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The article discusses the efforts of Amundsen Science, the organization managing the Canadian research icebreaker CCGS Amundsen, to promote equity, diversity, and inclusion (EDI) in Arctic marine science. The organization aims to create a safe and respectful research environment and integrate Indigenous-led research and Inuit culture during expeditions. They conducted a survey and interviews to gather feedback and used the insights gained to develop an EDI Action Plan. The plan includes commitments to diversify leadership, create a code of conduct, conduct annual EDI surveys, facilitate accommodations, and develop intersectional policies. Major steps have already been taken, such as implementing a code of conduct and providing a safe contact person for participants. The organization also emphasizes the importance of incorporating Inuit traditional knowledge and increasing Inuit-led research programs. Collaboration with the Canadian Coast Guard has allowed for the alignment of priorities and the dissemination of cultural awareness training. The organization acknowledges that building EDI practices is an iterative process and that positive impacts have already been observed. [Extracted from the article]

A 2-year-long time series of currents and acoustic backscatter from an acoustic Doppler current profiler, moored over the eastern Beaufort Sea continental slope from October 2003 to September 2005, were used to assess the dynamics and variability of the sound-scattering layer. It has been shown that acoustic backscatter is dominated by a synchronized diel vertical migration (DVM) of zooplankton. Our results show that DVM timings (i) were synchronous with sunlight and (ii) were modified by moonlight and sea ice, which attenuates light transmission to the water column. Moreover, DVM is modified or completely disrupted during highly energetic current events. Thicker ice observed during winter–spring 2005 lowered the backscatter values but favored extending DVM toward the midnight sun. In contrast to many previous studies, DVM occurred through the intermediate water layer during the ice-free season of the midnight sun in 2004. In 2005, the midnight-sun DVM was likely impacted by a high acoustic scattering generated by suspended particles. During full moon at low cloud cover, the nighttime moonlight illuminance led to zooplankton avoidance of the subsurface layer, disrupting DVM. Moreover, DVM was disrupted by upwelling, downwelling, and eddy passing. We suggest that these deviations are consistent with DVM adjusting to avoid enhanced water dynamics. For upwelling and downwelling, zooplankton likely respond to the along-slope water dynamics dominated by surface- and depth-intensified flow, respectively. This drives zooplankton to adjust DVM by aggregating in the low or upper intermediate water layer for upwelling and downwelling, respectively. The baroclinic eddy reversed DVM below the eddy core. [ABSTRACT FROM AUTHOR]

A two-year-long time series of currents and acoustic backscatter from an Acoustic Doppler Current Profiler, moored over the eastern Beaufort Sea continental slope from October 2003 to September 2005, were used to assess dynamics and variability of the sound-scattering layer. It has been shown that acoustic backscatter is dominated by a synchronized diel vertical migration (DVM) of the zooplankton. Our results show that DVM timings (i) were synchronous with sunlight, and (ii) were modified by moonlight and sea-ice, which attenuates light transmission to the water column. Moreover, DVM is modified or completely disrupted during highly energetic current events. Thicker ice observed during winter 2004-2005 lowered the backscatter values, but favored extending DVM toward the midnight sun. In contrast to many previous studies, DVM occurred through the intermediate water layer during the ice-free season of the midnight sun in 2004. In 2005, the midnight sun DVM was likely masked by a high acoustic scattering generated by suspended particles. During full moon at low cloud cover, the nighttime moonlight illuminance led to zooplankton avoidance of the sub-surface layer disrupting DVM. Moreover, DVM was disrupted by upwelling, downwelling and eddy passing. We suggest that these deviations are consistent with DVM adjusting to avoid enhanced water dynamics. For upwelling and downwelling, zooplankton likely respond to the along-slope water dynamics dominated by surface- and depth-intensified flow, respectively. This drives zooplankton to adjust DVM by aggregating in the low or upper intermediate water layer for upwelling and downwelling, respectively. The baroclinic eddy reversed DVM below the eddy core. [ABSTRACT FROM AUTHOR]

Osborne, P.D. and Forest, A., 2016. Sediment dynamics from coast to slope - Southern Canadian Beaufort Sea. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 537-541. Coconut Creek (Florida), ISSN 0749-0208. Profound changes in cross-shelf sediment fluxes are anticipated in coming decades in the southern Canadian Beaufort Sea where an accelerated increase in temperature could lead to large changes in Arctic river hydrology and coastal-marine geomorphologic processes. In the past decade sediment exported to the Beaufort Shelf has increased while sea level pressure has increased accelerating the Beaufort Gyre, strengthening coastal upwelling and expanding the Mackenzie River plume offshore. Sea-ice extent has decreased while storminess has increased increasing wave action, coastal downwelling, current surge and resuspension and transport on the shoreface and shelf. This paper investigates mechanisms, quantities and rates of sediment transport operating in this cold continental shelf-slope environment. Past studies from more than 2 decades of research are compared with recent measurements to develop improved estimates of sediment sources, pathways, fate and fluxes across the shelf and slope. In particular, we explore connections between data from a long term mooring observatory deployed over the continental shelf and slope during the ArcticNet-Industry Partnership (2009-2011) and Beaufort Regional Environmental Assessment (BREA 2011-2015) to those acquired in studies focusing on nearshore and shoreface. Sediment fluxes from the Mackenzie River and erosion of permafrost coasts are compared with outer shelf-slope measurements of settling particles and near-bottom fluxes. In turn, the role of atmospheric and cryospheric processes in forcing sediment transfer from coast to slope is investigated to assess system response to changing climate and evaluate implications for marine hydrocarbon resource development along the continental margin of the Arctic Ocean. [ABSTRACT FROM AUTHOR]

Arctic Ocean microbial eukaryote phytoplankton form subsurface chlorophyll maximum (SCM), where much of the annual summer production occurs. This SCM is particularly persistent in the Western Arctic Ocean, which is strongly salinity stratified. The recent loss of multiyear sea ice and increased particulate-rich river discharge in the Arctic Ocean results in a greater volume of fresher water that may displace nutrient-rich saltier waters to deeper depths and decrease light penetration in areas affected by river discharge. Here, we surveyed microbial eukaryotic assemblages in the surface waters, and within and below the SCM. In most samples, we detected the pronounced SCM that usually occurs at the interface of the upper mixed layer and Pacific Summer Water (PSW). Poorly developed SCM was seen under two conditions, one above PSW and associated with a downwelling eddy, and the second in a region influenced by the Mackenzie River plume. Four phylogenetically distinct communities were identified: surface, pronounced SCM, weak SCM and a deeper community just below the SCM. Distance-decay relationships and phylogenetic structure suggested distinct ecological processes operating within these communities. In the pronounced SCM, picophytoplanktons were prevalent and community assembly was attributed to water mass history. In contrast, environmental filtering impacted the composition of the weak SCM communities, where heterotrophic Picozoa were more numerous. These results imply that displacement of Pacific waters to greater depth and increased terrigenous input may act as a control on SCM development and result in lower net summer primary production with a more heterotroph dominated eukaryotic microbial community. [ABSTRACT FROM AUTHOR]

Given the volumetric nature of the ocean, 3D spatial modeling and interpolation could be a key to a better understanding of continuous abiotic and biotic phenomena that compose the marine ecosystem, although such techniques are rarely used and their actual performance is poorly studied. Here, we evaluate the performance of 3D spatial interpolation for five pelagic variables derived from a typical oceanographic campaign conducted in the southeastern Beaufort Sea (Canadian Arctic) in 2009. Our main objective is to evaluate and compare the performance of a deterministic interpolation method (inverse distance, IDW) and a geostatistical method (ordinary kriging, OK) with a variation of method input parameters (search neighborhood, weights) for variables with increasing complexity in terms of data anisotropy and sampling configuration. Performance of different 3D interpolation strategies is evaluated by cross-validation and a qualitative comparison of 3D spatial models. Our results show that OK was the optimal method. However, when the complexity of pelagic variables increased in terms of spatial autocorrelation and data variation, the error difference between OK and IDW was reduced. We recommend that recent advances in spatial 3D modeling tools developed primarily for geological modeling should be exploited to extend the usual interpretation of marine pelagic phenomena from a 2D to a 3D environment. [ABSTRACT FROM AUTHOR]

Regional variability in the annual fluxes of particulate organic carbon (POC) and biogenic silica (Si) at the periphery of the Mackenzie Shelf (Beaufort Sea) was investigated using eight long-term sediment traps moored at ~100-m depth. Relatively high autochthonous POC and Si fluxes were recorded in the Mackenzie Trough (4.1 and 8.9 g m year respectively) and off Cape Bathurst (6.6 and 79 g m year), two areas where upwelling events are frequently observed. Diatomaceous new production was minimum on the mid-slope of the Mackenzie Shelf (2.8 g C m year), moderate in the Mackenzie Trough (14.5 g C m year), and highest off Cape Bathurst (128.7 g C m year). High annual autochthonous POC flux corresponded to high diatom production. Among sites, the vertical attenuation of the POC flux increased with diatomaceous new production. Hence, the retention of autochthonous POC in the surface layer (<100 m) was highest (95%) at the highly productive site off Cape Bathurst, intermediate (72%) in the moderately productive Mackenzie Trough, and low (4%) at the unproductive mid-slope of the shelf. Our results indicate that, on Arctic shelves, upwelling and the production of diatoms increase the fraction of the POC which is retained in the surface layer and diverted to the pelagic food web. In the relatively unproductive waters of the Arctic Ocean, biological hot spots such as the one identified off Cape Bathurst where the food web promotes retention rather than vertical export could be disproportionately important as feeding grounds for higher trophic levels. [ABSTRACT FROM AUTHOR]

Calanoid copepods dominate mesozooplankton biomass in the Arctic Ocean. Variations in C content, C:N ratio and stable isotope composition (δ13C, δ15N) of Calanus hyperboreus, Calanus glacialis and Metridia longa collected from January to August 2008 in the southeast Beaufort Sea provided insights into their metabolism, feeding and reproduction. Seasonal differences in the C–prosome length relationships and C:N ratios were driven by distinct spawning strategies and changes in lipid content. Relatively high copepod biomass over the study period (2.6–9.7 g C m−2) corresponded to favorable growth conditions in 2007–2008. The mean 15N enrichment of copepods (+2.8–4.7‰) relative to particulate organic nitrogen values recorded at the ice bottom and at the chlorophyll maximum indicated a primarily herbivorous diet. In all species, δ13C and δ15N decreased markedly in April, reflecting the feeding onset on ice algae, but a rapid transition to feeding on phytoplankton occurred as a pelagic bloom was triggered by the early ice melt in May. A second decline in the δ13C and δ15N of copepods was recorded in June–July, coincident with a second increase in phytoplankton production. The two isotope depletion events in copepods were both followed by a return to high values and an increase in their C:N as a consequence of previous C fixation and nitrate limitation in phytoplankton and the likely formation of body reserves/tissue. Our results illustrate that Arctic calanoids respond quickly to any increase in primary production and can cope with changes in its nature and timing. [ABSTRACT FROM AUTHOR]

The lack of extended dataset has so far prevented an inclusive understanding of the long-term relationships between primary production (PP) and vertical export in the Arctic Ocean. It is urgent to investigate these connections as Arctic ecosystems are on the verge of climate-related shifts, which could be caused by the combined effects of increase in Pacific and Atlantic inflow, climate warming, and sea ice decline. For a period of 6 years we investigated the degree of coupling between PP and export by making use of modelled PP rates and vertical particle fluxes collected with sediment traps moored at ~300 m depth in the eastern Fram Strait. Our analyses indicate that total and new simulated PP averaged for different areas centered on the mooring location (5-200 km radius) explain at best 20-44% of the observed biogenic particle fluxes at 300 m, when applying extended time-lags (55-90 days) between PP and vertical fluxes. Based on this phasing, we define a conceptual framework that presents the temporal dimension as a prime determinant of the maximum strength of the PP-export coupling at a given depth. Our results support that planktonic food webs in the Fram Strait process heavily biogenic material in the epipelagic zone, but we further suggest that Atlantic-Arctic water interactions induce a particular ecological setting responsible for the extended turn-over. In conclusion, we hypothesize that global warming could promote a transition toward a more retentive ecosystem in the Fram Strait region despite the likely increase of pelagic PP in the Arctic Ocean. [ABSTRACT FROM AUTHOR]

Typically, all undecomposed metazoans found in formalin-poisoned cups of sediment traps are considered to be active intruders (or 'swimmers') and are removed to prevent an overestimation of the downward particle flux. However, intact metazoans dead before entering the trap should be included in the estimation of downward flux of carbon. Arctic copepods collected in the field were killed either by formalin to mimic death by actively swimming into the formalin-poisoned cups, or by crowding or high temperature and then preserved in formalin to simulate death before entering the trap. In the crowding and heat treatments, 64% of Calanus hyperboreus and C. glacialis and 44% of Pareuchaeta glacialis differed from copepods killed by formalin in the postmortem posture of the antennules or swimming legs. These frequencies were used to estimate the contribution of passively sinking copepods (PSCs) to the particulate organic carbon (POC) flux measured by a sediment trap moored at 70 m in the Beaufort Sea (Canadian sector of the Arctic Ocean). PSCs represented only a small fraction (<5%) of the copepods collected in the trap, thus justifying the removal of swimmers from samples to avoid a massive overestimation of fluxes. Nevertheless, PSCs contributed 36% of the overall POC flux of 6.8 g C m-2 yr-1, and discarding them along with the swimmers would have resulted in a significant underestimation of downward export. Given their rich carbon content (up to 50%), PSCs could be an important food resource for pelagic and benthic scavengers. [ABSTRACT FROM AUTHOR]

A variable fraction of fecal pellets produced in the epipelagic layer is intercepted and retained before reaching the bottom. We assessed fecal pellet retention in the ice-covered Beaufort Sea in early February by comparing the shape and size-frequency distribution of pellets collected by a sediment trap moored at 210 m to that produced in vitro. Appendicularian ellipsoidal and copepod cylindrical pellets made up 75 and 24% of the flux (165 μg C m−2 day−1). In contrast, production (135 μg C m−2 day−1) was dominated by cylindrical pellets (93%). The vertical flux of cylindrical pellets at 210 m was attenuated by 70%. Pellets >120 μm in width, represented 42% of the production, but were not detected in the trap. Retention most likely resulted from coprorhexic feeding by copepods such as Metridia longa. Our observations suggest that the detritivore food web prevailing under the ice of the Arctic Ocean in winter is dominated by appendicularians feeding on pellets fragmented by copepods. [ABSTRACT FROM AUTHOR]

The Arctic is warming and losing sea ice. Happening at a much faster rate than previously expected, these changes are causing multiple ecosystem feedbacks in the Arctic Ocean. The Arctic in Rapid Transition (ART) initiative was developed by early-career scientists as an integrative, international, multidisciplinary, long-term pan-Arctic network to study changes and feedbacks among the physical and biogeochemical components of the Arctic Ocean and their ultimate impacts on biological productivity on different timescales. In 2012, ART jointly organized with the Association of Polar Early Career Scientists their second science workshop—Overcoming Challenges of Observation to Model Integration in Marine Ecosystem Response to Sea Ice Transitions—at the Institute of Oceanology, Polish Academy of Sciences, in Sopot. This workshop aimed to identify linkages and feedbacks between atmosphere–ice–ocean forcing and biogeochemical processes, which are critical for ecosystem function, land–ocean interactions and productive capacity of the Arctic Ocean. This special thematic cluster of Polar Research brings together seven papers that grew out of workgroup discussions. Papers examine the climate change impacts on various ecosystem elements, providing important insights on the marine ecological and biogeochemical processes on various timescales. They also highlight priority areas for future research. [ABSTRACT FROM AUTHOR]

In the Arctic Ocean, vertical fluxes of particulate organic carbon (POC) remain low during the dark winter period because POC fluxes are derived from photosynthetic production. Passively sinking dead copepods are traditionally excluded from POC fluxes estimated using sediment traps, resulting in the underestimation of the total POC flux. Here, we present the seasonal variability of total POC export flux measured by a sediment trap moored at ~ 100 m in the Amundsen Gulf (southeastern Beaufort Sea) over October 2007-July 2008. Surprisingly, the integrated total POC flux for February (466 mg m-2) was the second highest flux during the study period (the highest was in Jul; 1015 mg C m-2) due to a contribution of 91% from sinking dead copepods. The total POC flux in February 2008 in the Amundsen Gulf was up to two orders of magnitude higher than the previously reported traditional POC winter fluxes that did not include the contribution of sinking dead copepods. Hence, the POC flux in February only could be equivalent to ~ 18% of the quasi-annual traditional POC flux. Our observations suggest that a substantial POC export flux occurred during winter 2007-2008 due to zooplankton life cycle. [ABSTRACT FROM AUTHOR]