The amazing talk at Botanic Gardens!

9 07 2007

After that surprise post by our amazing RS teacher, here’s what happened during the talk!

Dr Sasi Nayar, who works at the South Australia Research and Development Institure (SARDI), had been working on a project, to find out why the seagrasses, namely Posidonia and Amphibolis, off the shore of Adelaide have been disappearing.
So after an intensive 4 year study, which involved close shaves with sharks, he has come to the conclusion that eutrophication is the main cause for the loss of about 5000 Ha of seagrass.
How did he come to this conclusion?
Firstly, it was observed that loss of seagrass started from shallower areas, which is different from other places, where the loss of seagrass originated form deeper waters. Thus potential stressors were identified, and they are: Toxicants, Salinity, Turbidity, Eutrophication.
Then, over the course of the study, he and his team examined each stressor and slowly eliminated all the stressors except for eutrophication.
Thus, he has found the answers as to why the seagrasses off the shore of Adelaide have been disappearing – due to eutrophication!

(: nice work Dr Nayar! Thank goodness he was lucky enough not to be eaten by one of the many sharks off the coast of Adelaide, or he would never have been able to share with us his interesting findings 😀
for more information on eutrophication, look out for another link on causes for loss of seagrass coming soon!(:

“What killed the seagrasses off the coast of Adelaide?”

9 07 2007

Dr Sasi Nayar, recipient of the Tan Teck Guan Gold Medal, will talk about his current research on seagrasses at the Botanic Gardens.

The 4th Award of Nature Society ( Singapore) was awarded to the best Masters and Doctoral Thesis from National Tertiary Institutions of Singapore for the period 2003-2006 on a subject related to Nature Conservation or Environmental Protection/Improvement. The award, The Tan Teck Guan Gold Medal, recognizes the best thesis of the graduates on Nature and Environment in Singapore with the winners name inscribed on a Nature Society (Singapore) 20-gram 24 carat gold medal.


Since the 1940s, over 5000ha of near-shore meadow-forming seagrasses, Amphibolis and Posidonia, have been lost from Adelaide’s metropolitan coastline in Southern Australia. The loss of these seagrasses is a major concern due to their importance to near-shore productivity, seabed stability and biodiversity. Engineering works and urbanisation during the 20th century

Substantially increased water flow to the coast from rivers, stormwater drains, and wastewater treatment plant discharges, sullying the metropolitan coast. Elevated levels of nutrients, toxicants and turbidity have been detected and reported regularly over the last 30 years. Each of these potential stressors has been implicated in the historical loss of seagrasses. This talk will specifically address the effect of nutrients on seagrass assessed from in-situ chamber incubations, field experiments and mesocosm (simulation of real-life conditions) trials. The presentation and talk will take place from 7pm to 9pm in the Gardens Briefing Room (next to the Botanic Gardens Shop) at the Botanic Gardens Visitor Centre (at the junction of Cluny and Nassim Roads).

Further plans/updates for our research project

5 07 2007

On our RS Meeting in school, we discussed about what we had done, and what we haven’t done.

So basically, after some organising, we’re working along 3 tracks, all of which are thalassia.

  1. Measuring Lateral growth of Thalassia (GPS Recording, tracking outline)
    → Get GPS Recordings, upload onto map of Labrador Park

2. Measuring distribution (% Cover, using transects)

(After measuring: work)
→ Average % cover each quadrat per monitoring session/ quadrat per plot
→ Look for trends: e.g. Decrease in % cover per monitoring session
→ Canopy Height: Calculate using mode and mean (per quadrat per monitoring session)

(To be measured [Fieldwork])
→ Substrate/ Sediment type
→ Epiphytes Cover
→ Algae Cover
→ Soil Turbidity/ Gradient of Beach
→ Salinity

(To be Researched)
→Meteorological conditions:
→Precipitation [which affects salinity & exposure]
→ Climatic/ Seasonal conditions (Hot & Wet/ Hot & dry)


3. Growth of Thalassia Leaf
→ Calculate Percentage Error
→Organise data (choose appropriate method)
→ Analyse and look for trends

yup basically that’s all for our current to-do list! 😀
see ya!