The Relationships Between Weight, Length, Age and Intensity of Photosynthesis and Organotrophy of Macrophytes in the Barents Sea

Abstract

For Ascophyllum nodosum, Fucus vesiculosus, F. inflatus and Rhodymenia palmata in the Barents Sea a quantitative description is given of the relationship between length (L) and weight (W) of the thallus, and for A. nodosum also between weight (W) and age (T). The weight of the thallus has also been related to the intensity of 2 physiological functions, photosynthesis (Pi) and the consumption of organic substances (Po) dissolved in the water. According to the value of linear growth per unit of weight and the intensity of Pi, the different species form the series: R. palmata > F. inflatus > F. vesiculosus > A. nodosum. From the W-T relationship a lag phase ("early youth"), a logarithmic phase ("youth"), and the beginning of a stationary phase ("maturity") were disclosed in the ontogenesis of A. nodosum. The photosynthesis and organotrophy of the thallus diminish with the increase of its weight. This dependence is approximated by a power equation, which parameters were determined. In A. nodosum and F. vesiculosus the weight (w) ratios of tissues of different age (t) were determined. On the basis of these data, stages of youth, maturity and senescence of tissues were determined in A. nodosum. The comparison of the w-t curves of A. nodosum and F. vesiculosus shows that a different strategy of thallus formation is inherent in them.