Aquatic Sciences Meeting, Albuquerque 2001

SS08 Processes at the Benthic Interface (Environmental Connections)

Date: Monday, February 12, 2001, Time: 4:00:00 PM

Location: Ruidoso/Pecos

Fornes, W, L, Case Western Reserve University, Cleveland, OH, USA, wlf2@po.cwru.edu

Smith, C, R, University of Hawaii, Honolulu, HI, USA, csmith@soest.hawaii.edu

DeMaster, D, J, North Carolina State University, Raleigh, NC, USA, dave_demaster@ncsu.edu

THE RELATIONSHIP BETWEEN TIME SCALE AND MIXING INTENSITY IN MARINE SEDIMENTS

The time scale over which Db is evaluated affects the value of Db in most deep-sea sediments . A regression analysis incorporating Db values (n = 505) from several deep-sea and continental margin sites indicated a negative correlation between Db and time scale (R = 0.73, p << 0.0001). The statistical and physical significance of this relationship was strengthened when shallow water sites (z < 500 m) were excluded (R = 0.90, p << 0.0001) and persisted when time scales in which the diffusive analogy may be inappropriate (t < 70 d for z > 500 m) were excluded (R = 0.79, p << 0.0001). If selective mixing of labile organic carbon-enriched particles occurs, shorter time-scale tracers should yield higher Db values. Combining this model with the model derived by Middelburg (1989) indicated a positive correlation between Db and the first-order reaction rate constant for organic carbon degradationand predicted degradation rates constants consistent with literature values. This relationship supports the Age-Dependent Mixing hypothesis, in which younger, food-rich particles undergo more intense mixing than older, food-poor particles.

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Aquatic Sciences Meeting, Albuquerque 2001

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