Mireille Consalvey PhD Thesis - University of St Andrews

5.3.3. Eden Estuary (U. K. )
Physical measurements
ýi(14 illvestwalion n to 1111cloplivtobaltili" t
The sediment temperature changes in the surface layers of the sediment
followed the daily changes in ambient PPFD (Figure 5.10). On days 2 and 3 the
microphytobenthic biofilms were subject to rapid changes in ambient light
associated with sunrise and sunset. On day I the cells were subject to both an
increase and a decrease in PPFD as well as short-tenn fluctuations associated
with cloud cover. The maximum PPFD of 1919 [tMol M-2 s- I was attained on day
I at 13: 00. The greatest range in PPFD occurred on day 3 (0 _I Ogg [tMol M-2 s- 1)
Eden: Changes in the fluorescence parameters
On day 1, F, 15 significantly increased over the exposure period (F6,98 ý
10.86, p start
value). The light level was fluctuating over the exposure period and there was no
evidence of a relationship between F, 15 and PPFD. The F0 15 yield also
significantly increased on day 2 (H = 84.31, df = 6, p