We do not know the development of the biomass and the ability of ecosystems to capture solar energy. Let us—very tentative—assume that ponds represent a typical ecosystem 525 million years ago. In that case, the amount of solar energy captured should correspond to about 6000 g detritus/m2 yr (see Chapter 12), which means 112,200 kJ/ m2yr. The lagoon may correspond to the typical ecosystems 450 million years ago. It means that the solar radiation captured would correspond to 900 g detritus/m2 yr or 168,300kJ/m2yr. Let us—of course, again very tentative—presume that the typical ecosystems 330 million years ago could, with respect to the amount of solar energy it could capture, correspond to a coral reef or 27 g detritus/m2 yr or 504,900 kJ/m2 yr. Finally, we can be more certain if we presume that the typical ecosystem 35 million years ago would correspond to a typical rain forest today. It is able to capture 70% of the incoming solar radiation (see Table 1.5, Section 1.11). The solar radiation corresponds to about 2GJ/m2yr, 70% of which will therefore correspond to 1,400,000 kJ/m2yr. The typical ecosystem today is therefore about 12.5 times better to capture the solar radiation than the ecosystem 525 million years ago. We are moving on thin ice and it is a guess or maybe at least a qualified guess. If the guess is correct, the energy ascendency of the ecosystems has increased 1.5 times 12.5 ( see Table 15.1, Chapter 15). It means 19 times since the beginning of the Cambrian Explosion; and the amount of biomass sustained by a typical ecosystem could have increased 1.2 times 12.5 (see Table 15.2, Chapter 15), about 15 times in the same period.
Was this article helpful?