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| Titel |
Springtime phytoplankton dynamics in Arctic Krossfjorden and Kongsfjorden (Spitsbergen) as a function of glacier proximity |
| VerfasserIn |
A. M.-T. Piquet, W. H. van de Poll, R. J. W. Visser, C. Wiencke, H. Bolhuis, A. G. J. Buma |
| 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 ; 11, no. 8 ; Nr. 11, no. 8 (2014-04-23), S.2263-2279 |
| Datensatznummer |
250117373
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| Publikation (Nr.) |
 copernicus.org/bg-11-2263-2014.pdf |
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| Zusammenfassung |
| The hydrographic properties of the Kongsfjorden–Krossfjorden system
(79° N, Spitsbergen) are affected by Atlantic water incursions as
well as glacier meltwater runoff. This results in strong physical gradients
(temperature, salinity and irradiance) within the fjords. Here, we tested
the hypothesis that glaciers affect phytoplankton dynamics as early as the
productive spring bloom period. During two campaigns in 2007 (late spring)
and 2008 (early spring) we studied hydrographic characteristics and
phytoplankton variability along two transects in both fjords, using
high-performance liquid chromatography (HPLC)-CHEMTAX pigment fingerprinting, molecular fingerprinting
(denaturing gradient gel electrophoresis, or DGGE) and
sequencing of 18S rRNA genes. The sheltered inner fjord locations remained
colder during spring as opposed to the outer locations. Vertical light
attenuation coefficients increased from early spring onwards, at all
locations, but in particular at the inner locations. In late spring
meltwater input caused stratification of surface waters in both fjords. The
inner fjord locations were characterized by overall lower phytoplankton
biomass. Furthermore HPLC-CHEMTAX data revealed that diatoms and
Phaeocystis sp. were replaced by small nano- and picophytoplankton during late spring,
coinciding with low nutrient availability. The innermost stations showed
higher relative abundances of nano- and picophytoplankton throughout,
notably of cyanophytes and cryptophytes. Molecular fingerprinting revealed a
high similarity between inner fjord samples from early spring and late
spring samples from all locations, while outer samples from early spring
clustered separately. We conclude that glacier influence, mediated by early
meltwater input, modifies phytoplankton biomass and composition already
during the spring bloom period, in favor of low biomass and small cell size
communities. This may affect higher trophic levels especially when regional
warming further increases the period and volume of meltwater. |
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