ISSN:
1573-5117
Keywords:
Carbon cycling
;
nitrogen cycling
;
estuarine sediments
;
methane
;
nitrous oxide
;
mineralization
;
carbon dioxide
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Carbon and nitrogen cycling in intertidal mud flat sediments in the Scheldt Estuary was studied using measurements of carbon dioxide, methane and nitrous oxide emission rates and pore-water profiles of ΣCO2, ammonium and nitrate. A comparison between chamber measured carbon dioxide fluxes and those based on ΣCO2 pore-water gradients using Fick's First law indicates that apparent diffusion coefficients are 2 to 28 times higher than bulk sediment diffusion coefficients based on molecular diffusion. Seasonal changes in gaseous carbon fluxes or ΣCO2 pore water concentrations cannot be used directly, or in a simple way, to determine seasonal rates of mineralization, because of marked seasonal changes in pore-water storage and exchange parameters. The annual amount of carbon delivered to the sediment is 42 mol m−2, of which about 42% becomes buried, the remaining being emitted as methane (7%) or carbon dioxide (50%). Each year about 2.6 mol N m−2 of particulate nitrogen reaches the sediment; 1.1 mol m−2 is buried and 1.6 mol m−2 is mineralized to ammonium. Only 0.42 mol m−2 yr−1 of the ammonium produced escapes from the sediments, the remaining being first nitrified (1.2 mol m−2 yr−1) and then denitrified (1.7 mol m−2 yr−1). Simple calculations indicate that intertidal sediments may account for about 14% and 30% of the total estuarine retention of nitrogen and carbon, respectively.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00008571
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