Long-term Soil Environment Monitoring in the Rock Creek Watershed, Denali Park, Alaska

The research focus is on the soil environment monitoring in the
Rock Creek Watershed. Soil properties are the result of interactions
among atmosphere, biosphere, and lithosphere, thus soil properties are
also sensitive to environmental changes over time. Soils function not
only as water-nutrient life media but also as redistributors and
regulators of most of the important fluxes of matter and energy.
Therefore, soil environmental changes affect the immediate carrying
capacity of the land, through their influence on the vegetation and
land-use types, run-off, evaporation, groundwater quality. In recent
years, the arctic tundra has been identified as the major source of
global warming gas emission, i.e. CO2 and methane (Oechel et
al. 1993), yet there is only limited research on the subarctic
region. The environmental concerns within a few meters above or below
the ground surface constitute the microclimate of a soil map unit or
landscape unit and it is to these conditions that most soil organisms
must adapt. The microclimate (soil environmental factors) is
characterized by the radiation, temperature, and moisture regimes of
the near-surface atmospheric and soil layers (Dingman et al., 1980).
These regimes are determined by, and are also feedbacks to, regional
and global climate, as modified by local topography and through the
interaction with the biosphere. The soil and its environmental
function in the ecosystem are important to the productivity and
diversity of the terrestrial and aquatic biota. In addition, each
soil has a self-contained biota, and is an efficient trap or
collection system for many atmospheric contaminants. A careful
description and a set of quantitative measurements of the soil are
essential to estimating the sensitivity or stability of the ecosystem.
A carefully designed monitoring system of the soil environment is
essential to evaluate the effects of ecosystem changes caused by
regional and global climate change, and the anthropogenic changes as
well.

Geographic Description:
Rock Creek Watershed in the Denali National Park and Preserve, AK.
Denali National Park and Preserve is located in the central Alaska
Range, approximately 210 km southwest of Fairbanks, Alaska.

Methodology:
Select monitoring sites that cover the four major vegetation
communities and ecotone as specified in the Objectives section. A soil
inventory and soil characterization sampling were conducted with
cooperation from the USDA-Natural Resources Conservation Service
(NRCS) Alaska State Office. Complete soil analysis were performed by
NRCS - National Soil Survey Center according to national cooperative
soil survey procedures and standards. The soil characterization data
would serve as baseline data for soil parameters and also as reference
to future changes in these parameters. Soil and soil environment
parameters to be monitored: soil temperature, soil redox potential,
soil water table and soil water potential, air temperature,
instrumentation and monitoring - install micrometeorological stations
which have sensors for monitoring air temperature, soil temperature,
soil water matrix potential, relative humidity, wind, and solar
radiation. Soil temperature will be measured hourly at 2.5, 5, 10, 20,
and 50 cm depths (100 cm for deep soils) with thermocouple; soil
matrix water potential will be measured daily at 5, 10, 20, 50, and 75
cm with synthetic soil moisture blocks; relative humidity, wind, air
temperature, and solar radiation will also be monitored hourly and
recorded with datalogger. - Reduction-oxidation potential (redox)
potential was measured with Jensen's platinum-electrode at 2.5, 10,
20, and 50 cm depth from the soil surface weekly and more frequently
after rains, and recorded with Jensen's ORP meter with reference
electrode.