These molecules, combined with nutrients from the soil, are built up to create cells, tissues and bodies. The energy and nutrients are then passed through the entire ecosystem via herbivores, carnivores, parasites and decomposers. The diagrams show the distribution of nitrogen in the plants and in the soils of two different ecosystems. In cold ecosystems, such as tundra, the growing season is so short that much nitrogen remains in the soil and comparatively little is stored in the plants. By contrast, in rainforests, most of the nitrogen is rapidly taken up by the trees and very little is found in the soil.
Ecological processes are basically the same everywhere.
However, communities of organisms respond to each particular environment by developing their own variations. This is how the diversity of ecosystems develops. For example, the distribution of the vital nutrient nitrogen varies in different kinds of environments. In very cold climates, nitrogen accumulates in the soil and only a tiny proportion is used by plants because of the limited growing season. By contrast, plants in grasslands and forests consume vast quantities of nitrogen.