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| Pratap, H.B.; Mamboya, F.A.; Mtolera, M.S.P.; Björk, M.. |
| The effect of copper (Cu) on the daily growth rate (DGR) and photosynthetic efficiency (PE) of the brown macroalga Padina boergesenii was studied under controlled laboratory conditions. The DGR was measured as an increase in fresh weight while the PE was measured as the ratio of variable to maximal chlorophyll fluorescence (Fv/Fm). Padina boegesenii were exposed to 25, 50, 100 and 500mg Cu/l for 21 days. The DGR and PE of P. boergesenii decreased significantly with an increase in copper concentration in the growth media. This study shows that copper is acutely toxic to P. boergesenii at concentrations higher than 500mg Cu/l. Low concentration of copper is toxic to P. boergesenii after a prolonged exposure of 21 days. Similarly, exposure time has a... |
| Tipo: Proceedings Paper |
Palavras-chave: Copper; Algae. |
| Ano: 1999 |
URL: http://hdl.handle.net/1834/787 |
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| Mohammed, S.M.; Björk, M.; Björklund, M.; Semesi, A.. |
| The release of inorganic nutrients into the sea by domestic sewage is a major threat to many marine systems. This eutrophication affects coral-reef organisms indirectly by increased growth of microalgae, leading to increased sedimentation, decreased light availibility, rapid growth of opportunistic macroalgae, etc. In this paper, we report a decrease in the cover of important group of coral-reef builders, the coralline algae. This decrease might be caused by the outlets of sewage water from Zanzibar town. Laboratory and field experiments show that both the growth rate and the calcification of these organisms are negatively affected by high phosphate levels, but not by nitrate or ammonia. |
| Tipo: Journal Contribution |
Palavras-chave: Sewage; Algae; Eutrophication; Coral reefs; Nutrients; Environmental degradation; Http://aims.fao.org/aos/agrovoc/c_5274; Http://aims.fao.org/aos/agrovoc/c_34821. |
| Ano: 1995 |
URL: http://hdl.handle.net/1834/302 |
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