HR: 16:15h
AN: OS52H-08    [PDF]
TI: Radiocarbon Measurements of Benthic Fauna as Indicators of Bentho-Pelagic Coupling and Feeding Strategy
AU: * DeMaster, D J
EM: dave\_demaster@ncsu.edu
AF: Dept. of MEAS, No. Carolina State University, Raleigh, NC 27695 United States
AU: Smith, C R
EM: craigsmi@hawaii.edu
AF: Dept. of Oceanography, University of Hawaii, Honolulu, HI 96822 United States
AU: Thomas, C J
EM: cjthomas@unity.ncsu.edu
AF: Dept. of MEAS, No. Carolina State University, Raleigh, NC 27695 United States
AU: Purinton, B L
EM: Scuby43003@aol.com
AF: Dept. of MEAS, No. Carolina State University, Raleigh, NC 27695 United States
AB: $^{14}$C measurements have been made on benthic faunal body tissues, gut sediments, and surface sediments from the California Borderland and the Antarctic continental margin to track labile organic carbon dynamics in the benthic foodweb. The tissues of epifauna and infauna from these environments can be enriched in $^{14}$C (an index of labile organic matter) by as much as 70 to 200 per mil relative to the $^{14}$C content of surface sediments. Some of this enrichment occurs primarily through particle selection in the sediment column, as exemplified by 60 per mil $^{14}$C enrichments in the gut sediment (relative to surface sediments) of echiuran worms and the holothurian, {\it Peniagone sp.} Other fauna preferentially incorporate the labile organic material (enriched in $^{14}$C) primarily through preferential digestion, as exemplified by a 50 per mil $^{14}$C enrichment in the tissues of the head-down deposit feeding holothurian, {\it Molpadiid sp.}, relative to the $^{14}$C content of its gut sediment. Over the lifetime of these animals (typically many years), the benthic faunal tissues integrate the flux of labile organic material reaching the seabed, which in the Antarctic may by tagged by $^{14}$C activities ranging from --150 per mil (typical upwelling regime) to --40 per mil (enhanced air-sea gas exchange regime).
DE: 4804 Benthic processes/benthos
DE: 4806 Carbon cycling
DE: 4860 Radioactivity and radioisotopes
SC: Ocean Sciences [OS]
MN: 2004 Ocean Sciences Meeting