Pan-arctic trends in terrestrial dissolved organic matter from optical measurements
Climate change is causing extensive warming across arctic regions resulting in permafrost degradation, alterations to regional hydrology, and shifting amounts and composition of dissolved organic matter (DOM) transported by streams and rivers. Here, we characterize the DOM composition and optical pr...
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ftdoajarticles:oai:doaj.org/article:7056af62ceb2499ca3199ece32c2218b 2023-05-15T14:35:14+02:00 Pan-arctic trends in terrestrial dissolved organic matter from optical measurements Paul James Mann Robert GM Spencer Peter J Hernes Johan eSix George R Aiken Suzanne E Tank James W McClelland Kenna D Butler Rachael Y Dyda Robert M Holmes 2016-03-01T00:00:00Z https://doi.org/10.3389/feart.2016.00025 https://doaj.org/article/7056af62ceb2499ca3199ece32c2218b EN eng Frontiers Media S.A. http://journal.frontiersin.org/Journal/10.3389/feart.2016.00025/full https://doaj.org/toc/2296-6463 2296-6463 doi:10.3389/feart.2016.00025 https://doaj.org/article/7056af62ceb2499ca3199ece32c2218b Frontiers in Earth Science, Vol 4 (2016) Carbon Cycle Climate Change Lignin fluorescence Arctic Dissolved organic carbon (DOC) Science Q article 2016 ftdoajarticles https://doi.org/10.3389/feart.2016.00025 2022-12-31T12:16:59Z Climate change is causing extensive warming across arctic regions resulting in permafrost degradation, alterations to regional hydrology, and shifting amounts and composition of dissolved organic matter (DOM) transported by streams and rivers. Here, we characterize the DOM composition and optical properties of the six largest arctic rivers draining into the Arctic Ocean to examine the ability of optical measurements to provide meaningful insights into terrigenous carbon export patterns and biogeochemical cycling. The chemical composition of aquatic DOM varied with season, spring months were typified by highest lignin phenol and dissolved organic carbon (DOC) concentrations with greater hydrophobic acid content, and lower proportions of hydrophilic compounds, relative to summer and winter months. Chromophoric DOM (CDOM) spectral slope (S275-295) tracked seasonal shifts in DOM composition across river basins. Fluorescence and parallel factor analysis identified seven components across the six Arctic rivers. The ratios of ‘terrestrial humic-like’ versus ‘marine humic-like’ fluorescent components co-varied with lignin monomer ratios over summer and winter months, suggesting fluorescence may provide information on the age and degradation state of riverine DOM. CDOM absorbance (a350) proved a sensitive proxy for lignin phenol concentrations across all six river basins and over the hydrograph, enabling for the first time the development of a single pan-arctic relationship between a350 and terrigenous DOC (R2 = 0.93). Combining this lignin proxy with high-resolution monitoring of a350, pan-arctic estimates of annual lignin flux were calculated to range from 156 to 185 Gg, resulting in shorter and more constrained estimates of terrigenous DOM residence times in the Arctic Ocean (spanning 7 months to 2½ years). Furthermore, multiple linear regression models incorporating both absorbance and fluorescence variables proved capable of explaining much of the variability in lignin composition across rivers and seasons. Our ... Article in Journal/Newspaper Arctic Arctic Ocean Climate change permafrost Directory of Open Access Journals: DOAJ Articles Arctic Arctic Ocean Frontiers in Earth Science 4 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Carbon Cycle Climate Change Lignin fluorescence Arctic Dissolved organic carbon (DOC) Science Q |
spellingShingle |
Carbon Cycle Climate Change Lignin fluorescence Arctic Dissolved organic carbon (DOC) Science Q Paul James Mann Robert GM Spencer Peter J Hernes Johan eSix George R Aiken Suzanne E Tank James W McClelland Kenna D Butler Rachael Y Dyda Robert M Holmes Pan-arctic trends in terrestrial dissolved organic matter from optical measurements |
topic_facet |
Carbon Cycle Climate Change Lignin fluorescence Arctic Dissolved organic carbon (DOC) Science Q |
description |
Climate change is causing extensive warming across arctic regions resulting in permafrost degradation, alterations to regional hydrology, and shifting amounts and composition of dissolved organic matter (DOM) transported by streams and rivers. Here, we characterize the DOM composition and optical properties of the six largest arctic rivers draining into the Arctic Ocean to examine the ability of optical measurements to provide meaningful insights into terrigenous carbon export patterns and biogeochemical cycling. The chemical composition of aquatic DOM varied with season, spring months were typified by highest lignin phenol and dissolved organic carbon (DOC) concentrations with greater hydrophobic acid content, and lower proportions of hydrophilic compounds, relative to summer and winter months. Chromophoric DOM (CDOM) spectral slope (S275-295) tracked seasonal shifts in DOM composition across river basins. Fluorescence and parallel factor analysis identified seven components across the six Arctic rivers. The ratios of ‘terrestrial humic-like’ versus ‘marine humic-like’ fluorescent components co-varied with lignin monomer ratios over summer and winter months, suggesting fluorescence may provide information on the age and degradation state of riverine DOM. CDOM absorbance (a350) proved a sensitive proxy for lignin phenol concentrations across all six river basins and over the hydrograph, enabling for the first time the development of a single pan-arctic relationship between a350 and terrigenous DOC (R2 = 0.93). Combining this lignin proxy with high-resolution monitoring of a350, pan-arctic estimates of annual lignin flux were calculated to range from 156 to 185 Gg, resulting in shorter and more constrained estimates of terrigenous DOM residence times in the Arctic Ocean (spanning 7 months to 2½ years). Furthermore, multiple linear regression models incorporating both absorbance and fluorescence variables proved capable of explaining much of the variability in lignin composition across rivers and seasons. Our ... |
format |
Article in Journal/Newspaper |
author |
Paul James Mann Robert GM Spencer Peter J Hernes Johan eSix George R Aiken Suzanne E Tank James W McClelland Kenna D Butler Rachael Y Dyda Robert M Holmes |
author_facet |
Paul James Mann Robert GM Spencer Peter J Hernes Johan eSix George R Aiken Suzanne E Tank James W McClelland Kenna D Butler Rachael Y Dyda Robert M Holmes |
author_sort |
Paul James Mann |
title |
Pan-arctic trends in terrestrial dissolved organic matter from optical measurements |
title_short |
Pan-arctic trends in terrestrial dissolved organic matter from optical measurements |
title_full |
Pan-arctic trends in terrestrial dissolved organic matter from optical measurements |
title_fullStr |
Pan-arctic trends in terrestrial dissolved organic matter from optical measurements |
title_full_unstemmed |
Pan-arctic trends in terrestrial dissolved organic matter from optical measurements |
title_sort |
pan-arctic trends in terrestrial dissolved organic matter from optical measurements |
publisher |
Frontiers Media S.A. |
publishDate |
2016 |
url |
https://doi.org/10.3389/feart.2016.00025 https://doaj.org/article/7056af62ceb2499ca3199ece32c2218b |
geographic |
Arctic Arctic Ocean |
geographic_facet |
Arctic Arctic Ocean |
genre |
Arctic Arctic Ocean Climate change permafrost |
genre_facet |
Arctic Arctic Ocean Climate change permafrost |
op_source |
Frontiers in Earth Science, Vol 4 (2016) |
op_relation |
http://journal.frontiersin.org/Journal/10.3389/feart.2016.00025/full https://doaj.org/toc/2296-6463 2296-6463 doi:10.3389/feart.2016.00025 https://doaj.org/article/7056af62ceb2499ca3199ece32c2218b |
op_doi |
https://doi.org/10.3389/feart.2016.00025 |
container_title |
Frontiers in Earth Science |
container_volume |
4 |
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1766308103188381696 |