We propose plausible physical explanations based on geomagnetic activity and total solar irradiance effects over atmospheric circulation that could support the statistical result.
In some of the studies the expected effect was found (Thompson et al. 1990 Guedes et al. 2010 Leu et al. 2010), but differences were often small while sometimes no or opposite irradiance effects were found (Chrismadha and Borowitzka 1994 Tzovenis et al. 1997 Carvalho and Malcata 2005 Zhukova 2007 Guiheneuf et al. 2009).
However, in our study we did not aim to optimize growth rates and cell densities for the individual species under study: our goal was to compare temperature and irradiance effects on PUFA composition in dilute cultures under standardized, nutrient replete conditions at sub-optimal temperatures.
Strong irradiance effects were observed in these experiments, both in terms of O2 luminescence generation and treatment response.
Martin et al. (1985 , 1986 assessed North Carolina Spanish moss populations with respect to irradiance effects on morphology and physiology, finding that Spanish moss responds to irradiance by adjusting physiology more than morphology.
Irradiance effects have been observed by other authors (Feins et al, 1990; Gibson et al, 1990; Foster et al, 1993; Robinson et al, 1998; Sitnik et al, 1998) and have usually been attributed to rapid photochemical depletion of molecular oxygen at higher irradiances.
Quantitative enhancement analysis exploiting actual biological fluorescent spots perfectly confirms the irradiance amplification effect of a thin waveguide.
They have, with solar irradiance, large effects on the temperature and density of the buoyant gas.
In the other series of experiments, various light intensities (250, 500 and 750 µmol photons m−2 s−1, respectively) were used to study the irradiance-dependent effect of Se treatment (16 mg Se g−1 biomass added twice a day as Na2SeO3; final concentration of about 122 µmol L−1).
In addition, it is found that the performance of the Si-based PV rooftop systems operated under distinct four seasons could be improved by simply toggling the tilt angle considering the plane-of-array irradiance and snowfall effect.
