Impact of a warm anomaly in the Pacific Arctic region derived from time-series export fluxes

Unusually warm conditions recently observed in the Pacific Arctic region included a dramatic loss of sea ice cover and an enhanced inflow of warmer Pacific-derived waters. Moored sediment traps deployed at three biological hotspots of the Distributed Biological Observatory (DBO) during this anomalously warm period collected sinking particles nearly continuously from June 2017 to July 2019 in the northern Bering Sea (DBO2) and in the southern Chukchi Sea (DBO3), and from August 2018 to July 2019 in the northern Chukchi Sea (DBO4). Fluxes of living algal cells, chlorophyll a (chl a), total particulate matter (TPM), particulate organic carbon (POC), and zooplankton fecal pellets, along with zooplankton and meroplankton collected in the traps, were used to evaluate spatial and temporal variations in the development and composition of the phytoplankton and zooplankton communities in relation to sea ice cover and water temperature. The unprecedented sea ice loss of 2018 in the northern Bering Sea led to the export of a large bloom dominated by the exclusively pelagic diatoms Chaetoceros spp. at DBO2. Despite this intense bloom, early sea ice breakup resulted in shorter periods of enhanced chl a and diatom fluxes at all DBO sites, suggesting a weaker biological pump under reduced ice cover in the Pacific Arctic region, while the coincident increase or decrease in TPM and POC fluxes likely reflected variations in resuspension events. Meanwhile, the highest transport of warm Pacific waters during 2017–2018 led to a dominance of the small copepods Pseudocalanus at all sites. Whereas the export of ice-associated diatoms during 2019 suggested a return to more typical conditions in the northern Bering Sea, the impact on copepods persisted under the continuously enhanced transport of warm Pacific waters. Regardless, the biological pump remained strong on the shallow Pacific Arctic shelves.

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Recent Variability in Sea Ice Cover, Age, and Thickness in the Pacific Arctic Region

The Pacific Arctic Region ◽

10.1007/978-94-017-8863-2_3 ◽

2014 ◽

pp. 31-63 ◽

Cited By ~ 15

Author(s):

Karen E. Frey ◽

James A. Maslanik ◽

Jaclyn Clement Kinney ◽

Wieslaw Maslowski

Keyword(s):

Sea Ice ◽

Arctic Region ◽

Ice Cover ◽

The Pacific

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Phytoplankton distribution in unusually low sea ice cover over the Pacific Arctic

Biogeosciences ◽

10.5194/bg-9-4835-2012 ◽

2012 ◽

Vol 9 (11) ◽

pp. 4835-4850 ◽

Cited By ~ 52

Author(s):

P. Coupel ◽

H. Y. Jin ◽

M. Joo ◽

R. Horner ◽

H. A. Bouvet ◽

...

Keyword(s):

Sea Ice ◽

Marine Ecosystem ◽

Environmental Parameters ◽

Arctic Basin ◽

Ice Cover ◽

Phytoplankton Distribution ◽

The Pacific ◽

Ice Retreat ◽

Sea Ice Retreat ◽

The Impact

Abstract. A large part of the Pacific Arctic basin experiences ice-free conditions in summer as a result of sea ice cover steadily decreasing over the last decades. To evaluate the impact of sea ice retreat on the marine ecosystem, phytoplankton in situ observations were acquired over the Chukchi shelf and the Canadian basin in 2008, a year of high melting. Pigment analyses and taxonomy enumerations were used to characterise the distribution of main phytoplanktonic groups. Marked spatial variability of the phytoplankton distribution was observed in summer 2008. Comparison of eight phytoplankton functional groups and 3 size-classes (pico-, nano- and micro-phytoplankton) also showed significant differences in abundance, biomass and distribution between summer of low ice cover (2008) and heavy ice summer (1994). Environmental parameters such as freshening, stratification, light and nutrient availability are discussed as possible causes to explain the observed differences in phytoplankton community structure between 1994 and 2008.

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Phytoplankton distribution in unusually low sea ice cover over the Pacific Arctic

Biogeosciences Discussions ◽

10.5194/bgd-9-2055-2012 ◽

2012 ◽

Vol 9 (2) ◽

pp. 2055-2093 ◽

Cited By ~ 7

Author(s):

P. Coupel ◽

H. Y. Jin ◽

M. Joo ◽

R. Horner ◽

H. A. Bouvet ◽

...

Keyword(s):

Sea Ice ◽

Arctic Basin ◽

Ice Cover ◽

The Arctic ◽

In Situ Data ◽

Phytoplankton Distribution ◽

The Pacific ◽

Phytoplankton Communities ◽

Ice Retreat ◽

The Impact

Abstract. A large part of the Pacific Arctic basin experiences ice-free conditions in summer as a result of sea ice cover steadily decreasing over the last decades. To evaluate the impact of ice retreat on the Arctic ecosystem, we investigated phytoplankton communities from coastal sites (Chukchi shelf) to northern deep basins (up to 86° N), during year 2008 of high melting. Pigment and taxonomy in situ data were acquired under different ice regime: the ice -free basins (IFB, 74°–77° N), the marginal ice zone (MIZ, 77°–80° N) and the heavy ice covered basins (HIB, >80° N). Our results suggest that extensive ice melting provided favorable conditions to chrysophytes and prymnesiophytes growth and more hinospitable to pico-sized prasinophytes and micro-sized dinoflagellates. Larger cell diatoms were less abundant in the IFB while dominant in the MIZ of the deep Canadian basin. Our data were compared to those obtained during more icy years, 1994 and to a lesser extent, 2002. Freshening, stratification, light and nutrient availability are discussed as possible causes for observed phytoplankton communities under high and low sea ice cover.

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Phytoplankton Bloom Changes under Extreme Geophysical Conditions in the Northern Bering Sea and the Southern Chukchi Sea

Remote Sensing ◽

10.3390/rs13204035 ◽

2021 ◽

Vol 13 (20) ◽

pp. 4035

Author(s):

Jinku Park ◽

Sungjae Lee ◽

Young-Heon Jo ◽

Hyun-Cheol Kim

Keyword(s):

Heat Flux ◽

Sea Ice ◽

Bering Sea ◽

Phytoplankton Biomass ◽

Phytoplankton Bloom ◽

Chukchi Sea ◽

Open Water ◽

The Arctic ◽

Atmospheric Conditions ◽

Northern Bering Sea

The northern Bering Sea and the southern Chukchi Sea are undergoing rapid regional biophysical changes in connection with the recent extreme climate change in the Arctic. The ice concentration in 2018 was the lowest since observations began in the 1970s, due to the unusually warm southerly wind in winter, which continued in 2019. We analyzed the characteristics of spring phytoplankton biomass distribution under the extreme environmental conditions in 2018 and 2019. Our results show that higher phytoplankton biomass during late spring compared to the 18-year average was observed in the Bering Sea in both years. Their spatial distribution is closely related to the open water extent following winter-onset sea ice retreat in association with dramatic atmospheric conditions. However, despite a similar level of shortwave heat flux, the 2019 springtime biomass in the Chukchi Sea was lower than that in 2018, and was delayed to summer. We confirmed that this difference in bloom timing in the Chukchi Sea was due to changes in seawater properties, determined by a combination of northward oceanic heat flux modulation by the disturbance from more extensive sea ice in winter and higher surface net shortwave heat flux than usual.

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Climate warming and the loss of sea ice: the impact of sea-ice variability on the southeastern Bering Sea pelagic ecosystem

ICES Journal of Marine Science ◽

10.1093/icesjms/fsaa206 ◽

2020 ◽

Cited By ~ 2

Author(s):

George L Hunt ◽

Ellen M Yasumiishi ◽

Lisa B Eisner ◽

Phyllis J Stabeno ◽

Mary Beth Decker

Keyword(s):

Sea Ice ◽

Climate Warming ◽

Bering Sea ◽

Ice Cover ◽

Walleye Pollock ◽

Pelagic Ecosystem ◽

Eastern Bering Sea ◽

Calanus Glacialis ◽

Class Strength ◽

The Impact

Abstract We investigated relationships among three metrics of sea-ice cover in eight regions of the eastern Bering Sea and the abundance of Calanus copepods, jellyfish medusae, and year-class strength of walleye pollock (Gadus chalcogrammus). In summer, Calanus spp. were more abundant over the middle shelf when sea ice lingered late into spring, and, to a lesser extent, when February sea-ice cover was heavy. Between 1982 and 1999, there were no significant (p ≤ 0.05) relationships between the amount or timing of sea-ice cover and pollock recruitment. However, between 2000 and 2015, pollock year-class strength was positively correlated with sea ice in the outer and middle shelves, with 17 of 24 regressions significant. Pollock year-class strength was best predicted by days with sea-ice cover after February. Pollock recruitment was positively influenced by copepod numbers, particularly in the middle shelf, with r2 values from 0.36 to 0.47. We hypothesize that the Calanus spp. present in the southeastern Bering Sea are primarily Calanus glacialis that have been advected south in association with sea ice. None of our sea-ice metrics explained the variance in jellyfish biomass. Jellyfish biomass in our study area in the pollock age-0 year was not correlated with pollock recruitment 3 years later.

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Divergent patterns of recent sea ice cover across the Bering, Chukchi, and Beaufort seas of the Pacific Arctic Region

Progress In Oceanography ◽

10.1016/j.pocean.2015.05.009 ◽

2015 ◽

Vol 136 ◽

pp. 32-49 ◽

Cited By ~ 82

Author(s):

Karen E. Frey ◽

G.W.K. Moore ◽

Lee W. Cooper ◽

Jacqueline M. Grebmeier

Keyword(s):

Sea Ice ◽

Arctic Region ◽

Ice Cover ◽

The Pacific

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Impacts of unusually light sea-ice cover in winter 2017-2018 on the northern Bering Sea marine ecosystem – An introduction

Deep Sea Research Part II Topical Studies in Oceanography ◽

10.1016/j.dsr2.2020.104908 ◽

2020 ◽

Vol 181-182 ◽

pp. 104908

Author(s):

Toru Hirawake ◽

George L. Hunt

Keyword(s):

Sea Ice ◽

Bering Sea ◽

Marine Ecosystem ◽

Ice Cover ◽

Northern Bering Sea

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RECONSTRUCTING CHANGES IN SEA ICE COVER DURING MARINE ISOTOPE STAGE 11 FROM BERING SEA SEDIMENT CORES

10.1130/abs/2018nc-313273 ◽

2018 ◽

Author(s):

Natalie Thompson ◽

◽

Beth E. Caissie

Keyword(s):

Sea Ice ◽

Bering Sea ◽

Sediment Cores ◽

Ice Cover ◽

Marine Isotope Stage

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Contrasting trends in sea ice and primary production in the Bering Sea and Arctic Ocean

ICES Journal of Marine Science ◽

10.1093/icesjms/fss113 ◽

2012 ◽

Vol 69 (7) ◽

pp. 1180-1193 ◽

Cited By ~ 62

Author(s):

Zachary W. Brown ◽

Kevin R. Arrigo

Keyword(s):

Sea Ice ◽

Primary Production ◽

Arctic Ocean ◽

Bering Sea ◽

Net Primary Productivity ◽

Remote Sensing Data ◽

Ice Cover ◽

The Arctic ◽

Light Limitation ◽

The Bering Sea

Abstract Brown, Z. W., and Arrigo, K. R. 2012. Contrasting trends in sea ice and primary production in the Bering Sea and Arctic Ocean. – ICES Journal of Marine Science, 69: . Satellite remote sensing data were used to examine recent trends in sea-ice cover and net primary productivity (NPP) in the Bering Sea and Arctic Ocean. In nearly all regions, diminished sea-ice cover significantly enhanced annual NPP, indicating that light-limitation predominates across the seasonally ice-covered waters of the northern hemisphere. However, long-term trends have not been uniform spatially. The seasonal ice pack of the Bering Sea has remained consistent over time, partially because of winter winds that have continued to carry frigid Arctic air southwards over the past six decades. Hence, apart from the “Arctic-like” Chirikov Basin (where sea-ice loss has driven a 30% increase in NPP), no secular trends are evident in Bering Sea NPP, which averaged 288 ± 26 Tg C year−1 over the satellite ocean colour record (1998–2009). Conversely, sea-ice cover in the Arctic Ocean has plummeted, extending the open-water growing season by 45 d in just 12 years, and promoting a 20% increase in NPP (range 441–585 Tg C year−1). Future sea-ice loss will likely stimulate additional NPP over the productive Bering Sea shelves, potentially reducing nutrient flux to the downstream western Arctic Ocean.

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