 |
| Titel |
Turbulent nitrate fluxes near a sill in a large estuary |
| VerfasserIn |
Frédéric Cyr, Daniel Bourgault, Peter S. Galbraith, Michel Gosselin |
| Konferenz |
EGU General Assembly 2014
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250096967
|
| Publikation (Nr.) |
 EGU/EGU2014-12503.pdf |
|
|
|
|
|
| Zusammenfassung |
| Historical nitrate concentration profiles and new turbulent microstructure observations were
combined to calculate turbulent nitrate fluxes in the Lower St.Lawrence Estuary (LSLE),
Canada. Two stations were compared: the head of the Laurentian Channel (st.25), where
intense mixing occurs on the shallow sill that marks the upstream limit of the LSLE, and
another station located about 100 km downstream (st.23). Nitrate fluxes at the base of the
surface layer for both stations were respectively (with the 95% confidence interval):
F25 = 64(23,130)mmolm-2 d-1 and F23 = 0.11(0.04,0.23)mmolm-2 d-1.
Observations suggest that the interplay between large isopleths heaving near the sill and
strong turbulence is the key mechanism to sustain such high turbulent nitrate fluxes at
station25 (about 600 times those at station23). Calculations also suggest that these
localised large fluxes can sustain almost entirely the post-bloom new production over the
whole LSLE. |
|
|
|
|
|
|