Publication Details

Category Text Publication
Reference Category Journals
DOI 10.1016/j.scitotenv.2023.164421
Licence creative commons licence
Title (Primary) Large-scale nutrient and carbon dynamics along the river-estuary-ocean continuum
Author Kamjunke, N.; Brix, H.; Flöser, G.; Bussmann, I.; Schütze, C.; Achterberg, E.P.; Ködel, U.; Fischer, P.; Rewrie, L.; Sanders, T.; Borchardt, D.; Weitere, M.
Journal Science of the Total Environment
Year 2023
Department ASAM; FLOEK; MET
Volume 890
Page From art. 164421
Language englisch
Topic T5 Future Landscapes
T4 Coastal System
Keywords river-ocean continuum; phytoplankton; nutrients; oxygen; pH; autotrophic; heterotrophic
Abstract Nutrient and carbon dynamics within the river-estuary-coastal water systems are key processes in understanding the flux of matter from the terrestrial environment to the ocean. Here, we analysed those dynamics by following a sampling approach based on the travel time of water and an advanced calculation of nutrient fluxes in the tidal part. We started with a nearly Lagrangian sampling of the river (River Elbe, Germany; 580 km within 8 days). After a subsequent investigation of the estuary, we followed the plume of the river by raster sampling the German Bight (North Sea) using three ships simultaneously. In the river, we detected intensive longitudinal growth of phytoplankton connected with high oxygen saturation and pH values and an undersaturation of CO2, whereas concentrations of dissolved nutrients declined. In the estuary, the Elbe shifted from an autotrophic to a heterotrophic system: Phytoplankton died off upstream of the salinity gradient, causing minima in oxygen saturation and pH, supersaturation of CO2, and a release of nutrients. In the shelf region, phytoplankton and nutrient concentrations were low, oxygen was close to saturation, and pH was within a typical marine range. Over all sections, oxygen saturation was positively related to pH and negatively to pCO2. Corresponding to the significant particulated nutrient flux via phytoplankton, flux rates of dissolved nutrients from river into estuary were low and determined by depleted concentrations. In contrast, fluxes from the estuary to the coastal waters were higher and the pattern was determined by tidal current. Overall, the approach is appropriate to better understand land-ocean fluxes, particularly to illuminate the importance of these fluxes under different seasonal and hydrological conditions, including flood and drought events.
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Kamjunke, N., Brix, H., Flöser, G., Bussmann, I., Schütze, C., Achterberg, E.P., Ködel, U., Fischer, P., Rewrie, L., Sanders, T., Borchardt, D., Weitere, M. (2023):
Large-scale nutrient and carbon dynamics along the river-estuary-ocean continuum
Sci. Total Environ. 890 , art. 164421