Publication Date:
2019-07-17
Description:
Seasonal mesozooplankton community composition was studied monthly from
March to October 2007 in the high Arctic, Rijpfjorden (Svalbard), and related to
abiotic (hydrography, sea ice) and biotic (ice algae and phytoplankton biomass) environmental
conditions. The community was numerically dominated by the
cosmopolitan Oithona similis, whereas Arctic Calanus glacialis was the dominant
taxon in terms of biomass. Seasonal mesozooplankton community development
was largely influenced by the sea ice and hydrographic conditions, which impacted
the primary production regime in the fjord. Three distinct periods could be identified
based on species and life stages composition: (i) winter–spring transition
(March–June), with high ice algal biomass in April–June, characterized by peak
abundances of Pseudocalanus minutus, Calanus glacialis females and Clione limacina; (ii)
sea ice break-up and phytoplankton bloom (July), with high numbers of Calanus
nauplii and young copepodids, as well as larvae of benthic crustaceans such as
Cirripedia and Decapoda; and (iii) ice-free post-bloom period (August–October),
when the pulse of warm waters into the fjord resulted in development of a community
with Atlantic characteristics and peak abundances of Oithona similis, Oithona
atlantica, Limacina helicina and Echinodermata larvae within the upper 50 m. At the
same time, older copepodids of Calanus glacialis and Calanus finmarchicus had already
descended to overwintering depths (.100 m). Despite the 2–3 months delay in
the phytoplankton bloom compared with ice-free Svalbard fjords, the Rijpfjorden
mesozooplankton managed to fulfill their life cycles in a similar time, likely due to
the utilization of the ice algal bloom, and warmer water enhancing species growth
and development in late summer.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Article
,
isiRev
Format:
application/pdf
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