These data are chromophoric dissolved organic matter (CDOM) Naperian absorption coefficients (ag) of seawater from the North Atlantic subtropical gyre, collected as a part of the OCE-1635618 project, “Transforming our understanding of DIC Photoproduction in Oceanic Waters”. The goal of the project was to investigate and constrain the photoproduction rates and efficiencies of dissolved inorganic carbon (DIC) from photochemical degradation of dissolved organic carbon in the open ocean, which could...
Show moreWater sampling details
Water samples were gravity filtered from Niskin bottles through 0.2 μm Whatman Polycap 36 AS nylon membrane cartridge filters, directly into combusted borosilicate glass bottles. Filtered sample waters were stored in the dark at 4°C until measurements. Sample waters were left in the dark at room temperature (~20°C) so they were back to room temperature before absorbance measurements.
Measurement details
Absorbance (A(λ)) of the water samples were measured at 250–800 nm at 1.0 nm intervals, in triplicate. May 13th, 2017 samples were measured in 10-cm-pathlength quartz spectrophotometric cuvettes with an Agilent 8453 UV-visible spectrophotometer with ChemStation software; July 17th, 2018 samples were measured in a World Precision Instruments UltraPath capillary cell set at 50 cm pathlength using a Maya Pro 2000 spectrophotometer with SpectraSuite software, and the rest of the samples were measured in the same UltraPath capillary cell set at 200 cm pathlength using the same Maya spectrophotometer.
Milli-Q water was similarly measured to use as blanks. The average absorbance spectra of blanks were subtracted from the absorbance spectra of the sample water. Absorbance spectra were further corrected for potential offsets and instrument drift by subtracting the average absorbance at 690–710 nm, before converting A(λ) to Napierian absorption coefficients (ag(λ); m−1), using the following equation: ag(λ)= A(λ) ln10/L, where L (m) is the pathlength.
Brandes, J., Miller, W., Stubbins, A., Powers, L. (2024) Chromophoric Dissolved Organic Matter (CDOM) Napierian Absorption Coefficients from the North Atlantic Subtropical Gyre from R/V Atlantic Explorer AE1707, AE1829, AE1820, AE1905 from 2017-2019 (MODIE project). Biological and Chemical Oceanography Data Management Office (BCO-DMO). (Version 1) Version Date 2024-05-14 [if applicable, indicate subset used]. http://lod.bco-dmo.org/id/dataset/927300 [access date]
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