Seasonal variations in ash and alginic acid contents of seaweeds

Abstract

Growth, in terms of unit biomass and alginic acid content, of 3 seaweeds, viz. Cystoseira indica.
Sargasstim tenerrimum and S. johnstonii, collected from Porbandar and Okha reefs for one year, was
measured. A significant linear relationship between the ash and alginic acid contents on unit biomass basis
was observed. However, alginic acid showed inverse relationship with total carbon to ash ratio (C/ash). The
unit biomass parameter (weight/height) was advantageous than heigh t alone to explain the seasonal variation
of alginic acid with respect to growth in seaweeds. In addition to the cell sap minerals alginates contributed
to the ash content. Alginic acid was highest during rapid growth period, followed by the reproductive stage
and the lowest in the senescent growth period.