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Supplemental material, sj-docx-1-mpp-10.1177_23814683221094477 for Toward Food Sovereignty for Coastal Communities of Eastern Québec: Co-designing A Website to Support Consumption of Edible Resources from the St. Lawrence River, Estuary, and Gulf by Catherine Fallon, Mélanie Lemire, Dany Dumont, Elizabeth Parent, Esteban Figueroa, Isabelle Cummings, Julie Brousseau, Marie Marquis, Nicolas Paquet, Steve Plante and Holly O. Witteman in MDM Policy & Practice

The rapid physical changes affecting the Arctic Ocean alter the growth conditions of primary producers. In this context, a crucial question is whether these changes will affect the composition of phytoplankton communities, augment their productivity, and eventually enhance food webs. We combined satellite and model products with in situ datasets collected during fall and provide new insights into the response of phytoplankton biomass and production in the Canadian Arctic by comparing an interior shelf (Beaufort Sea) and an outflow shelf (Baffin Bay). Correlation analysis was used to distinguish between seasonal and interannual variability and revealed that most biological variables are responding to the interannual pressures of climate change. In southeast Beaufort Sea, a change in phytoplankton community composition occurred, with a significant increase in diatoms from 2% (2002) to 37% (2010-2011) of the total protist abundance. In 2011, photosynthetic picoeukaryotes were twice as abundant as in 2002. For these two phytoplankton groups, abundance was correlated with the duration of the open-water period, which also increased and affected vertical stratification and sea-surface temperature. In contrast, there was a sharp decline in centric diatom abundance as well as in phytoplankton biomass and production in northern Baffin Bay over the years considered. These decreases were linked to changes in seasonal progression and sea-ice dynamics through their impacts on vertical stratification and freshwater input. Overall, our results highlight the importance of stratification and the duration of the open-water period in shaping phytoplankton regimeseither oligotrophic or eutrophicin marine waters of the Canadian Arctic.

A wave-ice interaction model for the marginal ice zone (MIZ) is reported, which involves both the attenuation of ocean surface waves by sea ice and the concomitant breaking of the ice by waves. It is specifically designed to embed wave-ice interactions in an operational ice/ocean model for the first time. We investigate different methods of including the wave forcing, and different criteria for determining if they cause floes to break. We also investigate and discuss the effects of using various attenuation models, finding that predicted MIZ widths are quite sensitive to the choice of model. Additional sensitivity tests are performed on: (i) different parameterizations of the floe size distribution (FSD), including the initial FSD used; (ii) the properties of the wave field; and (iii) the sea ice properties such as concentration, thickness and breaking strain. Results are relatively insensitive to FSD parameterization but vary noticeably and systematically with its initial configuration, as they do with properties (ii-iii). An additional, somewhat surprising sensitivity, is the degree of influence of the numerical scheme that performs wave attenuation and advection. This is because a naive implementation of spatial and temporal discretizations can cause the waves to be over-attenuated, leading to a reduction of the predicted MIZ width by a substantial factor. Example simulations intended to represent conditions in the Fram Strait in 2007, which exploit reanalyzed wave and ice model data, are shown to conclude the results section. These compare favorably to estimates of MIZ width using concentrations obtained from remotely-sensed passive microwave images., Comment: 30 pages, 12 figures, 4 tables

Water from the Pacific Ocean flowing through the Bering Strait (BS) influences the circulation, heat and salt budget of the Arctic. With salinity between 31.4 and 32.9, it contributes a significantly amount to the Beaufort Gyre fresh water reservoir. The hydrography and volume transport of this inflow vary significantly over a seasonal cycle. Warm water intrusions may act as a trigger for the onset of the seasonal melt of ice, as in the 2007 extreme event. In the current version of the TOPAZ system the BS inflow is simulated with a constant barotropic inflow and a mean seasonal hydrographic cycle. A modeling approach is adopted to understand the importance of the seasonal and inter-annual variability of the transport and the hydrography of the Bering Strait inflow for the Arctic and North Atlantic oceanic climate., Technical Report no. 317.

The work presents the results of a validation study of the TOPAZ ice drift in the Arctic with different data sets including North Pole Stations, the International Arctic Buoy Program, and CERSAT drift data. TOPAZ is based on the HYCOM model with an elastic-viscous-plastic sea ice model. A regional nested model of the Fram Strait is used to assess the performance at high resolution (3.5 km). The temporal variability, mostly driven by the atmospheric forcing, is well simulated, but the drift amplitude is generally underestimated due to a documented bias towards low oceanic surface currents in this area. The coarse resolution TOPAZ model is also compared with data all over the Arctic Ocean, including a comparison between modeled and observed mean ice concentration in the Ajurak area., NERSC Technical Report no. 315. Funded by Exxon Mobil, Contract no. 08351

Climate changes in the Arctic may weaken the currently tight pelagic-benthic coupling. In response to decreasing sea ice cover, arctic marine systems are expected to shift from a ‘sea-ice algae–benthos' to a ‘phytoplankton-zooplankton’ dominance. We used mollusc shells as bioarchives and fatty acid trophic markers to estimate the effects of the reduction of sea ice cover on the food exported to the seafloor. Bathyal bivalve Astarte moerchi living at 600 m depth in northern Baffin Bay reveals a clear shift in growth variations and Ba/Ca ratios since the late 1970s, which we relate to a change in food availability. Tissue fatty acid compositions show that this species feeds mainly on microalgae exported from the euphotic zone to the seabed. We, therefore, suggest that changes in pelagic-benthic coupling are likely due either to local changes in sea ice dynamics, mediated through bottom-up regulation exerted by sea ice on phytoplankton production, or to a mismatch between phytoplankton bloom and zooplankton grazing due to phenological change. Both possibilities allow a more regular and increased transfer of food to the seabed.This article is part of the theme issue ‘The changing Arctic Ocean: consequences for biological communities, biogeochemical processes and ecosystems'.

Climate changes in the Arctic may weaken the currently tight pelagic-benthic coupling. In response to decreasing sea ice cover, arctic marine systems are expected to shift from a ‘sea-ice algae–benthos' to a ‘phytoplankton-zooplankton’ dominance. We used mollusc shells as bioarchives and fatty acid trophic markers to estimate the effects of the reduction of sea ice cover on the food exported to the seafloor. Bathyal bivalve Astarte moerchi living at 600 m depth in northern Baffin Bay reveals a clear shift in growth variations and Ba/Ca ratios since the late 1970s, which we relate to a change in food availability. Tissue fatty acid compositions show that this species feeds mainly on microalgae exported from the euphotic zone to the seabed. We, therefore, suggest that changes in pelagic-benthic coupling are likely due either to local changes in sea ice dynamics, mediated through bottom-up regulation exerted by sea ice on phytoplankton production, or to a mismatch between phytoplankton bloom and zooplankton grazing due to phenological change. Both possibilities allow a more regular and increased transfer of food to the seabed.This article is part of the theme issue ‘The changing Arctic Ocean: consequences for biological communities, biogeochemical processes and ecosystems'.