Supplementary material to "Extreme Flood Impact on Estuarine and Coastal Biogeochemistry: the 2013 Elbe Flood"

Abstract

Fig. S1. Correction of pH data measured at HPA Pile in the Elbe Estuary. Original hourly pH (black) was plotted along with a moving average (red line), and the corrected pH (blue), obtained by subtracting the moving average from the original dataset, and then adding the average of the first 1000 samples, where drift is minimal.

Intertidal regions changing coastal alkalinity: The Wadden Sea‐North Sea tidally coupled bioreactor

“…Since the North Sea coastal waters have lower DOC concentrations, we can expect that the error in TA measurements associated with organic TA is small (< 30 μ mol kg −1 ), and cannot account for the larger fluctuations discussed in this article. Moreover, CDOM, when used as a qualitative proxy for DOC variability, varied as a function of salinity (Voynova et al ) (Supporting Information Fig. S6a).…”

“…Two major rivers, the Elbe and the Rhine, should be considered when verifying this. The Elbe, which discharges to the German Bight near Cuxhaven and influences coastal biogeochemistry (Hickel et al ; Brockmann et al ; Voynova et al ), has an estimated TA of 2231 μ mol kg −1 (Pätsch and Lenhart ). This is lower than the TA concentrations in the adjacent coastal region (Fig.…”

“…The Elbe could contribute to TA generation on the coast, since the major form of nitrogen in the estuary is nitrate, and its concentrations can vary seasonally by up to 200 μ mol kg −1 (Schwichtenberg ). Major floods can be even more significant: after the 2013 Elbe flood, nitrate loading from the Elbe River increased up to 10‐fold (Voynova et al ).…”