Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Alterations to seabed raise fears for future

30.10.2018

Ocean acidification caused by high levels of human-made CO2 is dissolving the seafloor

The ocean floor as we know it is dissolving rapidly as a result of human activity.


Maps showing areas of the seafloor which have been affected, to varying degrees, by the increasing acidification of the oceans as a result of human activities.

Credit: McGill University

Normally the deep sea bottom is a chalky white. It's composed, to a large extent, of the mineral calcite (CaCO3) formed from the skeletons and shells of many planktonic organisms and corals. The seafloor plays a crucial role in controlling the degree of ocean acidification.

The dissolution of calcite neutralizes the acidity of the CO2, and in the process prevents seawater from becoming too acidic. But these days, at least in certain hotspots such as the Northern Atlantic and the southern Oceans, the ocean's chalky bed is becoming more of a murky brown.

As a result of human activities the level of CO2 in the water is so high, and the water is so acidic, that the calcite is simply being dissolved.

The McGill-led research team who published their results this week in a study in PNAS believe that what they are seeing today is only a foretaste of the way that the ocean floor will most likely be affected in future.

Long-lasting repercussions

"Because it takes decades or even centuries for CO2 to drop down to the bottom of the ocean, almost all the CO2 created through human activity is still at the surface. But in the future, it will invade the deep-ocean, spread above the ocean floor and cause even more calcite particles at the seafloor to dissolve," says lead author Olivier Sulpis who is working on his PhD in McGill's Dept. of Earth and Planetary Sciences.

"The rate at which CO2 is currently being emitted into the atmosphere is exceptionally high in Earth's history, faster than at any period since at least the extinction of the dinosaurs. And at a much faster rate than the natural mechanisms in the ocean can deal with, so it raises worries about the levels of ocean acidification in future."

In future work, the researchers plan to look at how this deep ocean bed dissolution is likely to evolve over the coming centuries, under various potential future CO2 emission scenarios. They believe that it is critical for scientists and policy makers to develop accurate estimates of how marine ecosystems will be affected, over the long-term, by acidification caused by humans.

How the work was done

Because it is difficult and expensive to obtain measurements in the deep-sea, the researchers created a set of seafloor-like microenvironments in the laboratory, reproducing abyssal bottom currents, seawater temperature and chemistry as well as sediment compositions.

These experiments helped them to understand what controls the dissolution of calcite in marine sediments and allowed them to quantify precisely its dissolution rate as a function of various environmental variables. By comparing pre-industrial and modern seafloor dissolution rates, they were able to extract the anthropogenic fraction of the total dissolution rates.

The speed estimates for ocean-bottom currents came from a high-resolution ocean model developed by University of Michigan physical oceanographer Brian Arbic and a former postdoctoral fellow in his laboratory, David Trossman, who is now a research associate at the University of Texas-Austin.

"When David and I developed these simulations, applications to the dissolution of geological material at the bottom of the oceans were far from our minds. It just goes to show you that scientific research can sometimes take unexpected detours and pay unexpected dividends," said Arbic, an associate professor in the University of Michigan Department of Earth and Environmental Sciences.

Trossman adds: "Just as climate change isn't just about polar bears, ocean acidification isn't just about coral reefs. Our study shows that the effects of human activities have become evident all the way down to the seafloor in many regions, and the resulting increased acidification in these regions may impact our ability to understand Earth's climate history."

"This study shows that human activities are dissolving the geological record at the bottom of the ocean," says Arbic. "This is important because the geological record provides evidence for natural and anthropogenic changes."

###

To read "CaCO3 dissolution at the seafloor caused by anthropogenic CO2" by Olivier Sulpis et al in PNAS:

The research was funded by Natural Sciences and Engineering Research Council of Canada (NSERC) and the U.S. National Science Foundation.

Contacts:

Olivier Sulpis, Ph D. student, Dept. Of Earth and Planetary Sciences, McGill University,
olivier.sulpis@mail.mcgill.ca (English & French interviews) +1-438-926-7009

Bernard Boudreau, Professor, Dept. Of Oceanography, Dalhousie University, bernie.boudreau@dal.ca (English interviews) +1-902-494-8895

Katherine Gombay, Media Relations, McGill University
Katherine.gombay@mcgill.ca, 514 398-2189

http://www.mcgill.ca/newsroom/

http://www.twitter.com/mcgillu

Katherine Gombay | EurekAlert!
Further information:
https://www.mcgill.ca/newsroom/channels/news/alterations-seabed-raise-fears-future-291163
http://dx.doi.org/10.1073/pnas.1804250115

More articles from Earth Sciences:

nachricht Upwards with the “bubble shuttle”: How sea floor microbes get involved with methane reduction in the water column
27.05.2020 | Leibniz-Institut für Ostseeforschung Warnemünde

nachricht An international team including scientists from MARUM discovered ongoing and future tropical diversity decline
26.05.2020 | MARUM - Zentrum für Marine Umweltwissenschaften an der Universität Bremen

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: K-State study reveals asymmetry in spin directions of galaxies

Research also suggests the early universe could have been spinning

An analysis of more than 200,000 spiral galaxies has revealed unexpected links between spin directions of galaxies, and the structure formed by these links...

Im Focus: New measurement exacerbates old problem

Two prominent X-ray emission lines of highly charged iron have puzzled astrophysicists for decades: their measured and calculated brightness ratios always disagree. This hinders good determinations of plasma temperatures and densities. New, careful high-precision measurements, together with top-level calculations now exclude all hitherto proposed explanations for this discrepancy, and thus deepen the problem.

Hot astrophysical plasmas fill the intergalactic space, and brightly shine in stellar coronae, active galactic nuclei, and supernova remnants. They contain...

Im Focus: Biotechnology: Triggered by light, a novel way to switch on an enzyme

In living cells, enzymes drive biochemical metabolic processes enabling reactions to take place efficiently. It is this very ability which allows them to be used as catalysts in biotechnology, for example to create chemical products such as pharmaceutics. Researchers now identified an enzyme that, when illuminated with blue light, becomes catalytically active and initiates a reaction that was previously unknown in enzymatics. The study was published in "Nature Communications".

Enzymes: they are the central drivers for biochemical metabolic processes in every living cell, enabling reactions to take place efficiently. It is this very...

Im Focus: New double-contrast technique picks up small tumors on MRI

Early detection of tumors is extremely important in treating cancer. A new technique developed by researchers at the University of California, Davis offers a significant advance in using magnetic resonance imaging to pick out even very small tumors from normal tissue. The work is published May 25 in the journal Nature Nanotechnology.

researchers at the University of California, Davis offers a significant advance in using magnetic resonance imaging to pick out even very small tumors from...

Im Focus: I-call - When microimplants communicate with each other / Innovation driver digitization - "Smart Health“

Microelectronics as a key technology enables numerous innovations in the field of intelligent medical technology. The Fraunhofer Institute for Biomedical Engineering IBMT coordinates the BMBF cooperative project "I-call" realizing the first electronic system for ultrasound-based, safe and interference-resistant data transmission between implants in the human body.

When microelectronic systems are used for medical applications, they have to meet high requirements in terms of biocompatibility, reliability, energy...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Dresden Nexus Conference 2020: Same Time, Virtual Format, Registration Opened

19.05.2020 | Event News

Aachen Machine Tool Colloquium AWK'21 will take place on June 10 and 11, 2021

07.04.2020 | Event News

International Coral Reef Symposium in Bremen Postponed by a Year

06.04.2020 | Event News

 
Latest News

An MRI technique has been developed to improve the detection of tumors

03.06.2020 | Medical Engineering

K-State study reveals asymmetry in spin directions of galaxies

03.06.2020 | Physics and Astronomy

The cascade to criticality

03.06.2020 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>