<div><p><strong>Sampling and analytical procedures: </strong></p>
<p>For samples in this study, Whatman glass-fiber filters (GF/F) with a nominal 0.7 µm pore size were used to filter samples collected on the P18-2016 and GOA2013 cruises. Polycarbonate filters with a nominal 0.4 µm pore size were used to filter samples collected on the CoFeMUG and WebbPacific2007 cruises. Polyesthersulfone (PES) filters with a nominal 0.2 µm pore size were used to filter samples collected from SCALE, SWINGS, P06-2017, ETSP2010, ETSP2011 and GOM2019 cruises. All samples were stored in high density polyethylene bottles at -20 ˚C until measuring total dissolved phosphorus (TDP) concentration.</p>
<p>DOP (Dissolved Organic Phosphorus) concentrations in this study were calculated as the difference between TDP concentrations ([TDP]) and SRP concentrations ([SRP]) of samples ([DOP] = [TDP] - [SRP]). For DOP concentrations reported here, TDP concentrations were measured by the ash/hydrolysis method based on Monaghan and Ruttenberg, 1999. Briefly, for samples collected >1 year prior to analysis, the sample pH was reduced to 1 by adding ~150 µL 6 M ACS-grade HCl to the sample bottle and placing the bottle in a reciprocal shaker overnight. Then, 6 ml of the acidified sample was added to an acid washed, 500 ˚C combusted glass vial, and 0.6 ml of 4.3 M NaCl/0.3 M MgSO4 solution was added to the acidified sample. Subsequently, vials were put into a drying oven at 70 ˚C until appearing dry (often 4-5 days). Then, each vial was covered with aluminum foil and transferred to a muffle oven to bake at 130 ˚C for 3 hours and then at 500 ˚C for 4.5 hours. Afterwards, 1.8 mL 0.75 M ACS-grade HCl was added to each vial and capped tightly with Teflon-lined caps, then heated at 80 ˚C for 20 min to hydrolyze the polyphosphate left after ashing. After heating, 4.2 mL ultra-pure water (18.2 MΩ_ cm) was added to each vial and heated at 80 ˚C for 10 min to dissolved all remaining solids. I assume quantitative conversion of DOP to SRP and the resulting SRP concentration was measured by using the colorimetric phosphomolybdate-blue method (Hansen and Koroleff, 1999). The final DOP concentration was calculated by the difference between SRP concentration and TDP concentration ([DOP] = [TDP] - [SRP]). </p>
<p>TDP concentrations collected from the published literature were measured by three methods: ash/hydrolysis, UV oxidation, and wet oxidation. The ash/hydrolysis method was also used on samples from the Pulse-26, STN F, KT00A, B, KT01Eq, EN391 and SJ0609 cruises. Wet oxidation is a chemical oxidation where a persulfate reagent is added to seawater and then heated to 120 ˚C for 30 minutes to convert DOP to SRP (Hansen and Koroleff, 1999). Wet oxidation methods were employed to determine TDP concentrations on cruises including BIOSOPE, OUTPACE, KH-11-10, KH-12-3, KH-13-7, KH-14-3, KH-17-4, SATL2004, KM0415, Line P and Latitude II cruises, and at the BATS site. UV oxidation is a photochemical oxidation method using UV radiation to covert DOP to SRP (Armstrong et al., 1966). UV oxidation methods were used to measure the TDP concentrations on cruises including AMT 10, AMT 12, AMT 14, AMT 15, AMT 16, D279, 36N, Line P, GB 93, MAB 94, MAB 96, Cavender-Barres cruises, and at Station ALOHA</p></div>
DOP concentration observations in the global ocean between 1990 and 2021.
<div><p>DOP (Dissolved Organic Phosphorus) concentration observations in the global ocean between 1990 and 2021.</p></div>
DOPv2021
<div><p><strong>Processing notes from researchers:</strong></p>
<p>Any reported negative DOP concentration (DOP concentrations <0 µM) is marked as “BDL”( below detection limits) in this dataset. A quality flag is added to the DOP concentration by using WOCE Water Sample Quality Codes. In this dataset, DOP concentrations with “BDL” are flagged with code 3 (“questionable measurements”) and other DOP concentrations are flagged with code 2 (“acceptable measurement”). </p>
<p><strong>Version 2 dataset updates:</strong></p>
<p>Data quality flag column added</p>
<p>The PO4 column has been renamed to SRP (soluble reactive phosphorus) to improve accuracy </p>
<p><strong>Version 3 dataset updates:</strong></p>
<p>Metadata (e.g. sampling date, Salinity, Temperature, NO3+NO2 and SRP) have been added for the cruise Gulf of Alaska 2013, AMT10, AMT12, AMT14, AMT15, AMT17, KH-11-10, KH-12-3, KH-13-7, KH-14-3, KH-17-4, OC279, OC297, OC318, and OC325.</p>
<p><strong>Version 4 dataset updates:</strong></p>
<p>Dr. Kaycie Lanpher shared DOP concentration observations from the GO-SHIP P06-2017 cruise based on the published article (Lanpher & Popendorf, 2021) with the Contact Zhou Liang, and these DOP concentration observations were added into the DOPv2021 dataset with their authorization.</p>
<p> </p></div>
855139
DOPv2021
2021-07-06T14:57:20-04:00
2021-07-06T14:57:20-04:00
2023-10-13T16:57:11-04:00
urn:bcodmo:dataset:855139
Fields renamed to conform with BCO-DMO standard data practices
Date format converted to yyyy-mm-dd from mm/dd/yy
Removed commas from the reference field
DOP concentration observations from the global ocean between 1990 and 2021 (DOP N2 fixation and export production project)
DOP (Dissolved Organic Phosphorus) concentration observations in the global ocean between 1990 and 2021 over multiple deployments. DOP concentrations in this study were calculated as the difference between TDP concentrations and SRP concentrations of samples. For DOP concentrations reported here, TDP concentrations were measured by the ash/hydrolysis method based on Monaghan and Ruttenberg, 1999.
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Knapp, A. N., Letscher, R. T., Liang, Z. (2023) DOP concentration observations from the global ocean between 1990 and 2021 (DOP N2 fixation and export production project). Biological and Chemical Oceanography Data Management Office (BCO-DMO). (Version 4) Version Date 2023-10-15 [if applicable, indicate subset used]. doi:10.26008/1912/bco-dmo.855139.4 [access date]
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2023-08-15
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