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!
NASA eyes Pineapple Express soaking California
24.02.2017 | NASA/Goddard Space Flight Center
'Quartz' crystals at the Earth's core power its magnetic field
23.02.2017 | Tokyo Institute of Technology
In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport
Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...
The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.
The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...
Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...
Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".
Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...
13.02.2017 | Event News
10.02.2017 | Event News
09.02.2017 | Event News
24.02.2017 | Life Sciences
24.02.2017 | Life Sciences
24.02.2017 | Trade Fair News