Land-to-sea Fluxes of N and P in the Mediterranean: A North-South Asymmetry
Abstract
Global water resources have deeply changed in the past century, and large changes are expected to occur in the near future as a consequence of human activities and global warming. The water cycle is tightly intertwined with the biogeochemical cycles of major elements -including carbon (C), nitrogen (N) or phosphorus (P)- so that changes in water resources may affect the fluxes and stocks of these elements in terrestrial and aquatic systems. Likewise, population growth and dietary change are placing unprecedented demands on food production, leading to increasing inputs of N and P worldwide.
The Mediterranean Basin houses 60% of the population of the world's water poor countries, and large divergences in the socio-economic development exist between the north and the south, including differences in water use and agricultural practices. This north-south asymmetry makes it a unique region to address the links between water and nutrient-related issues. Our study combines data on river discharge for over 500 Mediterranean rivers with data on the terrestrial inputs of N and P from the IMAGE model (5' x 5' spatial resolution) to assess what are the main nutrient fluxes in the different regions and what is the fraction of the total inputs that is exported to the sea. We use river basins as working units: basins are convenient geographical units in terms of management, because they often count on water agencies responsible for the application of regulatory practices. The study addresses differences between nitrogen and phosphorus fluxes in the north and the south, and examines to what extent nutrients' export to the coast and retention on land are modified by water management practices. A key feature of the study is the description of nutrient fluxes in southern Mediterranean basins, which have hitherto been poorly characterized.- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMGC22B..03P
- Keywords:
-
- 0402 Agricultural systems;
- BIOGEOSCIENCESDE: 0470 Nutrients and nutrient cycling;
- BIOGEOSCIENCESDE: 1615 Biogeochemical cycles;
- processes;
- and modeling;
- GLOBAL CHANGEDE: 1630 Impacts of global change;
- GLOBAL CHANGE