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Modeling the rate of turnover of DOC and particulate organic carbon in a UK, peat‐hosted stream: Including diurnal cycling in short‐residence time systems
Author(s) -
Worrall F.,
Moody C. S.
Publication year - 2014
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
eISSN - 2169-8961
pISSN - 2169-8953
DOI - 10.1002/2014jg002671
Subject(s) - dissolved organic carbon , particulates , organic matter , residence time (fluid dynamics) , peat , environmental chemistry , cycling , total organic carbon , environmental science , particulate organic matter , biogeochemical cycle , particulate organic carbon , carbon fibers , hydrology (agriculture) , chemistry , nutrient , ecology , phytoplankton , geology , history , materials science , geotechnical engineering , organic chemistry , archaeology , composite number , composite material , biology
This study proposes a multicomponent, multiprocess scheme to explain the turnover of organic matter (particulate and dissolved organic matter) in streams. The scheme allows for production and degradation of organic matter by both photic and aphotic processes with transformation of dissolved organic carbon (DOC) to increasingly refractory forms. The proposed scheme was compared to 10 months of experimental observations of the turnover and fate of particulate and dissolved organic matter in stream water from a peat‐covered catchment. The scheme was able to explain average decline in DOC concentration of 65% over 70 h with a 13% mean average percentage error based on turnover in three types of organic matter (particulate, labile dissolved, and refractory dissolved) although the order and rate of reactions did change between sets of experimental observations. The modeling suggests that activation energies are low for all except the most refractory forms of DOC in turn, suggesting that processes are not sensitive to temperature change. Application of the modeling scheme to organic matter turnover in the River Tees, northern England, showed that annual removal of total organic carbon was equivalent to between 13 and 33 t C/km 2 /yr from an at source export of between 22 and 56 t C/km 2 /yr giving a total in‐stream loss rate of between 53 and 62% over a median in‐stream residence time of 35 h.