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Sources and composition of sediment pore‐water dissolved organic matter in prairie pothole lakes
Author(s) -
Ziegelgruber Kate L.,
Zeng Teng,
Arnold William A.,
Chin Yu-Ping
Publication year - 2013
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.2013.58.3.1136
Subject(s) - dissolved organic carbon , environmental chemistry , biogeochemical cycle , sediment , pore water pressure , organic matter , total organic carbon , environmental science , surface water , chemistry , hydrology (agriculture) , geology , environmental engineering , geomorphology , geotechnical engineering , organic chemistry
Sediment pore‐water dissolved organic matter (DOM) in two North Dakota prairie pothole lakes was quantified by dissolved organic carbon analysis (DOC) and its composition was characterized as a function of sediment depth for molecular weight distribution (MWD), molar absorptivity at 280 nm ( ɛ 280), and fluorescence properties. Fluorescence excitation emission matrices were further analyzed by creating a Parallel Factor Analysis (PARAFAC) model specific to sedimentary pore‐water DOM. The range of absolute pore‐water DOC concentrations (∼ 26–183 mg C L −1 ) greatly exceeded abundances reported for other wetlands and generally increased with depth. Significant changes occurred in ɛ 280 and fluorescence seasonally. Prairie pothole pore‐water DOM is primarily allochthonous in nature and three ‘humic‐like’ components explained ∼ 90% of total sample fluorescence, while a single ‘non‐humic’ component was responsible for the remaining 10%. The contribution of the non‐humic component, however, was more significant in the top 7 cm of sediment in samples collected in early autumn and is presumably derived from algal precursor material produced by primary production in the water column over the summer. The PARAFAC results corroborate ɛ 280 and MWD changes in pore‐water DOM composition over the growing season. This dynamic process could affect the type of DOM available for biogeochemical processes seasonally.