Goh, Beverly P. L. (Beverly Pi Lee)

With increasing recognition that maximum oxygen demand is the unifying limit in tolerance, the first line of thermal sensitivity is, as a corollary, due to capacity limitations at a high level of organisational complexity before individual, molecular or membrane functions become disturbed. In this study the tropical mussel Perna viridis were subjected to temperature change of 0.4˚C per hour from ambient to 8~36˚C. By comparing thermal mortality against biochemical indices (hsp70, gluthathione), physiological indices (glycogen, FRAP, NRRT) and behavioural indices (clearance rate), a hierarchy of thermal tolerance was therein elucidated, ranging from systemic to cellular to molecular levels. Generally, while biochemical indices indicated a stress signal much earlier than the more integrated behavioural indices, failure of the latter (indicating a tolerance limit and transition to pejus state) occurred much earlier than the other indices tending towards thermal extremities at both ends of the thermal spectrum.

In the past year (July 2014 to March 2015), 90 secondary school students participated in an Environmental Science themed Project-Based Learning (PBL) program designed by scientists at the National Institute of Education, Singapore. The authenticity of the PBL program was enhanced by partnership with NParks' Coastal Biomonitoring program. A total of 22 school teachers were also involved as facilitators of their students' project work. The strategic partnership of NIE scientists, secondary schools and NParks created a unique experience for students engaging in PBL.

Effects on mortality and settlement of Pocillopora damicornis planula larvae during recovery from low levels of Ni++ were investigated. Results indicated that a nickel concentration of 9 ppm over 12 hr was sufficient to cause 50% mortality in larvae 39.6 hr after removal of the toxicant. Settlement in larvae was more sensitive, showing significantly reduced settlement rates from 9 days into recovery, after exposure to I ppm Ni++ at durations of 12-96 hr. It is recommended that coral planula larvae be utilized more extensively in pollution studies.

Since 2001, Singapore has consistently performed well at the International Biology Olympiads (IBO). A commentary piece is provided by Team Singapore Delegation Leaders in the 2012 – 2015 IBO competitions as well as the President of the 40th and 41st SIBiol Councils on factors that contributed to the Singapore Institute of Biology’s (SIBiol) sustained success in the IBO competition over the last five years.

Previous studies have shown marine bivalves to be suitable bioindicators for heavy metal pollution in the marine environment. In this study, the potential of the Green Mussel, Perna viridis to be a bioindicator of copper and cadmium contamination in the marine environment was explored. The study aimed to develop a toxicity bioassay using P. viridis, and explored if a dose-response relationship between fertilisation in P. viridis and increasing concentrations of copper and cadmium could be established. The effect of copper and cadmium on embryo formation was also examined. Few fertilisation assays involve the use of the P. viridis, a tropical marine bivalve. Rather, a temperate mussel Mytilus sp., is more commonly used. As such, this study is relevant to the Southeast Asian region. Mussel gametes were subjected to increasing concentrations of cadmium and copper over a 24h test period. Following this, the number of unfertilised eggs was counted under a microscope. Data obtained was then arcsine transformed and subjected to one way Analysis of Variance (ANOVA) and Dunnett’s test to determine if a significant dose-response curve could be established. Results indicated significant treatment effects and a degeneration of unfertilised eggs when gametes were subjected to cadmium and copper solutions.

The sea urchin Diadema setosum is often encountered in the coral reefs in the Southern Islands of Singapore. While sea urchins have been known to play a role in regulating algal communities and influencing coral recruitment in other parts of the world, their role in Singapore reefs has not been determined. This study was conducted to determine the distribution and abundance of sea urchins in Singapore reefs, to examine algal cover, algal biomass, algal species and live coral cover, and to determine any interactions between urchin density and algal communities that may impact coral cover. Several reefs in Singapore were surveyed using belt transects measuring 20m by 2m, laid down on the reef crest. Abundance of urchins, algal species, biomass, and live coral cover were determined by the use of quadrats within each belt transect. This study revealed an increasing abundance of the sea urchin Diadema setosum in reefs progressing southwards away from mainland Singapore with low density of urchins occurring in Sisters’ Island, St John’s Island, Pulau Tekukor, and Kusu Island, and the highest density observed at Raffles Lighthouse. A significant negative linear relationship between algal cover and live coral cover (P < 0.05) was established. The results of this study indicate that sea urchins may not be an important component of the herbivore guild in Singapore.

The gametogenic cycle of Platygyra pini was investigated at three sites around Singapore’s southern islands from Mar.2001 to Apr.2002. Equatorial locations, such as Singapore, typically experience moderate annual environmental variation. This has lead to the suggestion that the amplitude of environmental variation at the equator is insuffi cient to provide reliable cues to synchronise reproduction in marine invertebrates. However, distinct and predictable seasonal patterns of sea surface temperature and rainfall occur in Singapore as a result of the Southeast Asian Monsoon system. Platygyra pini had a seasonal pattern of gametogenesis, with maturation of gametes and spawning occurring predominantly in April. A second, smaller peak in reproductive activity occurred in November suggesting that some colonies also spawn at this time. The major spawning for this species followed a period of rising sea surface temperatures and occurred after the period of heaviest rainfall. While a correlation between environmental fluctuations and spawning timing is not proof of a causal link, these data do indicate that the amplitude of change in environmental parameters such as temperature in Singapore is sufficient to provide a seasonal cue for reproduction and spawning synchrony.