Just as on land, plants are the workhorses of the underwater world. Being the primary source of nutrition for many marine organisms, from sponges and corals to crustaceans, fish and mollusks, these heroic producers generally go unappreciated. Without the lowly algae and seagrasses, all forms of sea life would simply vanish. Yet rarely are marine plants photographed, or discussed upon the return of the tropical vacationer. Marine plants are just not very interesting when compared with the palate of colors and shapes visible in the underwater gardens of the Pacific coral reefs. In the semi shallow areas of the Pacific, where most vacationers get a chance to snorkel around and experience the superabundance of observable lifeforms, plants just don't catch the eye. Many, if not most of the gracefully dancing, brilliantly colored plant life are not actually plants at all, but are rather various forms of sea animals. Ranging from the very inconspicuous single-celled Foraminiferida, through the simple but ever filtering Sponges, to the complexity and beauty of the Hydrozoans, Anemones, and Corals, underwater gardens are filled with amazing beauty, vicious predators, and incredible illusion.
We are quite used to insects that resemble plants in order to lure their prey or avoid their predators. This form of species-bending illusion is the norm in the undersea gardens of coral reefs. However, in this liquid world you are never quite sure if what you are admiring is a plant that looks like an animal, or an animal that looks like a plant. Most don't change their appearance for protection or feeding...they always look as beautiful and confusing as they do the first time you are lucky enough to see them.
Our aquatic landscape is abundant with life. Everywhere you turn there is a beautiful new color or shape to dazzle the eye and rejuvenate the spirit. Who could help but smile at the clownfish darting in an out of their anemone homes? Most anemones are hidden from view, in rocks and crevices or under coral heads. But the incredibly beautiful Heteractis magnifica, the castle of our "Nemo" friend, is generally more conspicuous.
Anemones are closely related to that other master of illusion the reef building coral. There are over 500 species of the hard or stony coral that create the reefs upon which we love to play and explore. The thumbnail image at the beginning of this article shows a coral field with 7 different varieties. Without these wondrous creatures, there would be no reef, and very little else. Like trees are the skeletal bones of a rain forest, the coral is the bedrock - literally - of the reef. Though they look like lacy plant leaves, shrubs or even trees, corals are actually millions upon millions of tiny animals.
What garden would be complete without a few wildflowers? In our "octopus's garden", the wildflower niche is filled by soft corals and sea fans. Similar to, but slightly different from their hard cohabitants, soft corals lack the limestone skeleton found on the stony corals. Instead, they have a fleshy "stem" that anchors them to their perch. They depend upon the tides and currents to bring planktonic food their way, and they are generally found in deeper waters than the more solid variety. Some soft corals rival the beauty of land based flowers such as gardenia, jasmine or even daisies!
Of course, all gardens have their share of thugs...and underwater gardens are no exception. There are things that sting, things that bite, things that burn...and then there are the bad guys! The notorious Crown-of-thorns starfish looks intriguing, rather like an elaborate crocheted doily, but this felon has been known to decimate large areas of reef by feeding on the live coral polyps. For most of the other stings, bites and burns remedies are usually close at hand. And if all else fails, have a good friend pee on that urchin sting, and you will be fine shortly. A little red-faced, but healthy.
We all have our favorites in the terrestrial plant world, and the same is true of the aquatic forum. My favorite of the marine animals is the feather star. Gracefully waving in areas of strong current, the myriad arms reach out to gather in the plaktonic food. Feather stars are usually found perched high on sponges, coral heads or gorgonians, using the tiny appendages on their undersides called cirri to hang on. As their name implies, they are soft and peaceful, rarely bothered by fish and other predators, but often enjoying a symbiotic relationship with other animals such as lobster, shrimp and brittlestars.
There are so many other animals in this underwater garden, but I have kept your attention long enough for now. If you get a chance, you might like to look at pictures of crustaceans, marine worms, nudibranchs, sea urchins and holothurians. The ocean is full of fascinating creatures - quite literally!
There are coral reefs and underwater gardens in many parts of the world, not just the Pacific. I enjoy a DG friendship with caribblue of the Cayman Islands, and we share many of the same animals with enough variety to keep everything interesting. The underwater gardens of Greece, Coastal Spain, the Far East and the Atlantic are just as interesting and beautiful as those here, but the life forms are different. Our waters are bath-water warm year round, the sun is generally shining and our underwater gardens are kept beautiful and fascinating by the unheralded efforts of the marine plants. As long as they continue to convert that sunlight and the dissolved nutrients into energy rich organic compounds that feed the multitude of sea life that depend upon them, we may continue to take them for granted. They have been doing it for millennia, and doing it so well that we rarely even know they are there.
The only time we think about them is when someone brings them to our attention in an attempt to warm up a wintry day with a little discussion of the beauty to be found in the underwater gardens of the Pacific.