Abstract:

This dataset contains percent total carbon (%C), percent total nitrogen (%N), d13C values (in per mil units), and d15N values (in per mil units). Values reported are for inland soils collected 5 m from the a marsh vegetation edge (where the vegetation meets the open water). Worksheets are separated by CWC core site, and vegetation values are included on a separate worksheet. Samples are denoted for the sampling time (M13 for May 2013 and O13 for October 2013), marsh location, and then soil core depths, as ""A"" for 0-1 cm depth, ""B"" for 1-2 cm depth, ""C"" for 4-5 cm depth, and ""D"" for 9-10 cm depth.

Suggested Citation:

Engel, Annette. 2016. Marsh soil profiles of Carbon/Nitrogen and d13C/ d15N, Grand Isle, Port Sulphur, Terrebonne Bay, Louisiana, May-October 2013. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N7DZ067D

Purpose:

Determine the sources of and changes in soil organic matter at Louisiana marshes from carbon and nitrogen isotope compositions.

Data Parameters and Units:

These data are reported as percent total carbon (%C), percent total nitrogen (%N), d13C values (in per mil units), and d15N values (in per mil units).

Methods:

Sediment cores were collected in May 2013 and October 2013. Sediment core depths collected were 0-1cm below the surface (“A”), 1-2cm (“B”), 4-5cm (“C”), and 9-10cm (“D”). For isotopic analysis, portions of the sediment core sections were lyophilized; sieved into size fractions >2mm, 2mm-1mm, <1mm, and “bulk” (all size fractions); and ground with agate mortar and pestles. Duplicates of all sample size fractions were prepared as 2-6mg aliquots in tin cups; one replicate set was acid fumigated for organic d13C analysis (Harris et al., 2001). The carbon and nitrogen stable isotopic compositions were determined in a continuous flow mass spectrometer (Finnegan DELTAplus XL); total carbon and nitrogen contents were measured in a peripheral elemental analyzer (Costech ECS4010). Reference standards are UT729, acetCost, and KNO3cil. Harris, D., W. R. Horwáth and C. van Kessel (2001). Acid fumigation of soils to remove carbonates prior to total organic carbon or CARBON-13 isotopic analysis. Soil Sci. Soc. Am. J. 65(6): 1853-1856.

Instruments:

Finnegan DELTAplus XL Costech ECS 4010 Elemental Analyzer

Individual Files: