Sponges

Red Beard Sponge

Sponges grow at all depths, and in brackish and freshwater also. They may occur as thin encrusting coatings on rocks and wood, or as long thin branching fingers attached to the bottom, or in the typical rounded form that has been used for centuries as ... a sponge!

The Red Beard Sponge Microciona prolifera is the commonest and most colorful of several sponges that grow in the region. Sponges also occur in shades of yellow and white and often grow in a much lower, spreading, and encrusting form, especially in areas of high currents. They are the most primitive of multi-celled animals, lacking distinct tissues and organs.

Red Beard Sponge
Red Beard Sponge
A Sea Star crawls over a Red Beard sponge
Palmate Sponge
Palmate Sponge Isodyctia spp.
Boring Sponge
Boring Sponge Cliona spp.
Boring Sponge
Boring Sponge Cliona spp.( yawn )
Boring Sponge

Boring Sponges typically grow on mollusk shells, such as Oysters. While not parasitic, they do eat away at the shell, causing stress and sometimes death for the mollusk.

Sponges structure is based on microscopic interlocking spicules ( right ) which are built up from cell secretions. Depending on the species, these may take the form of pointed hard calcareous hooks or flexible nets. The spicules of some tropical species can cause severe skin reactions if the sponge is touched or handled. I am not aware of any such danger with northern sponges.

Sponge anatomy
Sponge "anatomy" - sponges don't really have anatomy.
sponges
Herb Segars Photography

An Explanation of Professor A.A. Buhlmann's ZH-L16 Algorithm

by Paul Chapman

Note to new divers and potential new divers:

This information is presented for general interest. Don't be scared off by what you see here - you don't need to learn any of this to become a safe and competent scuba diver. You will however need to understand dive planning.

The following is a summary of the decompression algorithm described by Dr A.A. Buhlmann in the fourth edition of his book Tauchmedizin ( diving medicine ) published in 1995 ( only in German. ) the book contains a considerable amount of other information and is published by Springer-Verlag ISBN 3-540-58970-8. Rumor has it that at the time of writing ( November 1999 ) an English translation is being prepared for publishing, so hopefully, in due course, this document will become redundant.

The algorithm is simply a "recipe" for modeling the behavior of inert gases, which diffuse in and out of our body tissues when breathed under varying pressures. The intention is that if the recipe models the actual processes in our bodies accurately enough, it can be used to plan dives ( and other pressure exposures ) with a view to avoiding decompression sickness.

Printed from njscuba.net