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| Le Moigne, F. A. C.; Gallinari, Morgane; Laurenceau, E.; De La Rocha, C. L.. |
| To examine the potentially competing influences of microzooplankton and calcite mineral ballast on organic matter remineralization, we incubated diatoms in darkness in rolling tanks with and without added calcite minerals (coccoliths) and microzooplankton (rotifers). Concentrations of particulate organic matter (POM in suspension or in aggregates), of dissolved organic matter (DOM), and of dissolved inorganic nutrients were monitored over 8 days. The presence of rotifers enhanced the remineralization of ammonium and phosphate, but not dissolved silicon, from the biogenic particulate matter, up to 40% of which became incorporated into aggregates early in the experiment. Added calcite resulted in rates of excretion of ammonium and phosphate by rotifers that... |
| Tipo: Text |
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| Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00157/26836/24957.pdf |
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| Joubert, W. R.; Thomalla, S. J.; Waldron, H. N.; Lucas, M. I.; Boye, M.; Le Moigne, F. A. C.; Planchon, F.; Speich, Sabrina. |
| As part of the Bonus-GoodHope (BGH) campaign, (15)N-labelled nitrate, ammonium and urea uptake measurements were made along the BGH transect from Cape Town to similar to 60 degrees S in late austral summer, 2008. Our results are categorised according to distinct hydrographic regions defined by oceanic fronts and open ocean zones. High regenerated nitrate uptake rate in the oligotrophic Subtropical Zone (STZ) resulted in low f-ratios (f = 0.2) with nitrogen uptake being dominated by rho urea, which contributed up to 70% of total nitrogen uptake. Size fractionated chlorophyll data showed that the greatest contribution (>50 %) of picophytoplankton (<2 mu m) were found in the STZ, consistent with a community based on regenerated production. The... |
| Tipo: Text |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00054/16563/14075.pdf |
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| Le Moigne, F. A. C.; Boye, Marie; Masson, A.; Corvaisier, Rudolph; Grossteffan, E.; Gueneugues, A.; Pondaven, Philippe. |
| Meridional and vertical distributions of several biogeochemical parameters were studied along a section in the southeastern Atlantic and the Southern Ocean south of South Africa during the austral summer 2008 of the International Polar Year to characterize the biogeochemical provinces and to assess the seasonal net diatom production. Based on analyses of macro-nutrients, ammonium (NH4), chlorophyll a, (Chl a), phaeopigments, biogenic silica (BSi), particulate inorganic carbon (PIC), and particulate organic carbon and nitrogen (POC and PON, respectively), four biogeochemical domains were distinguished along the section: the subtropical Atlantic, the confluence zone of the subtropical and subantarctic domains, the Polar Frontal Zone (PFZ) in the Antarctic... |
| Tipo: Text |
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| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00181/29207/27577.pdf |
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