Category Archives: Florida Keys reefs

Oregon State University: Large study shows pollution impact on coral reefs — and offers solution

Contact: Rebecca Vega-Thurber
Rebecca.vega-thurber@oregonstate.edu
541-737-1851

diver

IMAGE: Diver Andrew Schantz of Florida International University studies the effect of pollution on corals in the Florida Keys.
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CORVALLIS, Ore. – One of the largest and longest experiments ever done to test the impact of nutrient loading on coral reefs today confirmed what scientists have long suspected – that this type of pollution from sewage, agricultural practices or other sources can lead to coral disease and bleaching.

A three-year, controlled exposure of corals to elevated levels of nitrogen and phosphorus at a study site in the Florida Keys, done from 2009-12, showed that the prevalence of disease doubled and the amount of coral bleaching, an early sign of stress, more than tripled.

However, the study also found that once the injection of pollutants was stopped, the corals were able to recover in a surprisingly short time.

“We were shocked to see the rapid increase in disease and bleaching from a level of pollution that’s fairly common in areas affected by sewage discharge, or fertilizers from agricultural or urban use,” said Rebecca Vega-Thurber, an assistant professor in the College of Science at Oregon State University.

“But what was even more surprising is that corals were able to make a strong recovery within 10 months after the nutrient enrichment was stopped,” Vega-Thurber said. “The problems disappeared. This provides real evidence that not only can nutrient overload cause coral problems, but programs to reduce or eliminate this pollution should help restore coral health. This is actually very good news.”

The findings were published today in Global Change Biology, and offer a glimmer of hope for addressing at least some of the problems that have crippled coral reefs around the world. In the Caribbean Sea, more than 80 percent of the corals have disappeared in recent decades. These reefs, which host thousands of species of fish and other marine life, are a major component of biodiversity in the tropics.

coral

IMAGE: This coral, which was part of a scientific study, is bleached as a result of exposure to elevated levels of nitrogen and phosphorus.
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Researchers have observed for years the decline in coral reef health where sewage outflows or use of fertilizers, in either urban or agricultural areas, have caused an increase in the loading of nutrients such as nitrogen and phosphorus. But until now almost no large, long-term experiments have actually been done to pin down the impact of nutrient overloads and separate them from other possible causes of coral reef decline.

This research examined the effect of nutrient pollution on more than 1,200 corals in study plots near Key Largo, Fla., for signs of coral disease and bleaching, and removed other factors such as water depth, salinity or temperature that have complicated some previous surveys. Following regular injections of nutrients at the study sites, levels of coral disease and bleaching surged.

One disease that was particularly common was “dark spot syndrome,” found on about 50 percent of diseased individual corals. But researchers also noted that within one year after nutrient injections were stopped at the study site, the level of dark spot syndrome had receded to the same level as control study plots in which no nutrients had been injected.

The exact mechanism by which nutrient overload can affect corals is still unproven, researchers say, although there are theories. The nutrients may add pathogens, may provide the nutrients needed for existing pathogens to grow, may be directly toxic to corals and make them more vulnerable to pathogens – or some combination of these factors.

“A combination of increased stress and a higher level of pathogens is probably the mechanism that affects coral health,” Vega-Thurber said. “What’s exciting about this research is the clear experimental evidence that stopping the pollution can lead to coral recovery. A lot of people have been hoping for some news like this.

“Some of the corals left in the world are actually among the species that are most hardy,” she said. “The others are already dead. We’re desperately trying to save what’s left, and cleaning up the water may be one mechanism that has the most promise.”

VIDEO: This is an interview with Rebecca Vega-Thurber about new findings in a coral reef study off the Florida Keys.
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Nutrient overloads can increase disease prevalence or severity on many organisms, including plants, amphibians and fish. They’ve also long been suspected in coral reef problems, along with other factors such as temperature stress, reduced fish abundance, increasing human population, and other concerns.

However, unlike factors such as global warming or human population growth, nutrient loading is something that might be more easily addressed on at least a local basis, Vega-Thurber said. Improved sewage treatment or best-management practices to minimize fertilizer runoff from agricultural or urban use might offer practical approaches to mitigate some coral reef declines, she said.

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Collaborators on this research included Florida International University and the University of Florida. The work was supported by the National Science Foundation and Florida International University.

Editor’s Note: Digital images are available to illustrate this research:

Diver at study site: http://bit.ly/16bCW7w

Bleached coral: http://bit.ly/1bzLpjm

Nutrient dispenser: http://bit.ly/16gC8cp

A package of video interviews and associated B-roll, including underwater video, is also available for downloading in high resolution format:

Underwater b-roll:

http://oregonstate.edu/dept/ncs/media/rebecca-vega-thurber-underwater-b-roll-news-release.mov

Package interview with Dr. Rebecca Vega Thurber:

http://oregonstate.edu/dept/ncs/media/rebecca-vega-thurber-package-news-release.mov

Dr. Rebecca Vega Thurber Interview:

http://oregonstate.edu/dept/ncs/media/rebecca-vega-thurber-interview-news-release.mov

Laboratory b-roll:

http://oregonstate.edu/dept/ncs/media/rebecca-vega-thurber-b-roll-news-release.mov

Rebecca Vega Thurber Interview (audio only):

Coral-List: Nova Southeastern University Report on Coral Spawning 2013

Hello all,
After the full moon in July, August, and September, researchers in 7 regions of the Caribbean (Mexico, Curacao, Belize, St. Thomas, Florida, Flower Gardens, Columbia) monitoring 9 coral species (A. cervicornis, A. palmata, A.. prolifera, Diploria/Pseudodiploria strigosa , Dendrogyra cylindrus, Montastraea/Orbicella franksi, M. annularis, M. faveolata, Montastraea cavernosa) for spawning activity. Overall it was a great year for Caribbean coral spawning.
For detailed information on location, spawning times, and environmental conditions, log into google docs and follow this link:

https://docs.google.com/spreadsheet/ccc?key=0AuCz7WiTRAnkdGNpZ1k1VGwwb1NUYjdXR3BrQ0k3a1E&usp=sharing

Please email me (nicole.fogarty@nova.edu) if you have any corrections or additional spawning observations. You can also join us on the “coral spawning research” facebook page for real time accounts of coral spawning events.

Nicole D. Fogarty, PhD
Assistant Professor
Nova Southeastern University
Oceanographic Center
8000 N. Ocean Drive
Dania Beach, FL 33004-3078
(954) 262-3630

Why I am Still Opposed to Widening and Deepening Key West Harbor to Accommodate Larger Cruise Ships by DeeVon Quirolo

Points to consider in the discussion of whether to vote for a feasibility study to widen and deepen Key West harbor:

The science has been indisputable for a long long time on the negative impacts of siltation and dredging on or near coral reefs. Corals are living permanent structures on the ocean bottom comprised of colonies of living polyps that need clear, clean nutrient free waters to thrive. Dredging creates fine sediment and silt that covers corals, preventing photosynthesis and resulting in massive mortality, especially for Elkhorn and Staghorn corals–which cannot slough it off as can other corals. Such sedimentation also reduces the ability of all marinelife, including tarpon and other fish that utilize this area for habitat, to survive.

Episodic storm activity may stir up sediment but the wave action of those storms can also remove loose particulate matter from areas of the ocean bottom. While storm activities have historically affected visibility in the harbor and at the reefs, they do not compare in scale to the massive, chronic, intense effects of outright removal of habitat and the smothering of living formations by tons of dredge sediments that would occur immediately in the harbor and at nearby downstream coral reefs if additional widening and deepening of Key West Harbor were to occur.

It is incredulous to me that anyone associated with protecting coral reefs would dispute this elementary fact of coral ecology. In addition, the health of sea grasses and myriad other marinelife that depend upon this habitat would be severely impacted, including endangered sea turtles and dolphins.

The Key West Harbor Reconnaisance Report published November 2010 noted that the harbor is included in the “critical essential habitat” for both Elkhorn and Staghorn corals under the Endangered Species Listing for them. There has not been one case of allowing removal of critical essential habitat from the Jacksonville Corps of Engineers office in the last 15 years.

It states: “Under the Endangered Species Act (ESA) of 1973; the threatened coral Acropora cervicornis (staghorn coral) and Acropora palmata (elkhorn coral) could be located adjacent to the channel in the areas proposed for expansion as this area is designated as critical habitat for these species. While it is possible to relocate the actual colonies of coral, the critical habitat would be permanently removed. It is highly likely that the removal of several acres of occupied designated critical habitat (habitat where the species has been shown to be able to flourish under baseline conditions) could be considered an adverse modification of critical habitat under Section 7 of the ESA. This would be Jacksonville District’s first adverse modification of critical habitat determination in the last 15 years. It is also unknown what reasonable and prudent alternatives and measures National Marine Fisheries Service (NMFS) would include in a biological opinion to avoid the project adversely modifying designated critical habitat, as required under Section 7 of the Act.* It is expected that resource agencies would oppose any channel modifications outside the existing footprint.”

So this whole feasibility study could be a huge waste of money because there are good reasons why a permit would never be issued for the project thereafter. Surely we can find a more sustainable use of $5 million dollars—how about some stormwater treatment for the island of Key West to improve water quality?

The feasibility study is an effort to calculate the possibility of further widening and dredging in a harbor that was deepened just five years ago. Underneath Key West lies a fresh water aquifer. There are upwellings of fresh water in the harbor today. A massive deepening and widening may have severe unintended consequences on the aquifer, that at a minimum could result in salt water intrusion of that fresh water lens.

The last harbor dredging project just a few years ago included a mitigation plan by the Florida Keys National Marine Sanctuary to remove corals from the harbor with the purpose of restoring the damage. Despite their best efforts, there have been only a few of those corals planted in an offshore boat grounding site. For the most part, there has been no successful effort to restore the extent of coral colonies that existed in this area prior to the last dredging. It is therefore highly unlikely that another dredging project will succeed in restoring the habitat removed via mitigation this time either. It is just a false hope that the loss of biodiversity will be anything but an ecological disaster for this otherwise already stressed part of Key West’s coral reef ecosystem.

Often these dredge projects result in in-filling thereafter due to storm activity. Key West may be saddled with a harbor that produces chronic sedimentation without regular repeated environmentally destructive maintenance dredging. This will in turn affect the downstream coral reefs with additional chronic smothering contaminated sediment.

The greater question really is: How much more can the surrounding coral reef ecosystem of the Florida Keys handle in terms of human impacts? Isn’t it enough to have a thriving hotel, tourism and real estate industry? Can’t we draw a line in the sand and say “enough is enough”? Already the hoards of cruise ship visitors denigrates the downtown section to the exclusive benefit of a few businesses while high-end resorts and guesthouses hold their breath that this low-end massive impact to our quality of life will not repel their key markets. What about those who still hope that Key West can be a magic island home–don’t they deserve consideration?

Craig and I would encourage every voter in Key West to vote NO on the feasibility study to dredge Key West harbor….. again.

DeeVon Quirolo

Key West Harbor Reconnaissance Report by US Army Corp of Engineers

key_west_harbor_excerpt

Perhaps most importantly, this brief 7-page report ends with the following: DV

Under the Endangered Species Act (ESA) of 1973; the threatened coral Acropora cervicornis (staghorn coral) and Acropora palmata (elkhorn coral) could be located adjacent to the channel in the areas proposed for expansion (Figure 2) as this area is designated as critical habitat for these species. While it is possible to relocate the actual colonies of coral, the critical habitat would be permanently removed. It is highly likely that the removal of several acres of occupied designated critical habitat (habitat where the species has been shown to be able to flourish under baseline conditions) could be considered an adverse modification of critical habitat under Section 7 of the ESA. This would be Jacksonville District’s first adverse modification of critical habitat determination in the last 15 years. It is also unknown what reasonable and prudent alternatives and measures National Marine Fisheries Service (NMFS) would include in a biological opinion to avoid the project adversely modifying designated critical habitat, as required under Section 7 of the Act. It is expected that resource agencies would oppose any channel modifications outside the existing footprint.