External budgets - Nutrient Budgets

In contrast the external budgets pertain to the input and output of the entire ecosystem in relation to other ecosystems. For instance volcanic eruptions throw materials into the atmosphere or spread lava over a terrain, thus distributing nutrients over large areas.

Wind and water transport nutrients to long distances and serve as carriers for their action such as weathering of rocks or wind that carries nutrients between different ecosystems. Animals feed in one ecosystem defecate or die in another, or trees grow in one ecosystem and are burnt elsewhere. Humans are without question the most powerful agents that affect the internal and external nutrient budgets.