Background yield of phosphorus from drainage area and atmosphere: An empirical approach

The role of phosphorus in the eutrophication of lakes and marine coastal areas has created a need of more information on the size of a virgin background supply of phosphorus.The general pollution of the atmosphere has resulted in an increased amount of anthropogenic phosphorus in air masses over remote ocean areas in the Northern Hemisphere. As a consequence this applies also to remote land areas, where the phosphorus deposition of about 5 kg P km^-2 a^-1 may seem to be 2–3 times the virgin phosphorus deposition.The present background drainage basin yield of phosphorus is also elevated due to a general eutrophication of the terrestrial ecosystem. The background supply varies due to several factors of which drainage basin size, geology and vegetation are discussed. Background yields apparently have a range from 3–10 kg P km^-2 a^-1.