27 June 2024

Mass coral bleaching at Cyrene, no oil spill impact

A small team decided to survey Cyrene on a less than ideal tide on the last of the low spring tide cycle. Because Uncle Tony ODempsey shared with us this chart. Which suggests the oil escaping from the accident site spent some time over Cyrene. Thanks to Uncle Tony for this important information.
Fortunately, we didn't come across any smell or signs of oil on the shore. Ian did a great drone overview of the shore too. We saw dugong feeding trails, Knobbly sea stars, Giant clam and other marine life commonly seen here. But sadly mass coral bleaching seems to be getting worse here. We estimate about 50% of hard corals and 70% of leathery soft corals are bleaching. On our last visit here on 10 Jun 2024, the estimate was15% of hard corals were showing signs of stress and about 10% outright bleaching. While about 40% of soft corals were showing signs of stress and about 30% outright bleaching.

The Beacon on the eastern tip of Cyrene is just off the site at Pasir Panjang Container Terminal where the accident happened.
No oil on Cyrene, 27 Jun 2024
The Beacon is the most likely place for oil to collect because it emerges out of the water all the time. But I didn't see any signs or smell of oil. Neither with the pile of large debris that has been near the Beacon since we first started visiting. But when we passed a small floating buoy near Cyrene, there was a strong smell of oil, and a layer of oil seems to be at the bottom of the buoy.
The shore is still very much alive. We did not see any dead animals. Although we managed to only find one patch of about 20 Knobbly sea stars, we saw the usual animals we commonly see on our surveys, going about their usual business. From Common sea stars, to crabs, hermit crabs and snails. Also squishy slugs and sea cucumbers and sea anemones. In the sand were many clearly healthy worms making their usual long coils of poop. There were also lots of birds hunting on the shore.
Today, we saw only one Fluted giant clam - the 40cm one near the beacon. But it had fallen over! When I set it back upright (facing the sun), I noticed it's flesh had white patches. Giant clams also harbour symbiotic algae and can also bleach. I hope it will be okay. It soon squirted at me as it closed its shells.
Unfortunately, our shores are currently also being impacted by mass coral bleaching. Most of the hard corals on Cyrene are boulder shaped. There are many large colonies and most seemed alright.
Mass coral bleaching 2024 check at Cyrene, 27 Jun 2024
But many smaller hard coral colonies were outright bright white bleaching. We estimate about 50% of the hard corals here were bleaching. I looked at corals that in the past bleached first: Cauliflower corals (I saw only two and both were bleached), Sandpaper corals (I saw two, one was okay the other very pale). 
Near the beacon and around the eastern tip of Cyrene, there are a lot of large Leathery soft corals. Many of them were bright white bleaching or showing signs of stress (pale patches).
Mass coral bleaching 2024 check at Cyrene, 27 Jun 2024
Some colonies that were bleaching are next to others that seemed alright. Some colonies were 'melting' into smaller fragments. We estimate about 70% of leathery soft corals were outright bleaching or badly stressed.
For the first time, I noticed some normal coloured Leathery soft corals with odd ridges on their tissue. These ridges are also seen in submerged colonies. I'm not sure what this means.
Other cnidarians can also bleach, so I looked out for those too. Most of the Frilly anemones I saw were alright, only a few bleaching. Many large colonies of Sea mat zoanthids were alright, I saw a few 'melting' or with white patches. There was one large Leathery sea fan with sections that looked 'furry' with some kind of growth - not sure what is going on. I saw a few Asparagus flowery soft corals, most were okay. I saw a few small clumps of bleaching corallimorphs - but healthy ones are usually well camouflaged so I might have missed them.
Today I saw several sets of furrows that look like they were made by feeding dugong in the seagrasses facing Pasir Panjang Container Terminals. These trails are formed when dugongs chomp up seagrasses including their roots, leaving a shallow meandering furrow of about equal width and depth. Similar trails were seen on our recent surveys earlier this month and in Apr 2024Apr 2023Sep 2022Dec 2021 and Aug 2021.
Dugong feeding trails in seagrass meadows, Cyrene Reef, Jun 2024
There was still good seagrass cover on the Eastern end of Cyrene facing the container terminal. Mostly Spoon seagrass and other shorter seagrasses. Tape seagrasses were few and far between, with short leaf blades. Unlike our last survey in Apr 2024, the seagrasses I saw were mostly fresh and green and I didn't mat-like epiphytes on them.
The deep pool in the middle of Cyrene is becoming more shallow. It used to be thick with long Tape seagrass. These disappeared about 10 years ago. Today, there is thin cover of a variety of short seagrasses. But no long Tape seagrasses. This is similar to what I saw on our last survey in Apr 2024Apr 2023 and Sep 2022.
Seagrasses at Cyrene (East), Jun 2024
There were patches of fresh green Halimeda seaweeds here and there among the seagrass. During our oil spill check of East Coast Park on 22 Jun 2024, we noticed many dead white Halimeda seaweeds. There were also small fresh clumps of a variety of other seaweeds, as is commonly seen here.
Thanks to Ian for a valuable drone overview of this special shore at a time of great stress. The extent of mass coral bleaching more visible! But also nice to see seagrasses coming back (darkish patches, different from bare sand). And the 'deep hole' in the middle of the reef flat is now blue - full of seagrass again.

Alex brought us to take a closer look at the site of the accident. Seems like other vessels are already using the site. We went past the dredger VOX MARINER which had reported a sudden loss in engine and steering control before it struck the bunker vessel MARINE HONOUR on 14 June 2024. But we couldn't find the MARINE HONOUR in the vicinity. 
High res photos of all photos taken today on wildsingapore flickr.

Update: Uncle Tony shared further information about the chart he shared with us:

"That is the probable path of a cork released at ground-zero and time-zero and following the tidal stream with no allowance for wind. The tidal stream oscilates slightly out of sync with the tide. For an example of tidal stream maps you can refer to MPA web site:
Where the Western and Eastern anchorages are published. It is the most accurate model available because it is calibrated to tidal stream guages.

I just now checked the winds for 14 june. At time of spill winds we coming from the west and later from the north. These winds probably saved the cyrene reef from the oil being sushed about by the tide."

Photos by others on this survey

Richard Kuah

Mudh Nasry

Liz Lim


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