Internal cycling, also known as biogeochemical cycling within an ecosystem, refers to the processes by which nutrients are transformed and transferred among different components (e.g., soil, plants, microbes) without leaving the system.
Key processes include mineralization, where organic nutrients (from dead organisms or waste) are broken down into inorganic forms by decomposers, making them available for uptake. Chemical reactions like nitrification or denitrification alter the ionic forms of elements.
Biological uptake by roots of plants and absorption by microorganisms are crucial for incorporating these inorganic nutrients into living biomass.
Nutrient exchange on surfaces within the soil matrix, such as cation exchange on clay particles, also plays a significant role in nutrient availability.
Leaching, conversely, is a process of nutrient loss from the ecosystem, where dissolved nutrients are washed away by water, typically into groundwater or surface water bodies.
