Callies, U., Kreus, M., Petersen, W., & Voynova, Y.G. (2021): On Using Lagrangian Drift Simulations to Aid Interpretation of in situ Monitoring Data. Front. Mar. Sci., Vol 8, 2021, p 769, doi:10.3389/fmars.2021.666653
One key challenge of marine monitoring programs is to reasonably combine information from different in situ observations spread in space and time. In that context, we suggest the use of Lagrangian transport simulations extending both forward and backward in time to identify the movements of water bodies from the time they were observed to the time of their synopsis. We present examples of how synoptic maps of salinity generated by this method support the identification and tracing of river plumes in coastal regions. We also demonstrate how we can use synoptic maps to delineate different water masses in coastal margins. These examples involve quasi-continuous observations of salinity taken along ferry routes. A third application is the synchronization of measurements between fixed stations and nearby moving platforms. Both observational platforms often see the same water body, but at different times. We demonstrate how the measurements from a fixed platform can be synchronized to measurements from a moving platform by taking into account simulation-based time shifts.
Birchill, A.J., Beaton, A.D., Hull, T., Kaiser, J., Mowlem, M., Pascal, R., Schaap, A., Voynova, Y.G., Williams, C., & Palmer, M. (2021): Exploring Ocean Biogeochemistry Using a Lab-on-Chip Phosphate Analyser on an Underwater Glider. Front. Mar. Sci., 8:698102, doi:10.3389/fmars.2021.698102
The ability to make measurements of phosphate (PO43–) concentrations at temporal and spatial scales beyond those offered by shipboard observations offers new opportunities for investigations of the marine phosphorus cycle. We here report the first in situ PO43– dataset from an underwater glider (Kongsberg Seaglider) equipped with a PO43– Lab-on-Chip (LoC) analyser. Over 44 days, a 120 km transect was conducted in the northern North Sea during late summer (August and September). Surface depletion of PO43– (<0.2 μM) was observed above a seasonal thermocline, with elevated, but variable concentrations within the bottom layer (0.30–0.65 μM). Part of the variability in the bottom layer is attributed to the regional circulation and across shelf exchange, with the highest PO43– concentrations being associated with elevated salinities in northernmost regions, consistent with nutrient rich North Atlantic water intruding onto the shelf. Our study represents a significant step forward in autonomous underwater vehicle sensor capabilities and presents new capability to extend research into the marine phosphorous cycle and, when combined with other recent LoC developments, nutrient stoichiometry.
Macovei, V.A., Voynova, Y.G., Gehrung, M., & Petersen, W. (2021): Ship-of-Opportunity, FerryBox-integrated, membrane-based sensor pCO2, temperature and salinity measurements in the surface North Sea since 2013. PANGAEA, doi:10.1594/PANGAEA.930383
The submitted datasets contain surface seawater partial pressure of carbon dioxide (pCO2) values measured with Kongsberg Contros/4H-Jena HydroC-FT membrane-based sensors. These sensors were integrated on the FerryBoxes installed on commercial vessels travelling in the North Sea and maintained by the Institute of Coastal Ocean Dynamics at the Helmholtz-Zentrum Hereon, Germany. The pCO2 data were reprocessed from the raw data and corrected for sensor post-calibration where this was available. The instrument produces a result every second. 20-second averages are used for calculations and reported. Temperature and salinity results are also provided where available. These were measured from the underway with Falmouth Scientific Instruments / Teledyne Instruments sensors also integrated with the FerryBox. The sensors were regularly maintained and occasionally replaced. Each sensor replacement results in a new dataset within this publication series. The files are named using the ship name and date of the first measurement.