Open AccessCleaner air reveals growing influence of climate on dissolved organic carbon trends in northern headwaters
Author(s) -
Heleen A. de Wit,
John L. Stoddard,
Donald T. Monteith,
James Sample,
Kari Austnes,
Suzanne Couture,
Jens Fölster,
Scott N. Higgins,
Daniel Houle,
Jakub Hruška,
Pavel Krám,
Jiřı́ Kopáček,
Andrew M. Paterson,
Salar Valinia,
Herman van Dam,
Jussi Vuorenmaa,
Chris Evans
Publication year - 2021
Publication title -
environmental research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.37
H-Index - 124
ISSN - 1748-9326
DOI - 10.1088/1748-9326/ac2526
Subject(s) - dissolved organic carbon , environmental science , precipitation , ecosystem , carbon cycle , total organic carbon , deposition (geology) , sulfate , terrestrial ecosystem , surface water , carbon flux , hydrology (agriculture) , physical geography , environmental chemistry , ecology , chemistry , geography , geology , sediment , environmental engineering , meteorology , biology , paleontology , geotechnical engineering , organic chemistry
Surface water browning, the result of increasing concentrations of dissolved organic matter (DOM), has been widespread in northern ecosystems in recent decades. Here, we assess a database of 426 undisturbed headwater lakes and streams in Europe and North America for evidence of trends in DOM between 1990 and 2016. We describe contrasting changes in DOM trends in Europe (decelerating) and North America (accelerating), which are consistent with organic matter solubility responses to declines in sulfate deposition. While earlier trends (1990–2004) were almost entirely related to changes in atmospheric chemistry, climatic and chemical drivers were equally important in explaining recent DOM trends (2002–2016). We estimate that riverine DOM export from northern ecosystems increased by 27% during the study period. Increased summer precipitation strengthened upward dissolved organic carbon trends while warming apparently damped browning. Our results suggest strong but changing influences of air quality and climate on the terrestrial carbon cycle, and on the magnitude of carbon export from land to water.