Observed trends and climate projections affecting marine ecosystems in the Canadian Arctic

Abstract

20Past trends and future projections of key atmospheric, oceanic, sea ice and biogeochemical variables were 21 assessed to increase our understanding of climate change impacts on Canadian Arctic marine ecosystems. 22 Four subbasins: Beaufort Sea, Canadian Arctic Archipelago, Baffin Bay/Davis Strait and Hudson Bay are 23 evaluated. Limited observations, especially for ecosystem variables, compromise the trend analyses. Future 24 projections are predominately from global models with few contributions from available marine basin scale 25 models. The assessment indicates a significant increase in air temperature, slight increases in precipitation 26 and snow depth and appreciable changes in atmospheric circulation patterns. Projections suggest an 27 increase in storm strength and size leading to enhanced storm surges and coastal erosion, a slight increase in 28 wave heights, increases in gustiness and small changes in mean wind speed. An Arctic-wide decrease in the 29 extent of multiyear ice and a spatial and temporal increase in ice-free waters in summer have been observed 30 and are projected to continue into the future. Limited observations of ocean properties show local 31 freshening (Beaufort Sea) and summer warming (Baffin Bay). These trends are projected to continue along 32 with localized strengthening in stratification. Increased ocean acidification has been observed and is 33 projected to continue throughout the Canadian Arctic, leading to severely decreased saturation states of 34 calcium carbonate (aragonite and calcite). Qualitative analysis of biological observations indicate large 35 regional differences. Increased primary production and double bloom development is seen in areas of sea 36 ice retreat where nutrient supply is sufficient, and unchanged or reduced production is seen where nutrients 37 are low or suppressed in response to enhanced stratification. Future primary production projections show 38 inconsistent results, with light dependent increase or nutrient limited decrease dominating dependent on the 39 model. For the next decade, natural intradecadal variability is expected to be of similar importance as 40 longer-term trends. To improve our capacity to assess and project climate change adaptation in marine 41 ecosystems, more consistent observations are needed, especially over marine areas and for biogeochemical 42 variables. Higher resolution basin-scale models are also required to provide locally applicable projections 43 relevant for Arctic communities and management units.44 45

The future of the subsurface chlorophyll‐a maximum in the Canada Basin—A model intercomparison

“…Based on these constraints and the given sparsity of biological observations in the Arctic (e.g., review by Steiner et al . []), basin‐scale averaging and to a certain extent temporal averaging is the most reasonable way to evaluate the performance of biogeochemical modules in climate models at this point in time.…”

Response of the Arctic Marine Inorganic Carbon System to Ice Algae and Under‐Ice Phytoplankton Blooms: A Case Study Along the Fast‐Ice Edge of Baffin Bay

“…There will be undersaturation of at least 10% of Arctic surface waters within a decade, with over 50% of the Arctic surface waters undersaturated by year 2050 in the A2 emissions scenario. For the Baffin Bay region, in particular, Steiner et al () predict that the saturation depth of aragonite will rise about 60 m per decade. Building from the observation that our site near Qikiqtarjuaq is fairly typical for the Arctic, these projections suggest aragonite undersaturation at the depth of the clam shelves within three to four decades.…”

Effects of changing permafrost and snow conditions on tundra wildlife: critical places and times

“…Second, changes in wind speed modify the hardness of wind slabs and their ability to support travel (Kotlyakov 1961). Since wind speeds have overall been observed and predicted to increase in the coastal Arctic (Steiner et al 2015;Stopa et al 2016), partly because of the late freezeup that increases the thermal contrast between land and ocean, snow hardness is expected to increase. Third, episodes of temperatures above 0°C lead to the formation of melt-freeze crusts at the top of the snowpack (Jamieson 2006).…”