Table of Contents

• Coverage
• Dataset Description
  • Methods & Sampling
  • Data Processing Description
• Data Files
• Related Publications
• Parameters
• Instruments
• Deployments
• Project Information
• Funding

Samples were filtered straight from Niskin bottles following established protocols for trace-metal clean sampling (Sample handling protocols for GEOTRACES cruises).

Samples for DOC concentration were acidified to pH 2.5 and analyzed by high-temperature combustion on a Shimadzu TOC-L. DOC was calculated as the mean of between three and five injections using a six-point standard curve.

Lignin-derived phenols were determined following Yan and Kaiser (2018; Anal. Chem), and Yan and Kaiser (2018; Analytica Chimica Acta). Briefly, C18 extracts were redissolved in 200 μL of 1.1 mol L−1 argon- sparged (10 min) NaOH in a 400 uL Teflon vial (Savillex Corp) and amended with containing 500 mg CuO, and amended with 10μL of10 mmolL−1 CuSO4 and 10μ L of 0.2 molL−1 ascorbic acid. Oxidation was at 150 C for 120 minutes. Following oxidation, the samples were spiked with with a surrogate standard mixture of p- hydroxybenzoic acid-13C7, vanillin-13C6, and syringaldehyde-13C6 and acidified to pH ≈ 2.5 with 6 mol L−1 sulfuric acid in the reaction vials.  Clean-up of samples was performed with Waters HLB cartrides and final sample eluates were dried under ultra-high purity argon. Phenols were quantified by liquid chromatography/electrospray ionization-tandem mass spectrometry using a five-point calibration curve bracketing the concentration range. Quantified phenols (TDLP included vanillin, acetovanillone, vanillic acid, syringaldehyde, acetosyringone, syringic acid, coumaric acid, ferulic acid, p-hydroxy-benzaldehyde, p-hydroxy-acetophenone, and p-hydroxy-benzoic acid.

Samples were filtered straight from Niskin bottles following established protocols for trace-metal clean sampling (Sample handling protocols for GEOTRACES cruises)

Samples for DOC concentration were acidified to pH 2.5 and analyzed by high-temperature combustion on a Shimadzu TOC-L. DOC was calculated as the mean of between three and five injections using a six-point standard curve.

Lignin-derived phenols were determined following Yan and Kaiser (2018; Anal. Chem), and Yan and Kaiser (2018; Analytica Chimica Acta). Briefly, C18 extracts were redissolved in 200 μL of 1.1 mol L−1 argon- sparged (10 min) NaOH in a 400 uL Teflon vial (Savillex Corp) and amended with containing 500 mg CuO, and amended with 10μL of10 mmolL−1 CuSO4 and 10μ L of 0.2 molL−1 ascorbic acid. Oxidation was at 150 C for 120 minutes. Following oxidation, the samples were spiked with with a surrogate standard mixture of p- hydroxybenzoic acid-13C7, vanillin-13C6, and syringaldehyde-13C6 and acidified to pH ≈ 2.5 with 6 mol L−1 sulfuric acid in the reaction vials.  Clean-up of samples was performed with Waters HLB cartrides and final sample eluates were dried under ultra-high purity argon. Phenols were quantified by liquid chromatography/electrospray ionization-tandem mass spectrometry using a five-point calibration curve bracketing the concentration range. Quantified phenols: TDLP included vanillin, acetovanillone, vanillic acid, syringaldehyde, acetosyringone, syringic acid, coumaric acid, ferulic acid, p-hydroxy-benzaldehyde, p-hydroxy-acetophenone, and p-hydroxy-benzoic acid.

BCO-DMO Processing: modified parameter names (removed units; replaced spaces and slashes with underscores).

NSF Award Abstract:
The distribution and fate of land-derived, or terrigenous, organic matter in the ocean has long been of interest to oceanographers, but that interest has grown considerably as research on the marine and global carbon cycle intensifies. Lignin is a major structural polymer found only in vascular plants, making lignin a unique tracer of terrigenous organic matter input to the marine environment. The current analytical tool for analyzing lignin, breaking it into a suite of identifiable phenolic compounds, is complex, time consuming and requires 10 to 30 liters of water. Given these limitations, applications of lignin phenols as tracers of terrestrial organic carbon in the ocean have been sparse. Through this project, the researchers aim to redesign existing chemical methodology together with modified instrumental detection for even 3 times greater sensitivity using a sample of less than 200 milliliters. Outfitting the scientific community with new methodology to sensitively trace this marker of terrigenous organic carbon will provide a clearer understanding of organic matter fluxes between and within terrestrial and oceanic reservoirs, and potentially establish lignin phenols as a robust oceanographic tracer. This project will support the development of the next generation of scientists, including an early career investigator, and graduate and undergraduate students.

Lignin phenol measurements have been used to study general distribution patterns and mechanisms of decomposition of terrigenous dissolved organic carbon (tDOC) in the global ocean. The distribution pattern of tDOC among ocean basins is generally consistent with the global pattern of riverine discharge to the ocean basins. However, large scale generalizations required and more fully resolved distributions of lignin as a tracer of tDOC are hampered by the difficulties and limitations associated with the present lignin phenol method. The main objectives of this project are to (1) develop methodology for measuring dissolved lignin in ultra-low volumes at high sensitivity in open ocean seawater and (2) apply the new method to study terrigenous tDOC processing and transport in the Eurasian Basin of the Arctic Ocean, where large Siberian rivers deliver the bulk of tDOC to the shelf areas. Results from this research will help evaluate lignin phenols as robust oceanographic tracers, useful to study physical mixing in the Arctic Ocean and potentially improve our understanding of the fate and removal of terrigenous organic carbon in the oceans. Addressing the second objective would provide well-constrained decay constants for lignin and tDOC in the Arctic Ocean and provide novel information on halocline formation. Integration of tDOC budgets, freshwater budgets, and circulation and atmospheric patterns will ultimately improve understanding of biogeochemical cycles in the Arctic Ocean and its role in global climate.