Mireille Consalvey PhD Thesis - University of St Andrews

Bi0fillill formation jild
intervals Taylor and Paterson (1998) determined there to be a significant log
linear decrease in the concentration of colloidal carbohydrates in the top 2 mm.
Kelly et al. (2001) further characterised the depth distribution of chlorophyll a to
determine a linear decrease with depth. Kelly et al. (2001) significantly
positively correlated chlorophyll a and colloidal carbohydrate concentrations,
finding a greater co-vanation in micro-sectioned samples.
3.1.1. Aims
The aims of this work were to determine the physical and biological
changes associated with the growth and development of a microphytobenthic
biofilm under in situ and controlled laboratory conditions. Two separate
experiments were designed; the first was a simulated in situ disturbance event
following the growth and recovery of a biofilm after the removal of the surface
layer of sediment, and the second was a controlled laboratory study examining
the growth and development of a biofilm using fine scale sectioning (200 ttm)
techniques.
3.2. Materials and Methods
3.2.1. The Cohesive Strength Meter
The Cohesive Strength Meter (CSM; Paterson 1989; Figure 3. IA) is a
device that measures the erosion potential of sediments. The CSM consists of a
water filled chamber which is inserted into the sediment (Figure 3.1B). A
downward nozzle directs a vertical stream of water onto the sediment surface in
short pulses (Figure 3.1C). The velocity of the water jet is systematically
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