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The Fantastic Life of Coral
At first glance, it looks like a lifeless, eons-old rock. So much so that people will stand on it unaware of the life beneath the weight of their feet. The coral ecosystem is teeming with life, among the most diverse ecosystems in the world!
It’s the network of the oceans, much like mycelium is the network of forests. Twenty-five percent of the ocean’s fish depend on coral reefs for food, shelter, and nurseries for their young.
It’s easy to quickly pass by corals, dismissing them as responseless vegetation, a garden that fish, rays, and marine mammals cruise through. But the “plants” are animals! It’s all alive.
Isn’t the star coral beautiful!? All of these worms will tuck into a hole and disappear when predators (and snorkelers) get too close.
Now that I know, I slowly move over the coral, looking closely. I always find something beautiful, fascinating, and new to me.
Here’s what I’ve learned.
Hard Corals
Hard coral is composed of calcium carbonate (the rock-like stuff) that forms the framework for thousands of polyp colonies. These polyps are animals with a body and a mouth that feed on plankton and tiny fish. It is these colonies of polyps that form coral.
The healthy coral we see is a result of symbiosis with algae, a relationship that benefits both organisms. The algae live within the polyps and are what give coral its color. Algae produce carbohydrates that the polyps use for food. The coral provides a protected environment for the algae and aids in its photosynthesis.
Soft Corals
Soft corals rely on a flexible, protein-based mesoglea (jelly-like core) reinforced by sclerites, tiny, spiky calcium structures for support. Look at all those tiny polyps on the purple stalks of the sea plume!!
Sea Sponges
Another marine invertebrate that you might not associate with the animal kingdom is the sea sponge. They are filter feeders, structured with canals, chambers, and cavities that enable water to move through the sponge for feeding, gas exchange (“breathing”), and excretion. Sponge larvae are flagellated and can swim; however, adults are non-motile and remain attached to a single spot.
There are flat sponges and tube sponges. They are all so unique in structure, color, pattern, and texture. There are over 5000 known species of sponges inhabiting all of the world’s oceans.
Other Atypical Reef Animals
Some of my other favorite animals in coral reef ecosystems are anemones and sea urchins. Anemones are predatory invertebrate marine animals related to corals and jellyfish. Their mouths are surrounded by stinging tentacles that enable them to prey upon small animals such as fish, crabs, shrimp, and jellyfish. They can be found in deep seas and the intertidal zone, too, where they contract and fold their tentacles into their bodies to avoid drying out until the water returns.
There are 950 species of sea urchins, who like anemones, live from intertidal zones to deep seas. Urchins crawl along on tube feet, feeding on algae and sponges. They come in a variety of colors, long-spined and short-spined, pencil-thick and needle-thin. These dramatic creatures are usually found tucked away within a reef, making them difficult to photograph.
Next time you have the opportunity to see a reef, either below water, from a dock, or tidepooling, stop and stare. You will be amazed!
If you’re interested in purchasing or licensing any images you see here, please email me at SNewenham at exploringnaturephotos.com, and I’ll make it happen.
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The post The Fantastic Life of Coral appeared first on Exploring Nature by Sheila Newenham.
