic matter that will potentially be released to streams and the atmosphere with climatic warming and permafrost thaw.  This research is particularly exciting in the context of how groundwater inputs of nutrients and organic matter may shift with changing climate and resulting alterations in the extent of permafrost.  An interesting sidelight of this research is the role of forest fires and their influences on permafrost.  Fire alters the albedo of soil and, as a consequence, can lead to thawing of permafrost.  Fire frequency has been increasing in interior Alaska, which has important implications for permafrost and watershed hydrology.  This work is funded through the Bonanza Creek Long Term Ecological Program (http://www.lter.uaf.edu/) and is being conducted in the Caribou-Poker Creeks Research Watersheds (CPCRW; located near Fairbanks).  CPCRW covers an area of ~100 km2, and has a number of sub-catchments and streams that we have been studying.  Of these sub-catchments, we conducted a controlled burn of one watershed in July of 1999, and another sub-catchment was burned extensively in summer 2004 by a wild fire. More information about our research in on stream-watershed interactions can be found on the project webpage.

Scale, Consumers, and Lotic Ecosystem Rates (SCALER):

This project focuses on issues of scaling in stream ecology and is part of a larger collaborative effort focused in sites across North America.  Students working at the University of Alaska Fairbanks will focus their field work in the boreal forest at the Caribou-Poker Creeks Research Watershed (CPCRW; located near Fairbanks), but will be involved in cross-site synthesis. The overarching question that SCALER is addressing is: How can small-scale ecological experiments be applied to understand the behavior of entire ecological systems?  Specifically, we are focusing on: 1) How do the fundamental properties of streams ecosystems and the effects of animals on stream ecosystem  properties scale across stream networks; and 2) How do patterns of scaling vary across the wide array of ecological systems (from tundra to tropical forest) that occur across North American?  The broader SCALER project includes sites in the tropical forest, temperate deciduous forest, prairie, and tundra biomes.  Streams in each of these five regions will be examined at scales of centimeters to 1000’s of meters in small, medium and large streams.  Rates of stream metabolism (photosynthesis and respiration) and nutrient uptake will be measured, as well as the way these ecosystem processes respond to animal exclusions (used to mimic loss of animal diversity in streams) in small headwater to mid-order stream reaches.  Reach scale studies will be linked to the scale of watersheds and region by modeling, and verified by broader, but less intensive sampling.  The knowledge that will be generated by this project is essential to quantify controls on stream ecosystem processes as well as to manage human impacts on entire watersheds.  The experimental and modeling results will be relevant to general ecology because few nested, experimentally and theoretically coupled scaling experiments have been undertaken in any environment.

Climate-mediated coupling of hydrology and biogeochemistry in arctic hillslopes:

In this project, we will investigate coupled hydrology and biogeochemistry of arctic hillslopes, with the goal of understanding how climate-induced changes in water and nutrient cycles on land are propagated to stream networks.  Observed increases in fluxes of water, nitrogen, and phosphorus from river networks to the Arctic Ocean may be caused by release of nutrients from thawing permafrost, changing precipitation patterns, increased rates of biogeochemical reactions, or expanded storage capacity in thawed soils.  However, the flowpaths connecting terrestrial ecosystems to stream networks remain poorly understood.  We will focus on transport and reaction of water and solutes within water tracks, which are linear regions of surface and subsurface flow that connect hillslopes to streams and account for up to 35% of watershed area in arctic tundra.  Specific objectives are to: 1) quantify sources of water and dissolved nutrients to water tracks, 2) identify effects of snow accumulation, thaw depth, and storm characteristics on storage and transport of water and solutes, and 3) estimate the effects of hydrology on rates of nutrient cycling in water tracks.  We will apply hydrologic and end-member mixing models, solute addition experiments, and snowmelt manipulation to address these objectives.  The research team includes watershed ecologists (Tamara Harms, Jay Jones) at the University of Alaska-Fairbanks, and hydrologists (Sarah Godsey, Mike Gooseff) at Pennsylvania State University.  Field work for the project is based at the Toolik field station.

Thermokarsts in Arctic Ecosystems::

We have been studying the impacts of thermokarsts on Arctic and boreal forest ecosystems.  A thermokarst is a feature of landscapes with permafrost.  As permafrost thaws, the underlying soil can collapse generating mass wasting of the ground surface.  Depending on where these features form, thermokarsts can result in rather dramatic scares on the landscape, mobilize a lot of sediment, and rapidly release a large amount of old soil organic matter (organic matter that was previously stored in permafrost).  We are interested in the age and nature/quality of carbon released from soil following thermokarst formation, trace gas emissions, and role thermokarsts play on watershed nutrient cycling.  Our work on thermokarsts is being conducted near the Toolik Lake field station in northern Alaska (http://www.uaf.edu/toolik/) and in the Noatak National Preserve (http://www.nps.gov/noat/) in north-western Alaska.  The project website at Pennsylvania State University can be found at http://thermokarst.psu.edu/

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