『Abstract
The concentration and the isotopic ratios of noble gases He,
Ne, Ar, Kr and Xe were measured in porewater trapped in shallow
sediments of the estuary of the St-Lawrence River, Quebec(最初のeの頭に´), Canada. The gases are atmospheric
in origin but most samples have gas concentrations 1.7-28 times
higher than those expected in solution in water at equilibrium
with the atmosphere. Elemental fractionation of heavier noble
gases Kr and Xe compared to Ar strongly suggests that noble gases
were desorbed on sediments or organic matter and then desorbed
into porewaters due to depressurization, as collected samples
were brought to the surface. Atmospheric Ar in porewater is used
as a reference to measure the N2-fluxes at
the water-sediment interface. Ignoring the Ar enrichments observed
in porewater could lead to a severe underestimation of the denitrification
rate in oceans and estuaries.』
1. Introduction
2. Sampling and analytical methods
3. Results
4. Discussion
5. Conclusions
Acknowledgments
References