Saturday, December 8, 2007

sea fans

A small yellow fan that I picked up off the beach. The sea has been rough lately, and this little guy broke off from his footing and washed ashore. I'm guessing this fan to be four to six years old. There are some that are taller than I am, in deeper water, thirty feet and more, sometimes to 100 feet deep. ten to thirty meters, roughly. I have no idea how old they must be! Maybe even over a hundred years.

I love the patterns of the branches.

This is another fan that's lost the chalky covering on it's skeleton. Fans are made up of polyps just like stony coral. The polyps live embedded in this chalky layer that they grow, their bones! When the polyps are out feeding, the fan looks brownish, from the tentacles. I'll have to try to get a detailed photo on my next dive, tho' my camera isn't very good at extreme close-ups. These polyps are teenie tiny! They start out as eggs floating around, hatch, and in several weeks settle to the bottom hopefully finding a good place to stick and grow from. Each fan started out as one teeny tiny little critter that multiplied and gradually got bigger. The polyps do not separate, but form one living growing creature. Nothing on land to compare.

Another yellow fan, and the only purple one I found that day, it's kind of beat up from tossing in the surf. Before I had a good book that taught me that there are only two colors of fans, yellow and purple, I thought they came in lots of different colors. The purple is called 'Common' but sometimes is yellow, and the yellow is called 'Venus' but is sometimes purple!

It's fascinating how the fans grow around the edges, and as they keep going, the inside parts fuse together. Beautiful patterns! I've never seen an accurate drawing of these patterns, a project for me!

They grow flat, sideways to the waves coming into the shore, so they wave back and forth beautifully. The growth habit makes the seawater flow through the fan, so the polyps can catch the most food particles passing through.

Monday, December 3, 2007

Spiney urchins

Spiney urchins are very strange animals. Well named, and if you bump into one, you get stuck! Their spines aren't poisonous, but break easily, so you have a bit of a wound for a while, until the bits dissolve. Best to not bump them! This photo also shows a purple sea fan, a type of coral animal (!!) The brownish, and the white are both Blade Fire Coral, that's a real 'don't touch' coral, it burns, but just for an hour or two. The white color is bleached, not good, the sea was too hot. Sometimes coral can recover from bleaching, but sometimes not.

These urchins have been feasting! See how the rock bottom is clean and white in their vicinity. They move around slowly using tiny rubbery feet that are somewhat sticky. They also use their feet to pick up food, algae, and stuff it in their mouth, which is in the middle of their bottoms.

Looking down at lots of urchins in the rubbly rocks. If you get very close, they can sort of see you, and they wiggle their spines at you. "Go away!!" they cry in their tiny voices that we cannot hear. Funny little cows of the sea, happy to just graze around.

Saturday, December 1, 2007

Urchins, a sketchbook page...

Oh, dear, this doesn't read very well! Have to re-do. And I'll now have to go dig up photos, or maybe start a collection of photos to work from. Urchins are so elegant in their own way...