Flux variations and vertical distributions of siliceous Rhizaria (Radiolaria and Phaeodaria) in the western Arctic Ocean: indices of environmental changes

Abstract. The vertical distribution of radiolarians was investigated using a vertical multiple plankton sampler (100–0, 250–100, 500–250, and 1000–500 m water depths, 62 μm mesh size) at the Northwind Abyssal Plain and southwestern Canada Basin in September 2013. To investigate seasonal variations in the flux of radiolarians in relation to sea ice and water masses, a time-series sediment trap system was moored at Station NAP (75°00´ N, 162°00´ W; bottom depth 1975 m) in the western Arctic Ocean during October 2010–September 2012. The radiolarian flux was comparable to that in the North Pacific Ocean. Amphimelissa setosa was dominant during the season with open water as well as at the beginning and end of the seasons with sea-ice cover. During the sea-ice-cover season, however, oligotrophic and cold-water-tolerant actinommids were dominant, productivity of Radiolaria was lower, and species diversity was greater. These suggest that the dynamics of sea ice are a major factor affecting the productivity, distribution, and composition of the radiolarian fauna.

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Flux variations and vertical distributions of microzooplankton (Radiolaria) in the western Arctic Ocean: environmental indices in a warming Arctic

Biogeosciences Discussions ◽

10.5194/bgd-11-16645-2014 ◽

2014 ◽

Vol 11 (12) ◽

pp. 16645-16701 ◽

Cited By ~ 1

Author(s):

T. Ikenoue ◽

K. R. Bjørklund ◽

S. B. Kruglikova ◽

J. Onodera ◽

K. Kimoto ◽

...

Keyword(s):

Sea Ice ◽

Arctic Ocean ◽

Cold Water ◽

Mesh Size ◽

Open Water ◽

Ice Cover ◽

Water Masses ◽

Environmental Indices ◽

Western Arctic Ocean ◽

Western Arctic

Abstract. The vertical distribution of radiolarians was investigated using a vertical multiple plankton sampler (100–0, 250–100, 500–250 and 1000–500 m water depths, 62 μm mesh size) at the Northwind Abyssal Plain and southwestern Canada Basin in September 2013. To investigate seasonal variations in the flux of radiolarians in relation to sea-ice and water masses, time series sediment trap system was moored at Station NAP (75°00' N, 162°00' W, bottom depth 1975 m) in the western Arctic Ocean during October 2010–September 2012. We showed characteristics of fourteen abundant radiolarian taxa related to the vertical hydrographic structure in the western Arctic Ocean. We found the Ceratocyrtis histricosus, a warm Atlantic water species, in net samples, indicating that it has extended its habitat into the Pacific Winter Water. The radiolarian flux was comparable to that in the North Pacific Oceans. Amphimelissa setosa was dominant during the open water and the beginning and the end of ice cover seasons with well-grown ice algae, ice fauna and with alternation of stable water masses and deep vertical mixing. During the sea-ice cover season, however, oligotrophic and cold-water tolerant Actinommidae was dominant and the productivity of radiolaria was lower and its species diversity was greater, which might be associated with the seasonal increase of solar radiation that induce the growth of algae on the ice and the other phytoplankton species under the sea-ice. These indicated that the dynamics of sea-ice was a major factor affecting the productivity, distribution, and composition of radiolarian fauna.

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N2O dynamics in the western Arctic Ocean during the summer of 2017

Scientific Reports ◽

10.1038/s41598-021-92009-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Jang-Mu Heo ◽

Seong-Su Kim ◽

Sung-Ho Kang ◽

Eun Jin Yang ◽

Ki-Tae Park ◽

...

Keyword(s):

Arctic Ocean ◽

Environmental Changes ◽

Chukchi Sea ◽

Hot Spot ◽

Open Water ◽

Northern Region ◽

The Arctic ◽

Western Arctic Ocean ◽

Deep Layers ◽

Western Arctic

AbstractThe western Arctic Ocean (WAO) has experienced increased heat transport into the region, sea-ice reduction, and changes to the WAO nitrous oxide (N2O) cycles from greenhouse gases. We investigated WAO N2O dynamics through an intensive and precise N2O survey during the open-water season of summer 2017. The effects of physical processes (i.e., solubility and advection) were dominant in both the surface (0–50 m) and deep layers (200–2200 m) of the northern Chukchi Sea with an under-saturation of N2O. By contrast, both the surface layer (0–50 m) of the southern Chukchi Sea and the intermediate (50–200 m) layer of the northern Chukchi Sea were significantly influenced by biogeochemically derived N2O production (i.e., through nitrification), with N2O over-saturation. During summer 2017, the southern region acted as a source of atmospheric N2O (mean: + 2.3 ± 2.7 μmol N2O m−2 day−1), whereas the northern region acted as a sink (mean − 1.3 ± 1.5 μmol N2O m−2 day−1). If Arctic environmental changes continue to accelerate and consequently drive the productivity of the Arctic Ocean, the WAO may become a N2O “hot spot”, and therefore, a key region requiring continued observations to both understand N2O dynamics and possibly predict their future changes.

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Variability of sea ice cover in the Chukchi Sea (western Arctic Ocean) during the Holocene

Paleoceanography ◽

10.1029/2005pa001157 ◽

2005 ◽

Vol 20 (4) ◽

pp. n/a-n/a ◽

Cited By ~ 77

Author(s):

Anne de Vernal ◽

Claude Hillaire-Marcel ◽

Dennis A. Darby

Keyword(s):

Sea Ice ◽

Arctic Ocean ◽

Chukchi Sea ◽

Ice Cover ◽

Western Arctic Ocean ◽

The Holocene ◽

Western Arctic

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Quantifying the Bering Strait Oceanic Fluxes and their Impacts on Sea-Ice and Water Properties in the Chukchi and Beaufort Seas and Western Arctic Ocean for 2013-2014

10.21236/ada601251 ◽

2013 ◽

Author(s):

Rebecca Woodgate

Keyword(s):

Sea Ice ◽

Arctic Ocean ◽

Bering Strait ◽

Western Arctic Ocean ◽

Water Properties ◽

Western Arctic

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Timing of sea ice retreat can alter phytoplankton community structure in the western Arctic Ocean

Biogeosciences ◽

10.5194/bg-11-1705-2014 ◽

2014 ◽

Vol 11 (7) ◽

pp. 1705-1716 ◽

Cited By ~ 35

Author(s):

A. Fujiwara ◽

T. Hirawake ◽

K. Suzuki ◽

I. Imai ◽

S.-I. Saitoh

Keyword(s):

Community Structure ◽

Sea Ice ◽

Arctic Ocean ◽

Phytoplankton Community ◽

Phytoplankton Community Structure ◽

Western Arctic Ocean ◽

Phytoplankton Communities ◽

Ice Retreat ◽

Western Arctic ◽

Sea Ice Retreat

Abstract. This study assesses the response of phytoplankton assemblages to recent climate change, especially with regard to the shrinking of sea ice in the northern Chukchi Sea of the western Arctic Ocean. Distribution patterns of phytoplankton groups in the late summers of 2008–2010 were analysed based on HPLC pigment signatures and, the following four major algal groups were inferred via multiple regression and cluster analyses: prasinophytes, diatoms, haptophytes and dinoflagellates. A remarkable interannual difference in the distribution pattern of the groups was found in the northern basin area. Haptophytes dominated and dispersed widely in warm surface waters in 2008, whereas prasinophytes dominated in cold water in 2009 and 2010. A difference in the onset date of sea ice retreat was evident among years–the sea ice retreat in 2008 was 1–2 months earlier than in 2009 and 2010. The spatial distribution of early sea ice retreat matched the areas in which a shift in algal community composition was observed. Steel-Dwass's multiple comparison tests were used to assess the physical, chemical and biological parameters of the four clusters. We found a statistically significant difference in temperature between the haptophyte-dominated cluster and the other clusters, suggesting that the change in the phytoplankton communities was related to the earlier sea ice retreat in 2008 and the corollary increase in sea surface temperatures. Longer periods of open water during the summer, which are expected in the future, may affect food webs and biogeochemical cycles in the western Arctic due to shifts in phytoplankton community structure.

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