The cycle of phosphorus in the waters of the English Channel

Abstract

Determinations of total phosphorus in water samples have shown areas in the western English Channel with water containing as little as 10 mg. P/m.3, and other areas with double, and more than double, this concentration.The integral mean concentration of total P in the water column, 20 miles off-shore from Plymouth, has fluctuated between 10 and 16 mg. P/m.3 since June 1947.The changes which have taken place in this integral mean concentration are attributed to different water masses, of different total phosphorus concentration, passing through the area, rather than to a seasonal change in the total phosphorus content of a water mass. No marked deposition of phosphorus-containing detritus could be found.Changes in this integral mean were not coincident with changes in salinity. The geographical distribution of total phosphorus does not coincide with the geographical distribution of salinity.