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Dissolved Organic Carbon Stable Isotopes and Lignin Phenols from Everglades National Park (FCE LTER), South Florida, USA, 2018-ongoing


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Authors: Chris Osburn
Time period: to
Package id: knb-lter-fce.1240.1

How to cite:
Osburn, C.. 2022. Dissolved Organic Carbon Stable Isotopes and Lignin Phenols from Everglades National Park (FCE LTER), South Florida, USA, 2018-ongoing. Environmental Data Initiative. https://doi.org/. Dataset accessed 2024-04-25.

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  • Dataset Abstract
    Estuarine and coastal waters are home to more than half of the world's population and provide many social and economic benefits to society. Additionally, these ecosystems are sites of intense carbon cycling and are under pressure from changing land uses and climate. DOM is functionally defined as the OM passed through a 0.7 µm borosilicate glass fiber filter (GF/F) and is primarily made up of viruses, bacteria, colloids, lignins, humic substances, organic acids, and other small organic compounds (Repeta, 2015). Approximately 50% of DOM is generally considered to be dissolved organic carbon (DOC) (Stedmon and Nelson, 2015). Thus, DOC can be used as a proxy for quantifying DOM. Whole water samples were collected monthly from three different transects representing marl-dominated (Taylor Slough), peat-dominated (Shark River Slough), and seagrass-dominated (Florida Bay) environments. The water was filtered using 0.7 µm porosity glass fiber filters, then acidified to pH 2 and stored at 4°C until processing occurred. DOC concentration and the stable isotope ratio of DOC (δ13C-DOC) was measured on an OI Analytical TOC analyzer coupled to an Agilent Delta V plus Isotope Ratio Mass Spectrometer using high-temperature combustion (Lalonde et al., 2014). Dissolved vanillyl (vanillin, acetovanillone, vanillin acid), syringyl (syringaldehyde, acetosyringone, syringic acid), cinnamyl (p-coumaric acid, ferulic acid), and 3,5-hydroxybenzoic acid lignin phenols were isolated from ~2 liters of 0.7 µm filtered, acidified (pH 2) water by solid phase extraction (SPE) using 1g PPL cartridges that were pre-conditioned using pH 2 water and methanol. SPE cartridges were extracted using methanol, then dried and redissolved in 2N NaOH. Cupric oxide oxidation and liquid-liquid ethyl acetate extraction were used to extract lignin oxidation products (Hedges and Ertel, 1982, modified by Goñi and Hedges, 1995; Louchouarn et al., 2000; Goñi and Montgomery, 2000; Benner and Kaiser, 2011). Briefly, NaOH dissolved samples were added to teflon vessels with CuO, ferrous ammonium sulfate, and glucose then oxidized in a muffle furnace for 150 minutes at 155C (5C/min ramp rate). Samples were then rapidly cooled, vortexed then transferred to centrifuge tubes and centrifuged, then the supernatant was transferred to a new centrifuge tube and internal lignin standards are added and then supernatant is acidified. Ethyl acetate is added to preform liquid-liquid extraction. Ethyl acetate extract is dried over a sodium sulfate column, then extracts are dried. Extracts are redissolved in pyridine then derivatized using BSTFA in a muffle furnace for 1 hr at 60C. Dertivatized samples are then dried and redissolved in dichloromethane then immediately quantified using an Agilent Gas Chromatograph-Mass Spectrometer (GC-MS) according to the method provided by Kaiser and Benner (2012). Benner, R., & Kaiser, K. (2011). Biological and photochemical transformations of amino acids and lignin phenols in riverine dissolved organic matter. Biogeochemistry, 102(1), 209-222. Goñi, M. A., & Hedges, J. I. (1995). Sources and reactivities of marine-derived organic matter in coastal sediments as determined by alkaline CuO oxidation. Geochimica et Cosmochimica Acta, 59(14), 2965-2981. Goñi, M. A., & Montgomery, S. (2000). Alkaline CuO oxidation with a microwave digestion system: Lignin analyses of geochemical samples. Analytical chemistry, 72(14), 3116-3121. Hedges, J. I., & Ertel, J. R. (1982). Characterization of lignin by gas capillary chromatography of cupric oxide oxidation products. Analytical Chemistry, 54(2), 174-178. Kaiser, K., & Benner, R. (2012). Characterization of lignin by gas chromatography and mass spectrometry using a simplified CuO oxidation method. Analytical chemistry, 84(1), 459-464. Lalonde, K., Middlestead, P., & Gélinas, Y. (2014). Automation of 13C/12C ratio measurement for freshwater and seawater DOC using high temperature combustion. Limnology and Oceanography: Methods, 12(12), 816-829. Louchouarn, P.; Opsahl, S.; Benner, R. 2000. Isolation and quantification of dissolved lignin from natural waters using solid phase extraction and GC/MS. Analytical Chem. 2000, 2780-2787 Repeta, D. J. (2015). Chemical characterization and cycling of dissolved organic matter. In Biogeochemistry of marine dissolved organic matter (pp. 21-63). Academic Press. Stedmon, C. A., & Nelson, N. B. (2015). The optical properties of DOM in the ocean. In Biogeochemistry of marine dissolved organic matter (pp. 481-508). Academic Press.
  • Geographic Coverage
    Bounding Coordinates
    SRS1d
    N: 25.7463, S: 25.7463, E: -80.654, W: -80.654

    SRS2
    N: 25.54972811, S: 25.54972811, E: -80.78520692, W: -80.78520692

    SRS3
    N: 25.46820617, S: 25.46820617, E: -80.85327617, W: -80.85327617

    SRS4
    N: 25.40976421, S: 25.40976421, E: -80.96431016, W: -80.96431016

    SRS5
    N: 25.37702258, S: 25.37702258, E: -81.03234716, W: -81.03234716

    SRS6
    N: 25.36462994, S: 25.36462994, E: -81.07794623, W: -81.07794623

    TS/Ph2
    N: 25.40357188, S: 25.40357188, E: -80.60690341, W: -80.60690341

    TS/Ph3
    N: 25.25240534, S: 25.25240534, E: -80.66271768, W: -80.66271768

    TS/Ph9
    N: 25.17692874, S: 25.17692874, E: -80.48978207, W: -80.48978207

    TS/Ph10
    N: 25.02476744, S: 25.02476744, E: -80.68097374, W: -80.68097374

    TS/Ph11
    N: 24.91293492, S: 24.91293492, E: -80.93798347, W: -80.93798347

  • Attributes
    • Data Table:   FCE LTER dissolved carbon and lignin and stable carbon isotopes
      Attribute Name:
      Site
      Attribute Label:
      Site
      Attribute Definition:
      Sampling Site Location
      Storage Type:
      string
      Measurement Scale:
      SRS1d= Shark River Slough site 1d
      SRS2= Shark River Slough site 2
      SRS3= Shark River Slough site 3
      SRS4= Shark River Slough site 4
      SRS5= Shark River Slough site 5
      SRS6= Shark River Slough site 6
      TS1= Taylor River Slough site 1
      TS2= Taylor River Slough site 2
      TS3= Taylor River Slough site 3
      TS6= Taylor River Slough site 6
      TS7= Taylor River Slough site 7
      TS9= Taylor River Slough site 9
      TS10= Taylor River Slough site 10
      TS11= Taylor River Slough site 11
      Missing Value Code:
      -9999 (Sample not currently analyzed)

      Attribute Name:
      Month
      Attribute Label:
      Month
      Attribute Definition:
      Month of the year
      Storage Type:
      float
      Measurement Scale:
      Units: month
      Number Type: integer
      Missing Value Code:
       

      Attribute Name:
      Year
      Attribute Label:
      Year
      Attribute Definition:
      Sampling year
      Storage Type:
      dateTime
      Measurement Scale:
      Missing Value Code:
       

      Attribute Name:
      Date
      Attribute Label:
      Date
      Attribute Definition:
      Date of Sampling
      Storage Type:
      dateTime
      Measurement Scale:
      Missing Value Code:
       

      Attribute Name:
      Sample_Name
      Attribute Label:
      Sample_Name
      Attribute Definition:
      Lab Sample identification name
      Storage Type:
      string
      Measurement Scale:
      Lab Sample identification name
      Missing Value Code:
       

      Attribute Name:
      DOC_mg_L
      Attribute Label:
      DOC_mg_L
      Attribute Definition:
      Dissolved organic carbon concentration in mg per liter
      Storage Type:
      float
      Measurement Scale:
      Units: milligramPerLiter
      Number Type: real
      Missing Value Code:
      -9999 (Sample not currently analyzed)

      Attribute Name:
      d13C_DOC_per_mille
      Attribute Label:
      d13C_DOC_per_mille
      Attribute Definition:
      Stable isotope ratio of dissolved organic carbon
      Storage Type:
      float
      Measurement Scale:
      Units: permil
      Number Type: real
      Missing Value Code:
      -9999 (Sample not currently analyzed)

      Attribute Name:
      Vanillin_ug_L
      Attribute Label:
      Vanillin_ug_L
      Attribute Definition:
      Concentration of vanillin lignin phenol
      Storage Type:
      float
      Measurement Scale:
      Units: microgramPerLiter
      Number Type: real
      Missing Value Code:
      -9999 (Sample not currently analyzed)

      Attribute Name:
      Acetovanillone_ug_L
      Attribute Label:
      Acetovanillone_ug_L
      Attribute Definition:
      Concentration of acetovanillone lignin phenol
      Storage Type:
      float
      Measurement Scale:
      Units: microgramPerLiter
      Number Type: real
      Missing Value Code:
      -9999 (Sample not currently analyzed)

      Attribute Name:
      Vanillic_acid_ug_L
      Attribute Label:
      Vanillic_acid_ug_L
      Attribute Definition:
      Concentration of vanillic acid lignin phenol
      Storage Type:
      float
      Measurement Scale:
      Units: microgramPerLiter
      Number Type: real
      Missing Value Code:
      -9999 (Sample not currently analyzed)

      Attribute Name:
      Syringaldehyde_ug_L
      Attribute Label:
      Syringaldehyde_ug_L
      Attribute Definition:
      Concentration of syringaldehyde lignin phenol
      Storage Type:
      float
      Measurement Scale:
      Units: microgramPerLiter
      Number Type: real
      Missing Value Code:
      -9999 (Sample not currently analyzed)

      Attribute Name:
      Acetosyringone_ug_L
      Attribute Label:
      Acetosyringone_ug_L
      Attribute Definition:
      Concentration of acetosyringone lignin phenol
      Storage Type:
      float
      Measurement Scale:
      Units: microgramPerLiter
      Number Type: real
      Missing Value Code:
      -9999 (Sample not currently analyzed)

      Attribute Name:
      Syringic_acid_ug_L
      Attribute Label:
      Syringic_acid_ug_L
      Attribute Definition:
      Concentration of syringic acid lignin phenol
      Storage Type:
      float
      Measurement Scale:
      Units: microgramPerLiter
      Number Type: real
      Missing Value Code:
      -9999 (Sample not currently analyzed)

      Attribute Name:
      P_coumaric_acid_ug_L
      Attribute Label:
      P_coumaric_acid_ug_L
      Attribute Definition:
      Concentration of p-coumaric acid lignin phenol
      Storage Type:
      float
      Measurement Scale:
      Units: microgramPerLiter
      Number Type: real
      Missing Value Code:
      -9999 (Sample not currently analyzed)

      Attribute Name:
      Ferulic_acid_ug_L
      Attribute Label:
      Ferulic_acid_ug_L
      Attribute Definition:
      Concentration of ferulic acid lignin phenol
      Storage Type:
      float
      Measurement Scale:
      Units: microgramPerLiter
      Number Type: real
      Missing Value Code:
      -9999 (Sample not currently analyzed)

      Attribute Name:
      3_5_dihydroxy_benzoic_acid
      Attribute Label:
      3_5_dihydroxy_benzoic_acid
      Attribute Definition:
      Concentration of 3,5-dihydroxy-benzoic acid lignin phenol
      Storage Type:
      float
      Measurement Scale:
      Units: microgramPerLiter
      Number Type: real
      Missing Value Code:
      -9999 (Sample not currently analyzed)


  • Methods
    Method Step

    Description
    Sampling Description Water samples were collected monthly during January 2018 to January 2021 from a total of 14 sampling stations located in the coastal estuaries of the southern tip of the Florida Peninsula, USA. These stations were established for an on-going water quality monitoring program (http://www.serc.fiu.edu/wqmnetwork). Sampling stations can be largely grouped into 3 distinct districts based on the geomorphological features, that is, Florida Bay (FB, 3 sampling stations), Shark River Slough (SRS, 6 sampling stations), and Taylor Slough (TSPH, 8 sampling stations). Surface water samples were taken from these stations. The samples were collected using pre-washed, brown Nalgen polyethylene bottles (Nalge Nunc International). The samples were stored on ice and returned to the laboratory within 8 h for analysis. Subsamples for dissolved carbon and lignin analysis were filtered through precombusted Whatman GF/F glass fiber filters once received in the laboratory and acidified to pH 2 then kept at 4C until analysis at North Carolina State University could occur.


    Method Step

    Description
    Dissolved organic carbon (DOC) and stable isotope of DOC DOC stable C isotope ratios were measured using high-temperature combustion on an OI Analytical 1030D TOC analyzer coupled in continuous flow to the Delta V+ IRMS. Prior to analysis samples were acidified with 85% H3PO4 to pH 2 and sparged for 10 min with ultra-high purity argon to remove inorganic carbon as CO2). DOC concentrations were calibrated each analytical day with prepared solutions of caffeine, and δ13C values were calibrated VPDB scale with prepared solutions from IAEA-CH6 (δ13C = −10.8‰) and IAEA-600 (δ13C = −27.77‰).


    Method Step

    Description
    Dissolve lignin-derived phenols were isolated from FCE waters using solid-phase extraction (SPE) with 6 mL Agilent Bond Elut PPL filters, which contain 1 g of styrene-divinylbenzene polymer with a non-polar surface (Louchouarn et al., 2000; Arellano et al., 2018). Briefly, the filtered and acidified sample was conditioned with methanol and acidified Milli-Q Ultrapure water to ensure that the sorbent was saturated before the SPE (Louchouarn et al., 2000). An approximately 2 L acidifed sample was pumped through a PPL filter using a peristaltic pump at a rate of 10 mL min-1. The PPL cartridge was rinsed with 18 mL of acidified (pH 2) Milli-Q water to remove any remaining salts (Louchouarn et al., 2000). The PPL cartridge was then dried under ultra-high purity nitrogen gas (10-12 psi) and then eluted into borosilicate glass vials that were baked at 450C for 5 hours, using 9 mL HPLC grade methanol (Arellano et al., 2018). The cupric oxide oxidation (CuO) and liquid-liquid extraction methods (Hedges and Ertel, 1982, modified by Goñi and Hedges, 1995; Louchouarn et al., 2000; Goñi and Montgomery, 2000; Benner and Kaiser, 2011, respectively) were used to extract lignin oxidation products. 500 mg of CuO, 100 mg of ferrous ammonium sulfate (FAS), and 10 mg of glucose was then added to 6 mL Salvillex Teflon reaction vessels. The methanol eluent was split into two subsamples and then dried using nitrogen. One subsample of dried eluent was then redissolved in 3.5 mL of nitrogen-sparged 2 N NaOH and added to the Teflon reaction vessel. The reaction vessel was then briefly sparged with nitrogen to remove excess oxygen and then capped. Samples were then oxidized in a muffle furnace for 150 minutes at 155C (5C min -1 ramp rate). Once oxidation was complete the Teflon vessels were cooled in an ice bath, then vortexed, transferred to polycarbonate tubes and centrifuged at 3200 rpm for 20 minutes. Supernatant was transferred to a new centrifuge tube then ethyl vanillin and t-cinnamic acid are added prior to liquid-liquid extraction to be used as recovery standards. Next the sample was acidified with 85% H3PO4 to pH 2 and then vortexed and centrifuged. Liquid-liquid extraction was completed by addition of 4 mL of ethyl acetate to the acidified sample, followed by vortex and centrifuge, then passed over a Na2SO4 column to remove residual water. Lignin liquid-liquid extracts were then dried under nitrogen, redissolved in 500 uL of pyridine, and stored at -20C until analysis. 50 uL of liquid-liquid extract is then derivatized using 50 uL of N,O-bis (trimethylsilyl) trifluoroacetamide (BSTFA) at 60°C for 1 hour. Derivatized samples were then dried under nitrogen, redissolved in 100 uL of dichloromethane and then measured and quantified immediately on an Agilent Gas Chromatograph-Mass Spectrometer (GC-MS) according to the method provided by Kaiser and Benner (2012). Relative response factors were calculated using t-cinnamic acid to account for instrument variability. Concentrations of dissolved lignin oxidation products are calculated using calibration curves of 9 phenols (vanillyl, syringyl, cinnamyl, and 3,5 Bd) over the range of expected values.


  • Keywords
    dissolved organic carbon, carbon, carbon cycling, stable isotopes, concentration, organic matter, marshes, mangroves, rivers, estuaries, FCE LTER, Florida Coastal Everglades LTER, Everglades National Park, long-term monitoring, dissolved lignin phenols
  • Data Table and Format
    Data Table:  FCE LTER dissolved carbon and lignin and stable carbon isotopes

    Entity Name:
    FCE1240_DON
    Entity Description:
    FCE LTER dissolved carbon and lignin and stable carbon isotopes
    Object Name:
    FCE1240_DON.csv
    Number of Header Lines:
    1
    Attribute Orientation:
    column
    Field Delimiter:
    ,
    Number of Records:
    313