Seasonal Differences in Ash, Carbon, Fibre and Nitrogen Components of Furcellaria lumbricalis (Gigartinales, Rhodophyceae), Norway

Biology of Furcellaria lumbricalis (Hudson) Lamouroux (Rhodophyta: Gigartinales), a commercial carrageenophyte

“…Aspects of dry weight and gross chemical composition (ash, organic content) have been reported by a number of authors (Ross, 1953;Vinogradov, 1953;Voronova, 1970;Ravanko, 1972;Greenwell etal., 1984;Indergaard & Knutsen, 1990), and values for Furcellaria lumbricalis are generally comparable with those for other fleshy red algae. Dry matter is 15-23 % of fresh weight (Vinogradov, 1953;Ravanko, 1972;Greenwell et al, 1984).…”

“…However, F. lumbricalis apparently conserves nitrogen for periods of low nitrate availability. Indergaard and Knutsen (1990) observed that, during summer and autumn, when nitrate was negligible in the water, tissue nitrate was reduced to 20% of maximum concentrations but never fully depleted. Moreover, addition of nitrate to the culture medium did not increase tissue nitrate or stimulate growth.…”

“…In absolute terms, ash content increases slightly with increasing depth (Greenwell etal., 1984), but the percentage increase is exaggerated by a concomitant decline in the organic component. Ash content also has been observed to vary seasonally (Indergaard & Knutsen, 1990), undergoing a slight decline from spring to early summer. The elemental composition of ash (Vinogradov, 1953) is similar to that of other Rhodophyta; however, iodine content at 0.08 % of dry weight is moderately high among the red algae, although much lower than in most kelps.…”

“…Nitrogen content ranges from 1.1-4.8 % of dry weight (Ross, 1953;Citharel & Villeret, 1964;Krasil'nikova et al, 1972;Kornfeldt, 1982;Greenwell et al, 1984;Indergaard & Knutsen, 1990), making F. lumbricalis relatively nitrogenrich among the Rhodophyta. Seasonal variation occurs, apparently in response to available reactive inorganic nitrogen, with maxima in winter and minima in summer (Citharel & Villeret, 1964;Kornfeldt, 1982;Indergaard & Knutsen, 1990); nitrogen evidently was not limiting for an inner Baltic population that maintained a high nitrogen content (3.7-3.9%) during the summer (Krasil'nikova et al, 1972).…”

“…Seasonal variation occurs, apparently in response to available reactive inorganic nitrogen, with maxima in winter and minima in summer (Citharel & Villeret, 1964;Kornfeldt, 1982;Indergaard & Knutsen, 1990); nitrogen evidently was not limiting for an inner Baltic population that maintained a high nitrogen content (3.7-3.9%) during the summer (Krasil'nikova et al, 1972). In addition, younger tissues have been reported to contain more nitrogen than older ones (Citharel & Villeret, 1964;Indergaard & Knutsen, 1990), owing to the concentration of low-molecular-weight nitrogenous compounds in the apical meristem. On the other hand, this trend was apparently reversed (Indergaard & Knutsen, 1990) in 4-6-year-old fronds cultured in either high or low nitrate concentrations.…”