Premium
CO 2 and CH 4 emissions from streams in a lake‐rich landscape: Patterns, controls, and regional significance
Author(s) -
Crawford John T.,
Lottig Noah R.,
Stanley Emily H.,
Walker John F.,
Hanson Paul C.,
Finlay Jacques C.,
Striegl Robert G.
Publication year - 2014
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1002/2013gb004661
Subject(s) - streams , environmental science , greenhouse gas , groundwater , hydrology (agriculture) , ecosystem , carbon cycle , wetland , carbon dioxide , aquatic ecosystem , biosphere , ecology , environmental chemistry , geology , chemistry , computer network , geotechnical engineering , computer science , biology
Aquatic ecosystems are important components of landscape carbon budgets. In lake‐rich landscapes, both lakes and streams may be important sources of carbon gases (CO 2 and CH 4 ) to the atmosphere, but the processes that control gas concentrations and emissions in these interconnected landscapes have not been adequately addressed. We use multiple data sets that vary in their spatial and temporal extent during 2001–2012 to investigate the carbon gas source strength of streams in a lake‐rich landscape and to determine the contribution of lakes, metabolism, and groundwater to stream CO 2 and CH 4 . We show that streams emit roughly the same mass of CO 2 (23.4 Gg C yr −1 ; 0.49 mol CO 2 m −2 d −1 ) as lakes at a regional scale (27 Gg C yr −1 ) and that stream CH 4 emissions (189 Mg C yr −1 ; 8.46 mmol CH 4 m −2 d −1 ) are an important component of the regional greenhouse gas balance. Gas transfer velocity variability (range = 0.34 to 13.5 m d −1 ) contributed to the variability of gas flux in this landscape. Groundwater inputs and in‐stream metabolism control stream gas supersaturation at the landscape scale, while carbon cycling in lakes and deep groundwaters does not control downstream gas emissions. Our results indicate the need to consider connectivity of all aquatic ecosystems (lakes, streams, wetlands, and groundwater) in lake‐rich landscapes and their connections with the terrestrial environment in order to understand the full nature of the carbon cycle.