I'm back from Florida, but have been experiencing serious problems relative to diving. I haven't been in the water since Halloween when I completed my rescue diver certification with dive buddy Karen. I spent the first week of the month trying to recover from the data loss when three of my computer hard drives crashed within a week. The second week I was in Florida with family. And the third week I've been fighting badly congested lungs, probably due to breathing recycled air in an airplane full of sick kids (physically, not mentally). Ugh. My gills are seriously dehydrated. I'm not sure how one performs artificial respiration on a gill-breather like myself, but I'll settle for some good old mouth-to-mouth. After all, the holiday season is approaching and with it, mistletoe! Oops, I digress... on to the subject of this week's column! As the cold winter approaches, my thoughts turn towards the warm tropics. If only my bank balance were adequate to tickle that fancy.

Diving the tropics one is struck by the size and often the beauty of the many species of sponges there. I have seen ones I could easily settle into if playing a game of underwater hide-and-seek (and I'm no small "fry"). I have seen beautiful blues, oranges, and greens in both pastels and more saturated tones. Then there are the bright red ones, the color often signifying they have poisons that can affect even humans who are careless enough to touch them. The intent of these chemicals is part of their defense strategy as they are produced to prevent other life from infecting, eating or growing on them. These chemicals are being studied by scientists who feel they may have anti-bacterial and anti-cancer properties. Remember that when you reach for your bath sponge... its living relatives may one day save your life!

By contrast, the sponges in our temperate waters are nowhere near as spectacular. We do have bright yellow, orange, blue, green and red colors. Two of my favorites are the yellow sulfur sponge and the cobalt blue sponge. However our sponges would barely hide an undersized lobster much less a creature of my size. Most of them are very small in stature and almost look like blobs of paint spilled on the rock surface.

Thanks to my explorations on Scuba Luv's King Neptune, I have been diving some of the colder waters on Catalina's leeward coast. Recently I was diving at Bird Rock and Dynamite Shed (Empire Landing Quarry area) where I was able to get shots of the orange puffball sponge. This is a species I have never seen in the dive park or at normal diving depths from Long Point to the East End where our water is the warmest. However, I do see it at colder water sites off Catalina and in the northern Channel Islands.

This sponge is spherical and orange to yellow-orange in color. It may reach a diameter of up to 8" but the ones I've been seeing are about half that. The sponge's outer surface is rough and full of channels. The orange puffball attaches to rocky substrates. It may be found from SE Alaska to central Baja California, and from the lower intertidal to nearly 1,500 feet.

There are small pores called ostia in the surface of sponges through which water moves thanks to the beating of whip-like flagella that create a current. This water contains oxygen and food which are filtered out by the sponge's cells. The filtered water receives carbon dioxide and wastes from the sponge, and is then ejected through a central series of larger holes called oscula. Food filtered out of the water consists of bacteria, organic matter and dissolved substances. It is said that the clear waters of the tropics may be due, in part, to the filtering out of plankton and organic matter by the numerous and large sponges there. In turn sponges are food for sea stars, fishes and molluscs including snails like nudibranchs and chitons.

Sponges are invertebrates and therefore lack a backbone or central nerve chord. The sponge's body is composed of a number of different specialized cells with little advanced coordination. In other words, they are brainless (so how does SpongeBob SquarePants see or speak?). These cells act almost independently, and sponges have no true body tissues or organs. The cells are structurally supported by two components. First, there is an interlocking matrix of fibers made of a protein called spongin. Second, there is an interlocking skeleton of hard spicules which in some species are made of calcium carbonate (like our own bones) and in some of silicon.

Evolutionary biologists have long sought the ancestor of all life, some animal group that all the others may have been based on. Genetic researchers looking at DNA have suggested that all multicellular animals may have been based on the genes of a sponge! Of course we've heard the concern expressed by some religious fundamentalists who reject that man may have "descended" from apes. Imagine how some of them will react when they learn that both humans, apes and even lobster, starfish and clams may all have evolved from sponges (the real ones, not SpongeBob thank goodness).

© 2005 Dr. Bill Bushing. Watch the "Dive Dry with Dr. Bill" underwater videos on Catalina Cable TV channel 49, 10:00 AM and 5:00 PM weekdays. Buy my "Munching and Mating in the Macrocystis" DVD so you can take Dr. Bill home with you... we'll both be glad you did!

Three views of the orange puffball sponge in Catalina waters compared to
my tropical hiding place, a huge barrel sponge from Belize.

This document maintained by Dr. Bill Bushing.
Material and images © 2005 Star Thrower Educational Multimedia