Photosynthesis and negative entropy production

Reply to “Commentary on Photosynthesis and Negative Entropy Production by Jennings and coworkers” by J. Lavergne

It is argued that the chemical potential analogy does not provide useful information on the thermodynamics of photosystems, as the thermodynamic efficiency of an absorbed quantum is not considered. Instead, the approach based on either entropy balance or entropy flux considerations does provide this information. At high thermodynamic efficiencies, primary photochemistry can, in principle, viola...

Negative Entropy Production in Oscillatory Shear

Linear irreversible thermodynamics asserts that the instantaneous local spontaneous entropy production is always nonnegative. However for a viscoelastic uid this is not always the case. Given the fundamental status of the Second Law, this presents a problem. We provide a new derivation of the Second Law, from rst principles, which is valid for the appropriately time averaged entropy production ...

Negative Entropy of Welsh

Singlet oxygen production in photosynthesis.

A photosynthetic organism is subjected to photo-oxidative stress when more light energy is absorbed than is used in photosynthesis. In the light, highly reactive singlet oxygen can be produced via triplet chlorophyll formation in the reaction centre of photosystem II and in the antenna system. In the antenna, triplet chlorophyll is produced directly by excited singlet chlorophyll, while in the ...

Photosynthesis and fish production in the sea.

Numerous attempts have been made to estimate the production in the sea of fish and other organisms of existing or potential food value to man (1-4). These exercises, for the most part, are based on estimates of primary (photosynthetic) organic production rates in the ocean (5) and various assumed trophic-dynamic relationships between the photosynthetic producers and the organisms of interest to...