INDIGO Home University of Illinois at Urbana-Champaign logo uic building uic pavilion uic student center

Impacts of Changes in Winter Precipitation on C Stocks and Fluxes in Arctic Tussock Tundra

Show full item record

Bookmark or cite this item: http://hdl.handle.net/10027/21809

Files in this item

File Description Format
PDF BLANCBETES-DISSERTATION-2017.pdf (3MB) Restricted Access (no description provided) PDF
Title: Impacts of Changes in Winter Precipitation on C Stocks and Fluxes in Arctic Tussock Tundra
Author(s): Blanc Betes, Maria Elena
Advisor(s): Gonzalez-Meler, Miquel A
Contributor(s): Welker, Jeffrey M; Sturchio, Neil C; Bogner, Jean E; Minor, Emily S; Gonzalez-Meler, Miquel A
Department / Program: Biological Sciences
Degree Granting Institution: University of Illinois at Chicago
Degree: PhD, Doctor of Philosophy
Genre: Doctoral
Subject(s): Arctic Tundra Permafrost Winter precipitation Snow accumulation Climate change Soil organic carbon Carbon fluxes Methane Methanotrophy Methanogenesis Plant-mediated transport Carbon dioxide Gross primary productivity Net ecosystem exchange Heterotrophic respiration Global warming potential Carbon isotopes Radioisotopes
Abstract: The alteration of winter precipitation patterns in Arctic regions represents a potentially important climate forcing agent. However, climate/carbon (C) cycle forcing feedbacks from Arctic regions remain largely unresolved due to uncertainties in the strength, form (CO2 and CH4), direction and timing of ecosystem C fluxes under future precipitation scenarios. I combined C flux measurements and soil organic carbon (SOC) inventories with stable isotope and radioisotope methods in a multi-year, multi-level snow manipulation experiment in Arctic tundra to investigate: i) the rate at which permafrost C will become available for decomposition and will be released relative to ecosystem C inputs under future precipitation scenarios, ii) the magnitude, form and direction of derived climate/C-cycle feedbacks, and iii) the mechanisms driving long-term impacts of changes in winter precipitation on Arctic tundra C budget and fluxes. Results indicated the potential of Arctic tundra to become a transient C source through accelerated soil organic carbon (SOC) mineralization rates under future precipitation scenarios, but also to act as an additional long-term C sink with persistent increases in winter precipitation, as recently thawed SOC may remain largely immobilized over decades under thaw-induced near-water saturated conditions. This additional C sink however, may come at the cost of a substantial positive feedback on climate derived from increases in the net CH4 source strength of Arctic tundra, as warmer and wetter active layer stimulate CH4 production above CH4 oxidation further subsidized by enhanced plant-mediated transport associated to transitions in supported vegetation over the course of progressive permafrost degradation. Results suggested that much of current divergence among model predicted Arctic climate/C-cycle feedbacks may stem from inaccurate representations of the sensitivity of both physical and biological processes to changes in winter precipitation over time. Findings presented here indicate that projected precipitation scenarios will drive the Arctic tundra C budget and shape the radiative forcing from Arctic regions, critically affecting future climate.
Issue Date: 2017-03-03
Type: Thesis
URI: http://hdl.handle.net/10027/21809
Date Available in INDIGO: 2017-10-27
Date Deposited: May 2017
 

This item appears in the following Collection(s)

Show full item record

Statistics

Country Code Views
United States of America 15
China 11
Ukraine 5
Russian Federation 2
Germany 1

Browse

My Account

Information

Access Key