Fig. 6

Phycobilisome excitation energy transfer in L. glaciale under different light spectral compositions and PAR intensities after 9 months of experimentation. A Proportional ratio between PEB, PUB and PCB EET (as % of their total EET). B PEB:PCB contributions to PSI fluorescence based on fluorescence excitation spectra detected at 720 nm (PEB:PCB EET). C Relationship between PEB:PCB absorbance and PEB:PCB EET; modelled linear regression (black solid line) with 95% confidence intervals (dotted lines) is shown: y =  − 0.679 + 1.95 × , r² = 0.191, p = 0.012. Data in A presented as mean, and in B as mean ± SE where N = 4 individual algae (from different aquaria) per treatment (except mesophotic spectrum at 350 and 80 µmol photons m⁻² s⁻¹ where N = 3). Data points in B are jittered horizontally around the experimental light intensity for visual clarity. Shallow + red spectrum at 350 µmol photons m⁻² s.⁻¹ only. Statistical model test results of relationship between each measured parameter and light intensity / spectral treatments are provided in Additional File 1: Table S2