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
Greenland ice flow likely to speed up: New data assert glaciers move over sediment, which gets more slippery as it gets wetter
17.08.2017 | Swansea University
Climate change: In their old age, trees still accumulate large quantities of carbon
17.08.2017 | Universität Hamburg
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
18.08.2017 | Life Sciences
18.08.2017 | Physics and Astronomy
18.08.2017 | Materials Sciences