Annual life cycle and productivity of the brown alga Sargassum yezoense off the coast of the Oshika Peninsula, Japan
2002
Agatsuma, Y. (Tohoku Univ., Sendai (Japan)) | Narita, K. | Taniguchi, K.
The annual life cycle and productivity of the brown alga Sargassum yezoense (Yamada) Yoshida et T. Konno (Sargassaceae, Fucales) were investigated in populations at Tomari-hama on the Oshika Peninsula from May 1997 to November 1998. The annual life cycle was characterized by the following three stages: 1) germination period during August to November, when the standing crop and length of main branches were at minimum and the main branches <10cm in length increased in number, 2) the growth period during October or December to June, when the standing crop increased due to elongation of the main branches, and the ratio of dry to wet weight decreased, 3) the reproductive maturation period occurred during June to August, when the larger-sized main branches (>10cm) matured in sequence. The annual net production estimated by the stratified clip technique was 903.9g/squere m. Since the productive structure of S. yezoense is similar to that of grass type, of which standing crop is much at lower strata of the thalli by sufficient light, it is suggested that this alga maintains its population by an immediate colonization of juveniles throughout the year into gaps formed after older thalli are lost.
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