Bubbles – yes, bubbles – could help protect coral reefs, oyster farms, and other coastal ecosystems from increasing ocean acidification, according to new research by Stanford scientists
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 & 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 & 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 CO2concentration. 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.
Learn more: Protecting Coral Reefs with Bubbles
The Latest on: Coral reefs
via Google News
The Latest on: Coral reefs
- Biologists dive for secrets of coral reef that survives hot Gulf waterson June 26, 2020 at 2:29 pm
Coral reefs are sensitive ecosystems that rarely survive sea temperatures above 32 degrees Celsius, yet coral reef fauna thrives in the Persian Gulf, where scientists hope to find clues about climate ...
- This company is showing us how we can save our coral reefson June 26, 2020 at 1:24 pm
Coral Vita grows its own diverse and resilient corals and transplants them to threatened reefs. The company also works to preserve the ocean’s biodiversity in order to protect the communities and ...
- First completely remote at-sea science expedition in Australia's coral sea marine parkon June 25, 2020 at 12:34 pm
Scientists working remotely with Schmidt Ocean Institute, one of the only at-sea science expeditions to continue operating during the global pandemic, have completed afirst look at deep waters in the ...
- Device Start-Up, Acme Revival, Propagates Coral With Recycled Medical Deviceson June 24, 2020 at 11:39 am
Acme Revival, a start-up that connects clinics and physicians with medical devices that they refurbish in-house, incorporates an atypical element to their ...
- Underwater Photographer Chris Leidy On The Inspiration Behind His New Book, ‘The Coral Triangle’on June 23, 2020 at 1:08 pm
This month saw the release of Chris Leidy’s new book, 'The Coral Triangle.' The latest publication to join Assouline’s Classics Collection, this covetable title takes us beneath the surface of an ...
- Dimethylsulfoniopropionate concentration in coral reef invertebrateson June 23, 2020 at 8:53 am
New research highlights the effect of benthic assemblages on the sulfur metabolism of coral and giant clam species. The research was conducted at CRIOBE and ENTROPIE research units, with the ...
- Robot Divers Could Use Artificial Intelligence To Save Coral Reefs: NOAAon June 21, 2020 at 9:07 pm
While scientists have succeeded at restoring some coral reefs, the job is too vast for humans alone, acording to a NOAA reef restoration manager.
- Divers cut, plant coral off UAE coast to build reefon June 18, 2020 at 4:54 am
Off the east coast of the United Arab Emirates (UAE) coral freshly removed from a reef is cut into pieces and replanted by a group of divers in the waters below. The divers, from the Fujairah ...
- Sasakawa Peace Foundation: Coral skeletons record history of reef deterioration -- black bands in coral contain iron sulfide and bacteriaon June 18, 2020 at 12:30 am
Stock quotes by finanzen.net TOKYO, June 18, 2020 /PRNewswire/ -- The journal Scientific Reports published a research paper entitled "Anthropogenic Anoxic History of the Tuvalu Atoll Recorded as ...
- Coral reef loss helps some fish grow bigger, but perhaps not for longon June 16, 2020 at 2:35 pm
When sea temperatures rise, coral reefs get “stressed out.” They expel a microscopic algae called zooxanthellae from their tissues, and this process causes colorful coral polyps to “bleach” a stark ...
via Bing News