HELLO! :D
We are a group of 3 Secondary 3 girls who decided to adopt the seagrasses at Labrador Park for monitoring, with Team Seagrass helping us(:
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Monday, July 9, 2007
The amazing talk at Botanic Gardens!
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 :D
for more information on eutrophication, look out for another link on causes for loss of seagrass coming soon!(:Labels: additional info
- have you hugged a seagrass today? (: -
11:23 PM
WHAT ARE SEAGRASSES?
~DEFINITION~
Seagrasses are tidal and sub-tidal marine flowering plants (angiosperms) that have complete internal vascular systems and a structure of buried roots, with erected leaves.
~MISCONCEPTIONS~
Many people have the misconception that seagrasses are a type of algae, but that is not true! There are various differences between seagrasses and algae. For instance, algae does not have a vascular system nor roots, and while algae is made of duplicates of the same cells, seagrasses have different types of cells for different parts of the seagrass.
~FACTS~
There are currently 60 described species of seagrasses, with 23 species in the Indo-Pacific area.
The various seagrasses have evolved from water, to land, and back to water. All seagrasses are known to be able to complete their entire life cycles underwater, with the exception of one genus, the Enhalus, which has to pollinate above the water surface.
Singapore has a diverse range of seagrasses, which include the Halophila Ovalis (spoon seagrass), which are most common and generally grow in sand, mud or silt,
Where does seagrass grow?
Seagrasses tend to grow in sandy and muddy areas that generally have no rocks, coastal marine and estuarine habitats, and in sheltered and shallow areas where they are protected from the current and wave action.
WHY SEAGRASS?
Seagrass communities play a very important role in coastal ecosystems. They support life in more ways than one. They:
- are food sources for many animals such as dugongs, sea turtles and fish.
- provide a feeding place for shorebirds such as egrets.
- have a high primary productivity rate and are vital in nutrient cycling, they also provide
a shelter and is a nursery and feeding grounds for shrimps, prawns, fish and crabs,
which are commercially important.
- stabilize sediments and stops beach erosion.
- improve water quality, making the seas clearer when the sediments are stabilized.
- also act as oxygen pumps when they photosynthesize.
- stop land-based pollution as they act as nutrient, sediment and chemical filter.
- have a buffering effect (that they filter nutrient and chemical inputs from land and trap
the nutrients.), which stops land-based pollution .
- have important biological interactions with coral reef and mangrove habitat and without
seagrass communities to trap sediments, the beautiful coral reefs that we admire may
not be around!
- are also the 3rd most valuable ecosystem globally, after mangrove and rainforests
So you may ask, why should we monitor these habitats?
Well, monitoring seagrass habitats provides coastal management agencies with information and allows greater confidence in decision-making. You wouldn’t like the government to build the Integrated Resort right over a seagrass habitat, killing all the life within it, would you?
Global, regional and local trends also show that this important coastal habitat is in decline, and by monitoring, we would be able to save the habitat.
In addition, seagrasses are considered a bio-indicator, which means that they can “tell” us when major coastal changes are about to happen. This is possible as they are sessile populations – not able to move if they sense danger – and are easily measurable. They cannot run away, but have to adapt to any changes. Thus, by monitoring them, we would be able to observe for any unusual trends and give an early warning for any major coastal changes.
WHO'S WHO?
Here's an introduction to the people who contributed to this project in one way or another!
(:
Team Seagrass!
Team Seagrass is the local seagrass watch organisation! they comprise volunteers from all walks of life and are very enthusiatic about seagrasses!
Seagrass-Watch
Seagrass-Watch started the seagrass watch project and is based in Australia
NParks
link
ECOLOGY OF ROCKY SHORE
Rocky Shore Zonation
There are generally 4 zones on rocky shore: Splash Zone, Upper Shore, Middle Shore and Lower Shore.
Splash Zone
The splash zone is the highest part of the rocky shore, it only receives occasional splashes of seawater when the tide is unusually high. Thus, the organisms found here tend to be more terrestial, e.g. Lichens. Organisms found here can also survive without seawater.
Upper Shore
The upper shore is mostly covered only during extremely high tides (spring tides), thus it is usually exposed. There is little bio diversity here, and the organisms found here have special adaptations to prevent drying out and are able to cope with severe water loss.
Middle Shore
The middle shore is around mean sea level, and is submerged for roughly half a day for each day. It has more bio diversity than the upper shore and splash zone.
Lower Shore
The lower shore is covered for most of the day, exposed only during extremely low tides (spring tides). The organisms here are exposed to little sunlight, and are more marine than those found at the splash zone.
This is a very general overview of rocky shore zonation. The organisms found at each zone differ at different places and we apologise for not having much information on organisms found at the rocky shore at Labrador Park as we have not had time to explore much.
GALLERY
photos up soon!
Monday, July 9, 2007
The amazing talk at Botanic Gardens!
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 :D
for more information on eutrophication, look out for another link on causes for loss of seagrass coming soon!(:Labels: additional info
- have you hugged a seagrass today? (: -
11:23 PM