Thomsen, Soeren; Karstensen, Johannes; Kiko, Rainer; Krahmann, Gerd; Dengler, Marcus; Engel, Anja (2019): Remote and local drivers of oxygen and nitrate variability in the shallow oxygen minimum zone off Mauritania in June 2014. PANGAEA, https://doi.org/10.1594/PANGAEA.897940, Supplement to: Thomsen, S et al. (2019): Remote and local drivers of oxygen and nitrate variability in the shallow oxygen minimum zone off Mauritania in June 2014. Biogeosciences, 16(5), 979-998, https://doi.org/10.5194/bg-16-979-2019
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Upwelling systems play a key role in the global carbon and nitrogen cycles and are also of local relevance due to their high productivity and fish resources. To capture and understand the high spatial and temporal variability of physical and biogeochemical parameters found in these regions novel measurement technics have to be combined in an interdisciplinary manner. Here we use high-resolution glider-based physical-biogeochemical observations in combination with ship-based underwater vision profiler, sensor and bottle data to investigate the drivers of oxygen and nitrate variability across the shelf break off Mauritania in June 2014. Distinct oxygen and nitrate variability shows up in our glider data. High oxygen and low nitrate anomalies were clearly related to water mass variability and probably linked to ocean transport. Low oxygen and high nitrate patches co-occurred with enhanced turbidity signals close to the seabed, which suggests locally high microbial respiration of resuspended organic matter near the sea floor. This interpretation is supported by high particle abundance observed by the underwater vision profiler and enhanced particle-based respiration rate estimates close to the seabed. Discrete in-situ measurements of dissolved organic carbon and amino acids suggest the formation of dissolved organic carbon due to particle dissolution near the seabed fueling additional microbial respiration. Our high-resolution interdisciplinary observations highlight the complex interplay of remote and local physical-biogeochemical drivers of oxygen and nitrate variability off Mauritania, which cannot be captured by classical shipboard observations alone.
Kiko, Rainer; Hauss, Helena; Picheral, Marc; Stemmann, Lars (2018): Abundance of particles measured with an underwater vision profiler 5 (UVP5) during METEOR cruise M107. PANGAEA, https://doi.org/10.1594/PANGAEA.885759
Sommer, Stefan; Dengler, Marcus; Treude, Tina (2015): Benthic element cycling, fluxes and transport of solutes across the benthic boundary layer in the Mauritanian oxygen minimum zone, (SFB754) - Cruise No. M107 - May 30 - July 03, 2014 - Fortaleza (Brazil) - Las Palmas (Spain). METEOR-Berichte, DFG-Senatskommission für Ozeanographie, M107, 54 pp, https://doi.org/10.2312/cr_m107
German Science Foundation (DFG), grant/award no. 27542298: Climate - Biogeochemistry Interactions in the Tropical Ocean
Median Latitude: 16.291569 * Median Longitude: -11.239428 * South-bound Latitude: 11.454000 * West-bound Longitude: -22.998330 * North-bound Latitude: 19.900300 * East-bound Longitude: 22.998400
Date/Time Start: 2014-06-05T00:00:00 * Date/Time End: 2014-06-29T06:38:10
Datasets listed in this publication series
- Krahmann, G; Dengler, M; Thomsen, S (2017): Physical oceanography from glider mission IFM13_depl02. https://doi.org/10.1594/PANGAEA.877388
- Dengler, M; Thomsen, S; Krahmann, G (2019): ADCP current measurements (38 and 75 kHz) during METEOR cruise M107. https://doi.org/10.1594/PANGAEA.897534
- Engel, A (2018): Dissolved organic carbon and amino acids measured from water samples during METEOR cruise M107. https://doi.org/10.1594/PANGAEA.896321
- Sommer, S; Dengler, M (2018): Hydrochemistry of water samples during METEOR cruise M107. https://doi.org/10.1594/PANGAEA.885109
- Krahmann, G; Dengler, M; Thomsen, S (2016): Physical oceanography during METEOR cruise M107. https://doi.org/10.1594/PANGAEA.860480