Category Archives: Marine & Estuarine Life

Fringe Corals – Wetlands at the Outer Edge

Fringe. It’s the outer edge. Peripheral. Fringe, or fringing, reefs are connected to land and point toward sea; they occur in shallow water along coasts all over the world. Some wetlands are the boundary between land and deep water habitat; fringing corals fall into this group. Corals form in shallow, warm salt water habitats, usually tropical waters. Thousands of hard coral polyps grow together in masses and create a reef, whereas soft corals, like sea fans, do not form reefs. Fringe corals are similar to fringe mangrove ecosystems in that they grow at the edges of the land; sometimes the fringe coral and mangroves are neighbors in a closely-entwined habitat that provides a nursery for many marine animals. What lives in a fringe coral reef? Brittle stars, horseshoe crabs, sea anemone, sea urchins, snails and mollusks inhabit this strange ecosystem.

Darwin asserted that fringe reefs were the first kind of coral reef to form around a landmass in a long-term reef growth process. Until 1753, people did not know that corals were living organisms. Darwin’s Subsidence Theory, which focused on fringing reefs as an explanation for atolls and barrier reefs in the deep ocean, (aka the“coral reef theory”) is still the basis for the understanding of coral reefs today.

Fringe coral communities are unusual. For instance, finger coral (Porites furcata) and coralline algae grow interspersed with sea grasses in less than one foot of water. The two types of coral reefs that are most commonly known—atolls and barrier reefs—live in deep ocean water. Sponges, echinoderms, crustaceans and mollusks may also be found living in the fragile habitat of fringe corals, which are easily damaged by boats that drop anchor or people who walk on them.

Right now marine scientists are calling a “code blue” on coral reefs worldwide. Fringe reefs are threatened by coastal development, dredging and run-off, while all types of corals are stressed by warming sea temperatures as a result of climate change, a phenomenon called “coral bleaching.” The warming sea temperatures kill the algae that give the corals their color. Another problem is acidification of sea water, caused by run-off, certain algae and pollution from dredging or other human activities. Sediment discharge from coastal development can have a very negative impact on coastal wetlands including fringe reefs and mangroves.

In southwest Florida, the Department of Environmental Protection is currently dealing with enforcement issues on a boat lift in a canal, which city developers dredged to build Cape Coral the 1970s. The city developers dredged the canal through fringe mangroves. The original design of the canal allowed the fresh waters to be trapped and prevented that water from flowing into the saltwater estuaries of Matlacha Pass Aquatic Preserve. The preserve is home to four species of sea grasses, three species of mangroves, over 100 species of invertebrates, 200 species of fish and 150 species of shore and wading birds. The barrier lift protected the saltwater mangrove habitat and preserve. In the 2000s, the city developers removed the lift, initially with the intention of replacing it—but several years after-the-fact, there is still no barrier lift protecting the estuary.–votes-being-tallied-on-Cape-spreader-barrier.html?nav=5048

Hawaii’s Conservation Resource Enhancement Program’s strategy involves converting marginal pastureland into native grasses and wetlands. The state seeks to improve water quality and near-shore coral reef (fringe coral) communities by filtering agricultural run-off.
 Additionally the Hawaii Department of Land and Natural Resources has identified a way to use sea urchins to manage invasive algae in coral reefs. State aquatic biologists vacuumed the invasive seaweed off the coral with a “Super Sucker,” and have planted sea urchins to take on the job of eating the seaweed. For pictures, go here: Besides invasive algae, two other threats to coral reefs are hurricanes and overfishing, which have an impact on all types of reefs.

Other interesting links on coral reefs can be found below:

EPA Office of Wetlands & Oceans:

A Return to the Reefs: Smithsonian article by Gordon Chaplin (2006) on the Global Coral Reef Monitoring Network

Coastal Living Habitats:

Wetlands International – Coastal Wetlands (Coral reefs, mangroves, sand dunes, beaches)

Florida DEP coral reefs

Florida’s Coupon Bright Aquatic Preserve

Reef Check (a nonprofit organization)

Code Blue: A possible new coral reef in the Sargasso Sea? – Sylvia Earle’s research (2010),28804,2020806_2020805_2020

NOAA’s Coral Reef Conservation Program

Coral reefs in a climate change context – Climate Change Impacts on the United States
The Potential Consequences of Climate Variability and Change (2000)

Move over, Mangroves!

Oh, wait, if the mangrove swamps get developed, the beaches go out to sea! Hmmm. I got the email version of a postcard from my family, who are spending a week in the Caribbean, and everyone is upset at the lack of fish and destruction of mangrove forests. My mother studied reefs and seaweeds while a college student in the Virgin Islands more than thirty years ago. She told me stories of snorkeling in creepy eel-filled mangrove swamps, marvelous for a marine biology student to observe: mangroves are nurseries for many marine species, e.g. several species of sharks and fish. Mangroves are unique habitats because the plants live in saltwater, brackish water and freshwater; they are on the fringe between the land and sea.  Those in the Caribbean have declined by 42% over the last 25 years, according to the Mangrove Action Project. For a fact sheet on the importance of mangroves (published by Fish & Wildlife, USVI) see

Negril’s beaches (Jamaica) have undergone severe damages due to mangrove destruction, according to a study by the United Nations Environment Programme (UNEP) Division of Early Warning and Assessment. See:  Final Throes for Jamaica’s ‘Hippie Paradise’?(April 2010)

In addition to development pressure, mangrove charcoal, highly prized for its long-lasting heat, provides income for several communities in the Caribbean. Caribbean charcoal comes from two sources—mangrove swamps and dry forests. For a video on mangroves, see:

According to a recent Coastal Living article, “9 coastal wonders to see now,” mangrove forests are on the list of places to visit sooner rather than later due to the environmental pressures they currently face and their looming fate. (Incidentally, Casco Bay, Maine is also on the list but because of nitrogen run-off problems on beaches. USM’s Muskie School of Public Service also presented a recent study on the warming of Casco Bay with another set of warnings and their potential impact on the bay area. Mangroves are also affected by climate change impacts: Caribbean mangroves adjust to rising sea level through biotic controls on change in soil elevation by Karen L. McKee et. al. (2007)

Update: Vital Mangroves On The Edge Of Extinction Thanks to All-You-Can-Eat Shrimp (Book Review) – August 2011

Wetland Documentary Films & Videos

Good wetland documentaries come in all shapes and sizes – from four minutes to forty minutes to feature-length films. In addition to the list below, Wetland Watchers often has links to news related to wetland films In some cases, films have been made to raise awareness about environmental challenges facing people and wildlife that live in wetland areas; in other cases, the documentary film tool has been used to teach young people about the importance of wetlands. See “Shooting wetland documentary helps urban teens go green” (Filmmaker not content to watch Orange Lake (FL) wetlands die) (Sept. 2009)

Hurricane on the Bayou (summer 2009)

Iowa Wetland documentary with Ava Su (June 2009)
A Year on the Wing

Prairie Wetlands Documentary is a guided tour through the beautifully restored prairie wetlands, located just outside of Fergus Falls, MN (2006)

No Time to Lose – A documentary about a local heron rookery in Troy, MI, and the need for a wetlands ordinance to save it. Created by Zach Kilgore and Austin Schultz. 2008

Great Lakes: Waterlife – at official trailer: the official film website:

Houston’s disappearing wetlands To watch the documentary, go to: (Sept. 2009)

Cry of the Marsh – Wetlands of Minnesota documentary (1970s original and more recent re-make, Echoes of Cry of the Marsh)

Spike Lee’s documentary about Katrina:

Spike Lee’s ‘Levees’ sequel for HBO covers four hours over two nights

The Big Uneasy – Documentary

For those who are interested in making a wetland film, there are training opportunities. For example, there is an upcoming week-long workshop in Washington state (affiliated with University of Washington) called “Introduction to Scientific Filmmaking,” to be led by Jeff Morales (National Geographic Film & Television, & VONIGO Films) and Dr. Colin Bates (Bamfield Marine Sciences Centre & Department of Botany, University of British Columbia). The workshop will teach participants to communicate scientific findings, natural history information, or conservation messages by creating compelling, professional-quality videos. No prior film making experience is required. The workshop will run with a minimum of 10 participants, and a maximum of 16. Workshop will be held at Friday Harbor Marine Labs ( November 16 – 22, 2009.  Cost: US$1100. Registration deadline is Sunday, November 1st.  For further information and application materials, contact Colin Bates or

Update May 2012: Film about Indiana Wetlands is one big, unhappy ending

Updated April 2013: Playas Film Screened at Texas Film Festival

Sharks in Wetlands

This past week has been “Shark Week” on the Discovery Channel. Ever since I was a kid, I’ve been fascinated by marine biology and in particular, the group of elasmobranchs—rays, sawfish, skates and sharks. Growing up on the Maine coast, I never encountered a shark while swimming but read Peter Benchley novels like Jaws,The Deep and The Girl by the Sea of Cortez with a voracious appetite. In 1995, I eloped to Kaua’i with my mother (who got married to my step-dad there) where I saw dorsal fins and had some melodramatic desire to swim with them. But they left and I swam with a sea turtle instead. Then in summer of ’99, I was in the Bay of Fundy with classmates from College of the Atlantic, and a 30 foot basking shark surfaced near our research vessel. After that experience, I read everything I could find on shark and ray conservation. The shark-like smalltooth sawfish (Pristis pectinata), for example, which can go into freshwater, as well as shallow waters of bays and estuaries in the southeastern U.S. and Caribbean, is technically a ray. Listed as an endangered species, the smalltooth sawfish has become extirpated because of changes to coastal environments—namely losses of wetlands, such as the Everglades. According to the Mote Marine Laboratory in Florida, “even if effective conservation plans can be implemented it will take sawfish populations decades, or possibly even centuries, to recover to post-decline levels.” see

Meanwhile there is one shark, the bull shark, that regularly visits freshwater wetlands and waterways, and it is considered the most dangerous shark in the world. Bull sharks hang around coastal waters and islands (like Virgin Gorda, where I just went snorkeling in March) but also travel up rivers, such as the Mississippi River, and some rivers in New Jersey, to give birth to their pups. While the pups live in freshwater for a year or so, the mother may stick around and encounter people. Fully grown, they reach about 8 feet. Yikes! and see

The all-seeing lemon shark begins its life in mangrove swamps. The only shark to have eyelids and able to see in color, the females go into lagoons every April and give live birth to babies, which are attached by an umbilical cord. The young lemon sharks hang out in the mangroves for the first year before leading very independent lives. Lemons are very dangerous; known as the sprinters of the shark world, they can go from 0-20mph in 2 seconds. Fully grown, they reach about 8 feet, too. and see

Because several shark species use coastal estuaries as nursery areas, researchers have looked at conservation strategies to help protect wetland habitat for the sharks. According to the latest IUCN Red List of Threatened Species, published by the UK-based International Union for the Conservation of Nature, at least 17% of the 1,045 shark and ray species, over 12% of groupers and six of the seven marine turtle species are threatened with extinction. Over-fishing, climate change, invasive species, coastal development and pollution are believed to be the chief causes. In Florida, citizens in Delray Beach just voted to approve a ban on shark fishing at a city beach. (July 21, 2009),0,3967811.story

Initiatives for Shark Conservation at the Federal and State Level (2008 info)

Update: Cape Cod National Seashore has reported (May 2011) a recolonizing of marine life along the sandbar, including seals, which have attracted Great White Sharks.

Funny quiz:  What type of shark are you? Go to: According to that quiz, I am a goofy hammerhead. Ha! Leave a comment if you take the quiz to let us know what type of shark you are. If you think the quiz is fishy, feel free to say so. (I think I’m more like a ray anyway.)

Update: (August 2011) Largetooth sawfish to become second elasmobranch to receive Endangered Species Act protections.