Navigation Links
The 'slippery slope to slime': Overgrown algae causing coral reef declines
Date:9/19/2012

CORVALLIS, Ore. Researchers at Oregon State University for the first time have confirmed some of the mechanisms by which overfishing and nitrate pollution can help destroy coral reefs it appears they allow an overgrowth of algae that can bring with it unwanted pathogens, choke off oxygen and disrupt helpful bacteria.

These "macroalgae," or large algal species, are big enough to essentially smother corals. They can get out of control when sewage increases nitrate levels, feeds the algae, and some of the large fish that are most effective at reducing the algal buildup are removed by fishing.

Scientists found that macroalgal competition decreased coral growth rates by about 37 percent and had other detrimental effects. Other research has documented some persistent states of hypoxia.

Researchers call this process "the slippery slope to slime."

Findings on the research were just published in PLoS One, a professional journal. The work was supported by the National Science Foundation.

"There is evidence that coral reefs around the world are becoming more and more dominated by algae," said Rebecca Vega-Thurber, an OSU assistant professor of microbiology. "Some reefs are literally covered up in green slime, and we wanted to determine more precisely how this can affect coral health."

The new study found that higher levels of algae cause both a decrease in coral growth rate and an altered bacterial community. The algae can introduce some detrimental pathogens to the coral and at the same time reduce levels of helpful bacteria. The useful bacteria are needed to feed the corals in a symbiotic relationship, and also produce antibiotics that can help protect the corals from other pathogens.

One algae in particular, Sargassum, was found to vector, or introduce a microbe to corals, a direct mechanism that might allow introduction of foreign pathogens.

There are thousands of species of algae, and coral reefs have evolved with them in a relationship that often benefits the entire tropical marine ecosystem. When in balance, some algae grow on the reefs, providing food to both small and large fish that nibble at the algal growth. But the algal growth is normally limited by the availability of certain nutrients, especially nitrogen and phosphorus, and some large fish such as parrot fish help eat substantial amounts of algae and keep it under control.

All of those processes can be disrupted when algal growth is significantly increased by the nutrients and pollution from coastal waste water, and overfishing reduces algae consumption at the same time.

"This shows that some human actions, such as terrestrial pollution or overfishing, can affect everything in marine ecosystems right down to the microbes found on corals," Vega-Thurber said. "We've suspected before that increased algal growth can bring new diseases to corals, and now for the first time have demonstrated in experiments these shifts in microbial communities."

Some mitigation of the problem is already being done on high-value coral reefs by mechanically removing algae, Vega-Thurber said, but the best long-term solution is to reduce pollution and overfishing so that a natural balance can restore itself.

Corals are one of Earth's oldest animal life forms, evolving around 500 million years ago. They host thousands of species of fish and other animals, are a major component of marine biodiversity in the tropics, and are now in decline around the world. Reefs in the Caribbean Sea have declined more than 80 percent in recent decades.


'/>"/>

Contact: Rebecca Vega-Thurber
Rebecca.vega-thurber@oregonstate.edu
541-737-1851
Oregon State University
Source:Eurekalert

Related biology news :

1. Oil from algae closer to reality through studies by unique collaboration of scientists
2. U OF A expert pinpoints nutrient behind fresh water algae blooms
3. Ecologist: Genetically engineered algae for biofuel pose potential risks that should be studied
4. Viruses linked to algae that control coral health
5. A nanoscopic look at the estuarys green algae
6. Carbon is key for getting algae to pump out more oil
7. Algae biofuels: the wave of the future
8. A project to research biological and chemical aspects of microalgae to fuel approach
9. Researchers identify key culprit causing muscle atrophy
10. Frequent traveller: Dysentery-causing bacteria spreading from Europe to Australia
11. Bangladeshi women prefer pollution-causing cookstoves
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:4/13/2016)... CHICAGO , April 13, 2016  IMPOWER physicians ... are setting a new clinical standard in telehealth ... By leveraging the higi platform, IMPOWER patients can ... weight, pulse and body mass index, and, when they ... quick and convenient visit to a local retail location ...
(Date:3/29/2016)... , March 29, 2016 LegacyXChange, ... LegacyXChange "LEGX" and SelectaDNA/CSI Protect are pleased to announce ... used in a variety of writing instruments, ensuring athletes ... originally created collectibles from athletes on LegacyXChange will be ... of the DNA. Bill Bollander , ...
(Date:3/22/2016)... and SANDY, Utah , ... which operates the highest sample volume laboratory in ... Genomics and UNIConnect, leaders in clinical sequencing informatics and ... launch of a project to establish the informatics infrastructure ... NSO has been contracted by the Ontario ...
Breaking Biology News(10 mins):
(Date:4/27/2016)... ... April 27, 2016 , ... Most consumers ... with fingerprint recognition for secure access, voice recognition for hands-free communication, and facial ... are interacting with biometrics technology today. But if they asked Joey Pritikin, ...
(Date:4/27/2016)... ... April 27, 2016 , ... NDA Partners ... the company as an Expert Consultant. Mr. Clark was formerly a Vice ... the development of small molecule monographs based on analytical methods. NDA Partners ...
(Date:4/27/2016)... MIAMI (PRWEB) , ... April 27, 2016 , ... ... a mutual endorsement of an Asia-Pacific Symposium as other research and development initiatives for ... of Santiago officials and top Global Stem Cells Group executives began meeting to establish ...
(Date:4/26/2016)... ... April 26, 2016 , ... ... Arianpour has joined the company as Chief Business Officer. Arianpour, a genomics pioneer ... technologies to market, was most recently Chief Commercial Officer of Pathway Genomics. He ...
Breaking Biology Technology: