Open AccessThe origin and function of dissolved organic matter in agro‐urban coastal streams
Author(s) -
Petrone Kevin C.,
Fellman Jason B.,
Hood Eran,
Donn Michael J.,
Grierson Pauline F.
Publication year - 2011
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2010jg001537
Subject(s) - dissolved organic carbon , environmental science , colored dissolved organic matter , wetland , aquatic ecosystem , ecosystem , environmental chemistry , nutrient , organic matter , streams , hydrology (agriculture) , urban stream , surface water , water quality , ecology , chemistry , phytoplankton , geology , environmental engineering , biology , computer network , geotechnical engineering , computer science
Streams draining urban and agriculture catchments are often a source of inorganic nutrients to downstream aquatic ecosystems, but little is known about how changes in land use influence the quality and biodegradability of dissolved organic matter (DOM). We used parallel factor analysis of excitation‐emission fluorescence spectroscopy and biodegradation incubations to examine how DOM composition influences bioavailable dissolved organic carbon (DOC) in surface waters of urban and agricultural catchments during summer (low flow), winter (high flow) and spring (flow recession). Percent bioavailable DOC was variable for all catchments (2–57%) and negatively related to percent humic‐like fluorescence, but positively related to percent protein‐like fluorescence and simple fluorescence metrics of DOM precursor material (fluorescence index and β : α values). Conversely, highly variable DOC concentrations (2–140 mg L −1 ) were negatively related to protein‐like fluorescence and positively related to humic‐like fluorescence. Elevated concentrations of DOC (>30 mg L −1 ) in agro‐urban streams revealed fluorescence indices (<1.3) typical of wetland and forest‐dominated ecosystems, suggesting that enriched stream DOM is either derived from the destabilization of legacy soil carbon or currently produced from remnant wetlands and patches of native vegetation. Overall, we demonstrate that fluorescence characteristics can be used to predict bioavailable DOC in human‐dominated catchments to better understand the flow of carbon and nutrients in aquatic food webs for improved monitoring and management of coastal ecosystems.