Greenhouse Gasses: Monitoring of flux-measurements of CO2 and CH4 in tundra and boreal forest soils, Alaska

PI: Yongwon Kim
co-pi: Rikkie Suzuki (JAMSTEC)
co-investigators: Konosuke Sugiura (JAMSTEC), Hotaek Park (JAMSTEC), Akihito Ito (JAMSTEC, NIES), Masato Uchida (NIES), Seong-Deog Kim (Choongnam National University), Taro Nakai (IARC/UAF), Katey Walter (IARC/UAF)
Funding JAMSTEC

Overview

boreal forestBoreal black spruce forests typically have relatively open canopies that allow a significant portion of incoming radiation to reach the ground vegetation. Forest floor GPP (Gross Primary Productivity) is thus a potentially important process that can represent a significant portion of C assimilation in such ecosystems and can be as high as 50% on certain days.

The GPP of the forest floor vegetations depends on favorable light intensity, temperature, and moisture conditions   and on the composition and relative presence of different forest floor communities in the ecosystems.

The Re (Ecosystem Respiration) includes respiration by aboveground vegetations (stems, branches, twigs, and leaves) and soil. Soil respiration is a dominant component of CO2 exchange in the boreal ecosystem, accounting for at least half of Re. The temporal variability of respiratory metabolism is influenced mostly by temperature and moisture environments. Aboveground and belowground C exchange processes contributing to Re can respond in different ways to the seasonal variation of temperatures in air and soil, to the availability of water, and to substrate content/type.

The CO2 exchange between the boreal black spruce forest and the atmosphere is complex, with significant contributions by five physiological processes: black spruce photosynthesis, black spruce respiration, moss photosynthesis, moss respiration, and heterotrophic respiration. Although the five processes are important portions of forest C exchange, the roles of tussock and lichen on a boreal black spruce forest floor cannot be overlooked. The distribution area in the Northern Hemisphere of tussock, moss, and lichen is 6.5 × 1012 m2, and tussock is an important CO2 and CH4 source in black spruce forest soils during the winter. Hence, information on the rates of and controls on each of these processes is needed to improve understanding of the current and future carbon balance of the boreal forest.

Objectives

  1. Estimate CO2 flux-measurement on the ground level of boreal forest during the growing season.
  2. Understand carbon dynamics and evaluate regional carbon budget.

Integrated Activities

  • Diurnal variation of floor CO2 exchange
  • Seasonal variation of environmental factors and floor CO2 exchange

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