Navigation Links
How much nitrogen is fixed in the ocean?
Date:8/10/2012

Of course scientists like it when the results of measurements fit with each other. However, when they carry out measurements in nature and compare their values, the results are rarely "smooth". A contemporary example is the ocean's nitrogen budget. Here, the question is: how much nitrogen is being fixed in the ocean and how much is released? "The answer to this question is important to predicting future climate development. All organisms need fixed nitrogen in order to build genetic material and biomass", explains Professor Julie LaRoche from the GEOMAR | Helmholtz Centre for Ocean Research Kiel.

Despite scientific efforts, the nitrogen budget suffers from an apparent dilemma. The analysis of ocean sediment as a long-term climate archive has shown that the amounts of fixed nitrogen equaled those of released nitrogen for the past 3000 years. However, modern measurements in the ocean demonstrate that the amounts of released nitrogen exceed the amounts of nitrogen being fixed. These results leave a "gap" in the nitrogen budget and show inconsistencies between past, long-term reconstruction and short-term measurements.

In 2010, the GEOMAR microbiologist Wiebke Mohr pointed out that these inconsistencies could be partially due to the methods widely used to measure modern biological nitrogen fixation. Following this finding, scientists from GEOMAR, Christian-Albrechts-University of Kiel (CAU), Max Planck Institute for Marine Microbiology (MPI) Bremen and Dalhousie University in Halifax (Canada) tested a new approach in the Atlantic Ocean which had been suggested by Mohr: The results of the study are now presented in the international journal "Nature".

The study, which was funded by the Collaborative Research Centre 754 and the SOPRAN project, was carried out aboard the German research vessels METEOR and POLARSTERN where the participating scientists took water samples at various spots in the tropical and equatorial Atlantic and the temperate South Atlantic. At each station, one sample was treated with the widely applied "old" method and one sample with the new method for assesing nitrogen fixation. The samples were then measured at the MPI Bremen. "The results clearly showed that the old method very distinctly underestimated the nitrogen fixation rate by certain microorganisms", says GEOMAR scientist Tobias Groβkopf, first author of the "Nature" article. The new method measured rates that were between 62 and 600 percent higher than with the old method.

Groβkopf and his colleagues also analyzed the composition of the microbial community and found a correlation between the kind of microorganisms in the water and the difference in rates that the two methods revealed. "With the old method, the rate measured changes according to where the microorganisms live, closer to the surface or deeper in the water. The new method circumvents this bias", Groβkopf emphasizes.

The "gap" in the nitrogen budget, however, cannot be entirely closed even with improved measurements of nitrogen fixation. "This is also due to the fact that we still don't know all the microorganisms responsible for all these processes", Groβkopf says. Professor Ruth Schmitz-Streit, microbiologist at the CAU and co-author of the "Nature" article, adds: "Within the Collaborative Research Centre 754 we just identified seven new clusters of nitrogen-fixing microorganisms, and many species are still waiting to be found."

For Professor Julie LaRoche, who leads the research group at GEOMAR, this study is an important demonstration that scientific methods have to be carefully tested before their application. During an international workshop at GEOMAR in February 2012 LaRoche already advocated uniform and reliable methods in the analysis of biogeochemical fluxes in the ocean. "We have to work globally on a common basis in order to compare our results", LaRoche highlights.


'/>"/>
Contact: Jan Steffen
jsteffen@geomar.de
Helmholtz Centre for Ocean Research Kiel (GEOMAR)
Source:Eurekalert

Related biology news :

1. Modern hybrid corn makes better use of nitrogen, study shows
2. Nitrogen pollution changing Rocky Mountain National Park vegetation, says CU-Boulder-led study
3. Scientists develop new carbon accounting method to reduce farmers use of nitrogen fertilizer
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:4/3/2017)...  Data captured by IsoCode, IsoPlexis Corporation,s ... statistically significant association between the potency of ... objective response of cancer patients post-treatment. The ... cancer patients will respond to CAR-T cell ... to improve both pre-infusion potency testing and cell ...
(Date:3/29/2017)... March 29, 2017  higi, the health IT company ... North America , today announced a Series ... acquisition of EveryMove. The new investment and acquisition accelerates ... tools to transform population health activities through the collection ... higi collects and secures data today on ...
(Date:3/24/2017)... Mar 24, 2017 Research and Markets has ... Market Analysis & Trends - Industry Forecast to 2025" report ... ... at a CAGR of around 15.1% over the next decade to ... report analyzes the market estimates and forecasts for all the given ...
Breaking Biology News(10 mins):
(Date:5/18/2017)... ... May 17, 2017 , ... ... today that their Chief Executive Officer, Maik Jornitz, was recognized as a Top ... Power List celebrates 100 individuals “involved in bettering the pharma industry and bringing ...
(Date:5/18/2017)... (PRWEB) , ... May 18, 2017 , ... When James Sherley, was notified earlier this ... Most Valuable Brands for the Year 2017 by The Silicon Review , he was ... making good progress increasing Asymmetrex’s value, but this recognition by Silicon Valley was particularly meaningful. ...
(Date:5/16/2017)... ... May 16, 2017 , ... ... Hi-C metagenomic deconvolution service. ProxiMeta enables researchers to obtain complete, distinct genomes ... insights at lower cost. , “We’re very excited about the commercial launch ...
(Date:5/16/2017)... CA (PRWEB) , ... May 16, 2017 , ... ... medicine technology and cancer diagnostics, has released its ClearID Lung Cancer blood test. ... in lung cancer, this new test is designed to quickly and accurately identify ...
Breaking Biology Technology: