Allelopathic effects of Margalefidinium polykrikoides on Pyrodinium bahamense under different nutrient condition

Al-Has, Asilah and Mohammad Noor, Normawaty and Mohd Shaleh, Sitti Raehanah and Mustapha, Shuhadah and Darnis, Deny Susanti and Ayub, Mohd NorAzman and Adam, Aimimuliani and Mustakim, Ghaffur Rahim (2021) Allelopathic effects of Margalefidinium polykrikoides on Pyrodinium bahamense under different nutrient condition. In: The 19th International Conference on Harmful Algae, La Paz, Baja California, Mexico. (Unpublished)

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Abstract

Co-occurring of Margalefidinium polykrikoides, a fish killer and toxic Pyrodinum bahamense have been commonly observed in the coastal waters of Sabah, Malaysia. During most of the events, M. polykrikoides will dominate the bloom and suppress P. bahamense. The reason for this condition is unknown. Therefore, this study explores the interaction of these species and try to understand under which nutrient conditions M. polykrikoides will become dominant over P. bahamense. To achieve this, the allelopathic abilities of M. polykrikoides on P. bahamense were investigated in different ratio of Nitrogen (N) and Phosphorus (P) concentrations in bi- algal and filtrate conditions. The bioassays were tested via bi-algal experiments at three ratios: 1:1 (500 cells mL-1 of each species, M. polykrikoides and P. bahamense), 1: 5 (100 cells mL-1 of M. polykrikoides and 500 cells mL-1 P. bahamense) and 5:1 (500 cells mL-1 M. polykrikoides and 100 cells mL-1 P. bahamense). For culture filtrates condition, three different volumes of M. polykrikoides filtrates (10, 20 and 50 mL) harvested at exponential phase were combined with 150 mL P. bahamense. Result indicates M. polykrikoides inhibit the growth of P. bahamense and caused morphological changes of P. bahamense in bi-algal culture. The best inhibition of P. bahamense by M. polykrikoides was observed at nitrate concentration at 30 μM and phosphorus concentration at 5 μM. This information will increase our understanding in bloom mechanism of these two important harmful algal blooms (HABs) species.

Item Type:	Conference or Workshop Item (Slide Presentation)
Additional Information:	6635/94585
Uncontrolled Keywords:	Red tide, harmful algal bloom (HAB), fish killer
Subjects:	Q Science > Q Science (General)
Kulliyyahs/Centres/Divisions/Institutes (Can select more than one option. Press CONTROL button):	Kulliyyah of Science > Department of Marine Science
Depositing User:	Dr Normawaty Mohammad Noor
Date Deposited:	29 Dec 2021 14:27
Last Modified:	29 Dec 2021 16:57
URI:	http://irep.iium.edu.my/id/eprint/94585

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