TY - JOUR
T1 - A novel PARAFAC model for continental hot springs reveals unique dissolved organic carbon compositions
AU - Nye, Joshua J.
AU - Shock, Everett L.
AU - Hartnett, Hilairy E.
N1 - Funding Information:
We thank the members of the GEOPIG research group and the YNP field teams for help sampling the YNP hot springs and for critical discussion of these results. We thank Eric Boyd for helpful discussions, Jesse Coe and Brian St. Clair for their help sampling the Tengchong hot springs, and Monica Palta for help with the statistical analysis. We appreciate the helpful comments from three anonymous reviewers that allowed us to improve the manuscript. Yellowstone samples were collected as part of study YELL-5434 (E.L.S.). We gratefully acknowledge funding from NSF CAREER (0846188), NSF OISE/PIRE (0968421), and NASA NExSS (NNX15AD53G) awards to H.E.H. and NASA Exobiology grant (NNX16AJ61G) to E.L.S.
Funding Information:
We thank the members of the GEOPIG research group and the YNP field teams for help sampling the YNP hot springs and for critical discussion of these results. We thank Eric Boyd for helpful discussions, Jesse Coe and Brian St. Clair for their help sampling the Tengchong hot springs, and Monica Palta for help with the statistical analysis. We appreciate the helpful comments from three anonymous reviewers that allowed us to improve the manuscript. Yellowstone samples were collected as part of study YELL-5434 (E.L.S.). We gratefully acknowledge funding from NSF CAREER ( 0846188 ), NSF OISE/PIRE ( 0968421 ), and NASA NExSS ( NNX15AD53G ) awards to H.E.H., and NASA Exobiology grant ( NNX16AJ61G ) to E.L.S.
Publisher Copyright:
© 2020 Elsevier Ltd
PY - 2020/3
Y1 - 2020/3
N2 - Dissolved organic carbon in hot springs reflects a range of sources and biogeochemical processes. We evaluated ~200 continental hot spring samples, with a range in pH and temperature, collected from the Tengchong hydrothermal region, Yunnan Province, China and Yellowstone National Park, Wyoming, USA. Dissolved organic carbon concentrations ranged from 16.7 µM to 2.97 mM. Acidic springs displayed the highest values and widest range in carbon concentration. Alkaline springs had a narrower range and lower average concentrations. Carbon composition was evaluated using ultraviolet absorption and 3D-fluorescence spectroscopy. Total fluorescence was correlated (p < 0.05) with dissolved organic carbon (DOC) concentration. Fluorescence excitation-emission matrices were deconvolved using parallel factor analysis. We validated a five-component model that represented >97% of the total fluorescence. Our model includes three humic-like components, one protein-like component, and one novel component exclusively observed in highly acidic springs. The closest spectral match to the novel component is an acid-soluble lignin produced during high-temperature, acid digestion of wood pulp. Humic-like components were dominant in mid-pH springs (4 < pH < 7) indicating these springs had greater terrestrial carbon input. Acidic springs also exhibited evidence for terrestrial carbon input. Alkaline springs, in contrast, consistently had low dissolved organic carbon content and low fluorescence intensity suggesting that these springs had little terrestrial input. This absence of terrestrial carbon implies a predominantly hydrothermal fluid source. A comparison of the traditional fluorescence indices with our five model components suggest that these indices may have limited utility in continental hot springs with multiple organic matter sources and alteration processes.
AB - Dissolved organic carbon in hot springs reflects a range of sources and biogeochemical processes. We evaluated ~200 continental hot spring samples, with a range in pH and temperature, collected from the Tengchong hydrothermal region, Yunnan Province, China and Yellowstone National Park, Wyoming, USA. Dissolved organic carbon concentrations ranged from 16.7 µM to 2.97 mM. Acidic springs displayed the highest values and widest range in carbon concentration. Alkaline springs had a narrower range and lower average concentrations. Carbon composition was evaluated using ultraviolet absorption and 3D-fluorescence spectroscopy. Total fluorescence was correlated (p < 0.05) with dissolved organic carbon (DOC) concentration. Fluorescence excitation-emission matrices were deconvolved using parallel factor analysis. We validated a five-component model that represented >97% of the total fluorescence. Our model includes three humic-like components, one protein-like component, and one novel component exclusively observed in highly acidic springs. The closest spectral match to the novel component is an acid-soluble lignin produced during high-temperature, acid digestion of wood pulp. Humic-like components were dominant in mid-pH springs (4 < pH < 7) indicating these springs had greater terrestrial carbon input. Acidic springs also exhibited evidence for terrestrial carbon input. Alkaline springs, in contrast, consistently had low dissolved organic carbon content and low fluorescence intensity suggesting that these springs had little terrestrial input. This absence of terrestrial carbon implies a predominantly hydrothermal fluid source. A comparison of the traditional fluorescence indices with our five model components suggest that these indices may have limited utility in continental hot springs with multiple organic matter sources and alteration processes.
KW - 3D-fluorescence spectroscopy
KW - Dissolved organic matter
KW - Hot springs
KW - Humic acids
KW - Hydrothermal
KW - Parallel factor analysis
KW - Tengchong hydrothermal region
KW - Yellowstone National Park
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U2 - 10.1016/j.orggeochem.2019.103964
DO - 10.1016/j.orggeochem.2019.103964
M3 - Article
AN - SCOPUS:85079353548
SN - 0146-6380
VL - 141
JO - Organic Geochemistry
JF - Organic Geochemistry
M1 - 103964
ER -