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Low contribution of internal metabolism to carbon dioxide emissions along lotic and lentic environments of a Mediterranean fluvial network
Author(s) -
GómezGener Lluís,
Schiller Daniel,
Marcé Rafael,
Arroita Maite,
CasasRuiz Joan Pere,
Staehr Peter Anton,
Acuña Vicenç,
Sabater Sergi,
Obrador Biel
Publication year - 2016
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
eISSN - 2169-8961
pISSN - 2169-8953
DOI - 10.1002/2016jg003549
Subject(s) - fluvial , river ecosystem , environmental science , lake ecosystem , mediterranean climate , carbon dioxide , hydrology (agriculture) , ecosystem , drainage basin , ecology , geology , geomorphology , structural basin , biology , geography , geotechnical engineering , cartography
Inland waters are significant sources of carbon dioxide (CO 2 ) to the atmosphere. CO 2 supersaturation and subsequent CO 2 emissions from inland waters can be driven by internal metabolism, external inputs of dissolved inorganic carbon (DIC) derived from the catchment, and other processes (e.g., internal geochemical reactions of calcite precipitation or photochemical mineralization of organic solutes). However, the sensitivity of the magnitude and sources of CO 2 emissions to fluvial network hydromorphological alterations is still poorly understood. Here we investigated both the magnitude and sources of CO 2 emissions from lotic (i.e., running waters) and lentic (i.e., stagnant waters associated to small dams) waterbodies of a Mediterranean fluvial network by computing segment‐scale mass balances of CO 2 . Our results showed that sources other than internal metabolism sustained most (82%) of the CO 2 emissions from the studied fluvial network. The magnitude and sources of CO 2 emissions in lotic waterbodies were highly dependent on hydrology, with higher emissions dominated by DIC inputs derived from the catchment during high flows and lower emissions partially fueled by CO 2 produced biologically within the river during low flows. In contrast, CO 2 emissions in lentic waterbodies were low, relatively stable over the time and the space, and dominated by DIC inputs from the catchment regardless of the different hydrological situations. Overall, our results stress the sensitivity of fluvial networks to human activities and climate change and particularly highlight the role of hydromorphological conditions on modulating the magnitude and sources of CO 2 emissions from fluvial networks.