Exogenously produced CO2 doubles the CO2 efflux from three north temperate lakes. Issue 5 (4th March 2016)

• Record Type: Journal Article
• Authors: Wilkinson, Grace M.; Buelo, Cal D.; Cole, Jonathan J.; Pace, Michael L.
• Is Part Of: Geophysical research letters. Volume 43:Issue 5(2016)
• Page Start: 1996
• Page End: 2003
• Publication Date: 2016-03-04
• Subjects: carbon dioxide -- lakes -- exogenous carbon; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2016GL067732
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: It is well established that lakes are typically sources of CO2 to the atmosphere. However, it remains unclear what portion of CO2 efflux is from endogenously processed organic carbon or from exogenously produced CO2 transported into lakes. We estimated high‐frequency CO2 and O2 efflux from three north temperate lakes in summer to determine the proportion of the total CO2 efflux that was exogenously produced. Two of the lakes were amended with nutrients to experimentally enhance endogenous CO2 uptake. In the unfertilized lake, 50% of CO2 efflux was from exogenous sources and hydrology had a large influence on efflux. In the fertilized lakes, endogenous CO2 efflux was negative (into the lake) yet exogenous CO2 made the lakes net sources of CO2 to the atmosphere. Shifts in hydrologic regimes and nutrient loading have the potential to change whether small lakes act primarily as reactors or vents in the watershed. Key Points: A substantial portion of the CO2 released from three lakes was produced exogenously Despite positive net ecosystem production, lakes were carbon sources to the atmosphere