[Development of bacterial populations of telluric, enteric, and marine origin in planktonic systems exposed to urban pollution; mathematical data analysis]. / Etude de l'évolution des populations bactériennes d'origine tellurique, entérique et marine dans des systèmes planctoniques soumis à une pollution urbaine, traitement mathématique des données.

A study of the comparative distribution of different types of bacterial populations in the sea area where the city of Marseille rejects its waste water shows that, when in contact with the marine environment, a great part of the allochthonic bacterial population undergoes physiological stress expressed by an abrupt reduction of the effectives and by weak values of the energetic charge. The presence of coliforms and streptococci in waste water lens, at important distances from discharging conduits, shows the possibility of a large diffusion for a fraction of the bacterial populations that withstand the initial stress. From mathematical analyses, an inverse correlation is revealed between detergents and the bacterial population as a whole, and between phenols and various allochthonic bacterial populations. The above results were evidenced through a sampling strategy based upon a 24-h-cycle study and a search for mathematical correlations between several biological, chemical, and physical parameters.