CS33 Sediment-Water Interactions
Date: Wednesday, June 12, 2002
Location: Poster Session - VCC
 
AspdenRJ, University of St. Andrews,, St. Andrews,, United Kingdom, rja4@st-andrews
Paterson, D, M, University of St. Andrews, St. Andrews, United Kingdom, dp1@st-andrews.ac.uk
 
INFLUENCE OF THE GENUS RHODOTHAMNIELLA ON THE STABILISATION OF SANDY SEDIMENTS.
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The perennial rhodophyte Rhodothamniella is characterised by its ability to bind sand particles forming an encrusting turf on intertidal rocks. Turf formation reduces algal productivity, due to nutrient limitation and self-shading, but protects against grazing and hydrodynamic stresses, such as wave scour. Studies have been carried out to determine the responses of turf-forming algae to sediment deposition but there is little information on the mechanisms and efficacy of the sediment binding. Filamentous forms may bind sediment by producing a meshwork but may also produce extracellular polymers (e.g. Cynobacteria). This investigation examined the rapidity, effectiveness and mechanism of turf formation in Rhodothamniella. Low Temperature Scanning Electron Microscopy (LTSEM) was used to visualise turf microfabric, while carbohydrate analysis and cytochemical staining confirmed the presence of mucilage within the turf. The stabilising efficacy of this mucilage was tested using a linear flume (8m Armfield). The influence of the polymer on critical shear stress was significant but less than that of the polymer plus the algae, which increased erosion resistance by several orders of magnitude and showed increasing resistance with time.