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| Picoplankton are an ecologically important
component of pelagic Arctic marine ecosystems that may
be heavily impacted by climate change. In order to assess
potential impacts of a changing environment on this group,
it is necessary to develop a better understanding of their
population dynamics and seasonal distribution. This study,
carried out in Disko Bay, West Greenland, during spring
2012, demonstrates that fuco-algae (e.g. chrysophytes,
cryptophytes, diatoms and pelagophytes) dominated the
picophytoplankton during the spring bloom with minor
contributions from haptophytes. In the post-bloom phase,
fuco-algae were replaced by haptophytes. In contrast to
total chlorophyll a, which varied dramatically over the
study period, the picoplanktonic chlorophyll a remained
relatively stable despite the variability in picophytoplankton
community composition. Based on mostly molecular
studies, a general picture has emerged from the literature
that mamiellophytes (a group within the green algae)
dominate Arctic picophytoplankton. Here, however, green
algae were found to contribute with only about 10 % of the
picoplanktonic chlorophyll a. We suggest here that differences
in cell size may offer a plausible explanation for
the contrast between results obtained from molecular
studies and those obtained from pigment- and microscopybased
studies. | |
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