Temporal and spatial variation in agar from a population of Pterocladia capillacea (Gelidiales,Rhodophyta) from Brazil

Pterocladia capillacea forms dense intertidal belts in southeastern Brazil, on moderately exposed rocky coasts. The studied population extends along a gradient of water exposure, where slightly different morphotypes can be recognized. Specimens were collected monthly from 3 points along the exposure gradient of its distribution (lower, medium and higher exposure), and analyzed for agar, sulfate and 3,6 anhydrogalactose content. Agar varied from 5–32% of dried seaweed with lower yields in the winter, and higher yields in late spring/early summer. Specimens from the surf side of the distribution had a consistently higher agar content throughout the year. Sulfate varied from 1–5%, and 3,6 AG from 27–48% of dried agar, without a clear variation among the sites.