Mireille Consalvey PhD Thesis - University of St Andrews

5.4.1. Migration under in situ conditions 143
5.4.2. Migration in the absence of any light cues 150
5.4.3. Future work 151
5.4.4. Summary and conclusions 152
5.5. Acknowledgements 153
6 Microscale changes in intertidal biofilms over a diel period 154
6.1. Introduction 154
6.1.1. Examining changes in biomass (using Chl a and LTSEM) 154
6.1.2. Investigating the sediment light climate 158
6.1.3. Examining primary productivity on intertidal mudflats 162
6.1.4. Aims 164
6.2. Materials and Methods 164
6.3. Results 169
6.3.1 Diel changes in Chl a 169
6.3.2. Diel changes in water content 170
6.3.3. Diel changes in species composition 170
6.3.4. Diel changes in sediment light climate 171
6.3.5. The relationship between light attenuation and site parameters 174
6.3.6. Predicted and measured rates (14C) of primary productivity 174
6.3.7. Sediment grain size analysis 176
6.4. Discussion 176
6.4.1. Can microscale sectioning can be used to detect spatial and 176
temporal variations in biomass over a die] period?
6.4.2. How does assemblage type influence the spatial and temporal 177
distribution of microphytobenthic biomass?
6.4.3. Do cells sub-cycle at the sediment surface? 179
6.4.4. How does assemblage type/site and time influence the light 181
attenuation co-efficients of microphytobenthic biofilms?
6.4.5. Do modelled rates of primary productivity correlate with actual 186
rates of primary productivity?
6.4.6. Implications of study 187
6.4.7. Future studies 188
6.4.8. Summary and conclusions 189
6.5. Acknowledgements 190
7 What if diatoms couldn't move? Investigation into the 191
photophysiological
implications of a non-motile benthic existence
7.1. Introduction 191
7.1.1. Microphytobenthic responses to a changing light envirom-nent 191
7.1.2. The use of PAM fluorescence in microphytobenthic systems 193
7.1.3. Hypotheses 196
7.2. Materials and Methods 197
7.2.1. Creating an artificial non-migratory biofilm 197
7.2.2. Experiment 1: The effect of different light intensities and 199