Constructing a model including the cryptic sulfur cycle in Chesapeake Bay requires judicious choices for key processes and parameters.

A new biogeochemical model for Chesapeake Bay has been developed by merging two published models - the ECB model of Da et al. (2018) that has been calibrated for the Bay but only simulates nitrogen, carbon and oxygen and the BioRedoxCNPS model of al Azhar et al. (2014) and Hantsoo et al. (2018) that includes cryptic sulfur cycling. Comparison between these models shows that judicious choices are required for key processes and parameters. This manuscript documents the sources of differences between the two published models in order to select the most realistic configuration for our new model.•This study focuses on three sets of differences-processes only included in ECB (burial and dissolved organic matter), processes only included in BioRedoxCNPS (explicit dynamics for hydrogen sulfide, sulfate and nitrite, light attenuation that does not include CDOM or sediments), and differences in parameters common to the two codes.•Sensitivity studies that highlight particular choices (absorption by dissolved organic matter, nitrification rates, stoichiometric ratios) are also shown.•The new model includes sulfur cycling and has comparable skill in predicting oxygen as ECB, but also has improved simulation of nitrogen species compared with both original codes.

Upper Ocean Cooling in a Coupled Climate Model Due to Light Attenuation by Yellowing Materials.

Colored detrital matter consists of dissolved organic molecules and detrital materials that impart a yellow shift to the ocean's color. These materials reduce light penetration, concentrating heating by sunlight closer to the surface. We ran two climate model simulations: one of an ocean including colored detrital matter (Yellow Ocean) and one without (Green Ocean). Due to the decreased water clarity in the Yellow Ocean, upper ocean heat content was lower and temperatures were colder compared to the Green Ocean. The difference between these simulations is opposite to the ocean warming that has been observed in recent decades. Increasing precipitation in high-latitude regions has also been observed, with greater inputs of terrestrial organic materials to the ocean. We suggest that an increase in these yellowing materials behaves as a buffer that mitigates some effects of a warming climate. Future studies should investigate this link between the atmosphere, land, and ocean systems.

[Spatial heterogeneity of wind forcing: application to artificial reef functioning influenced by the circulation in the Bay of Marseilles, France]. / Hétérogénéité spatiale du forçage du vent: fonctionnement des récifs artificiels et circulation des eaux dans la baie sud de Marseille.

In the frame of the largest French project of artificial production reefs, initiated by the city of Marseilles in 2001, the present study aimed at describing the hydrodynamic pattern of the coastal area considered, by the use of a 3D numerical modelling. Results were local wind statistics, bottom current fields and drifting particle maps. The knowledge of the hydrodynamic connexions between particle (such as larvae) sources or targeted areas linked to the reefs, allows us to explain the success or failure of the reefs' colonizing. Moreover, the study confirms the wind spatial variability and demonstrates the error resulting from the use of an average but locally absent wind direction.