Mireille Consalvey PhD Thesis - University of St Andrews

Chapel -
but also because cells can change their light environment by migrating.
Therefore, cells in microphytobenthic assemblages may have higher efficiencies
than would be expected from the surface PPFD leading to an overestimation of
rETR (Perkins et al. 2001,2002).
7.1.3. Hypotheses
Whilst fluorescence has proven to be a valuable ecological tool (Chapters
4 and 5; Ser6dio et al. 1997,2001; Barranguet et al. 1998; Kromkamp et al.
1998; Honeywill 2001; Perkins et al. 2001,2002; Honeywill et al. 2002) much
remains to be elucidated about the envirom-nental variables that may affect the
fluorescence yield. Therefore, the aims of this chapter were to test the following
hypotheses:
1) Temperature will have a significant effect on F,,, F,, and F, IF,,
2) F, F,, 'and Fq'IF,, 'will vary with
light level
3) Exposure to light will lead to a significant increase in the minimum
fluorescence yield and significant decreases in the maximum fluorescence
yield and the light utilisation efficiency, with the largest changes
occumng at the highest light level
4) Continued exposure to light will lead to further changes in F', F,, ' and
Fq'IF,, '
5) NPQ will be highest in high light conditions
6) Treatment with far-red light will lead to a decrease in F, and an increase
in F,, and F,, IF,,,
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