Mireille Consalvey PhD Thesis - University of St Andrews

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Testing the model of Underwood and Smith (1998)
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Bi-olilm 1'erination and (level
Underwood and Smith (1998) constructed a model (Equation 3.1) to
predict diatom colloidal carbohydrate content from chlorophyll a; this
relationship was later verified by Kelly et al. (2001).
Log (conc. colloidal carbohydrates + 1) = 1.4 + 1.02 (chlorophyll a conc. + 1) Equation 3.1
Colloidal carbohydrates expressed as gg EPS per g freeze dried sediment
Chl a expressed as pg chl a per g freeze dried sediment
A predictive model was constructed using the data from this study and a two-
tailed test used to determine if the data fitted the model.
3.3. Results
3.3.1. In situ recovery of biofilms
Visual observations
There was an immediate and obvious difference between non-disturbed and
disturbed areas on the estuary. The sediments on undisturbed areas were
characteristically golden brown, indicating the presence of diatomaceous
biofilms, confirmed by LTSEM (Figure 3-3A) whereas this colouration was
absent on the disturbed site (Figure 3.3B) and no diatoms were present (Figure
3.3Q. There was an absence of invertebrate feeding trails following the
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