[EN] This work is an approach to estimate the relationships between incident energy on the sea surface and the manitol concentration in Bifurcaria bifurcata Ross, in the Ria of Vigo, as in index of photosynthesis intensity in this habitat. The samples of Bifurcaria have been collected monthly, through fourteen months. The energy data have been computed them with Mosby formula, fournished by Meteorological Observatory of Vigo. Manitol, the acyclic sugar alcohol, is ubiquitous in Pheophita, one of the early products of photosynthesis in brown algae. It has been estimated through its oxydation with periodic acid, analysing the amount of liberated iodine with sodium thiosulphate. We have calculated a regression curve on theoretical assumptions and can be seen that the experimental values of manitol concentration and calculated ones, fit reasonably well. In Gallician Rias, the nitrates are not a limiting factor; notwithstanding that, there is an obvious opposition, between both, the nitrates and the manitol concentration (see fig. 4)

[ES] Se han comparado las concentraciones de manitol en la especie Bifurcaria bifurcata, con las cantidades de energía incidente recibida, entre dos muestreos, en la superficie de la zona estudiada. Se ha aplicado una ecuación que permite apreciar una estrecha correlación entre ambos fenómenos

11 páginas, 4 figuras, 1 cuadro

Peer reviewed