Growth and toxin production of tropical Alexandrium minutum Halim (Dinophyceae) under various nitrogen to phosphorus ratios
Effects of nitrogen to phosphorous (N/P) ratios of two nitrogen sources (nitrate and ammonium) on growth and toxin production of a tropical estuarine dinoflagellate, Alexandrium minutum Halim, were examined using a strain isolated from a bloom at Tumpat Estuary, Malaysia in September 2001. Experimen...
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| Language: | English |
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Springer Netherlands
2010
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| Online Access: | http://ir.unimas.my/id/eprint/3347/ http://ir.unimas.my/id/eprint/3347/7/Growth.pdf |
| _version_ | 1848835194245611520 |
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| author | Po, T.L Chui, P.L Kobiyama, A. Ogata, T. |
| author_facet | Po, T.L Chui, P.L Kobiyama, A. Ogata, T. |
| author_sort | Po, T.L |
| building | UNIMAS Institutional Repository |
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| description | Effects of nitrogen to phosphorous (N/P) ratios of two nitrogen sources (nitrate and ammonium) on growth and toxin production of a tropical estuarine dinoflagellate, Alexandrium minutum Halim, were examined using a strain isolated from a bloom at Tumpat Estuary, Malaysia in September 2001. Experiments were carried out in batch cultures, using either nitrate (N-NO3) or ammonium (NNH4) as the nitrogen source at a constant amount, and with initial N/P ratios ranging from 5 to 500. Cell density, residual N and P in the medium, cellular toxin quota (Qt), and toxin composition were analyzed throughout the growths. Our results showed that cell densities and growth rates of A. minutum were severely suppressed under high N/P ratios (>100) in both N-NO3 and N-NH4 treatments. Cells tended to be larger at lower growth rate and P-limited cultures. Toxin profile was relatively constant throughout the experiments, with GTX4/GTX1 as the dominant toxin congeners. Cellular toxin quota (Qt) increased with elevated N/P ratios in both N-NO3 and N-NH4 treatments. Toxin production rate, Rtox, however was enhanced in N-NH4- grown cultures when P was limited, but showed no difference between N-NO3- and N-NH4-grown cultures when P was replete. Our results clearly showed that N/P ratios as well as the nitrogen compounds not only affected the growth of A. minutum, but also the cellular toxin quota and its toxin production rate. |
| first_indexed | 2025-11-15T06:03:59Z |
| format | Article |
| id | unimas-3347 |
| institution | Universiti Malaysia Sarawak |
| institution_category | Local University |
| language | English |
| last_indexed | 2025-11-15T06:03:59Z |
| publishDate | 2010 |
| publisher | Springer Netherlands |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | unimas-33472022-09-30T02:58:31Z http://ir.unimas.my/id/eprint/3347/ Growth and toxin production of tropical Alexandrium minutum Halim (Dinophyceae) under various nitrogen to phosphorus ratios Po, T.L Chui, P.L Kobiyama, A. Ogata, T. GE Environmental Sciences QL Zoology Effects of nitrogen to phosphorous (N/P) ratios of two nitrogen sources (nitrate and ammonium) on growth and toxin production of a tropical estuarine dinoflagellate, Alexandrium minutum Halim, were examined using a strain isolated from a bloom at Tumpat Estuary, Malaysia in September 2001. Experiments were carried out in batch cultures, using either nitrate (N-NO3) or ammonium (NNH4) as the nitrogen source at a constant amount, and with initial N/P ratios ranging from 5 to 500. Cell density, residual N and P in the medium, cellular toxin quota (Qt), and toxin composition were analyzed throughout the growths. Our results showed that cell densities and growth rates of A. minutum were severely suppressed under high N/P ratios (>100) in both N-NO3 and N-NH4 treatments. Cells tended to be larger at lower growth rate and P-limited cultures. Toxin profile was relatively constant throughout the experiments, with GTX4/GTX1 as the dominant toxin congeners. Cellular toxin quota (Qt) increased with elevated N/P ratios in both N-NO3 and N-NH4 treatments. Toxin production rate, Rtox, however was enhanced in N-NH4- grown cultures when P was limited, but showed no difference between N-NO3- and N-NH4-grown cultures when P was replete. Our results clearly showed that N/P ratios as well as the nitrogen compounds not only affected the growth of A. minutum, but also the cellular toxin quota and its toxin production rate. Springer Netherlands 2010 Article NonPeerReviewed text en http://ir.unimas.my/id/eprint/3347/7/Growth.pdf Po, T.L and Chui, P.L and Kobiyama, A. and Ogata, T. (2010) Growth and toxin production of tropical Alexandrium minutum Halim (Dinophyceae) under various nitrogen to phosphorus ratios. Journal of Applied Phycology, 22. pp. 203-210. |
| spellingShingle | GE Environmental Sciences QL Zoology Po, T.L Chui, P.L Kobiyama, A. Ogata, T. Growth and toxin production of tropical Alexandrium minutum Halim (Dinophyceae) under various nitrogen to phosphorus ratios |
| title | Growth and toxin production of tropical Alexandrium minutum Halim (Dinophyceae) under various nitrogen to phosphorus ratios |
| title_full | Growth and toxin production of tropical Alexandrium minutum Halim (Dinophyceae) under various nitrogen to phosphorus ratios |
| title_fullStr | Growth and toxin production of tropical Alexandrium minutum Halim (Dinophyceae) under various nitrogen to phosphorus ratios |
| title_full_unstemmed | Growth and toxin production of tropical Alexandrium minutum Halim (Dinophyceae) under various nitrogen to phosphorus ratios |
| title_short | Growth and toxin production of tropical Alexandrium minutum Halim (Dinophyceae) under various nitrogen to phosphorus ratios |
| title_sort | growth and toxin production of tropical alexandrium minutum halim (dinophyceae) under various nitrogen to phosphorus ratios |
| topic | GE Environmental Sciences QL Zoology |
| url | http://ir.unimas.my/id/eprint/3347/ http://ir.unimas.my/id/eprint/3347/7/Growth.pdf |