Modelling mass accumulation rates and 210Pb rain rates in the Skagerrak: lateral sediment transport dominates the sediment input.

Spiegel, T., Diesing, M., Dale, A.W., Lenz, N., Schmidt, M., Sommer, S., Böttner, C., Fuhr, M., Kalapurakkal, H.T., Schulze, C.-S., Wallmann, K., 2014, Frontiers in Marine Science.

In this study, we present spatial distributions of porosity, mass accumulation rates and 210Pb rain rates in the Skagerrak based on machine learning. Total mass accumulation rates in the Skagerrak yield 35 Mt yr-1, which is 40 - 80% of the total suspended sediment input into the North Sea. For APOC, the information on mass accumulation rates can be used to validate large-scale particle transport models that include the effect of natural and human processes in the North Sea. Furthermore, 210Pb rain rates can be used as a tool to differentiate between locally produced and laterally transported sediment inputs into the Skagerrak, which helps completing the picture of sediment cycling in the Skagerrak and North Sea.

Biogenic silica cycling in the Skagerrak

Spiegel, T., Dale, A.W., Lenz, N., Schmidt, M., Sommer, S., Kalapurakkal, H.T., Przibilla, A., Lindhorst, S., Wallmann, K., 2023, Frontiers in Marine Science.

Biogenic silica cycling in the Skagerrak is described in detail based on solid phase, pore water and in-situ benthic flux measurements. The results show that 1100 mmol m-2 yr-1 are annually settling onto the Skagerrak seafloor. Approximately 50% of the biogenic silica is recycled in the sediment and is released back to the water column as a benthic flux. The other half is permanently buried in the sediment. The biogenic silica flux to the seafloor determined in this study can be used as a tracer to quantify the proportion of organic carbon that derives from local primary production. For APOC, the differentiation between locally produced and laterally transported organic carbon into the Skagerrak is an important step towards a better understanding of the organic carbon cycle and transport in the Skagerrak and the North Sea.

Assessing global-scale organic matter reactivity patterns in marine sediments using a lognormal reactive continuum model

Xu, S., Liu, B., Arndt, S., Kasten, S., Wu, Z, 2023, Biogeosciences.

Organic matter (OM) degradation in marine sediments is largely controlled by its reactivity and profoundly affects the global carbon cycle. This study proposes a new framework that allows predicting OM reactivity in data-poor areas based on readily available (or more easily obtainable) information.

Temporal evolution of shallow marine diagenetic environments: Insights from carbonate concretions

Loyd, S.J., Meister, P., Liu, B., Nichols, K., Corsetti, F.A., Raiswell, R., Berelson, W., Shields, G., Hounslow, M., Waldron, J.W., Westrick-Snapp, B., Hoffman, J., 2023, Geochimica et Cosmochimica Acta.

Early diagenesis of marine organic matter dramatically affects Earth’s surface chemistry by changing the burial potential of carbon and promoting the formation of authigenic mineral phases including carbonate concretions. The isotope record of the latter in part reflects changes in organic matter availability and marine oxidation state, highlighting connections with the subsurface biosphere and diagenesis throughout geologic time.

A first estimate of the effect of offshore wind farms on sedimentary organic carbon stocks in the Southern North Sea

Heinatz, K., Scheffold, M. I. E., 2023, Frontiers in Marine Science.

Our study provides a first estimate of the net effect of offshore wind farms (OWFs) on organic carbon (OC) in surrounding sediments, considering the entire life cycle of OWFs (construction, operation and decommissioning phases). For this purpose, we balanced the increased OC flux to the sediment due to colonisation of new organisms at wind turbine foundations during the operation phase and the OC loss due to sediment-altering activities during construction and decommissioning. The balance showed that over the lifetime of the OWFs, about 4.6 ± 1.4 times more carbon is fixed in the sediment of the OWFs than is released.

Natural and anthropogenic influences on the development of mud depocenters in the southwestern Baltic Sea

Porz, L., Zhang, W., Schrum, C., 2022, Oceanologia.

The influence of bottom trawling on sediment resuspension in the Baltic Sea was investigated using a numerical ocean model. The results show that bottom trawling significantly increases sediment balance and transport compared to the natural state. For APOC, the model development resulting from the study is an important and necessary step to quantify the impact of bottom trawling on fluxes of particulate organic carbon in the North Sea.

Quantifying Importance of Macrobenthos for Benthic-Pelagic Coupling in a Temperate Coastal Shelf Sea

Zhang, W., Neumann, A., Daewel, U., Wirtz, K., van Beusekom, J. E. E., Eisele, A., Ma, M., Schrum, C., 2021, Journal of Geophysical Research: Oceans.

Quantifying the driving mechanisms behind the distinct annual cycle of benthic oxygen fluxes in the German Bight. A novel benthic-pelagic coupled 3D model reconstructs benthic states considering the interactions between macrobenthos, bioturbation, oxygen consumption and early carbon diagenesis.