Subscribe free to our newsletters via your
. Earth Science News .


Subscribe free to our newsletters via your




















WATER WORLD
Protecting coral reefs with bubbles
by Staff Writers
Stanford CA (SPX) Mar 24, 2016


File image.

Blowing tiny bubbles through seawater could help protect coral reefs and oyster farms from oceans turned increasingly acidic through human activities by stripping carbon dioxide (CO2) from coastal marine environments and transferring it to the atmosphere, Stanford scientists say.

The technique, outlined in a study published online in the journal Environmental Science and Technology, could provide a relatively inexpensive solution to one of the biggest threats facing coral reefs today. An estimated 30 to 60 percent of all the coral reefs have died since the Industrial Revolution as the oceans absorbs more CO2 and become increasingly acidic. Ocean acidification harms a variety of marine organisms, but especially those that use calcium carbonate to assemble their skeletons and shells, such as coral, mussels, and oysters.

"Ocean acidification is particularly troublesome for coral reefs because the entire structure of the ecosystems is built upon the calcium carbonate skeletal remains of dead coral," said lead author David Koweek, a doctoral candidate at Stanford's School of Earth, Energy and Environmental Sciences. "Ocean acidification makes it difficult for corals to calcify and makes it easier to erode these skeletal remains, threatening the integrity of the entire reef."

A further loss of coral reefs would be significant. Worldwide, coral reefs provide an estimated $30 billion net economic benefit each year. A healthy coral reef provides a home to thousands of organisms, which island subsistence communities rely on for the bulk of their diet. A reef's mere presence can quell the waves whipped up by a surging storm, thereby guarding low-lying coastal towns from flooding.

In the new study, Koweek and his coauthors demonstrated that bubbling air through seawater for a few hours in the early morning can enhance the transfer rate of CO2 between the ocean and the air up to 30 times faster than natural processes, resulting in a significant reduction in local marine concentrations of the greenhouse gas.

"The nice thing about the bubble pulse method is that it provides an engineering technique that can help bring us closer to conditions that coral reefs were used to 100 years ago, and to which they've been adapted for many thousands of years," said study coauthor Rob Dunbar, the W.M. Keck Professor of Earth Science at Stanford and Koweek's advisor.

An idea bubbles up
The idea to use bubbles to reduce localized ocean acidity arose from an observation that Koweek made while studying the natural chemical cycles of coral reefs and other shallow-water ecosystems. Koweek noticed CO2 levels in these environments rise and fall in a predictable pattern throughout the day: CO2 levels drop during the day as coral and other photosynthesizing marine organisms absorb the gas; when the sun sets and photosynthesis stops, plants and animals respire, and CO2 levels rise again.

Koweek wondered if it might be possible to spur coral growth by reducing CO2 levels in the water in the predawn hours - when the oceans are most acidic - by using air bubbles to draw the gas out of the seawater and transfer it to the atmosphere. If the bubbles have lower concentrations of CO2 than the surrounding water, the gas will naturally diffuse into the bubbles.

The team set up a bubbling experiment in a sensor-laden water tank at Stanford's Hopkins Marine Station. Each night, they would fill the tank with bags of giant kelp. Throughout the night, the kelp would respire, adding CO2 to the water, and thus acting to simulate the CO2 buildup that occurs from respiration in coastal ecosystems at night.

The team would then arrive the following morning, remove the kelp, and begin to bubble the high CO2 seawater in order to test how bubbling lowers the CO2 concentration. They found that just two hours of bubble-mediated ventilation could increase the transfer of CO2 from the ocean into the air by 10 to 30 times.

From tank to tides
The results from the water tank experiment closely matched the predictions from a computer model the team developed, giving the scientists confidence in the accuracy of their model. The scientists say that if timed correctly, bubble stripping could be an effective means of reducing extreme acidity in coastal ecosystems now and in the future.

If ocean acidification continues to increase, the normal changes in ocean chemistry that occur overnight will pose a greater threat to marine organisms as concentrations of CO2 reach harmful levels. A recent study by researchers at the Carnegie Department of Global Ecology at Stanford found that this is already happening in tide pools across California.

Koweek thinks bubble stripping could prove useful for protecting small sections of shallow coastline that are ecologically, culturally, or commercially important. Because the operations would be small, the benefits to the marine environments from lowering ocean acidity levels would greatly outweigh the relatively small amount of atmospheric CO2 generated by the bubbling process and by the compressors used to produce the bubbles.

"If this idea takes off, you could imagine people running these compressors on solar power," Koweek said. "In the tropics, where there's a lot of sunlight, you could charge your compressors with solar energy during the day and then bubble at night."

A little bubbling could go a long way, if done strategically. "Many Pacific coral reef terraces have a mostly unidirectional water flow," said Dunbar, who is also a senior fellow at the Stanford Woods Institute for the Environment. "If you operate your bubbler in an area that is upstream of a large section of coral, you could reduce CO2 levels for an entire reef."

Ultimately, bubble stripping could help protect more than just coral. "Many coastal ecosystems, including salt marshes, seagrass meadows, and mangroves undergo daily variations in CO2 due to photosynthesis during daylight hours and respiration during nighttime hours," Koweek said.

David Mucciarone, a science lab manager at Stanford, co-authored the study. Funding for the study was provided by the National Science Foundation and a McGee research grant from the Stanford School of Earth, Energy and Environmental Sciences.

.


Related Links
Stanford's School of Earth, Energy and Environmental Sciences
Water News - Science, Technology and Politics






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

Previous Report
WATER WORLD
Calls for climate action over Great Barrier Reef bleaching
Sydney (AFP) March 21, 2016
Environmental groups Monday urged greater action on climate change after the government sounded the alarm over severe coral bleaching in the pristine northern reaches of Australia's Great Barrier Reef. The government said Sunday that corals had turned white and grey in parts of the World Heritage-listed marine park, with the bleaching "severe" in northern areas. Environmental group WWF s ... read more


WATER WORLD
No hope of survivors in northern Pakistan avalanche: officials

Maths could help search and rescue ships sail more safely in heavy seas

Two schoolchildren killed, nine missing in Pakistan avalanche

Hope fades to fear for Chinese refugees in junta-run Thailand

WATER WORLD
The quest for spin liquids

A foldable material that can change size, volume and shape

New insights into atomic disordering of complex metal oxides

How electrons travel through exotic new material

WATER WORLD
In Florida, calls to keep 'saving the manatees'

Malaysia tribes say controversial Borneo dam is scrapped

Indian city bans gatherings over water riot fears

Pacific nations lead the way on Paris climate accord

WATER WORLD
Digging deeper: Study improves permafrost models, reduces uncertainties

Climate warming accelerating carbon loss from thawing Arctic soils

Nature study reveals rapid ice-wedge loss across Arctic

Early Earth was colder than previously thought

WATER WORLD
Climate Change Shifting Wine Grape Harvests in France and Switzerland

China sales help Bordeaux wines turn around two-year slump

Cousteau warns of reef damage in Florida port project

Production of butter from shea trees in West Africa pushed back 1,000 years

WATER WORLD
Wetland enhancement in Midwest could help reduce catastrophic floods of the future

Pakistan rains leave 42 dead: officials

Japan's tsunami: Five things after five years

Pakistan rains leave 28 dead: officials

WATER WORLD
Burundi soldier kills colonel blamed in crackdown: source

65 Shebab insurgents killed in NE Somalia: army

Niger president scores landslide win in boycotted run-off

Kenya army says killed 34 Shebab in Somalia firefights

WATER WORLD
Why did humans make more pottery after the last ice age?

Ancient Denisovan DNA excavated in modern Pacific Islanders

Researchers find ancient DNA preserved in modern-day humans

400,000-year-old fossils from Spain provide earliest genetic evidence of Neandertals




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News








The content herein, unless otherwise known to be public domain, are Copyright 1995-2016 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.