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Titel |
Estimates of micro-, nano-, and picoplankton contributions to particle export in the northeast Pacific |
VerfasserIn |
B. L. Mackinson, S. B. Moran, M. W. Lomas, G. M. Stewart, R. P. Kelly |
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. 11 ; Nr. 12, no. 11 (2015-06-05), S.3429-3446 |
Datensatznummer |
250117970
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Publikation (Nr.) |
copernicus.org/bg-12-3429-2015.pdf |
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Zusammenfassung |
The contributions of micro-, nano-, and picoplankton to particle export were
estimated from measurements of size-fractionated particulate 234Th,
organic carbon, and phytoplankton indicator pigments obtained during five
cruises between 2010 and 2012 along Line P in the subarctic northeast Pacific
Ocean. Sinking fluxes of particulate organic carbon (POC) and indicator
pigments were calculated from 234Th–238U disequilibria and, during
two cruises, measured by a sediment trap at Ocean Station Papa. POC fluxes at
100 m ranged from 0.65 to 7.95 mmol m−2 d−1, similar in magnitude
to previous results at Line P. Microplankton pigments dominate indicator
pigment fluxes (averaging 69 ± 19% of total pigment flux), while
nanoplankton pigments comprised the majority of pigment standing stocks
(averaging 64 ± 23% of total pigment standing stocks). Indicator
pigment loss rates (the ratio of pigment export flux to pigment standing
stocks) point to preferential export of larger microplankton relative to
smaller nano- and picoplankton. However, indicator pigments do not
quantitatively trace particle export resulting from zooplankton grazing,
which may be an important pathway for the export of small phytoplankton.
These results have important implications for understanding the magnitude and
mechanisms controlling the biological pump at Line P in particular, and more
generally in oligotrophic gyres and high-nutrient, low-chlorophyll (HNLC) regions
where small phytoplankton represent a major component of the autotrophic
community. |
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