Featured Research

from universities, journals, and other organizations

How some microorganisms bore their way into carbonate substrates: Implications for coral reefs and mussel aquaculture

Date:
November 30, 2010
Source:
Arizona State University
Summary:
Geo-microbiologists have solved a long-standing conundrum about how some photosynthetic microorganisms, endolithic cyanobacteria, bore their way into limestone, sand grains, mussel shells, coral skeletons and other substrates composed of carbonate.

Blue-green filaments of cyanobacteria bore into a chip of crystalline calcite.
Credit: Edgardo Ramνrez-Reinat/ASU

Geo-microbiologists from Arizona State University have solved a long-standing conundrum about how some photosynthetic microorganisms, endolithic cyanobacteria, bore their way into limestone, sand grains, mussel shells, coral skeletons and other substrates composed of carbonate.

Related Articles


According to the lead investigator, ASU professor Ferran Garcia-Pichel, the answer to the mystery of what is "at the heart of an erosive force of global proportions" is a calcium-driven pump, similar to that which we use to power our muscles.

The results of Garcia-Pichel's study were published Nov. 29 in the Proceedings of the National Academy of Sciences (PNAS).

While the dissolution of the carbonate coral reefs was noted more than a century ago by Louis Agassiz, the father of American naturalists, the specifics of how this physiological process occurs has remained a mystery. In fact, the process has presented a geochemical paradox to scientists, in that most cyanobacteria tend to precipitate new carbonates, not dissolve them.

Typically cyanobacteria, by photosynthesizing, raise the pH of the water (and lower the acidity); this process typically causes carbonate to precipitate if the change is large enough. While that is the "normal" case, the paradox with boring cyanobacteria is that photosynthesis occurs at the same time that they dissolve carbonate structures (which typically requires the pH to go down, making the environment more, rather than less acidic).

Garcia-Pichel and coauthors, Edgardo Ramνrez-Reinat, a doctoral candidate, and Qunjie Gao, a faculty research associate, in the School of Life Sciences in ASU's College of Liberal Arts and Sciences, set about trying to understand how this select group of carbonate-boring species can excavate by coaxing a strain of Mastigocoleus testarum, a filamentous, branching cyanobacterium, to grow in the laboratory under controlled conditions. Using real-time microscopic examinations, including calcium imaging and photosynthetic analysis, coupled with molecular genetics, the trio examined the cyanobacteria's invasion of calcite chips and the physiological mechanisms at play.

The ASU group found supersaturation of calcium near the surface of the borehole, but undersaturation at the boring front. This finding meant that the mass transfer of calcium could not happen extracellularly, by diffusion in the bored hole, which would require calcium to move against a concentration gradient.

Instead, they discovered that the endolithic cyanobacteria took up calcium from the tips of their boring filaments, directly into their cells. This action promoted the localized dissolution of the calcium-containing carbonate substrate. The calcium was then transported from cell to cell away from the area being quarried, and finally excreted at the entrance of a borehole. The consequences of this transient, but significantly high, concentration of intracellular calcium in the cells remains a question that the Garcia-Pichel laboratory hopes to pursue.

Garcia-Pichel says that he hopes that the newly gained knowledge allows the scientists to explain a variety of geological phenomena and points to new research directions to combat microbial pests of shellfish, such as cultured mussels.

"While it is hard to quantify the losses to the shellfish industry, the impact of endolithic bacteria has been described as a plague by Canadian fisheries," says Garcia-Pichel. "We have identified compounds that abolish the boring activity by inhibiting the enzymatic calcium pumps involved in the process, which may be implemented eventually to protect targets, either by direct application or through genetic engineering of the mussels."

Such studies as these will also help researchers to understand the impact of changes in calcium saturation states of ocean waters, says Garcia-Pichel, which are driven by increased atmospheric carbon dioxide. These are expected to result in a global enhancement of bioerosion, including the already impacted coral reefs.

Ferran Garcia-Pichel and his colleagues' laboratory studies will now also translate to their field research, where they will try and quantify the effect of ocean acidification on cyanobacterial borings. They will also pursue studies of other endolithic cyanobacteria, and other minerals, such as dolomites, calcophosphates and magnesites.


Story Source:

The above story is based on materials provided by Arizona State University. Note: Materials may be edited for content and length.


Journal Reference:

  1. F. Garcia-Pichel, E. Ramirez-Reinat, Q. Gao. Microbial excavation of solid carbonates powered by P-type ATPase-mediated transcellular Ca2 transport. Proceedings of the National Academy of Sciences, 2010; DOI: 10.1073/pnas.1011884108

Cite This Page:

Arizona State University. "How some microorganisms bore their way into carbonate substrates: Implications for coral reefs and mussel aquaculture." ScienceDaily. ScienceDaily, 30 November 2010. <www.sciencedaily.com/releases/2010/11/101130100522.htm>.
Arizona State University. (2010, November 30). How some microorganisms bore their way into carbonate substrates: Implications for coral reefs and mussel aquaculture. ScienceDaily. Retrieved October 24, 2014 from www.sciencedaily.com/releases/2010/11/101130100522.htm
Arizona State University. "How some microorganisms bore their way into carbonate substrates: Implications for coral reefs and mussel aquaculture." ScienceDaily. www.sciencedaily.com/releases/2010/11/101130100522.htm (accessed October 24, 2014).

Share This



More Earth & Climate News

Friday, October 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Dances With Wolves in China's Wild West

Dances With Wolves in China's Wild West

AFP (Oct. 23, 2014) — One man is on a mission to boost the population of wolves in China's violence-wracked far west. The animal - symbol of the Uighur minority there - is under threat with a massive human resettlement program in the region. Duration: 00:41 Video provided by AFP
Powered by NewsLook.com
San Diego Zoo's White Rhinos Provide Hope for the Critically Endangered Species

San Diego Zoo's White Rhinos Provide Hope for the Critically Endangered Species

Reuters - Light News Video Online (Oct. 22, 2014) — The pair of rare white northern rhinos bring hope for their species as only six remain in the world. Elly Park reports. Video provided by Reuters
Powered by NewsLook.com
Trick-or-Treating Banned Because of Polar Bears

Trick-or-Treating Banned Because of Polar Bears

Buzz60 (Oct. 21, 2014) — Mother Nature is pulling a trick on the kids of Arviat, Canada. As Mara Montalbano (@maramontalbano) tells us, the effects of global warming caused the town to ban trick-or-treating this Halloween. Video provided by Buzz60
Powered by NewsLook.com
Traditional Farming Methods Gaining Ground in Mali

Traditional Farming Methods Gaining Ground in Mali

AFP (Oct. 20, 2014) — He is leading a one man agricultural revolution in Mali - Oumar Diatabe uses traditional farming methods to get the most out of his land and is teaching others across the country how to do the same. Duration: 01:44 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins