Kinetics of tidal resuspension of microbiota: Testing the effects of sediment cohesiveness and bioturbation using flume experiments
|Author(s)||Blanchard Gérard F1, 2, Sauriau P.G.1, 2, Cariou-Le Gall Valerie1, 2, Gouleau D1, 2, Garet Mj1, 2, Olivier F3|
|Affiliation(s)||1 : IFREMER, CNRS, CTR RECH ECOL MARINE & AQUACULTURE, BP 5, F-17137 LHOUMEAU, FRANCE.
2 : CNRS, FRANCE
3 : LAB MARITIME DINARD, F-35801 DINARD, FRANCE.
|Source||Marine Ecology Progress Series (0171-8630) (Inter-research), 1997 , Vol. 151 , N. 1-3 , P. 17-25|
|WOS© Times Cited||63|
|Keyword(s)||microphytobenthos, bacteria, resuspension, bioturbation, Hydrobia ulvae, shear velocity, sediment cohesiveness, flume experiment|
|Abstract||Resuspension of the top few sediment layers of tidal mud flats is known to enhance planktonic biomass of microbiota (benthic diatoms and bacteria). This process is mainly controlled by tidal shear stress and cohesiveness of mud, and is also influenced by bioturbation activities. Laboratory experiments in a race track flume were performed to test the interactive effects of these factors on both the critical entrainment and resuspension kinetics of microbiota from silt-clay sediments from the Marennes-Oleron Bay, France. The marine snail Hydrobia ulvae was used to mimic surface bioturbation activities. As expected, the kinetics of microbial resuspension versus shear stress were largely controlled by the cohesiveness of silt-clay sediments. However, our results indicate that the effect of surface tracking by H. ulvae on microbial resuspension was clearly dependent on the interaction between sediment cohesiveness and shear velocity. Evidence was also found that microphytobenthos and bacteria are not simultaneously resuspended from silt-clay bioturbated sediments. This supports the theory that diatoms within the easily eroded mucus matrix behave actively and bacteria adhering to fine silt particles eroded at higher critical shear velocities behave passively.|