Tamborski J., Van Beek P., Rodellas V., Monnin C., Bergsma E., Stieglitz Thomas, Heilbrun C., Cochran J.K., Charbonnier C., Anschutz P., Bejannin S., Beck A. (2019). Temporal variability of lagoon-sea water exchange and seawater circulation through a Mediterranean barrier beach. Limnology and Oceanography, 64 (5), 2059-2080. ISSN 0024-3590.
Titre du document
Temporal variability of lagoon-sea water exchange and seawater circulation through a Mediterranean barrier beach
Année de publication
2019
Auteurs
Tamborski J., Van Beek P., Rodellas V., Monnin C., Bergsma E., Stieglitz Thomas, Heilbrun C., Cochran J.K., Charbonnier C., Anschutz P., Bejannin S., Beck A.
Source
Limnology and Oceanography, 2019,
64 (5), 2059-2080 ISSN 0024-3590
The subterranean flow of water through sand barriers between coastal lagoons and the sea, driven by a positive hydraulic gradient, is a net new pathway for solute transfer to the sea. On the sea side of sand barriers, sea-water circulation in the swash-zone generates a flux of recycled and new solutes. The significance and temporal variability of these vectors to the French Mediterranean Sea is unknown, despite lagoons constituting ~ 50% of the coastline. A one-dimensional 224 Raex /223 Ra reactive-transport model was used to quantify water flow between a coastal lagoon (La Palme) and the sea over a 6-month period. Horizontal flow between the lagoon and sea decreased from ~ 85 cm d-1 during May 2017 (0.3 m 3 d-1 m-1 of shoreline) to ~ 20 cm d-1 in July and was negligible in the summer months thereafter due to a decreasing hydraulic gradient. Seawater circulation in the swash-zone varied from 10 to 52 cm d-1 (0.4-2.1 m3 d-1 m-1), driven by short-term changes in the prevailing wind and wave regimes. Both flow paths supply minor dissolved silica fluxes on the order of ~ 3-10 mmol Si d-1 m-1. Lagoon-sea water exchange supplies a net dissolved inorganic carbon (DIC) flux (320-1100 mmol C d-1 m-1) two orders of magnitude greater than seawater circulation and may impact coastal ocean acidification. The subterranean flow of water through sand barriers represents a significant source of new DIC, and potentially other solutes, to the Mediterranean Sea during high lagoon water-level periods and should be considered in seasonal element budgets.
Plan de classement
Limnologie / Océanographie : généralités [030]
Localisation
Fonds IRD [F B010088441]
Identifiant IRD
fdi:010088441
