The Estimation of Phosphate and of Total Phosphorus in Sea Waters

Abstract

A simple photoelectric meter is described which allows the molybdenum blue formed in sea water, due to the presence of phosphate, to be estimated within that due to ± 0·25 mg. phosphate-P per m.3.The effects of concentration of acid, molybdate, reductant, temperature and suspended particles on the rate of formation, fading and amount of molybdenum blue, formed in sea waters containing phosphate are detailed.Intramolecular changes taking place during storage of molybdate solutions, and while being mixed with acidified sea water, have been investigated.The hydrolysis of organic phosphorus compounds in acidified sea water at 140° C , and the prevention of arsenate formation, are described.Procedures, resulting from these investigations, for the estimation of phosphate, and of total phosphorus, are described.The growth of bacteria and the physical adsorption of organic phosphorus compounds in solution on the walls of glass vessels used for storage of sea water have been investigated, and a method of prevention evolved.

Filtering, feeding, and digestion in the lamellibranch Lasaea rubra

“…2A). Filtering rates were determined by the measurement of the optical density of the medium by means of a Harvey absorptiometer, constructed as described by Harvey (1948). The chief modifications introduced were those outlined by Spencer (1954) for use with micro-organisms.…”

A Single-Solution Method for the Determination of Soluble Phosphate in Sea Water

“…Of the reagents so far suggested for the reduction of phosphomolybdic acid to molybdenum blue in the determination of phosphate, only stannous chloride (Atkins, 1923;Harvey, 1948), metol (Burton & Riley, 1956), and ascorbic acid (Greenfield & Kalber, 1954), give colours of sufficient intensity to be used in the analysis of sea water. Burton & Riley (1956) have recently reviewed the use of stannous chloride as a reducing agent in the molybdenum-blue method for the determination of phosphate in sea water.…”

Changes in Inorganic Phosphate Concentration Occurring During Seawater Sample Storage1

“…Various solutions to this problem have been recommended (for example, Ibanez Gomez 1933;Harvey 1948;Heron 1962). Currently, the two most commonly used techniques utilize polyethylene storage bottles, with chloroform treatment for short-term storage (Harvey 1955) and quick-freezing for long-term storage (Collier and Marvin 1953).…”

“…Currently, the two most commonly used techniques utilize polyethylene storage bottles, with chloroform treatment for short-term storage (Harvey 1955) and quick-freezing for long-term storage (Collier and Marvin 1953). However, the effectiveness of even these methods has been questioned (Murphy and Riley 1956;Hassenteufel, Jagitsch, and Koczy 1963;Jones 1963 ) .…”