Particulate biogenic barium tracer of mesopelagic carbon remineralization in the Mediterranean Sea (PEACETIME project)
<p>We report on the sub-basin variability in particulate organic carbon (POC) remineralization in the western and central Mediterranean Sea in late spring during the PEACETIME (ProcEss studies at the Air–sEa Interface after dust deposition in the MEditerranean sea) cruise. POC remineralization...
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| Autores principales: | , , , , , , , |
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| Formato: | article |
| Lenguaje: | EN |
| Publicado: |
Copernicus Publications
2021
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| Materias: | |
| Acceso en línea: | https://doaj.org/article/a7b86cf5453d46b5a37290edfd5ca8ba |
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| Sumario: | <p>We report on the sub-basin variability in particulate organic carbon (POC)
remineralization in the western and central Mediterranean Sea in late spring
during the PEACETIME (ProcEss studies at the
Air–sEa Interface after dust deposition in the MEditerranean sea) cruise. POC remineralization rates were estimated using
the excess biogenic particulate barium (Ba<span class="inline-formula"><sub>xs</sub></span>) inventories in the
mesopelagic layers (100–1000 m depth) and compared with prokaryotic
heterotrophic production (PHP). Ba<span class="inline-formula"><sub>xs</sub></span>-based mesopelagic remineralization
rates (MRs) ranged from <span class="inline-formula">25±2</span> to <span class="inline-formula">306±70</span> <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M5" display="inline" overflow="scroll" dspmath="mathml"><mrow class="unit"><mi mathvariant="normal">mg</mi><mspace width="0.125em" linebreak="nobreak"/><mi mathvariant="normal">C</mi><mspace linebreak="nobreak" width="0.125em"/><msup><mi mathvariant="normal">m</mi><mrow><mo>-</mo><mn mathvariant="normal">2</mn></mrow></msup><mspace linebreak="nobreak" width="0.125em"/><msup><mi mathvariant="normal">d</mi><mrow><mo>-</mo><mn mathvariant="normal">1</mn></mrow></msup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="65pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="4fefc29e267f9d3301a40e775f89bd80"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="bg-18-5891-2021-ie00001.svg" width="65pt" height="15pt" src="bg-18-5891-2021-ie00001.png"/></svg:svg></span></span>.
MRs were larger in the Algero-Provençal (ALG) Basin than in the
Tyrrhenian (TYR) and Ionian (ION) basins. Our Ba<span class="inline-formula"><sub>xs</sub></span> inventories and
integrated PHP data also indicated that significant mesopelagic
remineralization occurred down to 1000 m depth in the ALG Basin in contrast
to the ION and TYR basins, where remineralization was mainly located above
500 m depth. We propose that the higher and deeper MRs in the ALG
Basin were sustained by an additional particle export event driven by deep
convection. The TYR Basin (in contrast to the ALG and ION basins) presented
the impact of a previous dust event, as reflected by our particulate Al water
column concentrations. The ION and TYR basins showed small-scale
heterogeneity in remineralization processes, reflected by our Ba<span class="inline-formula"><sub>xs</sub></span>
inventories and integrated PHP data at the Tyrr long-duration station.
This heterogeneity was linked to the mosaic of blooming and non-blooming
patches reported in this area during the cruise. In contrast to the western
Mediterranean Sea (ALG Basin), the central Mediterranean Sea (ION and TYR
basins) showed lower remineralization rates restricted to the upper
mesopelagic layer during the late spring PEACETIME cruise.</p> |
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