Abstract
The concentrations of two greenhouse gases, nitrous oxide (N2O) and methane (CH4), and the bacterial processes involved in their production (nitrification and denitrification for N2O, and methanogenesis for CH4) were determined in a water column, along the Rhone River plume, in the Gulf of Lions, northwestern Mediterranean Sea. High concentrations of dissolved CH4 and N2O were recorded in the surface waters, up to 1,300 nM for CH4 and 40 nM for N2O, versus, 2–3 nM, and 5 nM in the open ocean surface waters. Along the Rhone River plume, the highest concentrations of CH4 were detected near the river mouth, whereas N2O remained present throughout the plume, up to the marine station. Bacterial production rates of N2O and CH4 indicated that the Rhone River plume constituted an area favorable for the development of nitrifiers, denitrifiers, and methanogens, promoting their activities in suspended particles. Nonetheless, no direct relationship could be found between the concentration and the production of the biogases, suggesting that the dissolved gases were not necessarily produced in situ, in surface seawater, but could be produced in deep water or bottom sediment, and then transported to the surface waters. The presence of extremely high concentrations of CH4 and N2O, in superficial seawater implies they can escape directly to the atmosphere; consequently, these near-shore waters enriched in greenhouse gases may play an important role in the atmospheric increase of both CH4 and N2O concentration, and thus in the global climate change.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.