Chapter 8 - Energy flow in ecosystems

Abstract

Thermal physics and chemistry dictate the basic principle of energy flux through organisms, trophic levels, and entire ecosystems of which these components are a part. Just as metabolism integrates the functional processes of plants and animals, so does metabolism integrate the biogeochemical processes in ecosystems. Within the ecosystem, energy flows through it, obeying the laws of thermodynamics, while carbon is recycled, thus, the terms “energy flow” and “carbon cycle.” The ocean plays an important role in the global carbon cycle and is called a carbon “sink” because it takes up more carbon from the atmosphere than it releases. Carbon moves in and out of the ocean daily, but it is also stored there for thousands of years. Terrestrial ecosystems are characterized by having a larger standing crop biomass than aquatic ecosystems, but with more moderate rates of primary production.