Modern mankind's influence on the natural cycles of phosphorus

When the molten surface of the earth solidified over 4 X 10(9) years ago the quantity of phosphorus to be contained in the storehouse of the new planet had already been resolved. The phosphorus was locked in an igneous lithosphere as orthophosphate. With the advent of the first primitive rainstorms the slow endless process of liberating the phosphorus from the igneous rock strata had begun. It required about 3 X 10(9) years for this process to supply enough soluble phosphates for the seas of the earth to become saturated with respect to apatites. Today slightly more than half of the phosphate is contained in sedimentary deposits. The established phosphorus cycles of the earth were almost independent of the activities of mankind for more than 4 X 10(9) years. Only in the past 200 years has the influence been worthy of consideration and as late as the 1960s too few reliable data were available for us to assess the status of our activities on the natural cycles. Today a reasonably clear picture is emerging.