Sources, deposition rates and decomposition of organic carbon in recent sediment of Sachem Head Harbor, Long Island Sound

Michael D. Krom, Joseph T. Bennett

Research output: Contribution to journalArticlepeer-review

Abstract

The vertical distributions of excess 210Pb and fall out 239, 240Pu imply a uniform sedimentation rate of 1·4-1·6 cm year-1 from 0 to 105-110 cm. This sediment accumulation rate is compatible with sulfate reduction rate data from this location. Below 70 cm only 'aged' refractory carbon is present (CR = 1·8% C) with an age of approximately 2400 years. This phase is present in a number of locations across Long Island Sound. Planktonic carbon (CP) is present above the 60-67 cm horizon. A value of 1·0 for AP (14C activity) at 32-37 cm was taken, AP = 1·285 was used for contemporary plankton. This was obtained by correcting the measured AP of a plankton tow sample for admixed refractory carbon. These values were then used to calculate CR, CP and CF (fossil carbon) at 32-37 cm and 6-12 cm. The only values compatible with the known sulfate reduction rate data are CR equal to pre 60-67 cm levels (1·6-1·8% C), CF being 0·3% C at both depths, and CP decreasing with depth from 0·3 to 0·4% C at 6-12 cm to close to zero at 32-37 cm.

Original languageEnglish
Pages (from-to)325-336
Number of pages12
JournalEstuarine, Coastal and Shelf Science
Volume21
Issue number3
DOIs
StatePublished - Sep 1985
Externally publishedYes

Keywords

  • carbon
  • Connecticut coast
  • fossils
  • isotopes
  • plankton
  • sediment scources

ASJC Scopus subject areas

  • Oceanography
  • Aquatic Science

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