Assessing seasonal flow dynamics at a lagoon saltwater–freshwater interface using a dual tracer approach

Publikation: Bidrag til tidsskrift/Konferencebidrag i tidsskrift /Bidrag til avisTidsskriftartikelForskningpeer review

Dokumenter

DOI

  • S. Müller, Københavns Universitet
  • ,
  • S. Jessen, Københavns Universitet
  • ,
  • C. Duque
  • Sebök, Københavns Universitet
  • ,
  • B. Neilson, Utah State University
  • ,
  • P. Engesgaard, Københavns Universitet

Study region: Eastern shore of Ringkøbing Fjord, a coastal lagoon at the west coast of Denmark Study focus: A dual tracer approach based on salinity and δ18O is used to assess seasonal dynamics at the saltwater-freshwater interface of a coastal lagoon. At the site, salinity is prone to vary on a sub-seasonal or daily frequency due to riverine freshwater inputs to the lagoon. In contrast, δ18O compositions of end-members only vary seasonally. New hydrological insights: The dual tracer approach shows to be valuable in coastal settings where end-member concentrations vary substantially over the seasons and hence, an unambiguous end-member definition does not exist. Calculated mixing fractions using only salinity, deviated from the dual tracer approach on average by 18%, but were as high as 97%. Although, these differences decrease to 6% on average when using only δ18O, our study strongly suggests their simultaneous application. Moreover, we found that seawater intrusion occurs during the summer when salinity in the lagoon is high and fresh submarine groundwater discharge (SGD) is low. This process reverses during the winter (wet season) when SGD increases by a factor of 2–3, due to the recession of the saltwater wedge from land. Our findings show that in absence of waves and tides, density-driven dynamics, and particularly the terrestrial freshwater fluxes, create a major impact on saltwater wedge dynamics.

OriginalsprogEngelsk
TidsskriftJournal of Hydrology: Regional Studies
Vol/bind17
Sider (fra-til)24-35
Antal sider12
ISSN2214-5818
DOI
StatusUdgivet - 1 jun. 2018

Se relationer på Aarhus Universitet Citationsformater

Download-statistik

Ingen data tilgængelig

ID: 126777725