An overview of the field work research projects under the LOIS Biological I
nfluences On interTidal Areas (BIOTA) programme is presented. The main obje
ctive of BIOTA is to characterize and quantify fluxes of sediments and the
influence of biological components within the intertidal saltmarsh and mudf
lat zones of the main LOIS study area. Three studies concerned with sedimen
t dynamics and the biota at a variety of sites and salt marsh types on the
east coast are described, acid a saltmarsh flux study at a single site in N
orfolk is briefly outlined (Fig, I), Some examples of the preliminary resea
rch findings are shown with reference to selected sites in the Humber estua
ry.
Regular monitoring of sediment levels out on the sand and mudflats showed r
emarkable stability, with the amplitude of variation rarely exceeding 5 cm
over the four years of measurement. Some sites (generally the more cohesive
sediments) displayed a seasonal pattern of elevation change. Oscillations
of surface level changes decreased towards the marsh and damping continued
with increasing vegetation cover. As expected net accretion generally decre
ases landward under reduced submergence times, particularly on the open coa
st marshes; however different sedimentation profiles were observed. In the
Humber estuary, net accretion was generally greatest in the middle to lower
marsh, with periods of erosion at the seaward edge. The role of vegetation
in accretion is complex and may be site specific, affected by a variety of
physical factors. The cord grass, Spar tina anglica appears to have little
effect on sediment deposition, but is more important as a sediment stabili
zer during periods of erosion. The types of models that can be derived from
the BIOTA study are briefly outlined. (C) 1999 Published by Elsevier Scien
ce Ltd. All rights reserved.