Natural History

Fans, Rods, Plumes and Whips

deepwatergorgonianSoft corals play an integral role in the coral ecosystem.

Story by Suzanne Gerber ~ Photos by Barbara Shively

You can’t dip below the water’s surface in any tropical paradise without noticing the amazing Technicolor world that exists there—“the inner planet,” as it’s been called. It truly is another world, teeming with more life and color, shapes and textures than most places of comparable size on land. Over the past two years, this column has looked at fish and, in the last issue, hard corals, but what would the underwater world be without its delicate, gracefully undulating soft corals that turn it into the planet’s largest and lushest garden? Most dive destinations have a site called Coral Gardens and invariably they rank as divers’ and snorkelers’ favorites. That’s because to attract great fish, you’ve got to have great corals.

A precarious situation

They make up a mere 0.25% of Earth’s entire aquatic environment, but our precious coral reefs house more than 25% of the world’s fish species. In terms of biological diversity, their closest competitor is their terra-firma cousin, the tropical rain forest. Like rain forests, reefs support life on a fundamental level, and like rain forests, they are so severely threatened by natural and manmade activities that our grandkids, should they stumble upon this article, might not have a clue what we are talking about. And that’s pretty sad, considering that corals have been around for 200 million to 400 million years and reached their current level of diversity some 50 million years ago.

But coral reefs aren’t merely a thing of extraordinary beauty; as hard-working colonies that support the fish that feed 75% of the world, they provide food. They also contribute greatly to the $375 billion tourism industry that indirectly keeps people fed, sheltered and clothed. On top of that, some of them, like barrier reefs, directly protect us landlubber bipeds and our shorelines from erosion and storm damage. Reef research is constantly offering clues to new healing modalities and medicines, like antibiotics. In short, we owe our collective existence to them.

Yet most of us take corals for granted: Not only do we ignore their beauty but we minimize their contribution to life on earth. And we pay them the ultimate disgrace by trampling them with anchors, fins, scuba tanks, errant hands and feet. Of course, the greatest harm comes from nature herself, from the rising temperatures in the world’s oceans. A report last summer by the National Geographic news service focused on the devastating effects of the soft-coral bleaching that has been the result of sustained high water temperatures. Hudi Benayahu, a marine biologist and head of the Porter School of Environmental Studies at Tel Aviv University, observed sites in Okinawa, Japan, before and after bleaching events. “It was remarkable to see a massive disappearance of soft corals,” Benayahu said. “Just two years passed, and the entire area was deserted, lifeless. Once soft corals disappear, the entire ecosystem is threatened.” Benayahu added that until recently, soft corals had covered 50 to 60% of some of the sites he studies. This figure has dropped to an average of 5%. Benayahu, along with other experts, fear that if bleaching continues, entire soft coral species may become extinct—including some that haven’t even been catalogued yet.

It starts with knowledge

giantslit-poresearodsHard coral is the more prevalent type (with some notable exceptions, like Fiji) and is the foundation of many reefs and even tropical islands. Its complement, soft coral, comes in a kaleidoscope of colors (including bright reds, oranges, yellows, greens, blues, purples and all shades of white and tan) and in as many shapes, sizes and textures as a beach garden. While they don’t directly build up reefs, soft corals play an integral role in the coral ecosystem. In fact, to maintain the delicate balance of its marine environment, a reef requires precise interaction of hard and soft corals, as well as sponges, anemones and critters as diverse as snails, rays, crabs, lobsters, turtles and dolphins.

Like its hard cousins, soft coral begins life as a larva secreted by its parent. Simply explained, soft corals (also known as gorgonians or, more properly, Alcyonacea, or Octocorallia) can be distinguished from hard corals by their eight tentacles, while hard coral polyps have multiples of six tentacles. (Hence the “octo” in the name.) Because soft coral secrete little to no calcium the way the hard, or stony, ones do, they grow more quickly, are far more flexible and require less light to exist. All corals are made up of polyps, and many types of soft coral have small side branches, giving them a featherlike appearance. Like hard corals, most soft coral species rely on internalized single-celled algae (called zooxanthellae) to deliver their food supply, which is supplemented by free-floating food in the ocean like plankton or brine shrimp.

There are many varieties of soft corals: sea fans, sea rods, sea plumes, sea pens and sea whips, which can be found in the shallowest waters right down to depths of several thousand feet. Gorgonians’ size and shape are correlated to their location: In shallower depths with stronger currents you see more fan-shaped and flexible ones, whereas you will find taller, thinner and stiffer ones in deeper, calmer waters. Research tells us there are some 500 different species of gorgonians found in the oceans of the world, and that they’re most readily found in the shallow Atlantic waters surrounding Florida, Bermuda, the West Indies and right here in Turks & Caicos.

One of the things Barbara and I love about gorgonians is what we’ve learned to discover hiding out in their delicate, regal “branches,” namely adorable fish like the sharp-nosed pufferfish and the slender filefish (sometimes as tiny as half an inch long). These little guys, and the very occasional seahorse, take shelter from predators in the branches. And because it’s nearly impossible to spot them, they are indeed safe!

Another category of soft coral are those that imitate land plants. There’s the tree coral, with a large, rubbery body that actually looks like a tree. Usually under three feet tall, these elegant forms are found in lagoons and calm oceans. A rare site is the daisy coral, which bears a striking resemblance to its namesake, the gerbera daisy. Varieties are distinguished by the number of petals or tentacles that surround the polyp. A favorite of divers and snorkelers alike is the sea fan (technically a “horny coral”).  Typically a beautiful shade of light lavender, the fan can also be brown, gold, orange or even red. It sports a lacy web of polyps embedded in a soft layer of tissue that grows out of an internal stalk, often a vibrant shade of deep purple. You can watch the fan wave in mild to strong current. An unusual but thrilling site is when delicate polyps come out to feed and cover the branches with featherlike tentacles.

Hope for the future?

purplebipinnateseaplumesAs research continues, the news that leaks out is mostly grim—but not entirely. In Indonesia, for example, a region legendary for vast coral diversity, scientists are discovering that there are not just one but several species of the zooxanthellae algae in coral and that some of them seem resistant to rising water temperatures. A monitoring system is in place, and researchers are watching closely to see which algae survive, which may help preserve other reefs in the future. Elsewhere, manmade electrical-stimulation tiles are proving effective in growing new coral where the colonies are particularly threatened.

In a study released in February 2008, a group of researchers at the National Center for Ecological Analysis and Synthesis in Santa Barbara, CA, published data from 17 different studies that sadly concurred that almost 50% of the world’s coral reefs were experiencing “medium high to very high impact” from human pressures, which included the effects of rising temperatures, fishing practices and pollution. We may feel there’s nothing we as individuals can do—we don’t pollute the waterways, don’t run our boats aground in shallow waters and never touch corals when underwater—but there’s a reason global warming is called “global.” We’re all in this together. Small steps we take (or don’t take) in our everyday lives ultimately affect all other areas of life on the planets. We can live lighter, more greenly, be mindful of all our interactions with nature—and seek out good organizations to contribute funds for ongoing research. Following are a few of my favorites:

  • REEF (Reef Environmental Education Foundation) is a grassroots organization that seeks to conserve marine ecosystems by educating, enlisting and enabling divers and other marine enthusiasts to become active ocean stewards and citizen scientists. www.reef.org.
  • The Coral Reef Alliance is the only international organization working exclusively to save the Earth’s coral reefs. www.coralreefalliance.org.
  • Oceana is the largest international ocean environmental advocacy group dedicated to protecting and restoring the world’s oceans and its inhabitants. www.oceana.org.

New York-based Suzanne Gerber writes about scuba, travel and health for a variety of publications. Book your next dive trip by contacting Suzanne at suzanne@worldofdiving.com.

Avid underwater photographer Barbara Shively discovered Grand Turk diving in 1997 and has returned every year. It is her passion to share the coral reefs’ beauty through her photographs, many of which can be viewed and purchased at http://shivelygallery.com/. A variety of her prints are on sale at Art Provo, located in The Regent Village, Providenciales.



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