It was full yesterday. But today, it looked like a quarter moon. And it was slowly shrinking too!It was Liana who shared that it was a lunar eclipse!
We didn't pay it much mind aside from taking a few photos, and headed off to explore Changi on what should have been a good low tide.
What a wonderful find! A sea cucumber that looks like the unknown sea cucumber we saw at Cyrene Reef last month.
Although it's a burrowing sea cucumber, it has a distinct underside. How odd! Kok Sheng says he's seen something like this on Chek Jawa too. That's great to know.
This was another unidentified sea cucumber seen on the shore.
Its tube feet emerge in rows along the body length and appear to end in rounded tips. Hmmm.
I finally managed to get a clear shot of the pretty Warty sea cucumber (Cercodemas anceps) with its tentacles extended, well, sort of. I've never actually seen this animal with its tentacles fully expanded.
Alas, we realise after a time, that the tide wasn't really going down. In fact, it seemed to be coming back in! Anyway, it was a good opportunity to explore the high shore, and take a closer look at our seagrasses. Changi has long, thin Needle seagrasses (Halodule univervis).
As well as the beautiful Fern seagrass (Halophila spinulosa) and the oval-leaved Spoon seagrasses (Halophila ovalis).
I took a really close look at the seagrasses and noticed many were covered in a fine lattice-like structure. Could these be bryozoans? Bryozoans are colonial animals that build a thin skeleton. These are my first photos of them, although I'm sure these animals are abundant on our seagrasses. I've just never looked closely enough at them!
There were also really tiny snails that probably graze on the tiny algae that grow on the leaves, and clumps of what look like eggs. Seagrasses form an important habitat, providing permanent attachment for small animals. Their roots stabilise the ground so that burrowing animals can shelter and avoid being swept away in the waves. All these tiny animals in turn form the base of a food chain for larger animals, including shrimps, prawns and fishes.
Among the seagrasses was this really tiny Biscuit sea star (Goniodiscaster scaber).
And a Dove snail (Family Columbellidae).
There was a tiny sea anemone too. This might be Stichodactyla tapetum, and not a small Stichodactyla haddoni, the more commonly seen large carpet anemones on our Northern shores. We shall send this photo to Dr Daphne and see if it's useful to her.
There was also a very small patch of tiny Button snails (Umbonium vestiarum). The snails are really small so they might have only just settled into their sandy home.
The bigger Button shells are occupied by tiny hermit crabs!
The hermit crabs are great fun to observe when the tide is not very low. Here's one in a spiral shell of a snail that I've yet to see alive.
Hermit crabs are often seen gathered in groups. Dr Dan told us that hermit crabs can smell when a snail has died. This smell attracts lots of hermit crabs who are always in the market for upgrading to a better shell. So a newly 'vacated' shell will often result in a gathering of hermit crabs.
Here's another pair of hermit crabs with what seems to be an empty shell. When one hermit crab takes the 'new' shell, another hermit crab may take its 'old' shell, which triggers more shell exchanges among the gathered hermit crabs. This shell 'musical chairs' may go on for sometime, because the animals often change their mind!Before I could witness any swopping between these hermit crabs, the tide had come in!
Oh dear. But I had a nice day out, and the others also saw lots of other interesting things such a dead shark (possibly it was still born), and a 'squeaky' clam, noble volute, sand stars, sea pens and other stuff. Kok Sheng shares more about these on his wonderful creations blog.There were also sand dollars, more 'sea pencils' than I've seen on the last visits, and the big white sea urchins were still present in some numbers.
We wonder whether the lunar eclipse had affected the accuracy of the tidal prediction. On the other hand, these are among the very last of the morning tides for the year. The tides will soon switch to evening for the rest of the year. Usually, in our experience, during this switch over period, the tidal predications can be a little off in terms of height.
The lunar eclipse intrigued me. Here's what I found out about this event from space.com
A lunar eclipse happens when the earth gets between the sun and the moon. It is the earth's shadow that we see moving across the moon. Wow!Today's eclipse was a partial lunar eclipse.
Eclipses of the sun and moon usually come in pairs. A solar eclipse is almost always accompanied by a lunar eclipse two weeks before or after it.
The next lunar eclipse will occur on 9 Feb 2009 and will favor Alaska, Hawaii, eastern and central Asia, Australia and New Zealand.
The next total lunar eclipse will be on 21 Dec 2010.
Read the Top 10 lunar eclipse facts on space.com to find out answers to questions such as why lunar eclipses don't occur every month, at every full moon.
As well as read about how lunar eclipses affected ancient civilisations and created myths. It must have been quite scary to see the moon being 'eaten' every now and then.
So unbeknownst to us, we were experiencing a special astronomical event!
