Release and Capillary Movement of Phosphorus 667 



Bay sediments may contain up to 5 per cent organic matter. The 

 surface organic matter (0-0.5 cm depth) may fluctuate dining 

 a year cycle from 4.6 per cent in the summer to 0.8 per cent in 

 the winter (16). Information on tlie sorption of phosphate to 

 ferric hydroxide as a possible mechanism in sediment building 

 is summarized by Hayes, Reed, and Cameron (5). Stephenson 

 ( 13 ) indicates that agitation of sediment affects the release of 

 phosphate due to the mechanical disruption of organisms and 

 the liberation of bacterially produced phosphate. 



This paper reports measurements of phosphate and chloride 

 contents of the salts, sediments below the salts, and water in ad- 

 jacent ponds or bays in vicinities where salts are present on the 

 sediment surface. The experiments were prompted by the idea 

 that soluble phosphates are transported by capillary action to 

 the sediment surface as part of a cycle between sediment and 

 water. This release of bound phosphorus may in part explain the 

 fairly high productivity of these shallow bays reported by Odum 

 and Hoskin ( 6 ) . Emphasis will be placed on the possible explana- 

 tion of bacterial activities which effectively release bound phos- 

 phonas from the sediment. 



PROCEDURE 



Samples were collected from areas indicated by numerals in 

 Figure 1. Each area was representative of an extensive mud flat 

 which was alternately dry or covered by water. The salts pre- 

 cipitated on the surface and underlying sediments were carefully 

 removed with a spatula and placed in small glass containers. Wa- 

 ter from adjacent bay or pond was collected in glass bottles. The 

 water samples were immediately analyzed for chloride and total 

 and inorganic phosphorus. The sediment samples were returned 

 to the laboratory and refrigerated or dried immediately at 110 C. 

 The dried samples v* ere weighed into flasks and the salts dissolved 

 in double distilled water. In aliquots for chloride analysis, the 

 solids were allowed to settle out. Chloride was determined by 

 the standard silver nitrate method for sea water. Inorganic phos- 



Fig. 2. (A) Aerial photograph of Lydia Ann Channel showing intricate 

 pattern of mud flats. (B) Mud flat with salt precipitated on surface. 



