|Intertidal bedforms, sediment transport, and stabilization by benthic microalgae|
Grant, J. (1988). Intertidal bedforms, sediment transport, and stabilization by benthic microalgae, in: de Boer, P.L. et al. (Ed.) Tide-influenced sedimentary environments and facies. Extended versions of papers presented at the Symposium on Classic Tidal Deposits, held August 1985 in Utrecht, Netherlands. pp. 499-510
In: de Boer, P.L. et al. (Ed.) (1988). Tide-influenced sedimentary environments and facies. Extended versions of papers presented at the Symposium on Classic Tidal Deposits, held August 1985 in Utrecht, Netherlands. D. Reidel Publishing: Dordrecht. ISBN 90-277-2622-1. ix, 530 pp., more
Extracellular products of benthic diatoms are known to stabilize intertidal sand sediments, but few quantitative studies of this process have been carried out. Based on the literature as well as new field and flume observations, I summarize the salient features of diatom-sediment relations, and review studies of their effects on sediment transport. Diatom mucus is apparently spread throughout the interstices of surface and subsurface sediments by motile epipelic diatoms which undergo daily vertical migrations. Stabilization (decrease in critical erosion velocity) by these biofilms is caused by both increased cohesion between sediment grains and decreased skin friction. Diatom films may be common on rippled beds, where their heterogeneous distribution is the result of an interaction between removal, burial and stabilization. Diatom binding affects the size and morphology of ripples as well as the supply of fine and coarse grained sediment available for transport. Prediction of the effects of diatom biofilms on sediment transport will require further research efforts on (a) factors affecting the distribution of diatoms on tidal flats (b) chemical indicators of binding which correlate with critical erosion criteria and (c) flume studies of diatom biofilms, sediment erosion, and deposition on both plane and rippled beds.