Seasonal patterns of biomass, growth and reproduction in Dictyota cervicornis and Stoechospermum polypodioides (Dictyotales, Phaeophyta) on a shallow reef flat in the southern Red Sea (Eritrea)

Abstract : Seasonal patterns in thallus length, biomass, reproduction, total biomass m-2 and size structure were monitored in populations of Dictyota cervicornis and Stoechospermum polypodioides on a shallow reef flat in the southern Red Sea. These tropical reef flats are exposed to extreme temperatures of about 34°C in summer and to temperatures of about 25°C in winter. Both species showed peaks in length, biomass and reproduction in winter; macrothalli were absent in summer. Thallus length, biomass and the proportion of reproductive thalli showed a strong negative correlation with seawater temperature. Young thalli first appeared in November, following a drop in seawater temperature from about 33 to 31°C. Macroscopic thalli had disappeared in May, when temperatures had reached the same values as those at the start of the growth season (33°C). When reef substrata collected in summer were kept at sub-ambient temperatures (29–31°C), macroscopic thalli of D. cervicornis developed. Size structure varied over time, probably because of non-synchronous development and tissue loss among thalli. Reproduction was size-dependent. We conclude that D. cervicornis and S. polypodioides have highly seasonal patterns of growth and reproduction related to the seasonal variation in the environment, especially temperature.
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http://hal.univ-reunion.fr/hal-01372529
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Soumis le : mardi 27 septembre 2016 - 13:00:26
Dernière modification le : dimanche 5 novembre 2017 - 15:58:04

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Mebrahtu Ateweberhan, J. Henrich Bruggemann, Anneke M. Breeman. Seasonal patterns of biomass, growth and reproduction in Dictyota cervicornis and Stoechospermum polypodioides (Dictyotales, Phaeophyta) on a shallow reef flat in the southern Red Sea (Eritrea). Botanica Marina, De Gruyter, 2005, 48 (1), pp.8-17. 〈10.1515/BOT.2005.001〉. 〈hal-01372529〉

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