Population Studies and Carrageenan Properties in Eight Gigartinales (Rhodophyta) from Western Coast of Portugal

Abstract

Eight carrageenophytes, representing seven genera and three families of Gigartinales (Florideophyceae), were studied for 15 months. The reproductive status, dry weight, and carrageenan content have been followed by a monthly random sampling. The highest carrageenan yields were found inChondracanthus acicularis(61.1%),Gigartina pistillata(59.7%), andChondracanthus teedeivar.lusitanicus(58.0%). Species of Cystocloniaceae family produces predominantly iota-carrageenans; Gigartinaceae family produces hybrid kappa-iota carrageenans (gametophytic plants) and lambda-family carrageenans (sporophytic plants); Phyllophoraceae family produces kappa-iota-hybrid carrageenans. Quadrate destructive sampling method was used to determine the biomass and line transect. Quadrate nondestructive sampling method, applied along a perpendicular transect to the shoreline, was used to calculate the carrageenophytes cover in two periods: autumn/winter and spring/summer. The highest cover and biomass were found inChondrus crispus(3.75%–570 g/m2),Chondracanthus acicularis(3.45%–99 g/m2),Chondracanthus teedeivar.lusitanicus(2.45%–207.5 g/m2), andMastocarpus stellatus(2.02%–520 g/m2).