Once again we dive into Cnidaria, a large phylum that contains approximately 10,000 species. Phylum members include many animals that attract attention because of their bright colors: sea anemones, corals, sea pens, gorgonians and jellyfish. These creatures can afford to flaunt their beauty because most of them have defensive polyps loaded with nematocysts (also called cnidocytes) that can fire venomous miniature harpoons. Lucky for us, most of these weapons are too tiny to penetrate our skin. Cnidarians currently belong to one of four classes: Anthozoa […]
Marine Life
Sea Slug Courtship and Reproduction
Except for having to dissect a frog, I enjoyed high school biology. As an adult, however, I have found marine biology even more fascinating. Reproduction specifically. I had no idea it could be so complicated under the sea. Take, for instance, nudibranch mating and egg laying. Over the years I have taken photos of a lot of things I could not positively identify. Among them were egg cases. Figuring out the source of some of them was easy because the parent was in the photo […]
Exciting Diving Off Anacapa: Celebrating Eel Encounters
“Blub, blub — oooe‚ — ooooooh, glub!” With the excellent visibility, it was easy to see my dive buddy wildly waving her arms in an excited attempt to get my attention. I’ve seen this many times, and even from afar I can tell it means “excitement” rather than “distress.” I really appreciate when another diver wants to show me something underwater, so I quickly made my way over to her. As I searched the area, looking into a small crevice I noticed what she was […]
A Little Burst of Sunshine: Enjoying Yellow Dorids
Writing articles for this column motivated me to sort my thousands of California marine life images into specific folders such as bryozoans, hydrocorals, crabs, fish, nudibranchs, etc. Nudibranchs are further separated into aeolid and dorid folders — including 40-plus “yellow dorids.” In the beginning, all of my yellow dorids looked alike to me. However, as time went on, I became more adept at recognizing the subtle differences among the colorful slugs. There are more than 170 species of nudibranchs living off the Pacific Coast and […]
Awesome Nature: Predator Versus Prey
There comes a time in the evolution of a diver, and particularly underwater photographers, when we graduate from reef scenics and little macro creatures and set our sights on more exciting subjects — that is to say big subjects. While there are many places in the world where divers may safely interact with large animals, the Revillagigedo Archipelago off Mexico’s west coast stands out as one of the very best, both for numbers of species and numbers of animals. My buddies and I recently spent […]
Shell Games: Classifying SoCal Gastropods
Intriguing shapes and gem-like colors distinguish the seashells shown here — but the vast majority of these fascinating marine creatures are much more cryptic. Many of them live in shells so covered with growth they are difficult to see, let alone identify. Seashells have been around for 500 million years. Many are collected, some are eaten, and some have been used as currency. There’s even a “money cowrie.” Seashells belong to the second largest phylum, Mollusca, which is exceeded in size only by Arthropoda. Various […]
Not Your Average Anemones: Examining Unusual Species
We’ve discussed cnidarians in this column several times and will likely do so many more. There are about 10,000 species in this phylum and since most of them live in the ocean, divers encounter them all the time. Many are photogenic, which is why my files are full of their images. The two forms of cnidarians, polyps and medusae, are, according to The Shape of Life, “essentially mirrors of each other.” Polyps (i.e., anemones) are attached to a surface on one end by the pedal […]
The Mysteries of Marine Algae, Part Two
Last month’s article pointed out that algae are classified as red, brown or green based on the color of their photosynthetic pigments and their evolutionary lineage. They all have chlorophyll a but only green algae look green. Other pigments mask green chlorophyll a in brown and red algae. In this article you will learn that basing an ID on the color of an alga in an underwater photo won’t always result in the correct classification. I thought I had several photos of green algae but […]
The Mysteries of Marine Algae, Part One
Writing and taking photos for this column has been a journey of discovery and enlightenment. I’ve learned the common names of many marine creatures I encountered (most specifically in SoCal, where I have spent the most time) but didn’t delve into anything bordering on the scientific. I also photographed a lot of “stuff” I couldn’t identify. While looking for material for this column, I’ve made a lot of progress on that. The Internet is a godsend, but, this article proved more difficult to research than […]
Admiring California Hydrocoral
Much prized by underwater photographers for its beautiful colors, California hydrocoral (Stylaster californicus) is one of the 350 species of hydroids in the Phylum Cnidaria. A close cousin of the fire corals found in tropical waters, it is not a true (stony) coral. Cnidaria (the “C” is silent) is not a small, insignificant phylum. It contains approximately 10,000 species, at least 100 of which are dangerous to humans. The phylum name means “nettle” in Greek and its members include some of the most photogenic animals […]
