Aug 24, 2009

Tuas (24 Aug 09)

Back on the shores again to monitor seagrasses, this time at Tuas with the amazing volunteers from Schering Plough. Led by Helen (leftmost) and Sheryl (not in photo as she is unable to go down to the shore today).

NASA scientists study seagrasses

Even with satellite information, it is important to get data literally on the ground. The work of TeamSeagrass helps us better understand our seagrass meadows and what is happening to them.

At this moment, a fleet of NASA Earth-observing satellites is silently passing overhead, gathering vital information about our planet. NASA scientists Maury Estes and Mohammad Al-Hamdan are combining that heavenly data with local water samples to help check the health of the coast.

"We're most interested in sea grass and marine vegetation," says Al-Hamdan. "A region's plant health tells you a lot about the health of the area itself."

"It's fair to say that if seagrass is in trouble, so is everything else in the area," explains Dr. Ken Heck of the Dauphin Island Sea Lab in Mobile. "Sea grass beds provide shelter and food for many ecologically and economically important fish and shellfish, and even for the manatee -- an endangered gentle giant that regularly visits Mobile Bay. These beds also stabilize the shoreline, prevent erosion, and even help filter and cleanse the water that enters our estuaries from the watershed."

When Estes and Al-Hamdan aren't in the office pouring over satellite images to help foresee the coastal future, they're heading out to sea, where they collect water samples to analyze for "ground truth" to validate their model. The ocean voyages also give them a first-hand view of what they're studying and why.

"You do science in the real world – not in the office," explains Estes. "Going out there gives you a good perspective on the research data. If you don't physically know the area you're studying, it limits your understanding."

Full article on the wildsingapore news blog.

Aug 23, 2009

Sentosa's last resort


The shore below Tanjong Rimau is Sentosa’s last resort for the corals and seagrasses that used to grow all around Singapore’s largest southern island. To get data on the extent and health of the shore’s seagrasses shore over the seasons, TeamSeagrass monitors this narrow stretch of sand and rubble that straddles the island’s natural cliffs and a sloping seawall.


Thanks to a last minute round-up of gullible souls, we had enough volunteers on 21 Aug Friday to brave the soul-sapping journey across the causeway and within sight of a monstrous money-sucking pit. The team was joined by the water quality monitoring team from Singapore Polytechnic.


There are three parallel sites. As the reef flat is not wide enough for the standard 50m transect line, the volunteers use a semi-random sampling procedure, throwing the quadrant within the site boundaries and charting their observations wherever it falls.


The team managed to elude ferocious peafowl and suspicious hotel guards to plunge down the treacherous heights of the seawall. It was still dark when the monitoring began, so torches were needed.


On the exposed flat, the seagrasses grew mainly close to the seawall, while the outer fringe consisted of rubble, seaweed and corals.


Soft corals are quite common, even close to the seawall.


There are also scattered colonies of hard corals, mainly faviids or Porites.

The two species of seagrass known to occur here are the massive Enhalus acoroides and the puny Halophila ovalis.


Various seaweed, which are to seagrass like what flatworms are to nudibranchs, also cover the flat. Sargassum appears to be in mild bloom, while luxurious growths of Caulerpa cover parts of the sand.


Many little creatures, such as this banded hermit crab, lurk among the seaweed, using these ‘plants’ as food or shelter.

After the monitoring, there was a little time to hop around the shore and rock pools further down.


Before it got too bright, octopuses could be seen dawdling on the rubble. From a pale bleachy colour, they quickly activate their chromatophores to match the substrate when they sense an alien presence.


Red egg crabs, though locally threatened, are not uncommon here. A floral egg crab was also spotted. Both these crustaceans are known to harbour toxins, making them excellent choices for a last meal. Many hairy crabs lurk on the outcrops, but their camouflage helps to hide these animals unless they make a sudden movement.


Another disguised creature is the brown sweetlips. This inch-long juvenile was hovering in a pool pretending to be a piece of debris.


Frilly tentacled anemones are also quite common in rocky crevices. They are quite variable in colour, but the ones here tend to be the standard issue green variety.


Apart from the ubiquitous transparent long-armed shrimps, some little tide pools also contained these 2 cm-long striped shrimps. Arthur Anker, an expert in decapods, particularly snapping shrimps, has identified this to be Athanas dimorphus. Unlike most other snapping shrimps, which live in a burrow, these shrimps didn’t seem to retreat anywhere but simply darted about when disturbed.


Up on the rocks below the cliff, the crew found lots of barnacles, sea slaters, nerites, limpets and other splash zone dwellers. Lightning dove snails were particular abundant, gathering in small groups on algae-covered stones.


While the team was exploring, a mysterious man came down and prowled around the shallow water with a little plastic bag. We are unable to confirm if he survived the incoming tide.


By about eight, the work area was fully immersed. Some of the team had to be dragged kicking and screaming back to base, but most complied after threats to stuff a hairy crab down their throat. As the photo shows, they were happy to raise their arms in relief at surviving another morning on a shore exposed to the dangers of desperate resorts.

Those who survived the morning’s trip are: Serene, Kah Ming, Joo Yong and Chia Rui, Abby and Chung Fong.

Other posts about this trip

Chek Jawa (23 Aug 09)

Today is our last monitoring trip at Chek Jawa for the year. And the last of the morning trips by the Team.
Despite the wet weather and early hours, a small team gathers just before sunrise to get the job done.

We are joined today by Lee Qi's crab team. She is doing a project about the crabs found in seagrasses and the team has strange cut-out buckets and lots of other gear!
Kok Sheng also did a quick follow-up survey in relation to his project on the mass death and recovery at Chek Jawa.

As we head out, the sky clears and we get a lovely pink dawn.
We put up the TeamSeagrass banner on the boardwalk to inform visitors about our work.
Before clambering down the ladder to the shore. Or in my case, barely squeezing past the narrow ladder bars. If I get any fatter, I won't be able to make it down anymore.As we are setting up the transects, there is a glorious sunrise show overhead.
Today we are very short handed. So I get to do a line on my own. Siti and Jocelyn helps me set up my line before they do theirs. And with their help, I got it straight (almost) at the first try! Wow. That's a first for me. And what glorious surroundings to do work in! Cool dewy morning, and pink skies.
This is my first time doing Site 1 and it's now full of Smooth ribbon seagrasses (Cymodocea rotundata). See how much of it fills my transect square! This seagrass is not widely distributed in Singapore and Chek Jawa is one of our few shores with extensive growths of it.
Under the longer seagrass grows the shorter Spoon seagrasses (Halophila ovalis). In our site, we also got little bits of Fern seagrasses (Halophila spinulosa).
After we're done with the monitoring, I have a quick look around at the seagrasses. The Smooth ribbon seagrass is growing right up to the sandbar where public walks are conducted! That's great, so that visitors can take a closer look at this special seagrass.
On the other side of the sandbar facing the sea are wide areas full of more seagrasses!
But today I head inland to check out the mangroves that ring the upper shores of Chek Jawa. Past Richard and Yen-Ling who are still hard at work on their transect. Behind them is the Chek Jawa boardwalk and Jejawi viewing tower.
Along the way, I came across various Haddon's carpet anemones (Stichodactyla haddoni) big and small. A smooth sea cucumber out of the ground, as well as a half buried Garlic bread sea cucumber (Holothuria scabra).
As I got closer to the mangroves, I saw a little Striated heron (Butorides striatus) hunting little fishes among the seagrassy pools left behind at low tide.
The ground got a little more silty as I got nearer the mangroves.
And here, I saw a Sand star (Astropecten sp.) and a mangrove sea anemone.
And a tiny sea anemone that turned out to be attached to a living snail!
Here's a view of the seagrass meadows from the mangroves.
Chek Jawa is one of the few shores left in Singapore where the mangroves and seagrass ecosystems are found next to one another as it is naturally meant to be. There is a delicate flow of nutrients between the ecosystems, and various marine life depend on these ecosystems.

All too soon, it was time to go home. We spent a fair bit of time waiting in mosquito-infested areas. While the rest of us were busy waving our arms to keep the pesky critters away, Richard shows us how to stay cool in such a situation.
The team today were:

Jocelyne, Yen-ling, Richard, Andy, Suizlyn, Vanitha, Suryati, Chay Hoon, Adelle, Kok Sheng, Siti and me. With the Singapore Poly Water Quality Team: Nuan Qin, Joycelyn, Suzanna; and Lee Qi's Team Aldrin and Kan Meng.

Other blog posts about this trip