Modulation of the North Atlantic Deoxygenation by The Slowdown of the Nutrient Stream
Western boundary currents act as transport pathways for nutrient-rich waters from low to high latitudes (nutrient streams) and are responsible for maintaining mid- and high-latitude productivity in the North Atlantic and North Pacific. This study investigates the centennial oxygen (O 2 ) and nutrien...
| Main Authors: | , , |
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| Format: | Text |
| Language: | English |
| Published: |
2019
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| Subjects: | |
| Online Access: | https://doi.org/10.5194/bg-2019-187 https://www.biogeosciences-discuss.net/bg-2019-187/ |
| Summary: | Western boundary currents act as transport pathways for nutrient-rich waters from low to high latitudes (nutrient streams) and are responsible for maintaining mid- and high-latitude productivity in the North Atlantic and North Pacific. This study investigates the centennial oxygen (O 2 ) and nutrient changes over the Northern Hemisphere in the context of the projected warming and general weakening of the Atlantic Meridional Overturning Circulation (AMOC) in a subset of Earth System Models included in the CMIP5 catalogue. In all models examined, the Atlantic warms faster than the Pacific Ocean, resulting in a greater basin-scale solubility decrease. However, this thermodynamic tendency is compensated by the changes in the biologically-driven O 2 consumption which dominates the overall O 2 budget. These changes are linked to the slow-down of the nutrient stream in this basin, in response to the AMOC weakening. The North Atlantic resists the warming-induced deoxygenation due to the weakened biological carbon export and remineralization, leading to higher O 2 levels. On the contrary, the projected nutrient stream and macro-nutrient inventory in the North Pacific remain nearly unchanged. |
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