Friday, June 5, 2009

Qld tropics

This coral head has christmas tree worms and in the foreground of the photo is a clam. The mantle(the fleshy lip) of the clam can be very brightly coloured , iridescent blues and greens are common. These clams are in the giant clam family, can grow to as big as 1.5m(5ft), and live for as long as 200 years. All this family have a symbiotic relationship with an organism called zooxanthellae(a type of microscopic algal cells) which live on the mantle (the fleshy exposed lip). These cells produce food for the clam by means of photosynthesis and provide it with nearly all its nutritional requirements. Many corals also have this relationship with zooxanthellae. The coral in the front of the photo is hard coral and the spongy looking finger like projections at the very back of the photo are soft coral. When it is feeding it looks very different.-(like in the next photo)

The tiny tentacle like arms you can see here belong to individual coral polyps. Corals are made up of colonies of these. Much of the time all that we see of coral is the skeleton, some hard which are made of limstone secreted by each polyp, and some soft which are generally sort of spongy. This is soft coral, when the polyps are out like this they are feeding, they capture tiny bits of plankton floating in the water. Usually they feed at night and when the day is dull. Even though they look plant like they are primitive colonial animals (some of the earliest to evolve!) and there are hundreds of different species of them mainly living in the worlds tropical oceans.

Many of the really fascinating things that we see diving are invertebrates and tiny. The pretty blue whirls you can see in this picture are actually double sets of tentacles, which are used for catching tiny particles of food, that belong to creatures known as a Christmas Tree worms.(There are two worms in this pic.) If you look closely you can see a little door-the operculum, that can close over and conceal the worm completely in an instance if the worm feels threatend in any way. It can be infuriating trying to take a close up photo of them as one move too suddenly and they're gone. They come in many different colours and on a white coral head they look really beatiful and just as colourful as christmas decorations. Who would have thought that a worm could be pretty.

Green turtle swimming in the warm waters off Lowe Isles.

Turtles are not only sea creatures. There are many types of freshwater turtles, often seen swimming in water bodies in throughout Australia, but more commonly seen in the tropics with the warmer year round temperature. This one was warming itself in the sun along side a lagoon near Port Douglas in Qld. It is a Saw-Shelled turtle and this species has aparantly come to regard the introduced Cane Toads as a food source! Sometimes these turtles are seen wandering aparantly nowhere near water, maybe searching for a new water body ( if theirs has dried up) or sometimes they travel to new water bodies to find a mate.

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