Light harvesting excitation and electron capture

Light is the visible part of the spectrum of electromagnetic radiation emanating from the sun. Electromagnetic energy occurs in indivisible units, called quanta, that travel along sinusoidal trajectories, at a velocity (in air) of c 3 x 108 m s-1. The wavelengths of the quanta define their properties - those with wavelengths (X) between 400 and 700 nm (400 - 700 x 10-9 m) correspond with the visible wavelengths we call light (and within which waveband the quanta are called photons). The...

Sources and fluxes of available inorganic carbon

Hco3 Determination Water

The sea-level, air-equilibrated concentration of carbon dioxide in water at 0 C is 23 M, falling to 13 M at 20 C say, 0.5-1.0mg CO2 L-1, or 0.15-0.3mgC L-1 . Besides being sensitive to temperature, the equilibrium concentration depends upon the atmospheric partial pressure of CO2, which is, in turn, affected by altitude. In many natural waters, carbonic acid is the only free acid present and, thus, the concentrations of alkalinity base ions , carbon dioxide The pH-carbon dioxide-carbonate...

Photoprotection photoinhibition and photooxidation

Against the background of environmental variability, there may be superimposed variations in the contemporary ambient range of fluctuations, subjecting hitherto supposedly acclimated plank-ters to additional demands of accommodation. Among the most crucial of these is a weakening of the mechanical forcing, either as a result of a sharp reduction in the wind speed or of sharp increase in the photon flux perhaps as the cloud clears or, as is often the case, the coincidence of both events. In all...