Researchers from the Max Planck Institute for Marine Microbiology in Bremen, Germany and the Massachusetts Institute of Technology (M.I.T.) in Cambridge, Massachusetts have found a remarkable effect while studying how marine particles sink, which could affect the way scientists assess global carbon fluxes.
An aquatic aggregate of one centmeter diameter from Lake Constance, Germany (courtesy of Hans-Peter Grossart, IGB, Leibniz-Institute of Freshwater Ecology and Inland Fisheries) Hans-Peter Grossart, IGB
Their question - How fast does organic material and debris clumped together forming porous particles settle to the sea floor? Microbes colonizing these particles degrade the organic matter and release carbon dioxide back to the water. The downward velocity of the particles determines the amount of carbon exported to the deep sea. The results from this study are now presented in the Proceedings of the National Academy of Sciences (DOI: 10.1073/pnas.1012319108).
Structured like sponges, the marine particles are porous aggregates that are mostly void and made of water to 95% or more. Because the world's oceans are stratified due to temperature and/or salinity, water density increases with depth. On their way down to the deep ocean, marine aggregates can reach a depth where they approach neutral buoyancy, stopping in their descent until the exchange of low-density water and heavier ambient water allows settling to resume. Kolja Kindler, a scientist at the Max Planck Institute for Marine Microbiology and the Massachusetts Institute of Technology, points out that although thin layers of marine aggregates have often been observed in nature, this effect has been previously neglected in particle transport models.
In this study by Kindler and colleagues, the results from laboratory experiments and a mathematical model demonstrate this effect for the first time. As the particles are impermeable to flow, the only means of exchanging water is by diffusion. As a result, the larger the size of the aggregates, the more time they spend in the stratified layer.
Arzhang Khalili from the Max Planck Institute for Marine Microbiology says, "Large marine aggregates may have a longer residence time in the water column than previously expected. This shows that we should revisit current approaches to particle settling to include the effect of porosity, if we want to improve our estimate of the carbon flux in the ocean."
“The deeper we look at microscale phenomena in the ocean, the more we discover that they are the processes that really govern how the Oceans work. Our chances of developing a sustainable approach to how we interact with and use the Oceans hinge on how well we can understand processes at these small scales” adds Roman Stocker from the Massachusetts Institute of Technology.
Further questions to be addressed to:Arzhang Khalili
Climate change weakens Walker circulation
20.10.2017 | MARUM - Zentrum für Marine Umweltwissenschaften an der Universität Bremen
Shallow soils promote savannas in South America
20.10.2017 | Senckenberg Forschungsinstitut und Naturmuseen
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
20.10.2017 | Information Technology
20.10.2017 | Materials Sciences
20.10.2017 | Interdisciplinary Research