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Bulk chemistry of sediment core BOFS31/3M-1

Publication Date
DOI: 10.1594/pangaea.199918
  • Biogeochemical Ocean Flux Study
  • Bofs
  • Bofs31/3M
  • Bofs31#3
  • Carbon
  • Organic
  • Total
  • Cd53
  • Charles Darwin
  • Jgofs
  • Joint Global Ocean Flux Study
  • Multicorer
  • Northeast Atlantic
  • Chemistry


Biomarkers in Surface Sediments Introduction This document describes the methodology used to obtain the biomarker profiles presented in the files LSBULK (bulk chemistry), LSANE (alkanes), LSAA (alkanoic acids), LSANOL (alkanols) LIPSED1 and LIPSED2 (lipids in two groups). These files parallel each other containing the same records in the same order, but different channels: they have been subdivided solely to keep the record length reasonable. The methodology is described more fully in Madureira et al (1991). Sampling The cores were taken using a Duncan and Associates multicorer (Barnett (1984)). Essentially, this consists of up to twelve 5.5cm core tubes, 20cm apart mounted on a central block (area 1 m2) connected to a large frame, manufactured from heavy steel tube, through hydraulic dampers. When deployed, the frame settles on the sea bed and the core tubes are gently pressed into the sediment under pressure from a lead weight. On lifting, the core tubes are sealed at each end by spring-loaded plugs. The primary feature of this device is that the sediment-water interface within the core tubes is virtually undisturbed. The cores produced are short, generally less than 20cm and are overlain by approximately the same amount of bottom water. The cores were fine sectioned on board using a Precision Core Extruder (Conte et al (submitted)) capable of producing core segments 1mm in length. Sufficient material for analysis was obtained by pooling segments from two of the core tubes. The samples were immediately immersed in solvent (1:1 CH2Cl2:CH3OH) to prevent oxidation of unsaturated compounds and stored at -20°C until analysed. Analytical Techniques Immediately prior to lipid extraction, the storage solvent was evaporated and the sediment freeze dried and homogenised. An aliquot was taken for bulk chemistry determinations. Carbonate, organic carbon and nitrogen were measured in duplicate using a Perkin Elmer 240B CHN analyser. Organic carbon was determined as the difference between

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