Foliar release of soluble reactive phosphorus from Spartina alterniflora in a Georgia (USA) salt marsh

Foliar release of soluble reactive phosphorus (SRP) from live shoots of Spartina alterniflora (Loisel.) was investigated in a Georgia (USA) salt marsh.Average foliar SRP release rates varied from ~t h values from individual plants as high as 61.7 pg P (g dry undetectable to 7.5 pg P (g dry wt)-' h-' Wwt)-' h-'.Release rates of SRP generally exhibited little die1 variation and were highest in midsummer.Estimates of extrafoliar SRP accumulated on leaf surfaces varied from < 1 to 41 pg P (g dry wt leaf)-' and 0.8 to 1.7 mg P m-2 normalized to marsh area.Time course experiments revealed that SRP release was a 2-step process with a rapid solubillzation of extrafoliar SRP and a constant release thereafter.Releases of SRP from creekbank stands of S. alterniflora during tldal submergence were estimated to be 3.1 to 8.2 mg P m-2 d-l, with annual releases of 1.7 g P m-2 yr-l Foliar releases of SRP from the live plants are equivalent to 60 % of the annual production of particulate phosphorus as S. alterniflora detritus reported from Georgia salt marshes.