Changes of the phytobenthos biomass according to depth

Abstract

       The biomass of the phytobenthos was studied on a selected profile of the Istrian coast in the Northern Adriatic.

        The biomass was expressed as fresh weight per square metre of the seafloor and further analysed for the ash content as well as for the contents of mannitol, ether soluble substances, alginic acid and protein.

        An increase of the algal biomass with the increasing depth and distance from the shore was found, this increase being rather pronounced on the level of the eulittoral - sublittoral junction. Maximum values of the biomass were observed in the upper sublittoral.

         The biomass of phytobenthos showed a rather abrupt decrease where the rocky slopes give way to a sandy-muddy ground and thus meadows of the seagrass Cymodocea nodosa replace the Cystoseira settlements.