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| Titel |
Short-term changes in the mesozooplankton community and copepod gut pigment in the Chukchi Sea in autumn: reflections of a strong wind event |
| VerfasserIn |
K. Matsuno, A. Yamaguchi, S. Nishino, J. Inoue, T. Kikuchi |
| 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. 13 ; Nr. 12, no. 13 (2015-07-03), S.4005-4015 |
| Datensatznummer |
250118009
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| Publikation (Nr.) |
 copernicus.org/bg-12-4005-2015.pdf |
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| Zusammenfassung |
| To evaluate the effect of atmospheric turbulence on a marine ecosystem,
high-frequency samplings (two to four times per day) of a mesozooplankton
community and the gut pigment of dominant copepods were performed at a fixed
station in the Chukchi Sea from 10 to 25 September 2013. During the study
period, a strong wind event (SWE) was observed on 18 September. After the
SWE, the biomass of chlorophyll a (Chl a) increased, especially for
micro-size (> 10 μm) fractions. The zooplankton abundance ranged
from 23 610 to 56 809 ind. m−2 and exhibited no clear changes as a
result of the SWE. In terms of abundance, calanoid copepods constituted the
dominant taxa (mean: 57 %), followed by barnacle larvae (31 %).
Within the calanoid copepods, small-sized Pseudocalanus spp.
(65 %) and large-sized C. glacialis (30 %) dominated.
In the population structure of C. glacialis, copepodid stage 5 (C5)
dominated, and the mean copepodid stage did not vary with the SWE. The
dominance of accumulated lipids in C5 and C6 females with immature gonads
indicated that they were preparing for seasonal diapause. The gut pigment of
C. glacialis C5 was higher at night and was correlated with ambient
Chl a (Chl a, and a significant increase was observed after the SWE (2.6 vs. 4.5 ng pigment ind.−1). The grazing impact by C. glacialis C5 was
estimated to be 4.14 mg C m−2 day−1, which corresponded to
0.5−4.6 % of the biomass of the micro-size phytoplankton. Compared with
the metabolic food requirement, C. glacialis feeding on
phytoplankton accounted for 12.6 % of their total food requirement. These
facts suggest that C. glacialis could not maintain their population
by feeding solely on phytoplankton and that other food sources (i.e.,
microzooplankton) must be important in autumn. As observed by the increase in
gut pigment, the temporal phytoplankton bloom, which is enhanced by the
atmospheric turbulence (SWE) in autumn, may have a positive effect on copepod
nutrition. |
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