Navigation Links
In the turf war against seaweed, coral reefs more resilient than expected

There's little doubt that coral reefs the world over face threats on many fronts: pollution, diseases, destructive fishing practices and warming oceans. But reefs appear to be more resistant to one potential menace seaweed than previously thought, according to new research by a team of marine scientists from the United States and Australia.

Their study is the first global-scale analysis of thousands of surveys of individual reefs in all, more than 3,500 examinations of about 1,800 reefs performed between 1996 and 2006. The study appears the June issue of the journal Ecology, which is published by the Ecological Society of America.

"Until now, many scientists have concluded that the world's coral reefs are being overrun by seaweed," said John Bruno of the University of North Carolina at Chapel Hill and lead author of the study. "Our findings show that's not the case. Seaweed have taken over and are dominating some reefs, but far fewer than assumed."

The problem with too much seaweed, researchers say, is that it can smother the baby corals, reducing the ability of reefs to recover from other disturbances such as hurricanes and disease outbreaks. Over recent decades, there have been several dramatic examples of such shifts, with one of the most widely known and striking cases occurring in the Caribbean in the 1980s. Following a series of events that disturbed the marine environment (including two major hurricanes, a disease outbreak and the loss of a seaweed-grazing urchin), coral cover on several reefs in Jamaica plummeted from about 70 percent to less than 10 percent, and macroalgae became the dominant life form.

So Bruno, along with colleagues Hugh Sweatman from the Australian Institute of Marine Science and William F. Precht, a Florida-based marine ecologist, set out to determine how bad and how widespread the problem of seaweed-dominated reefs really is.

The team came up with a "phase-shift index" to determine the state of each reef. Pristine reefs where coral was still abundant had an index number of -2 to -3, while areas where macroalgae have overwhelmed reefs' surfaces were given an index ranking of between 3 and 5.

They found that while there were moderate local increases in seaweed cover over the study period, only four percent of reefs worldwide were dominated by macroalgae that is, more than 50 percent of a reef's surface was covered in seaweed. Researchers also found overall "phase shift severity" decreased in the Caribbean, did not change in the Florida Keys and the Indo-Pacific, and increased slightly on the Great Barrier Reef due to moderate coral loss.

"Overall, our results indicate that there is no general recent trend (i.e., post-1995) toward marcoralgal dominance," the researchers wrote.

"The results from this study question many of the prevailing paradigms that coral reef ecologists have developed over the past two decades," Precht said. "These findings will change the way we view and manage these fragile yet resilient ecosystems."

Said Sweatman: "I hope this study leads to clearer definition of what coral-algal phase shifts are and broadens our perspective on the serious loss of corals in many parts of the world. Australian reefs have been relatively lucky so far, but there is no reason for complacency."

The study team noted that while their analysis suggests the threat posed by macroalgae has been exaggerated, individual case studies such as the degradation of Jamaican reefs have been invaluable warnings of the consequences of subjecting reefs to multiple natural and manmade disturbances.


Contact: John Bruno
Ecological Society of America

Related biology news :

1. Cells united against cancer
2. Progress Against Malaria: Developments on the Horizon
3. Genes that both extend life and protect against cancer identified
4. Gamma interferon could aid fight against fungal infections
5. In the laboratory, green tea proves a powerful medicine against severe sepsis
6. Omega-3 fatty acids protect against Parkinsons, study says
7. Protein protects brain against compound in lead poisoning, liver disease
8. Blood pressure drug telmisartan shows powerful activity against stroke
9. CWRU School of Medicine has evidence vaccine against malaria will reduce disease
10. A search for protection against chemotherapy cardiotoxicity
11. Translational research patented first experimental treatment against idiopathic pulmonary fibrosis
Post Your Comments:
(Date:10/29/2015)... 29, 2015   MedNet Solutions , an innovative ... of clinical research, is pleased to announce that it ... (MHTA) as one of only three finalists for a ... Small and Growing" category. The Tekne Awards honor ... superior technology innovation and leadership. iMedNet™ ...
(Date:10/29/2015)... Va. , Oct. 29, 2015 Daon, ... today that it has released a new version of ... customers in North America have ... IdentityX v4.0 also includes a FIDO UAF certified ... are already preparing to activate FIDO features. These customers ...
(Date:10/29/2015)... 2015  Connected health pioneer, Joseph C. Kvedar ... technology-enabled health and wellness, and the business opportunities that ... The Internet of Healthy Things . Long before ... existed, Dr. Kvedar, vice president, Connected Health, Partners HealthCare, ... moving care from the hospital or doctor,s office into ...
Breaking Biology News(10 mins):
(Date:11/24/2015)... ... November 24, 2015 , ... ... Inc., on being named to Deloitte's 2015 Technology Fast 500 list of the ... manufactures AcceleDent®, a FDA-cleared, Class II medical device that speeds up orthodontic tooth ...
(Date:11/24/2015)... , Nov. 24, 2015 Capricor ... company focused on the discovery, development and commercialization of ... Ph.D., Chief Executive Officer, is scheduled to present at ... 2015 at 10:50 a.m. EST, at The Lotte New ... . . --> ...
(Date:11/24/2015)... 2015  PDL BioPharma, Inc. (PDL) (NASDAQ: PDLI ) ... president and chief executive officer, will present at the 27 ... New York City . The presentation will ... 2015 at 9:30 a.m. EST. and ... at least 15 minutes prior to the presentation to allow ...
(Date:11/24/2015)... ... 24, 2015 , ... Whitehouse Laboratories is pleased to announce that it has ... be strictly dedicated to basic USP 61, USP 62 and USP 51 testing specific ... complete chemistry and micro testing performed by one supplier. Management has formally ...
Breaking Biology Technology: