A small portion of nutrients is lost annually through the hydrological cycle and biological export to the atmosphere (Barnes et al. 1998). Major pathways in which these nutrients are lost include: soil erosion, leaching and gaseous losses.

Leaching is a physical process where nutrients exit terrestrial ecosystems in the downward flow of water through the soil. It is important to note that nutrients are only subject to leaching when water is moving downward through the soil. Once nutrients are transported below the roots of plants they are lost from the terrestrial ecosystem (Barnes et al. 1998). However as they move into the ground water they become part of the aquatic ecosystem, therefore the hydrological process of leaching links the terrestrial ecosystem and aquatic ecosystem together.

Another loss of nutrients from ecosystems is due to denitrification. Denitrofication is the microbial reduction of NO3 to N2O, which results in the loss of nitrogen to the atmosphere (Barnes et al 1998). Denitrofication has been of great interest to the scientific community for two main reasons, first the loss of nitrogen could have implications for plant growth and second N2O is a greenhouse gas. However the requirements of denitrofication limit where this process can occur.

Other processes such as wildfires and forest harvesting also can effect both nutrient loss and gain in ecosystems.