Mireille Consalvey PhD Thesis - University of St Andrews

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in water content. If water was draining from the sediments there may be an
increase in compaction which might explain the decrease in chlorophyll a
content, however, one would predict that the concentration would increase as a
result of drainage, which did not happen. Therefore, this result remains
unexplained.
It is important to note for this study that the chlorophyll a content could
not be correlated with the fluorescence yield. Sampling occurred at a depth
deeper than the photic zone, which will lower the significance or even cause the
relationship between chlorophyll a and F, 15 to break down (Barranguet and
Kromkamp 2000; Honeywill 2001; Honeywill et aL 2002).
Following migration using F,, 15
All three experiments exhibited a significant change in the F, 15 yield at
the sediment surface over time. The rate of change was maximal in the first hour
for the Tay and Eden (February) but for the Eden (April) the rate remained high
for the first 3h of exposure before declining. The Tay and the Eden (February)
both showed a similar pattern of increase, with the mean F, 15 maxima occurring
after the time of low tide. It took considerably longer for a significant increase to
be detected in the Eden (April) and the maximum F, 15 yield only occurred prior
to the time of immersion. Ser6dio et al. (1997) described a maximum
increase in
F, of 400%, the Tay and Eden (February) showed 375 and 320% respectively,
whereas the Eden (April) was significantly lower at 139%. This could indicate
that biofilms of higher biomass show less migrational activity but this would
require further investigation.
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