A SEASONAL COMPARISON OF CARBON, NITROGEN, AND PIGMENT CONTENT IN LAMINARIA SOLIDUNGULA AND L. SACCHARINA (PHAEOPHYTA) IN THE ALASKAN ARCTIC 1

• Published in: Journal of Phycology
• Main Authors: Henley, William J., Dunton, Kenneth H.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1995
• Subjects: Arctic; Pacific; Arctic Population; Beaufort Sea
• Online Access: http://dx.doi.org/10.1111/j.0022-3646.1995.00325.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.0022-3646.1995.00325.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.0022-3646.1995.00325.x

ABSTRACT Laminaria solidungula and L. saccharina inhabit the Beaufort Sea in the Alaskan High Arctic . Laminaria solidungula is an Arctic endemic, whereas L. saccharina extends from north temperate Pacific and Atlantic waters to the Arctic. Previous studies have shown that the two species have different seasonal timing of growth, but little comparative physiological information exists. As a first step in characterizing these two species from a mixed Arctic population, we measured variations in carbon, nitrogen, and photosynthetic pigment content in blade tissue from plants collected under the fast ice in April and during the open water Period in late July, Both species exhibited seasonal differences in many measured variables; seasonal differences in L. solidungula were most pronounced in growing basal blades. For example, the molar CIN ratio of basal blades averaged 11 in April and 21 in July for L. solidungula and 11.5 in April and 28 in July for L. saccharina. Basal and mature second blades differed in pigment content in April but not in July: chlorophyll a + c in L. solidungula basal and mature second blades averaged 19 and 27 nmol.cm −2 in April and 30 and 29 nmol. cm −2 in July, respectively. The corresponding values for L. saccharina were 17 and 29 nmol.cm −2 in April and 16 and 16 nmol.cm −2 in July (95% confidence intervals approximately 1–3 nmol. cm −2 ). Carotenoids exhibited similar patterns. Species differences in pigments, carbon, and nitrogen were minor and were probably effects rather than causes of the different seasonal patterns of growth and development. The primary difference between the two species may be the ability of L. solidungula to retain multiple metabolically active blades and to fuel areal growth with stored carbohydrates during winter near‐darkness, whereas L. saccharina growth is more closely tied to active photosynthesis in the growing basal blade. The cause of old blade retention in L. solidungula and the possibility of other physiological differences between the two species, ...