Impacts of water depth, sediment pigment concentration, and benthic macrofaunal biomass on sediment oxygen demand in the western Arctic Ocean

2005 ◽  
Vol 62 (8) ◽  
pp. 1756-1765 ◽  
Author(s):  
Lisa M Clough ◽  
Paul E Renaud ◽  
William G Ambrose Jr.
Keyword(s):  
Arctic Ocean ◽  
Water Depth ◽  
Surface Sediment ◽  
Oxygen Demand ◽  
Sediment Oxygen Demand ◽  
Pigment Concentration ◽  
The Arctic ◽  
Western Arctic Ocean ◽  
Western Arctic ◽  
Shelf Station

We investigated the impacts of water depth, sediment pigment concentration, and benthic macrofaunal biomass on sediment oxygen demand (SOD) during three cruises to the western Arctic Ocean. SOD values were similar to those of most studies from the Arctic and ranged from a high of 20.68 mmol O2·m–2·day–1 at a shallow shelf station to a low of 0.29 mmol O2·m–2·day–1 at the deepest basin station (3648 m). SOD was significantly greater at shallow sites (<500 m; mean = 7.39 mmol O2·m–2·day–1; standard deviation (SD) = ±5.38) than at deep sites (>500 m; mean = 1.39 mmol O2·m–2·day–1; SD = ±0.96). As hypothesized, SOD was negatively correlated with water depth and positively correlated with both surface-sediment pigment concentration and macrofaunal biomass, with macrofaunal biomass explaining approximately 74% of the variability in SOD. We propose that higher macrofauna-normalized respiration rates (i.e., SOD divided by macrofaunal biomass) in deep water indicate that microbial–meiofaunal respiration predominates in deep versus shallow water. Finally, deeper stations associated with Barrow Canyon had SODs, benthic macrofaunal biomass, and surface-sediment pigment concentrations that were similar to those of shallower shelf locations, suggesting down-canyon transport of organic material.

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

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.

Importance of Seasonal Sea Ice in the Western Arctic Ocean to the Arctic and Global Microplastic Budgets

2021 ◽  
pp. 125971
Author(s):  
Seung-Kyu Kim ◽  
Hee-Jee Lee ◽  
Ji-Su Kim ◽  
Sung-Ho Kang ◽  
Eun-Jin Yang ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
The Arctic ◽  
Western Arctic Ocean ◽  
Western Arctic

Summer N₂O dynamics in the western Arctic Ocean : Distributions, Processes, and Fluxes

2020 ◽  
Author(s):  
Seong-Su Kim ◽  
Sung-Ho Kang ◽  
Eun Jin Yang ◽  
Il-Nam Kim
Keyword(s):  
Arctic Ocean ◽  
Positive Relationship ◽  
Chukchi Sea ◽  
Negative Relationship ◽  
The Arctic ◽  
Biogeochemical Processes ◽  
High Solubility ◽  
Western Arctic Ocean ◽  
Western Arctic ◽  
Relationship Of

&lt;p&gt;We collect seawater samples from 32 stations for N&lt;sub&gt;2&lt;/sub&gt;O analysis between August 6 and August 25, during 2017 ARA08B cruise in western Arctic Ocean (WAO), covering from Southern Chukchi Sea (SC) to Northern Chukchi Sea (NC). At surface depth (~50 m), N&lt;sub&gt;2&lt;/sub&gt;O concentrations were 10.9&amp;#8210;19.4 nmol L&lt;sup&gt;-1&lt;/sup&gt;, and distinct pattern was observed between SC and NC. N&lt;sub&gt;2&lt;/sub&gt;O concentrations were increased from surface to bottom (~50 m) at SC, corresponding to positive relationship of &amp;#8710;N&lt;sub&gt;2&lt;/sub&gt;O (N&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;measured &lt;/sub&gt;- N&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;equilibrium&lt;/sub&gt;) with DIN (NO&lt;sub&gt;3&amp;#173;&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt; + NO&lt;sub&gt;2&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt;) and negative relationship between &amp;#8710;N&lt;sub&gt;2&lt;/sub&gt;O and N&lt;sup&gt;*&lt;/sup&gt;. It suggests that nitrification and denitrification are the main processes to produce N&lt;sub&gt;2&lt;/sub&gt;O at SC. On the other hand, N&lt;sub&gt;2&lt;/sub&gt;O concentration at NC increased from the south to north, and remained vertically constant. It may be the result of physical processes such as dilution by sea ice melting water, and high solubility that affected by low temperature and low salinity. The highest N&lt;sub&gt;2&lt;/sub&gt;O concentrations were observed at intermediate depth (50&amp;#8210;200 m), ranging 13.4&amp;#8210;21.9 nmol L&lt;sup&gt;-1&lt;/sup&gt;. It would be determined by high solubility and active biogeochemical processes synthetically. Concentrations of N&lt;sub&gt;2&lt;/sub&gt;O were rapidly diminished to 400 m, ranging 10.2&amp;#8210;14.1 nmol L&lt;sup&gt;-1&lt;/sup&gt;, and did not be remarkably altered under 400 m, ranging 11.3&amp;#8210;13.7 nmol L&lt;sup&gt;-1&lt;/sup&gt;. It might be affected by advection of Atlantic Water (AW) and existence of Arctic Bottom Water (ABW), and influence of biogeochemical processes was negligible at deep and bottom depth (below 200 m). N&lt;sub&gt;2&lt;/sub&gt;O flux was calculated to determine that the WAO is sources or sinks region for atmospheric N&lt;sub&gt;2&lt;/sub&gt;O. Positive N&lt;sub&gt;2&lt;/sub&gt;O flux was observed at SC, and it indicate that N&lt;sub&gt;2&lt;/sub&gt;O gas is released to atmosphere at SC. Negative value of N&lt;sub&gt;2&lt;/sub&gt;O flux at NC suggest that atmospheric N&lt;sub&gt;2&lt;/sub&gt;O is absorbed into NC. Furthermore, positive relationship of N&lt;sub&gt;2&lt;/sub&gt;O flux with environmental parameters (temperature, salinity, and &amp;#8710;N&lt;sub&gt;2&lt;/sub&gt;O) also observed in WAO. These results provide comprehensive information of the spatial N&lt;sub&gt;2&lt;/sub&gt;O distribution and main processes which decide N&lt;sub&gt;2&lt;/sub&gt;O distribution in WAO, and also suggest that air-sea N&lt;sub&gt;2&lt;/sub&gt;O flux could be affected by changing environments of the Arctic Ocean.&lt;/p&gt;

scholarly journals The Wavenumber–Frequency Spectrum of Vortical and Internal-Wave Shear in the Western Arctic Ocean

2008 ◽  
Vol 38 (2) ◽  
pp. 277-290 ◽  
Author(s):  
Robert Pinkel
Keyword(s):  
Internal Wave ◽  
Arctic Ocean ◽  
Heat Budget ◽  
The Arctic ◽  
Motion Field ◽  
Wave Band ◽  
Frequency Spectra ◽  
Western Arctic Ocean ◽  
Western Arctic ◽  
Vertical Scales

Abstract Upper-ocean velocity and shear data were obtained from Doppler sonars operated at the Surface Heat Budget of the Arctic Ocean (SHEBA) ice camp during the camp’s year-long drift across the western Arctic Ocean. These are used to estimate wavenumber–frequency spectra of shear E(κz, σ) during three selected time intervals. The Arctic shear spectra are similar in form to typical oceanic spectra, except that they have roughly an order-of-magnitude less variance. The slope of the frequency dependence is also steeper (σ−3–σ−4 for σ &lt; −f, where f is the Coriolis frequency) in the internal-wave band, and the vertical wavenumber dependence is centered at higher wavenumber. Given the small vertical scales and low velocities of Arctic signals, a careful assessment of sonar precision is performed. Fluctuations at vertical scales &gt; 10 m and time scales &gt; 1 h are deemed significant. At subinertial frequencies, a vortical (quasigeostrophic) contribution to the shear spectrum is seen. The vertical wavenumber dependence of the shear spectrum in this frequency range is distinctly red, in contrast to the band-limited form of the superinertial spectrum; that is, E(κz, σ) ∼ κ−1z for |σ| &lt; f. A fundamental characteristic of both the internal-wave and vortical spectral contributions is that the observed frequency bandwidth increases linearly with increasing vertical wavenumber magnitude. This is interpreted as the signature of the Doppler shifting of the observations by random “background” currents and by ice motion and is responsible for the distinctly “nonseparable” nature of the shear spectrum. As a consequence, the vertical wavenumber spectrum of the subinertial motion field is white: Evort(κz) = ∫Evort(κz, σ) dσ ∼ κ0z.

scholarly journals Autumn in the Arctic

Eos ◽  
2018 ◽  
Vol 99 ◽  
Author(s):  
Jim Thomson
Keyword(s):  
Arctic Ocean ◽  
Field Research ◽  
The Arctic ◽  
Western Arctic Ocean ◽  
Western Arctic

With refreezing in the western Arctic Ocean shifting later into the autumn, field research on changing air-ocean-ice interactions suggests that the Arctic is shifting to a more seasonal system.

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.

Mesozooplankton prey preference and grazing impact in the western Arctic Ocean

2009 ◽  
Vol 56 (17) ◽  
pp. 1274-1289 ◽  
Author(s):  
Robert G. Campbell ◽  
Evelyn B. Sherr ◽  
Carin J. Ashjian ◽  
Stéphane Plourde ◽  
Barry F. Sherr ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Prey Preference ◽  
Grazing Impact ◽  
Western Arctic Ocean ◽  
Western Arctic
Sign in / Sign up

Export Citation Format

Share Document