A new perspective on changing Arctic marine ecosystems: panarchy adaptive cycles in pan-Arctic spatial and temporal scales - Ocean Sustainability in the 21st Century - page 174

reduced alkalinity associated with sea ice melt, and increased upwelling of deeper and less
CaCO 3 -saturated water (Yamamoto-Kawai et al ., 2009 , 2011 ; Mathis et al ., 2011 ) .
The next spatio-temporal scale (Domain 3 in Figure 5.3 , Table 5.1 ) to consider is
that of mesoscale (of order 10-20 km) oceanographic processes and forcings that exist on
seasonal and sub-seasonal time-scales and which, collectively, differ between the shallow
shelf and deep basin domains. Mechanisms such as wind and topographically driven up-
welling, tidal mixing through passages or over topography, and frontal zone convergence
can act to first supply nutrients of phytoplankton growth and then produce aggregations of
zooplankton to facilitate foraging by predators (Carmack and Chapman, 2003 ; Rogachev et
al ., 2008 ; Hannah et al ., 2009 ). For example, the ice edge where light meets nutrient-rich
stratified waters in spring and early summer can be a highly productive zone, allowing for
highly efficient grazing and/or enhanced vertical export, thus fuelling both pelagic and/or
benthic food webs (e.g. Reigstad et al ., 2011 ) .
The scales of these physical mechanisms thus impose temporal and spatial foraging
scales for biota across a highly heterogeneous, though patterned, landscape. Ice edge
blooms will remain a feature and may develop over the entire Arctic Ocean, but their re-
lative importance will depend on the locally available supply of nutrients and on grazing
intensity. The bloom is likely to occur earlier than it has in the past decade as ice is thinner
and retreats more quickly, and incident light reaches the water column sooner (as noted
in Loeng et al ., 2005 ). Melt ponds on multi-year ice floes that form sooner and freeze
later will also alter the underwater light climate. Consequently, extensive under-ice pelagic
blooms will become more common (Arrigo et al ., 2012 ; Mundy et al ., 2013 ). There will
be, however, regional variability, depending on snow cover. The timing of ice-associated
versus pelagic algal blooms relative to each other will potentially change under such condi-
tions,decreasingthetimelagbetweenthetwobloomevents(Ji et al ., 2013 ).Thismayhave
far-reaching consequences for the successful recruitment, e.g. of the key pelagic grazer in
Arctic shelf seas, Calanus glacialis , which is able to take advantage of both blooms to
achieve high egg production (females grazing on sea ice algae), and optimal growth condi-