Map of German Bight, Elbe estuary, Wadden Sea and the continental regions around them. Stations are indicated with different symbols: Neu Darchau discharge gauging station (magenta square), operated by the German Federal Waterways and Shipping Administration (WSV); HPA pile (black square), operated by Bundesamt für Seeschifffahrt und Hydrographie (BSH) and Helmholtz Zentrum Geesthacht (HZG); Cuxhaven FerryBox (FB, blue square), operated by HZG; M/V Funny Girl FB transect (blue line) between Büsum and Helgoland, operated by HZG; BSH discrete sampling stations (grey circles); Biological Station Helgoland at the Alfred Wegener Institute (BAH AWI) discrete sampling stations (red triangles); Deutsche Bucht MARNET monitoring station, operated by BSH (cyan square).start
Salinity changes in the German Bight persisted for about two months after the peak discharge. The Elbe flood generated a large influx of nutrients and dissolved and particulate organic carbon on the coast. These conditions subsequently led to the onset of a phytoplankton bloom, observed by dissolved oxygen supersaturation, and higher than usual pH in surface coastal waters. The prolonged stratification also led to widespread bottom water dissolved oxygen depletion, unusual for the southeastern German Bight in the summer.start
Hourly measurements of temperature, salinity, DO (% saturation), pH, chlorophyll (fluorescence) and turbidity (F/NTU), measured at Cuxhaven (725 river km, black line) and HPA pile (710 river km, gray line) in the Elbe estuary, for 2012 (left panels) and 2013 (right panels). As a reference, the Elbe discharge (m3 s-1 at Neu Darchau station (thick black line), scaled by dividing it by 100, is included in the temperature plots.
PH ferry data between Büsum and Helgoland for each summer between 2008 and 2014. There were two pH probes available on the ferry M/V Funny Girl. The white sections represent times when data were not available.
Schematic representation of processes during the 2013 Elbe river flood: (1) Rain saturated soils: (May-June); (2) Extreme Elbe discharge (June); (3) Large freshwater influx, high nutrients, DOC & POC from Elbe River and onto the German Bight (June-July); (4) 2-month stratification; high primary production in surface; widespread DO depletion in bottom waters.
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