Department of Biological Sciences, NUS
Date: 23 May 2016, Monday
Venue: S1A Seminar Room (S1A, #02-17)
Supervisor: Asst Prof Darren Yeo Chong Jinn
Co-supervisor: Dr Sandric Leong Chee Yew
Harmful algal blooms (HABs) can lead to deleterious outcomes including human-toxicity. The three commonly causative marine phytoplankton groups are diatoms, dinoflagellates, and raphidophytes. Of the three, the Raphidophyceae group was categorised most recently and is generally not well-understood. Nevertheless, raphidophyte blooms previously resulting in massive fish-kill events have led to increased focus upon such groups. In general, studies have demonstrated the wide tolerance of raphidophytes to a range of environmental conditions. Bloom patterns involving the group have also highlighted overlapping niche conditions, which is referred in the literature as “raphidophyte niche”. However, present understanding about raphidophytes has largely derived from temperate studies, and there is a lack of knowledge regarding tropical conditions. Accordingly, the present work seeks to fill two general gaps. Firstly, present approaches toward understanding HAB outcomes do not account for the presence of a “raphidophyte niche”, indicating a need to expand present conceptual frameworks. Secondly, many studies have observed that raphidophyte blooms coincide with seasonal changes, which is lacking in tropical regions. My present work examines two raphidophyte species isolated from the East Johor Straits, Singapore—Heterosigma akashiwo and Chattonella subsalsa. Current findings highlight matching nitrogen-uptake patterns between temperate and tropical strains. However, the resting-cell stage of Heterosigma akashiwo reported in temperate environments does not seem to be supported under the higher tropical temperatures. Such life-cycle differences may have significant implications for the bloom potential of tropical raphidophyte strains.
All are welcome