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| Titel |
A comparison of biogenic iron quotas during a diatom spring bloom using multiple approaches |
| VerfasserIn |
A. L. King, S. A. Sañudo-Wilhelmy, P. W. Boyd, B. S. Twining, S. W. Wilhelm, C. Breene, M. J. Ellwood, D. A. Hutchins |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 9, no. 2 ; Nr. 9, no. 2 (2012-02-03), S.667-687 |
| Datensatznummer |
250006759
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| Publikation (Nr.) |
 copernicus.org/bg-9-667-2012.pdf |
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| Zusammenfassung |
| Biogenic Fe quotas were determined using three distinct techniques on
samples collected concurrently in the subtropical Pacific Ocean east of New
Zealand. Fe quotas were measured using radioisotope uptake experiments (24 h
incubation), bulk filtration and analysis by inductively-coupled plasma mass
spectrometer (ICPMS), and single-cell synchrotron x-ray fluorescence (SXRF)
analysis over a sixteen-day period (year days 263 to 278 of 2008) during a
quasi-Lagrangian drifter experiment that tracked the evolution of the annual
spring diatom bloom within a counter-clockwise open-ocean eddy. Overall,
radioisotope uptake-determined Fe quotas (washed with oxalate reagent to
remove extracellular Fe) were the lowest (0.5–1.0 mmol Fe:mol P;
4–8 μmol Fe:mol C), followed by single-cell Fe quotas (2.3–7.5 mmol Fe:mol P;
17–57 μmol Fe:mol C), and the highest and most variable quotas were
from the bulk filtration ICPMS approach that used the oxalate reagent wash,
corrected for lithogenic Fe using Al (0.8–21 mmol Fe:mol P; 4–136 μmol Fe:mol C). During the evolution of the spring bloom within the eddy (year
days 263 to 272), the surface mixed layer inventories of particulate
biogenic elements (C, N, P, Si) and chlorophyll increased while Fe quotas
estimated from all three approaches exhibited a general decline. After the
onset of the bloom decline, the drogued buoys exited the eddy center (days
273 to 277). Fe quotas returned to pre-bloom values during this part of the
study. Our standardized and coordinated sampling protocols reveal the
general observed trend in Fe quotas: ICPMS > SXRF > radioisotope uptake.
We discuss the inherent differences between the techniques and argue that
each technique has its individual merits and uniquely contributes to the
characterization of the oceanic particulate Fe pool. |
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