Publication Date:
2016-02-12
Description:
Marine ecosystems at high latitudes are characterized by extreme seasonal changes in light conditions, as
well as a limited period of high primary production during spring and early summer. As light returns at
the end of winter to Arctic ice-covered seas, a first algal bloom takes place in the bottom layer of the sea
ice. This bottom ice algae community develops through three distinct phases in the transition from winter
to spring, starting with phase I, a predominantly net heterotroph community that has limited interaction
with the pelagic or benthic realms. Phase II begins in the spring once light for photosynthesis
becomes available at the ice bottom, although interaction with the water column and benthos remains
limited. The transition to the final phase III is then mainly driven by a balance of atmospheric and oceanographic
forcing that induce structural changes in the sea ice and ultimately the removal of algal biomass
from the ice. Due to limited data availability an incomplete understanding exists of all the processes
determining ice algal bloom phenology and the considerable geographic differences in sympagic algal
standing stocks and primary production. We present here the first pan-Arctic compilation of available
time-series data on vernal sea ice algal bloom development and identify the most important factors controlling
its development and termination. Using data from the area surrounding Resolute Bay (Nunavut,
Canada) as an example, we support previous investigations that snow cover on top of the ice influences
sea ice algal phenology, with highest biomass development, but also earliest termination of blooms,
under low snow cover. We also provide a pan-Arctic overview of sea ice algae standing stocks and primary
production, and discuss the pertinent processes behind the geographic differences we observed.
Finally, we assess potential future changes in vernal algal bloom phenology as a consequence of climate
change, including their importance to different groups of grazers.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Article
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isiRev
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