Microorganisms do not degrade this material because each of the compounds that make it up are found in too low concentrations
Researchers from the Malaspina Expedition have made strides in the understanding of the mechanisms governing the persistence of dissolved organic carbon (DOC) for hundreds or thousands of years in the deep ocean. Most of this material is below 1,000 meters deep, but it is not degraded by bacteria.
Until now, it was thought that it consisted of non-degradable chemical compounds, but this study shows that it actually comprises very low concentrations of thousands of readily degradable compounds. The finding, published in the latest issue of the Science journal, provides new keys to further deepen the understanding of the regulation of the carbon cycle and the global climate.
The ocean contains an enormous amount of carbon in the form of dissolved organic matter. Its volume, about 700 billion kilograms, is comparable to all the carbon dioxide accumulated in the atmosphere, or more than 200 times greater than the sum of all the carbon contained in marine organisms.
Jesus Maria Arrieta, researcher from the Malaspina Expedition, states: "It is estimated that between 30% and 50% of the production of organic matter from the ocean, which, in turn, is half the production of the global organic matter, is released in the form of DOC in the ocean. Recognizing the mechanisms that enable this dissolved organic material to be persistent in the deep ocean is crucial to understand the regulation of the carbon cycle and the global climate".
The circumnavigation, performed by the Hesperides vessel as part of the Malaspina project, was a unique opportunity to obtain samples from the Atlantic and Pacific oceans. For this study, scientists have used samples of dissolved organic material from the deep ocean obtained at different depths between 1,000 and 4,000 meters.
Up to present, it was thought that this organic material dissolved in the deep ocean was resistant to microbial degradation as it consists of recalcitrant or highly resistant chemical structures. According to this new study, if bacteria can not cope with the thousands of different molecules that make up the carbon is because they are found in a very low concentration. The expenditure of energy by bacteria to use each of these molecules can not be compensated by the low concentration available, which prevents its degradation.
CSIC researcher emphasizes: "By offering concentrated organic material from the deep water to bacteria, we have observed a stimulation of growth at higher concentrations, i.e., this organic material from the deep ocean, hitherto considered to be little or not degradable at all, is actually readily degradable for the deep-ocean microorganisms. The reason is that this large amount of organic carbon is a mixture of "leftovers" from easily degradable materials, but their use is limited by the existing low concentrations of each compound".
Mechanisms governing the climate
According to previous studies, an increase in the concentration of DOC in the deep ocean in the past might have entailed a removal of CO2 from the atmosphere and a cooling effect on the planet. Arrieta adds: "It has been recently proposed to attempt to promote the microbial production of recalcitrant natural compounds in order to sequester carbon dioxide from the atmosphere and store it in the ocean. Our work indicates that the potential of this proposal would be very limited".
The Malaspina Expedition is a Consolider-Ingenio 2010 project managed by CSIC and funded by the Spanish Ministry of Economy and Competitiveness. Malaspina comprises about 50 research groups, including 27 Spanish groups from CSIC, the Spanish Institute of Oceanography (IEO), 16 Spanish universities, a museum, the research foundation AZTI-Tecnalia, and the Spanish Navy. The total funding, in which CSIC, IEO, BBVA Foundation, AZTI-TEcnalia (as well as several Spanish universities and public research organizations) have collaborated, is about 6 millions euros.
Alda Ólafsson | EurekAlert!
Hidden river once flowed beneath Antarctic ice
22.08.2017 | Rice University
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
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
23.08.2017 | Life Sciences
23.08.2017 | Life Sciences
23.08.2017 | Physics and Astronomy