Sunday, August 30, 2009

South Cottesloe Beach - Chitons - Ischnochiton torri

I dug into my image folders again and found that had actually taken some proper shots of Ischnochiton torri. If you remember from my last post, it's the one with eight brown plates with white streaks on each plate, and the plates are surrounded by a distinctive orange girdle.




The last two shots show another chiton curling up. Never having seen a chiton curling up before, I initially thought it was some kind of shrimp : ) Chitons can curl up to protect the muscular foot.

They scrape off algae and small animals off rocky surfaces using their wonder toothed tongue. Chitons have teeth coated by magnetite, making their teeth comparable in hardness to a kitchen kife!

David Macey, a scientist from Murdoch University said this about chiton's teeth in an interview with ABC Television: "Their hardness on a scale of 0-10 is 6.5. .. And a kitchen knife would be around about 6.3 , 6.4 depending on how good your kitchen knife was. So they are really are very hard, they could eat steel if they wanted to." Aren't you impressed!

Saturday, August 29, 2009

South Cottesloe Beach - Chitons

I have taken these photos of chitons some time this January- actually in two of them, I wanted to take the photos of sea stars. I found them under rocks during low tide. These chitons surely look more interesting than the dark, grey ones that I usually find clinging to rocks on the beach.

Later, I was fortunate enough to get Leon Altoff's and his colleagues' help to ID these chitons. I have wanted to put these photos up for months but just kept forgetting to do it.

Leon has a fantastic website (http://www.bluering.org.au) with heaps of photos of marine species, with careful documentation of their family and specific names, distribution, and location where the photos were taken.



Rhyssoplax torrianus (left)


Ischnochiton cariosus


Ischnochiton virgatus next to a sea star

These chitons are so lovely. They are definitely the oens that I want to take some close-up shots of the next time I see them.


Ischnochiton torri (top) and Cryptoplax striata

Ischnochiton torri has a distinctive orange girdle surrounding brown plates with white streaks in the middle. I must get a better shot of it when I can access the rocky shore at South Cottesloe this coming summer.


Cryptoplax striata

According to Leon, this and the one in the last photo are both Cryptoplax striata. Cryptoplax species has very small plates, unlike many other chitons.

Saturday, August 22, 2009

Another goose barnacle species - Smilium peronii

A pretty goose barnacle species that I found washed up the South Cottesloe shore last weekend - Smilium peronii.

I was lucky to have contacted Diana Jones, who works for the Western Australian Museum. She immediately identified the barnacle species and provided me with additional information about the animal.



Below is what I could make out from her reply:


Australian Distribution
:
Western Australia (4-31 m); South Australia, East Bass Strait, Victory (15-46 m); New South Wales (sublittoral-9 m); Queensland (4-48 m).

General Distribution:
Indo-Malaya-Australia, Kai Islands, Amboina Bay, Jedan Island.

Habitat:
Attached to organic substrata, e.g. seagrass (Cymodocea sp.), corallines, ascidians (e.g. Pyura pachydermatina Herdman var. gibbosa Kott)(Chai's note: Pyura pachydermatina is a sea tulip); wooden stakes.

Remarks:
  1. First records from Australia are by Darwin (1851), who recorded specimens from Bass Strait, and the Swan River, Western Australia, which had been collected by Astrolabe. (Chai's note: I have yet to find out what/who is Astrolabe.)
  2. The species occurs off the west coast of Western Australia in shallow water and is commonly found stranded on the shore during the winter months after storm activity.




This last photo, taken from an earlier post on this blog, shows a bunch of the goose barnacles (blue arrows) attached to the stalk of a sea tulip (pink arrows).

UPDATE (23 August 09): Fellow nature blogger Denis has provided me with some information about "the The Astrolabe". See the COMMENTS section below.

Monday, August 17, 2009

Beachcombing finds II: Blue bottle, violet sea snail, by-the-wind sailor & blue button

As I mentioned in my last post, I found heaps of blue bottles (Physalia utriculus (?)) that were washed ashore. I saw the same thing at South Cottesloe as well as the South Beach, Fremantle.



Hundreds and hundreds of blue bottles were washed ashore, marking the high tide line.



They are reasons why you don't want to walk on the beach bare-footed. They have stinging cells on their tentacles (red arrows).

I got stung anyway, not because I was bare-footed but somehow one of them got caught in my sandal when the tide came in. It was painful but bearable. And thankfully, there's no swelling or anything like that. By the way, its tentacle seemed quite sticky and it took a bit of effort to get it off my sandal.



If you look carefully amid the blue bottles, you might find the by-the-wind sailor (Vellela vellela) (blue arrow) and violet sea snail (Janthina janthina) (red arrow). The violet sea snail, which I thought would be rather harmless, is actually a predator of blue bottles and by-the-wind sailors (see here).



This blue bottle has a tentacle 1-1.5 m in length. It must be a nasty experience to come into contact with one while swimming. The red arrow indicates the float. The air in the float may contain rather high levels of carbon monoxide, which the blue bottle produces! Amazing. Steve Reynolds has written two interesting articles about blue bottles in the Marine Life Society of South Australia Newsletter (October 2008; March 2009).

The Mote Marine Laboratory website also has an article about how they keep blue bottles in a tank so that their floats won't dry up too fast and their tentacles won't just stick to everything they touch.



Lovely violet sea snail! The raft of mucus bubbles helps the animal stays afloat upside down. Preying on floating creatures like bluebottles is also a way it helps itself stays afloat. How "clever" - if that means anything to a sea snail : )



This by-the-wind sailor is about 2 cm across. The red arrow points at the sail. The blue arrow points at the disc which contains many small air chambers to help the animal stay afloat.



This is the first time I saw some blue buttons (Porpita species) with the disc (blue arrow) and the tentacles (red arrow) still intact. A Porpita with its tentacles fully extended is just incredibly beautiful ( see here). The first time I saw the dead ones which had lost their tentacles, I thought they were some dress buttons!

My previous posts about the Blue Layer:
The Blue Layer - Blue bottle, by-the-wind sailor, violet shell
The Blue Layer - Sea lizard




Sunday, August 16, 2009

Beachcombing finds I: Live goose barnacles

Friday was wet and windy. So I went beachcombing on Saturday, hoping that the strong winds had brought to shore some interesting creatures. The weather was still wet and windy on Saturday.

I started from the South Cottesloe beach and walked ~ 4 km to North Fremantle (Port Beach). The walk was not very comfortable as it was cold and windy. Within an hour, my nose started to run freely. And the water droplets in the wind kept blurring my glasses and the lens of my camera.

Anyway, I found some live goose barnacles on a broken wooden pallet. And the beach was also littered with lots of blue bottles and dislodged seaweeds (see my next post).



The broken wooden pallet, about 1 m x 1 m in size, that was covered with goose barnacles.


There were very few goose barnacles on the upper surface of the pallet, but the lower surface seemed to be full of them. So I turned the pallet over.




There must be hundreds of them making the pallet their home. They didn't look desiccated, like those I found on a log last weekend. So I suspect these barnacles must have arrived on the South Cottesloe beach not very long ago.


The jointed legs of a goose barnacle - one of the indications that these animals are crustaceans, like shrimps.
A barnacle uses its legs to comb the water for food particles and small planktonic animals and sweep them to its mouth.





Quite a number of the barnacles were still alive and they were slowly extending and then retracting their legs. So I was able to take a few close-up shots of their legs. In close-up shots, these animals don't seem so creepy after all.

Friday, August 14, 2009

South Beach, Fremantle - Goose barnacles

"Goose barnacles acquired their common name from a weird medieval myth. According to this myth, stalked barnacles attached to floating tree trunks were the fruit of the trees themselves, and had the tree kept growing,
each fruit would have developed into a sea bird called the Barnacle Goose!!"

(source: http://www.reef.edu.au)


Last
Sunday, having reached a point when I just couldn't take another look at my thesis anymore, I went for a walk on the beach. It has been a long, long time since I last did this.

I was quite excited to find a log with dead goose barnacles on it. The log, at least five meters in length, must have been washed ashore for quite some time. The goose barnacles were all dry and dead.









Last year, I saw a log covered in live goose barnacles on the South Cottesloe beach. Alive, these creatures look really bizarre!
I must be lucky to find them, considering that a log covered in goose barnacles is not an everyday sight on the beach.

Thursday, August 13, 2009

"100 Best Blogs for Career-Minded Students"

I was informed by Amber Johnson of www.onlineschools.org that this site was listed in a recent post (100 Best Blogs for Career-Minded Students) on their blog. I am not sure how well this blog fits the bill. But it's always interesting to hear how others see this blog.


"Bloggers in Various Careers

Many students attend college to discover careers that interest them. The bloggers below write about their jobs with passion and dedication, allowing students a window into different lives.

...

46. Chai's Marine Life Blog: Some people are drawn to water and Chai is definitely one of them. Read this blog from a marine biologist demonstrating passion for his work.

..."

Wednesday, August 12, 2009

PhinisheD!

Finally, after three and a half years, I submitted my thesis for examination this afternoon.

And it was really without much ceremony: I gave four copies of my thesis to the graduate school, was told that I will stop receiving my living stipend beginning from tomorrow, and that I will have to start paying for the health insurance from my own pocket beginning from next month. So after submitting my thesis I have become poorer. How anticlimactic!

At UWA, they will give you a "PhinisheD!" mug when you hand in your thesis for examination.


The fun thing today was that I made the rounds with the mug in my hand, telling everyone I know that I have finally given birth after such a long gestation period!

Followers