scholarly journals Dissolved iron in the Arctic shelf seas and surface waters of the central Arctic Ocean: Impact of Arctic river water and ice-melt

2012 ◽  
Vol 117 (C1) ◽  
Author(s):  
M. B. Klunder ◽  
D. Bauch ◽  
P. Laan ◽  
H. J. W. de Baar ◽  
S. van Heuven ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
River Water ◽  
Surface Waters ◽  
Arctic Shelf ◽  
The Arctic ◽  
Central Arctic Ocean ◽  
Ice Melt ◽  
Dissolved Iron ◽  
Shelf Seas

scholarly journals Arctic Ocean stratification set by sea level and freshwater inputs since the last ice age

2021 ◽  
Author(s):  
Jesse R. Farmer ◽  
Daniel M. Sigman ◽  
Julie Granger ◽  
Ona M. Underwood ◽  
François Fripiat ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Surface Waters ◽  
Ice Age ◽  
The Arctic ◽  
Bering Strait ◽  
Central Arctic Ocean ◽  
Phytoplankton Productivity ◽  
Nitrate Consumption ◽  
Western Arctic ◽  
Last Ice Age

AbstractSalinity-driven density stratification of the upper Arctic Ocean isolates sea-ice cover and cold, nutrient-poor surface waters from underlying warmer, nutrient-rich waters. Recently, stratification has strengthened in the western Arctic but has weakened in the eastern Arctic; it is unknown if these trends will continue. Here we present foraminifera-bound nitrogen isotopes from Arctic Ocean sediments since 35,000 years ago to reconstruct past changes in nutrient sources and the degree of nutrient consumption in surface waters, the latter reflecting stratification. During the last ice age and early deglaciation, the Arctic was dominated by Atlantic-sourced nitrate and incomplete nitrate consumption, indicating weaker stratification. Starting at 11,000 years ago in the western Arctic, there is a clear isotopic signal of Pacific-sourced nitrate and complete nitrate consumption associated with the flooding of the Bering Strait. These changes reveal that the strong stratification of the western Arctic relies on low-salinity inflow through the Bering Strait. In the central Arctic, nitrate consumption was complete during the early Holocene, then declined after 5,000 years ago as summer insolation decreased. This sequence suggests that precipitation and riverine freshwater fluxes control the stratification of the central Arctic Ocean. Based on these findings, ongoing warming will cause strong stratification to expand into the central Arctic, slowing the nutrient supply to surface waters and thus limiting future phytoplankton productivity.

scholarly journals Cyclone impact on sea ice in the central Arctic Ocean: a statistical study

2014 ◽  
Vol 8 (1) ◽  
pp. 303-317 ◽  
Author(s):  
A. Kriegsmann ◽  
B. Brümmer
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Ocean Model ◽  
The Arctic ◽  
Central Arctic Ocean ◽  
Cumulative Impact ◽  
Model Composite ◽  
Ice Melt ◽  
The Arctic Ocean ◽  
The Impact

Abstract. This study investigates the impact of cyclones on the Arctic Ocean sea ice for the first time in a statistical manner. We apply the coupled ice–ocean model NAOSIM which is forced by the ECMWF analyses for the period 2006–2008. Cyclone position and radius detected in the ECMWF data are used to extract fields of wind, ice drift, and concentration from the ice–ocean model. Composite fields around the cyclone centre are calculated for different cyclone intensities, the four seasons, and different sub-regions of the Arctic Ocean. In total about 3500 cyclone events are analyzed. In general, cyclones reduce the ice concentration in the order of a few percent increasing towards the cyclone centre. This is confirmed by independent AMSR-E satellite data. The reduction increases with cyclone intensity and is most pronounced in summer and on the Siberian side of the Arctic Ocean. For the Arctic ice cover the cumulative impact of cyclones has climatologic consequences. In winter, the cyclone-induced openings refreeze so that the ice mass is increased. In summer, the openings remain open and the ice melt is accelerated via the positive albedo feedback. Strong summer storms on the Siberian side of the Arctic Ocean may have been important contributions to the recent ice extent minima in 2007 and 2012.

scholarly journals Cyclone impact on sea ice in the central Arctic Ocean: a statistical study

2013 ◽  
Vol 7 (2) ◽  
pp. 1141-1176 ◽  
Author(s):  
A. Kriegsmann ◽  
B. Brümmer
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Ocean Model ◽  
The Arctic ◽  
Central Arctic Ocean ◽  
Model Composite ◽  
Ice Melt ◽  
The Arctic Ocean ◽  
Arctic Ice ◽  
The Impact

Abstract. This study investigates the impact of cyclones on the Arctic Ocean sea ice for the first time in a statistical manner. We apply the coupled ice–ocean model NAOSIM which is forced by the ECMWF analyses for the period 2006–2008. Cyclone position and radius detected in the ECMWF data are used to extract fields of wind, ice drift, and concentration from the ice–ocean model. Composite fields around the cyclone centre are calculated for different cyclone intensities, the four seasons, and different regions of the Arctic Ocean. In total about 3500 cyclone events are analyzed. In general, cyclones reduce the ice concentration on the order of a few percent increasing towards the cyclone centre. This is confirmed by independent AMSR-E satellite data. The reduction increases with cyclone intensity and is most pronounced in summer and on the Siberian side of the Arctic Ocean. For the Arctic ice cover the impact of cyclones has climatologic consequences. In winter, the cyclone-induced openings refreeze so that the ice mass is increased. In summer, the openings remain open and the ice melt is accelerated via the positive albedo feedback. Strong summer storms on the Siberian side of the Arctic Ocean may have been important reasons for the recent ice extent minima in 2007 and 2012.

scholarly journals The impact of land-fast ice on the distribution of terrestrial dissolved organic matter in the Siberian Arctic shelf seas

2021 ◽  
Author(s):  
Jens A. Hölemann ◽  
Bennet Juhls ◽  
Dorothea Bauch ◽  
Markus Janout ◽  
Boris P. Koch ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
River Water ◽  
Arctic Shelf ◽  
The Arctic ◽  
Permafrost Degradation ◽  
Surface Mixed Layer ◽  
Siberian Arctic ◽  
Shelf Seas ◽  
Fast Ice

Abstract. Remobilization of soil carbon as a result of permafrost degradation in the drainage basin of the major Siberian rivers combined with higher precipitation in a warming climate potentially increase the flux of terrestrial derived dissolved organic matter (tDOM) into the Arctic Ocean. The Laptev (LS) and East Siberian Seas (ESS) receive enormous amounts of tDOM-rich river water, which undergoes at least one freeze-melt cycle in the Siberian Arctic shelf seas. To better understand how freezing and melting affect the tDOM dynamics in the LS and ESS, we sampled sea ice, river and seawater for their dissolved organic carbon (DOC) concentration and the colored fraction of dissolved organic matter. The sampling took place in different seasons over a period of 9 years (2010–2019). Our results suggest that the main factor regulating the tDOM distribution in the LS and ESS is the mixing of marine waters with freshwater sources carrying different tDOM concentrations. Of particular importance in this context are the 211 km3 of meltwater from land-fast ice from the LS, containing ~ 0.3 Tg DOC, which in spring mixes with 245 km3 of river water from the peak spring discharge of the Lena River, carrying ~ 2.4 Tg DOC into the LS. During the ice-free season, tDOM transport on the shelves takes place in the surface mixed layer, with the direction of transport depending on the prevailing wind direction. In winter, about 1.2 Tg of brine-related DOC, which was expelled from the growing land-fast ice in the LS, is transported in the near-surface water layer into the Transpolar Drift Stream that flows from the Siberian Shelf toward Greenland. The actual water depth in which the tDOM-rich brines are transported, depends mainly on the density stratification of the LS and ESS in the preceding summer and the amount of ice produced in winter. We suspect that climate change in the Arctic will fundamentally alter the dynamics of tDOM transport in the Arctic marginal seas, which will also have consequences for the Arctic carbon cycle.

scholarly journals Diazotroph Diversity in the Sea Ice, Melt Ponds, and Surface Waters of the Eurasian Basin of the Central Arctic Ocean

2016 ◽  
Vol 7 ◽  
Author(s):  
Mar Fernández-Méndez ◽  
Kendra A. Turk-Kubo ◽  
Pier L. Buttigieg ◽  
Josephine Z. Rapp ◽  
Thomas Krumpen ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Surface Waters ◽  
Central Arctic Ocean ◽  
Ice Melt ◽  
Melt Ponds ◽  
Eurasian Basin

scholarly journals The Rossby radius in the Arctic Ocean

Ocean Science ◽  
2014 ◽  
Vol 10 (6) ◽  
pp. 967-975 ◽  
Author(s):  
A. J. G. Nurser ◽  
S. Bacon
Keyword(s):  
Arctic Ocean ◽  
General Circulation ◽  
Circulation Model ◽  
Ocean General Circulation Model ◽  
High Arctic ◽  
The Arctic ◽  
Hudson Bay ◽  
Ocean Eddies ◽  
Shelf Seas ◽  
The Impact

Abstract. The first (and second) baroclinic deformation (or Rossby) radii are presented north of ~60° N, focusing on deep basins and shelf seas in the high Arctic Ocean, the Nordic seas, Baffin Bay, Hudson Bay and the Canadian Arctic Archipelago, derived from climatological ocean data. In the high Arctic Ocean, the first Rossby radius increases from ~5 km in the Nansen Basin to ~15 km in the central Canadian Basin. In the shelf seas and elsewhere, values are low (1–7 km), reflecting weak density stratification, shallow water, or both. Seasonality strongly impacts the Rossby radius only in shallow seas, where winter homogenization of the water column can reduce it to below 1 km. Greater detail is seen in the output from an ice–ocean general circulation model, of higher resolution than the climatology. To assess the impact of secular variability, 10 years (2003–2012) of hydrographic stations along 150° W in the Beaufort Gyre are also analysed. The first-mode Rossby radius increases over this period by ~20%. Finally, we review the observed scales of Arctic Ocean eddies.

scholarly journals Diversity of Arctic pelagic <i>Bacteria</i> with an emphasis on photoheterotrophs: a review

2014 ◽  
Vol 11 (12) ◽  
pp. 3309-3322 ◽  
Author(s):  
D. Boeuf ◽  
F. Humily ◽  
C. Jeanthon
Keyword(s):  
Arctic Ocean ◽  
Heterotrophic Bacteria ◽  
Euphotic Zone ◽  
The Arctic ◽  
Major Influence ◽  
Distinctive Features ◽  
Ice Melt ◽  
Energy Needs ◽  
Continental Shelves ◽  
The Arctic Ocean

Abstract. The Arctic Ocean is a unique marine environment with respect to seasonality of light, temperature, perennial ice cover, and strong stratification. Other important distinctive features are the influence of extensive continental shelves and its interactions with Atlantic and Pacific water masses and freshwater from sea ice melt and rivers. These characteristics have major influence on the biological and biogeochemical processes occurring in this complex natural system. Heterotrophic bacteria are crucial components of marine food webs and have key roles in controlling carbon fluxes in the oceans. Although it was previously thought that these organisms relied on the organic carbon in seawater for all of their energy needs, several recent discoveries now suggest that pelagic bacteria can depart from a strictly heterotrophic lifestyle by obtaining energy through unconventional mechanisms that are linked to the penetration of sunlight into surface waters. These photoheterotrophic mechanisms may play a significant role in the energy budget in the euphotic zone of marine environments. Modifications of light and carbon availability triggered by climate change may favor the photoheterotrophic lifestyle. Here we review advances in our knowledge of the diversity of marine photoheterotrophic bacteria and discuss their significance in the Arctic Ocean gained in the framework of the Malina cruise.

Arctic Ocean State-Changes: Self Interests and Common Interests

2009 ◽  
Vol 1 (1) ◽  
pp. 511-525
Author(s):  
Paul Arthur Berkman
Keyword(s):  
Arctic Ocean ◽  
The Arctic ◽  
International Governance ◽  
State Change ◽  
Central Arctic Ocean ◽  
Nation States ◽  
Free Region ◽  
The Arctic Ocean ◽  
Challenges And Opportunities ◽  
State Changes

Abstract Environmental and geopolitical state-changes are the underlying first principles of the diverse stakeholder positioning in the Arctic Ocean. The Arctic Ocean is changing from an ice-covered region to an ice-free region during the summer, which is an environmental state-change. As provided under the framework of the United Nations Convention on the Law of the Sea (UNCLOS), the central Arctic Ocean currently involves “High-Seas” (beyond the “Exclusive Economic Zones”) and the underlying “Area” of the deep-sea floor (beyond the “Continental Shelves”). Governance applications of this ‘donut’ demography – with international space surrounded by sovereign sectors – would be a geopolitical state-change in the Arctic Ocean. International governance strategies and applications for the central Arctic Ocean have far-reaching implications for the stewardship of other international spaces, which between Antarctica and the ocean beyond national jurisdictions account for nearly 75 percent of the Earth’s surface. In view of planetary-scale strategies for humankind, with frameworks such as climate, the Arctic Ocean underscores the challenges and opportunities to balance the governance of nation states and international spaces centuries into the future.

Characteristics of the Russian shelf seas in the Arctic Ocean regarding the content of heavy minerals in surface sediments: new data

2021 ◽  
Author(s):  
Elena Popova
Keyword(s):  
Arctic Ocean ◽  
Environmental Science ◽  
Barents Sea ◽  
Source Rocks ◽  
Heavy Minerals ◽  
The Arctic ◽  
Arctic Seas ◽  
Riverine Input ◽  
The Arctic Ocean ◽  
Shelf Seas

&lt;p&gt;Such factors as climate, currents, morphology, riverine input, and the source rocks influence the composition of the sediments in the Arctic Ocean. Heavy minerals being quite inert in terms of transport can reflect the geology of the source rock clearly and indicate the riverine input. There is a long history of studying the heavy mineral composition of the sediments in the Arctic Ocean. The works by Vogt (1997), Kosheleva (1999), Stein (2008), and others study the distribution of the minerals both on a sea scale and oceanwide. The current study covers Russian shelf seas: Barents, Kara, Laptev, East Siberian, and Chukchi Seas. To collect the material several data sources were used: data collected by the institute VNIIOkeangeologia during numerous expeditions since 2000 for mapping the shelf, data from the old expedition reports (earlier than 2000) taken from the geological funds, and datasets from PANGAEA (www.pangaea.de). About 82 minerals and groups of minerals were included in the joint dataset. The density of the sample points varied significantly in all seas: 1394 data points in the Barents Sea, 713 in the Kara Sea, 487 in the Laptev Sea, 196 in the East Siberian Sea, and 245 in the Chukchi Sea. These data allowed comparing the areas in terms of major minerals and associations. Maps of prevailing and significant components were created in ODV (Schlitzer, 2020) to demonstrate the differences between the seas and indicate the sites of remarkable changes in the source rocks. Additionally, the standardized ratio was calculated to perform quantitative comparison: the sea average was divided by the weighted sea average and then the ratio of that number to the mineral average was found. Only the minerals present in at least four seas and amounting to at least 20 points per sea were considered. As a result, water areas with the highest content of particular minerals were detected. The ratio varied from 0 to 3,4. Combining the ratio data for various minerals allowed mapping specific groups or provinces for every sea and within the seas.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;Kosheleva, V.A., &amp; Yashin, D.S. (1999). Bottom Sediments of the Arctic Seas. St. Petersburg: VNIIOkeangeologia, 286pp. (in Russian).&lt;/p&gt;&lt;p&gt;PANGAEA. Data Publisher for Earth &amp; Environmental Science https://www.pangaea.de/&lt;/p&gt;&lt;p&gt;Schlitzer, R. (2020). Ocean Data View, Retrieved from https://odv.awi.de.&lt;/p&gt;&lt;p&gt;Stein, R. (2008). Arctic Ocean Sediments: Processes, Proxies, and Paleoenvironment. Oxford: Elsevier, 602pp.&lt;/p&gt;&lt;p&gt;Vogt, C. (1997). Regional and temporal variations of mineral assemblages in Arctic Ocean sediments as a climatic indicator during glacial/interglacial changes. Berichte Zur Polarforschung, 251, 309pp.&lt;/p&gt;

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