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Title: Response of a Tundra Ecosystem to Elevated Atmospheric Carbon Dioxide and CO 2-Induced Climate Change: A Renewal Research Proposal

Abstract

Northern ecosystems contain up to 455 Gt of C in the soil active layer and upper permafrost. The soil carbon in these layers is equivalent to approximately 60% of the carbon currently in the atmosphere as CO 2. Much of this carbon is stored in the soil as dead organic matter. Its fate is subject to the net effects of global change on the plant and soil systems of northern ecosystems. The arctic alone contains about 60 Gt C, 90% of which is present in the soil active layer and upper permafrost. The arctic is assumed to have been a sink for CO 2 during the historic and recent geologic past. The arctic has the potential to be a very large, long-term source or sink of CO 2 with respect to the atmosphere. In situ experimental manipulations of atmospheric CO 2, indicated that there is little effect of elevated atmospheric CO 2 on leaf level photosynthesis or whole-ecosystem CO 2 flux over the course of weeks to years, respectively. However, there may be longer-term ecosystem responses to elevated CO 2 that could ultimately affect ecosystem CO 2 balance. In addition to atmospheric CO 2, climate may affect net ecosystem carbonmore » balance. Recent results indicate that the arctic has become a source of CO 2 to the atmosphere. This change coincides with recent climatic variation in the arctic, and suggests a positive feedback of arctic ecosystems on atmospheric CO 2 and global change. Measurements along a latitudinal gradient across the north slope of Alaska indicate a loss of carbon from tussock tundra of 156 g m -2 y -1, and from the wet tundra of 34 g m -2 y -1. If these rates are representative of the circumpolar tundra, then they equate to a net annual global loss of carbon as CO 2 to the atmosphere of 0.17 Gt C, 0.14 Gt from tussock tundra, and 0.03 Gt from wet coastal tundra. Depending on the nature, rate, and magnitude of global environmental change, the arctic may have a positive or negative feedback on global change. At present, the initial response of the arctic indicates a net loss of carbon to the atmosphere which could result in a positive feedback on atmospheric C0 2 concentration and greenhouse warming. There are obvious potential errors in scaling plot level measurements to landscape, mesoscale, and global spatial scales. The research proposed in this application has four principal aspects: (A) Long-term response of arctic plants and ecosystems to elevated atmospheric CO 2; (B) Circumpolar patterns of net ecosystem CO 2 flux; (C) In situ controls by temperature and moisture on net ecosystem CO 2 flux; (D) Scaling of CO 2 flux from plot, to landscape, to regional scales (In conjunction with research proposed for NSF support). In Iceland, we will evaluate the long-term (hundreds to thousands of years) effect of atmospheric CO 2 enrichment from cold, CO 2-rich springs on plant photosynthesis, ecosystem CO 2 flux, and community composition and structure. CO 2 flux estimates at a circumpolar scale will be initiated with research in the Russian arctic and Iceland (measurements in Iceland will be obtained in the process of determining the long-term effect of elevated CO 2 on arctic ecosystems). Temperature and moisture will be manipulated in the field to determine their effects on net ecosystem CO 2 flux. In cooperation with a project proposed for funding from NSF's ARCSS LAII program, measurements of CO 2 and other trace gas flux at three spatial scales (plot, landscape, and mesoscale) using chamber, tower-based eddy correlation techniques and aircraft-based eddy correlation techniques will be made. The information obtained from each of these techniques will be analyzed and compared, especially in light of defining the most efficient approaches for estimating large spatial scale CO 2 in the arctic. Remotely-sensed spectral indices, GIS, process models, and phenomenological models will be used to develop a methodology for efficiently estimating ecosystem CO 2 flux over meso- and global scales. Initial testing of the applicability of these methods will be undertaken. Support from the Department of Energy is requested for plat level measurements. support from NSF is also requested for other aspects of scaling.« less

Authors:
 [1]
  1. San Diego State Univ., CA (United States)
Publication Date:
Research Org.:
San Diego State Univ., CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
230262
Report Number(s):
DOE/ER/60479-T6
ON: DE96009525
DOE Contract Number:  
FG03-86ER60479
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: Apr 1992
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; carbon dioxide; environmental effects; tundra; arctic regions; terrestrial ecosystems; progress report; seasonal variations; climatic change; climate models; photosynthesis; plants; air pollution abatement

Citation Formats

Oechel, Walter C. Response of a Tundra Ecosystem to Elevated Atmospheric Carbon Dioxide and CO2-Induced Climate Change: A Renewal Research Proposal. United States: N. p., 1992. Web. doi:10.2172/230262.
Oechel, Walter C. Response of a Tundra Ecosystem to Elevated Atmospheric Carbon Dioxide and CO2-Induced Climate Change: A Renewal Research Proposal. United States. doi:10.2172/230262.
Oechel, Walter C. Wed . "Response of a Tundra Ecosystem to Elevated Atmospheric Carbon Dioxide and CO2-Induced Climate Change: A Renewal Research Proposal". United States. doi:10.2172/230262. https://www.osti.gov/servlets/purl/230262.
@article{osti_230262,
title = {Response of a Tundra Ecosystem to Elevated Atmospheric Carbon Dioxide and CO2-Induced Climate Change: A Renewal Research Proposal},
author = {Oechel, Walter C.},
abstractNote = {Northern ecosystems contain up to 455 Gt of C in the soil active layer and upper permafrost. The soil carbon in these layers is equivalent to approximately 60% of the carbon currently in the atmosphere as CO2. Much of this carbon is stored in the soil as dead organic matter. Its fate is subject to the net effects of global change on the plant and soil systems of northern ecosystems. The arctic alone contains about 60 Gt C, 90% of which is present in the soil active layer and upper permafrost. The arctic is assumed to have been a sink for CO2 during the historic and recent geologic past. The arctic has the potential to be a very large, long-term source or sink of CO2 with respect to the atmosphere. In situ experimental manipulations of atmospheric CO2, indicated that there is little effect of elevated atmospheric CO2 on leaf level photosynthesis or whole-ecosystem CO2 flux over the course of weeks to years, respectively. However, there may be longer-term ecosystem responses to elevated CO2 that could ultimately affect ecosystem CO2 balance. In addition to atmospheric CO2, climate may affect net ecosystem carbon balance. Recent results indicate that the arctic has become a source of CO2 to the atmosphere. This change coincides with recent climatic variation in the arctic, and suggests a positive feedback of arctic ecosystems on atmospheric CO2 and global change. Measurements along a latitudinal gradient across the north slope of Alaska indicate a loss of carbon from tussock tundra of 156 g m-2 y-1, and from the wet tundra of 34 g m-2 y-1. If these rates are representative of the circumpolar tundra, then they equate to a net annual global loss of carbon as CO2 to the atmosphere of 0.17 Gt C, 0.14 Gt from tussock tundra, and 0.03 Gt from wet coastal tundra. Depending on the nature, rate, and magnitude of global environmental change, the arctic may have a positive or negative feedback on global change. At present, the initial response of the arctic indicates a net loss of carbon to the atmosphere which could result in a positive feedback on atmospheric C02 concentration and greenhouse warming. There are obvious potential errors in scaling plot level measurements to landscape, mesoscale, and global spatial scales. The research proposed in this application has four principal aspects: (A) Long-term response of arctic plants and ecosystems to elevated atmospheric CO2; (B) Circumpolar patterns of net ecosystem CO2 flux; (C) In situ controls by temperature and moisture on net ecosystem CO2 flux; (D) Scaling of CO2 flux from plot, to landscape, to regional scales (In conjunction with research proposed for NSF support). In Iceland, we will evaluate the long-term (hundreds to thousands of years) effect of atmospheric CO2 enrichment from cold, CO2-rich springs on plant photosynthesis, ecosystem CO2 flux, and community composition and structure. CO2 flux estimates at a circumpolar scale will be initiated with research in the Russian arctic and Iceland (measurements in Iceland will be obtained in the process of determining the long-term effect of elevated CO2 on arctic ecosystems). Temperature and moisture will be manipulated in the field to determine their effects on net ecosystem CO2 flux. In cooperation with a project proposed for funding from NSF's ARCSS LAII program, measurements of CO2 and other trace gas flux at three spatial scales (plot, landscape, and mesoscale) using chamber, tower-based eddy correlation techniques and aircraft-based eddy correlation techniques will be made. The information obtained from each of these techniques will be analyzed and compared, especially in light of defining the most efficient approaches for estimating large spatial scale CO2 in the arctic. Remotely-sensed spectral indices, GIS, process models, and phenomenological models will be used to develop a methodology for efficiently estimating ecosystem CO2 flux over meso- and global scales. Initial testing of the applicability of these methods will be undertaken. Support from the Department of Energy is requested for plat level measurements. support from NSF is also requested for other aspects of scaling.},
doi = {10.2172/230262},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1992},
month = {4}
}