Arctic Ocean outflow shelves in the changing Arctic: A review and perspectives

Michel, Christine; Hamilton, Jim; Hansen, Edmond; Barber, David G.; Reigstad, Marit; Iacozza, John; Seuthe, Lena; Niemi, Andrea

doi:10.1016/j.pocean.2015.08.007

Cited by 70 publications

(77 citation statements)

References 193 publications

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“…Waters coming from the Pacific Ocean circulate through the Arctic Ocean and finally reach the North Atlantic Ocean through the outflow shelves, including Baffin Bay (Michel et al ). The initial physical and chemical properties of incoming Pacific waters are modified across the Arctic Ocean (Tremblay et al ), and the freshwater content of the surface mixed layer increases with sea ice melt as it flows toward the North Atlantic Ocean.…”

Section: Resultsmentioning

confidence: 99%

Contrasting interannual changes in phytoplankton productivity and community structure in the coastal Canadian Arctic Ocean

Blais

Ardyna

Gosselin

et al. 2017

Limnology & Oceanography

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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 regimes-either oligotrophic or eutrophic-in marine waters of the Canadian Arctic.

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Section: Resultsmentioning

confidence: 99%

Contrasting interannual changes in phytoplankton productivity and community structure in the coastal Canadian Arctic Ocean

Blais

Ardyna

Gosselin

et al. 2017

Limnology & Oceanography

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“…Similar ecosystem regime shifts like poleward movement have been previously observed in “inflow shelves” (i.e., in the Atlantic sector [ Drinkwater , ] and in the Bering Sea [ Napp and Hunt , ; Grebmeier et al ., ; Mueter and Litzow , ]). However, these ongoing poleward shifts observed in the inflow shelves cannot be translated to “interior” (i.e., Beaufort and Russian seas) and “outflow shelves” (i.e., Baffin Bay, Canadian Archipelago, East Greenland shelf…), due to their entirely different functional type [ Carmack and Wassmann ; Michel et al ]. In the less sea‐ice‐covered interior shelves, stronger atmosphere‐ocean interactions promote the existence of coastal hotspots of high phytoplankton productivity crucial for supporting marine ecosystems [ Tremblay et al ., ; Ardyna et al ., ; Blais et al ., ].…”

Section: Discussionmentioning

confidence: 99%

Role for Atlantic inflows and sea ice loss on shifting phytoplankton blooms in the Barents Sea

et al. 2017

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Phytoplankton blooms in the Barents Sea are highly sensitive to seasonal and interannual changes in sea ice extent, water mass distribution, and oceanic fronts. With the ongoing increase of Atlantic Water inflows, we expect an impact on these blooms. Here, we use a state‐of‐the‐art collection of in situ hydrogeochemical data for the period 1998–2014, which includes ocean color satellite‐derived proxies for the biomass of calcifying and noncalcifying phytoplankton. Over the last 17 years, sea ice extent anomalies were evidenced having direct consequences for the spatial extent of spring blooms in the Barents Sea. In years of minimal sea ice extent, two spatially distinct blooms were clearly observed: one along the ice edge and another in ice‐free water. These blooms are thought to be triggered by different stratification mechanisms: heating of the surface layers in ice‐free waters and melting of the sea ice along the ice edge. In years of maximal sea ice extent, no such spatial delimitation was observed. The spring bloom generally ended in June when nutrients in the surface layer were depleted. This was followed by a stratified and oligotrophic summer period. A coccolithophore bloom generally developed in August, but was confined only to Atlantic Waters. In these same waters, a late summer bloom of noncalcifying algae was observed in September, triggered by enhanced mixing, which replenishes surface waters with nutrients. Altogether, the 17 year time‐series revealed a northward and eastward shift of the spring and summer phytoplankton blooms.

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“…These changes include shifts toward smaller cells, possibly with different physiology, especially in the freshening Beaufort Sea and Canadian Arctic Archipelago [Li et al, 2009;Tremblay et al, 2009], which will again affect vertical export fluxes. Changes in bloom phenology have been described as lengthening bloom periods or even the presence of fall blooms (reviewed by Babin et al [2015]; Michel et al [2006Michel et al [ , 2015). However, these changes are fairly recent and likely not yet simulated by models nor captured by the in situ data used for our exercise, despite covering five decades back (i.e., diminishing the likelihood of an effect in our field data set).…”

Section: 1002/2016jc011993mentioning

confidence: 99%

Net primary productivity estimates and environmental variables in the Arctic Ocean: An assessment of coupled physical-biogeochemical models

Lee

Matrai

Friedrichs

et al. 2016

J. Geophys. Res. Oceans

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The relative skill of 21 regional and global biogeochemical models was assessed in terms of how well the models reproduced observed net primary productivity (NPP) and environmental variables such as nitrate concentration (NO3), mixed layer depth (MLD), euphotic layer depth (Zeu), and sea ice concentration, by comparing results against a newly updated, quality‐controlled in situ NPP database for the Arctic Ocean (1959–2011). The models broadly captured the spatial features of integrated NPP (iNPP) on a pan‐Arctic scale. Most models underestimated iNPP by varying degrees in spite of overestimating surface NO3, MLD, and Zeu throughout the regions. Among the models, iNPP exhibited little difference over sea ice condition (ice‐free versus ice‐influenced) and bottom depth (shelf versus deep ocean). The models performed relatively well for the most recent decade and toward the end of Arctic summer. In the Barents and Greenland Seas, regional model skill of surface NO3 was best associated with how well MLD was reproduced. Regionally, iNPP was relatively well simulated in the Beaufort Sea and the central Arctic Basin, where in situ NPP is low and nutrients are mostly depleted. Models performed less well at simulating iNPP in the Greenland and Chukchi Seas, despite the higher model skill in MLD and sea ice concentration, respectively. iNPP model skill was constrained by different factors in different Arctic Ocean regions. Our study suggests that better parameterization of biological and ecological microbial rates (phytoplankton growth and zooplankton grazing) are needed for improved Arctic Ocean biogeochemical modeling.

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Arctic Ocean outflow shelves in the changing Arctic: A review and perspectives

Cited by 70 publications

References 193 publications

Contrasting interannual changes in phytoplankton productivity and community structure in the coastal Canadian Arctic Ocean

Contrasting interannual changes in phytoplankton productivity and community structure in the coastal Canadian Arctic Ocean

Role for Atlantic inflows and sea ice loss on shifting phytoplankton blooms in the Barents Sea

Net primary productivity estimates and environmental variables in the Arctic Ocean: An assessment of coupled physical-biogeochemical models

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