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Disentangling anthropogenic and natural causes for global coastal hypoxia

Periodic Reporting for period 1 - Coastal Hypoxia (Disentangling anthropogenic and natural causes for global coastal hypoxia)

Reporting period: 2015-06-01 to 2017-05-31

The current objective of the project are to explore the extent of hypoxia in the waters of the global shelf. I further seek to see what are the anthropogenic impacts (via socioeconomic activities) on oxygen dynamics in shelf systems. For this purposes I'm using data analysis and modelling techniques to sort through the ample geochemical, socioeconomical and environmental data available.
A reaction-transport model has been developed to track the fate of oxygen in marine sediments: This model has been published in January 2016 as:

Mewes, K., Mogollón, J.M. Picard, A., Rühlemann, C., Eisenhauer, A., Kuhn, T., Ziebis, W. & Kasten, S. (01.01.2016). Diffusive transfer of oxygen from seamount basaltic crust into overlying sediments: An example from the Clarion–Clipperton Fracture Zone. Earth and Planetary Science Letters, 433, (pp. 215-225).

A global nutrient model which couples integrated assessment models (those which link socioeconomic and natural systems) has been coupled to a nutrient stream retention model to track the fate of nitrogen and phosphorus in the global freshwater system. The description of this model, known as IMAGE-GNM (Integrated Model to Assess the Global Environment-Global Nutrient Model) was published in December of 2015 as:

Beusen, A.H.W. van Beek, L.P.H. Bouwman, Lex, Mogollon, J.M. & Middelburg, J.B.M. (21.12.2015). Coupling global models for hydrology and nutrient loading to simulate nitrogen and phosphorus retention in surface water – description of IMAGE–GNM and analysis of performance. Geoscientific model development, 8 (12), (pp. 4045-4067).
IMAGE-GNM has shown that intensifying anthropogenic activity over the 20th century including agriculture, water consumption, urbanization, and aquaculture, has almost doubled the global nitrogen and phosphorus delivery to streams and steadily increased the N:P ratio in freshwater bodies. Concurrently, the cumulative number of reservoirs has driven a rise in freshwater nutrient retention and removal. Still, river nutrient transport to the ocean has also nearly doubled potentially stressing coastal environments.
Global overview of coastal hypoxia