Why do we need a database for oceanic methane and nitrous oxide?
Methane (CH4) and nitrous oxide (N2O) are trace gases in the atmosphere that contribute significantly to the earth's greenhouse effect. N2O is furthermore becoming the most important substance responsible for ozone depletion in the stratosphere. The ocean contributes moderately to global CH4 (up to 10% of natural emissions) and strongly to N2O emissions (up to 34% of natural emissions).
Oceanic emissions of nitrous oxide and methane are produced during natural microbial processes, and the distribution of methane and nitrous oxide in the ocean varies strongly over space and time. Their production and consumption in the ocean are sensitive to environmental changes, such as changes in temperature, oxygen concentration or primary productivity. Climate change may thus affect the oceanic emissions of nitrous oxide and methane.
A compilation of all available measurements into a global database is a useful tool to identify regions with strong emissions, to assess their variability and to quantify the oceanic CH4 and N2O emissions. It also serves as a powerful resource for validation of biogeochemical models.
The MEMENTO database currently contains about 120,000 surface and depth profile measurements of N2O and more than 20,000 measurements for CH4 all over the oceans.
Watersampling on board of RC Littorina.
N2O measurements in the laboratory.