Open AccessHydrologic controls on pCO 2 and CO 2 efflux in US streams and rivers
Author(s) -
Liu Shaoda,
Raymond Peter A.
Publication year - 2018
Publication title -
limnology and oceanography letters
Language(s) - English
Resource type - Journals
ISSN - 2378-2242
DOI - 10.1002/lol2.10095
Subject(s) - streams , efflux , discharge , environmental science , hydrology (agriculture) , chemistry , environmental chemistry , drainage basin , geography , geology , biochemistry , geotechnical engineering , computer science , computer network , cartography
Streams and rivers emit petagrams of CO 2 , yet there is little known about how discharge variability impacts stream CO 2 at broad scales. This article analyzed changes of pCO 2 and CO 2 efflux with discharge in 813 conterminous US streams and rivers. Half of the streams and rivers (49%) showed positive pCO 2 –discharge responses, while significantly more (80%) showed positive CO 2 efflux–discharge responses. More CO 2 efflux therefore occurred at higher discharge. While CO 2 efflux tended to increase with discharge at all stream orders, pCO 2 tended to decrease with discharge in small rivers (stream order 1–6) and increase in large rivers (stream order 7–10). Small streams and rivers tended to release more CO 2 at higher discharge due to highly responsive gas transfer velocity. While high CO 2 efflux in small streams (stream order 1–3) pointed to strong terrestrial input, high CO 2 responsiveness in large rivers was likely due to increased riverine metabolism and river–corridor exchanges.