Premium
Mobilization of optically invisible dissolved organic matter in response to rainstorm events in a tropical forest headwater river
Author(s) -
Pereira Ryan,
Isabella Bovolo C.,
Spencer Robert G. M.,
Hernes Peter J.,
Tipping Edward,
ViethHillebrand Andrea,
Pedentchouk Nikolai,
Chappell Nick A.,
Parkin Geoff,
Wagner Thomas
Publication year - 2014
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2013gl058658
Subject(s) - dissolved organic carbon , environmental science , topsoil , organic matter , tropical rainforest , dry season , hydrology (agriculture) , total organic carbon , rainforest , environmental chemistry , tropics , litter , soil water , ecology , chemistry , geology , soil science , geotechnical engineering , biology
This study emphasizes the importance of rainstorm events in mobilizing carbon at the soil‐stream interface from tropical rainforests. Half‐hourly geochemical/isotopic records over a 13.5 h period from a 20 km 2 tropical rainforest headwater in Guyana show an order of magnitude increase in dissolved organic carbon (DOC) concentration in less than 30 mins (10.6–114 mg/L). The composition of DOC varies significantly and includes optically invisible dissolved organic matter (iDOM) that accounts for a large proportion (4–89%) of the total DOC, quantified using size exclusion chromatography (SEC). SEC suggests that iDOM is comprised of low molecular weight organic moieties, which are likely sourced from fresh leaf litter and/or topsoil, as shown in soils from the surrounding environment. Although poorly constrained at present, the presence of iDOM further downstream during the wet season suggests that this organic matter fraction may represent an unquantified source of riverine CO 2 outgassing in tropical headwaters, requiring further consideration.