The Selforganizing Biosphere Theses on Biospheric Evolution

For the strict neodarwinian, the biosphere cannot evolve in the sense that the biota evolves. However, it may be fruitful to explore the consequences of considering the analogues of genotype and phenotype in the biosphere itself, indeed its evolution in a different sense from the usual definition of evolution for transbiological systems (e.g., superficial descriptive social and cultural evolution). Let us be clear that use of the terms genotype and phenotype for the biosphere in the discussion...

The Carbonate Silicate Geochemical Cycle at Ga for an Abiotic Earth Surface Just at the Transition to Biotic

I assume here that the late bombardment, with its potential for continual large sterilizing surface impacts, was over by 3.8 Ga, thus taking this time as the transition time to biotic colonization of the early continents (Oberbeck and Mancinelli 1994). With the assumptions made above, the product of outgassing rate and land area ratios, (V V)(AJ A), at t 3.8 Ga for two limiting models (models a and c) and a preferred model (b) is given in table 8-3. The variation of A Ao, V Vo, and (V VJ(Ao A)...

Estimates of Biotic Enhancement of Weathering from Field Studies

The earliest study attempting to estimate the effect of vegetation on chemical weathering rates was apparently that of Cawley et al. (1969). Their estimate of biotic enhancement was about 3, based on a comparison of bicarbonate concentrations (not fluxes, which would be expressed for example as moles km 2 yr_1) in water draining barren and vegetated basalt lava in Iceland. They concluded that plants have had only modest effects on chemical weathering. Several caveats are in order in the...