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Titel |
A simple optical index shows spatial and temporal heterogeneity in phytoplankton community composition during the 2008 North Atlantic Bloom Experiment |
VerfasserIn |
I. Cetinić, M. J. Perry, E. D'Asaro, N. Briggs, N. Poulton, M. E. Sieracki, C. M. Lee |
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 ; 12, no. 7 ; Nr. 12, no. 7 (2015-04-14), S.2179-2194 |
Datensatznummer |
250117895
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Publikation (Nr.) |
copernicus.org/bg-12-2179-2015.pdf |
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Zusammenfassung |
The ratio of two in situ optical measurements – chlorophyll fluorescence
(Chl F) and optical particulate backscattering (bbp) – varied
with changes in phytoplankton community composition during the North Atlantic
Bloom Experiment in the Iceland Basin in 2008. Using ship-based measurements
of Chl F, bbp, chlorophyll a (Chl), high-performance liquid chromatography (HPLC) pigments,
phytoplankton composition and carbon biomass, we found that oscillations in
the ratio varied with changes in plankton community composition; hence we
refer to Chl F/bbp as an "optical community index". The index
varied by more than a factor of 2, with low values associated with pico-
and nanophytoplankton and high values associated with diatom-dominated
phytoplankton communities. Observed changes in the optical index were driven by
taxa-specific chlorophyll-to-autotrophic carbon ratios and by physiological
changes in Chl F associated with the silica limitation. A Lagrangian mixed-layer
float and four Seagliders, operating continuously for 2 months, made
similar measurements of the optical community index and followed the
evolution and later demise of the diatom spring bloom. Temporal changes in
optical community index and, by implication, the transition in community
composition from diatom to post-diatom bloom communities were not
simultaneous over the spatial domain surveyed by the ship, float and gliders.
The ratio of simple optical properties measured from autonomous platforms,
when carefully validated, provides a unique tool for studying phytoplankton
patchiness on extended temporal scales and ecologically relevant spatial
scales and should offer new insights into the processes regulating
patchiness. |
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