A MODEL OF PHYCOTOXIN RELEASE BY CYANOBACTERIAL CELLS

The paper presents a semi-empirical mathematical model for phycotoxin release into water during the development of the freshwater cyanobacte rial population. The data obtained from field observation and laborato ry experiments demonstrate correlation between the development of cell population and phycotoxin concentration in water (National Rivers Aut hority, 1990. Toxic Blue-Green Algae. A Report by the National Rivers Authority. Water Quality Series, September 1990. London, pp. 128). Thi s information provides an approach to model phycotoxin release process . This probability for toxin production and release is used to derive an explicit formula for toxin concentration in water. This formula pre dicts the appearance of the peak toxicity in water between 3 and 6 mon ths from the beginning of population growth. The peak toxin concentrat ion in water and the time of its occurrence depend on environmental co nditions and the toxin release function. The logistic equation with re sources depletion is used to describe population development. The expl icit model makes it possible to be calibrated, and assumptions about p robability distributions being validated in light of laboratory experi ments and field observations. (C) 1998 Elsevier Science B.V. All right s reserved.