Contrasting spatial distributions of surface sediment compositions from the Emperor Seamount Chain, North Pacific

2020 ◽  
Author(s):  
Jie Chen ◽  
Jianjun Zou ◽  
Xuefa Shi ◽  
Lester Lembke-Jene ◽  
Dirk Nürnberg ◽  
...  
Keyword(s):  
Negative Correlation ◽  
North Pacific ◽  
Surface Sediments ◽  
Marine Ecosystem ◽  
Spatial Distributions ◽  
Geochemical Composition ◽  
The North ◽  
Clayey Silt ◽  
Seamount Chain ◽  
Emperor Seamount Chain

<p>The Emperor Seamount chain is located in the North Pacific Ocean and beneath the Northern Westerly wind belt. It extends from the subtropical to subarctic North Pacific oceans between 30°N-50°N. Modern observations have shown this region has complex physical oceanic processes, including the Kuroshio Extension, the Oyashio Current, the polar front and the subarctic front. A large amount of dust from the central Asian continent is delivered to this area, which affects the regional marine ecosystem and the global carbon cycle. Due to the lack of sediments from the Emperor Seamount chain, few studies have examined the composition of surface sediments in this ocean realm. On the basis of 50 samples collected during the SO264 Expedition in 2018 using multicorers, we investigate the spatial distributions of sediment grainsize, total organic carbon, CaCO<sub>3</sub> and major and minor elements in surface sediments of this ocean realm. Our data show that the detritus sediments mainly consist of siltly sand and clayey silt with more coarse fractions between ~45°N and 48°N, which has strong negative correlations with water depth. The content of CaCO<sub>3</sub> varies between 0.04% and 83.67% with higher values at the south of 48°N. The TOC content ranges between 0.07% and 1.36% with lower values (<0.3%) occurring at the north of ~45°N. The concentration of ∑REEs ranges from 31 ppm to 136 ppm with lower values between ~45° N and 48°N. There is significant positive Eu anomaly at all stations, indicating widespread occurrence of volcanic detritus. A significant negative correlation between sediment grainsize and ∑REEs and some lithophile elements, such as Al<sub>2</sub>O<sub>3</sub>, Fe<sub>2</sub>O<sub>3</sub>, K<sub>2</sub>O, Th, REEs, etc., indicates a strong effect of sediment grainsize on sediment geochemical composition. A strong negative correlation between Al and CaCO<sub>3</sub> suggests contrasting sources, such as terrigenous vs biogenic sources, respectively. Our data confirms the contributions of terrigenous, volcanic and biogenic materials to the bulk sediment with contrasting spatial distribution along the Emperor Seamount Chain.</p><p>Note: This study was supported by the National Natural Science Foundation of China (Grant No.41876065, U1606401) and National Program on Global Change and Air-Sea Interaction(GASI-GEOGE-04). </p>

scholarly journals Geochemistry of Surface Sediments From the Emperor Seamount Chain, North Pacific

2021 ◽  
Vol 9 ◽  
Author(s):  
Jie Chen ◽  
Jianjun Zou ◽  
Aimei Zhu ◽  
Xuefa Shi ◽  
Dirk Nürnberg ◽  
...  
Keyword(s):  
Grain Size ◽  
Rare Earth ◽  
Rare Earth Elements ◽  
Water Depth ◽  
Surface Sediment ◽  
North Pacific ◽  
The North ◽  
Seamount Chain ◽  
The North Pacific ◽  
Emperor Seamount Chain

Investigating the composition and distribution of pelagic marine sediments is fundamental in the field of marine sedimentology. The spatial distributions of surface sediment are unclear due to limited investigation along the Emperor Seamount Chain of the North Pacific. In this study, a suite of sedimentological and geochemical proxies were analyzed, including the sediment grain size, organic carbon, CaCO3, major and rare earth elements of 50 surface sediment samples from the Emperor Seamount Chain, spanning from ∼33°N to ∼52°N. On the basis of sedimentary components, we divide them into three Zones (I, II, and III) spatially with distinct features. Sediments in Zone I (∼33°N–44°N) and Zone III (49.8°N–53°N) are dominated by clayey silt, and mainly consist of sand and silty sand in Zone II. The mean grain size of the sortable silt shows that the hydrodynamic condition in the study area is significantly stronger than that of the abyssal plain, especially at the water depth of 1,000–2,500 m. The CaCO3 contents in sediments above 4,000 m range from 20 to 84% but decrease sharply to less than 1.5% below 4,000 m, confirming that the water depth of 4,000 m is the carbonate compensation depth of the study area. Strong positive correlations between Al2O3 and Fe2O3, TiO2, MgO, and K2O (R > 0.9) in the bulk sediments indicate pronounced contributions of terrigenous materials from surrounding continent mass to the study area. Furthermore, the eolian dust makes contributions to the composition of bulk sediments as confirmed by rare earth elements. There is no significant correlation between grain size and major and minor elements, which indicates that the sedimentary grain size does not exert important effects on terrigenous components. There is significant negative δCe and positive δEu anomalies at all stations. The negative Ce anomaly mainly exists in carbonate-rich sediments, inheriting the signal of seawater. The positive Eu anomaly indicates widespread volcanism contributions to the study area from active volcanic islands arcs around the North Pacific. The relative contributions of terrestrial, volcanic, and biogenic materials vary with latitude and water depth in the study area.

Diagenetic manganese and iron cycling and implications for past redox conditions in sediments along the Emperor Seamount Chain, NW Pacific Ocean

2020 ◽  
Author(s):  
Sabine Kasten ◽  
Jessica Volz ◽  
Walter Geibert ◽  
Ingrid Stimac ◽  
Denise Bethke ◽  
...  
Keyword(s):  
Carbon Sequestration ◽  
Pacific Ocean ◽  
Pore Water ◽  
North Pacific ◽  
Oxygen Depletion ◽  
Redox Conditions ◽  
Northwest Pacific ◽  
The North ◽  
Seamount Chain ◽  
Emperor Seamount Chain

<p>The deep water of the North Pacific Ocean is enriched in CO<sub>2</sub> and nutrients as a result of organic matter degradation in the water column and surface sediments. Due to its large volume, the deep North Pacific may have played a fundamental role for the postulated glacial carbon sequestration leading to the observed drawdown of atmospheric CO<sub>2</sub>. As a consequence of increased CO<sub>2</sub> levels in the deep glacial ocean, bottom-water oxygen concentrations must have been correspondingly low compared to current oxygenated conditions (e.g., Anderson et al., 2019). Previous studies on sediments from the NW Pacific Ocean have provided evidence that glacial bottom‑water O<sub>2</sub> concentrations were significantly lower than today, which have induced suboxic surface sediment redox conditions (Jaccard et al., 2009) and have altered the primary sediment composition and properties of glacial deposits (e.g., magnetic susceptibility) due to diagenetic processes (Korff et al., 2016).</p><p>We have investigated seven 10- to 15-m-long sediment cores along a S-N transect at the Emperor Seamount Chain taken during RV SONNE cruise SO264 in order to (1) geochemically characterize the sediments and, (2) reconstruct past sediment redox conditions. The cores were retrieved from water depths between 3.5 and 5.7 km from organic-poor siliciclastic‑carbonaceous sediments in the South to more organic-rich siliciclastic‑siliceous sediments in the North with tephra layers found throughout all cores (Nürnberg et al., 2018).</p><p>Mn<sup>2+</sup> is released into the pore water at all study sites with increasing Mn<sup>2+</sup> concentrations below 20‑30 cm sediment depth. Pore-water Mn<sup>2+</sup> reraches up to 190 µM in siliciclastic‑siliceous sediments most likely associated with high rates of dissimilatory Mn(IV) reduction. The solid‑phase composition of a core taken from the Minnetonka Seamount (47°44’N, 168°40’E) at 4 km water depth shows Mn/Al ratios below 0.0003. These ratios are much lower than the average MORB Mn/Al value of 0.013 (Klein, 2004), which further indicates that Mn has been diagenetically lost from these sediments. As pore-water Fe<sup>2+</sup> concentrations are below detection limit at the Minnetonka Seamount and the depth distribution of solid-phase Fe/Al is mostly constant with ratios close to the average MORB Mn/Al value of 0.59 (Klein, 2004), Fe has probably not been diagenetically redistributed at this site. Pore‑water Fe<sup>2+</sup> concentrations of up to 20 µM are only found at two sites most likely as a result of dissimilatory Fe(III) reduction due to higher fluxes of organic material to the seafloor compared to the other sites.</p><p>References</p><p>Anderson, R.F., et al., 2019. Deep-sea oxygen depletion and ocean carbon sequestration during the last ice age. Global Biogeochem. Cycles 33, 301-317. </p><p>Jaccard, S.L., et al., 2009. Subarctic Pacific evidence for a glacial deepening of the oceanic respired carbon pool. Earth Planet. Sci. Lett. 277, 156‑165. </p><p>Klein, E.M., 2004. Geochemistry of the Igneous Oceanic Crust. In: Holland, H.D., Turekian, K.K. (Eds.), Treatise on Geochemistry, Vol.3. Elsevier, Amsterdam, pp. 433‑463.</p><p>Korff, L., et al., 2016. Cyclic magnetite dissolution in Pleistocene sediments of the abyssal northwest Pacific Ocean: evidence for glacial oxygen depletion and carbon trapping. Paleoceanography 31, 600‑624. </p><p>Nürnberg, D., 2018. RV SONNE Fahrtbericht /Cruise Report SO264, SONNE-EMPEROR, 30.6. – 24.8.2018. </p>

scholarly journals Quantifying the influence of CO<sub>2</sub> seasonality on future ocean acidification

2015 ◽  
Vol 12 (8) ◽  
pp. 5907-5940
Author(s):  
T. P. Sasse ◽  
B. I. McNeil ◽  
R. J. Matear ◽  
A. Lenton
Keyword(s):  
Ocean Acidification ◽  
North Pacific ◽  
Dissolved Inorganic Carbon ◽  
Marine Ecosystem ◽  
Global Ocean ◽  
Saturation State ◽  
The North ◽  
Data Limitations ◽  
The Future ◽  
The North Pacific

Abstract. Ocean acidification is a predictable consequence of rising atmospheric carbon dioxide (CO2), and is highly likely to impact the entire marine ecosystem – from plankton at the base to fish at the top. Factors which are expected to be impacted include reproductive health, organism growth and species composition and distribution. Predicting when critical threshold values will be reached is crucial for projecting the future health of marine ecosystems and for marine resources planning and management. The impacts of ocean acidification will be first felt at the seasonal scale, however our understanding how seasonal variability will influence rates of future ocean acidification remains poorly constrained due to current model and data limitations. To address this issue, we first quantified the seasonal cycle of aragonite saturation state utilizing new data-based estimates of global ocean surface dissolved inorganic carbon and alkalinity. This seasonality was then combined with earth system model projections under different emissions scenarios (RCPs 2.6, 4.5 and 8.5) to provide new insights into future aragonite under-saturation onset. Under a high emissions scenario (RCP 8.5), our results suggest accounting for seasonality will bring forward the initial onset of month-long under-saturation by 17 years compared to annual-mean estimates, with differences extending up to 35 ± 17 years in the North Pacific due to strong regional seasonality. Our results also show large-scale under-saturation once atmospheric CO2 reaches 486 ppm in the North Pacific and 511 ppm in the Southern Ocean independent of emission scenario. Our results suggest that accounting for seasonality is critical to projecting the future impacts of ocean acidification on the marine environment.

scholarly journals Report on hydrozoans (Cnidaria), excluding Stylasteridae, from the Emperor Seamounts, western North Pacific Ocean

Zootaxa ◽  
2021 ◽  
Vol 4950 (2) ◽  
pp. 201-247
Author(s):  
DALE R. CALDER ◽  
LES WATLING
Keyword(s):  
Pacific Ocean ◽  
North Pacific ◽  
Western North Pacific ◽  
Cold Water ◽  
North Pacific Ocean ◽  
First Record ◽  
Western North Pacific Ocean ◽  
The North ◽  
Seamount Chain ◽  
The North Pacific

Fourteen species of hydroids, collected during August 2019 by ROV SuBastian of the Schmidt Ocean Institute, are reported from the Emperor Seamount chain in the western North Pacific Ocean. Two others, Candelabrum sp. and Eudendrium sp., were observed only on videos taken by the ROV. From collections and video observations, eight species of hydroids were found at Jingū Seamount, three at Yomei, Nintoku, and Annei seamounts, and one at Koko Seamount and Hess Rise. At Suiko and Godaigo seamounts, hydroids were seen in videos but they could not be identified. Latebrahydra schulzei, an endobiotic associate of the hexactinellid sponge Walteria flemmingii Schulze, 1886 from Annei Seamount and Hess Rise, is described as a new genus and species tentatively attributed to Hydractiniidae L. Agassiz, 1862. Another new species, Hydractinia galeai, is described from Jingū Seamount. Among its distinctive characters is a zooid termed a sellectozooid, likely serving in both food capture and defence. Hydroids examined from Yomei, Nintoku, and Jingū seamounts are elements of a cold-water fauna occurring in the North Pacific Boreal Bathyal province, while those of Annei and Koko seamounts, and Hess Rise, are part of the biota of the Central North Pacific Bathyal province. Hydroids identified as Bouillonia sp., from Nintoku Seamount, represent the first record of this predominantly deep water tubulariid genus in the North Pacific Ocean. Bonneviella superba Nutting, 1915, from Jingū Seamount, is reported for the first time outside the Aleutian Islands. Bonneviella cf. gracilis Fraser, 1939, known elsewhere only from Dease Strait in the western Canadian Arctic, was also collected on Jingū. In addition to hydroids, medusae of Ptychogastria polaris Allman, 1878 were observed on videos from Nintoku, Jingū, Annei, and Koko seamounts at depths between 2423–1422 m. An unidentified siphonophore was observed near bottom at 2282 m on Nintoku Seamount. 

A Global Eddy-Resolving Coupled Physical-Biological Model: Physical Influences on a Marine Ecosystem in the North Pacific

SIMULATION ◽  
2006 ◽  
Vol 82 (7) ◽  
pp. 467-474 ◽  
Author(s):  
Yoshikazu Sasai ◽  
Akio Ishida ◽  
Hideharu Sasaki ◽  
Shintaro Kawahara ◽  
Hitoshi Uehara ◽  
...  
Keyword(s):  
North Pacific ◽  
Marine Ecosystem ◽  
Biological Model ◽  
The North ◽  
The North Pacific

scholarly journals Longer Time-Scale Variability of Atmospheric Vertical Motion over the Tibetan Plateau and North Pacific and the Climate in East Asia

Atmosphere ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 630
Author(s):  
Rongxiang Tian ◽  
Yaoming Ma ◽  
Weiqiang Ma ◽  
Xiuyi Zhao ◽  
Duo Zha
Keyword(s):  
Tibetan Plateau ◽  
East Asia ◽  
Negative Correlation ◽  
North Pacific ◽  
Maximum Velocity ◽  
Vertical Motion ◽  
The Tibetan Plateau ◽  
Upward Movement ◽  
The North ◽  
The North Pacific

The vertical motion of air is closely related to the amount of precipitation that falls in a particular region. The Tibetan Plateau and the North Pacific are important determinants of the East Asian climate. We use climate diagnosis and statistical analysis to study the vertical motion of the air over the North Pacific and Tibetan Plateau and the relationship between the vertical motion of air over them and the climate in East Asia. Here we show that there is a downward movement of air over the Tibetan Plateau during the winter, with a maximum velocity of downward movement at 500 hPa, whereas there is an upward movement of air with a maximum velocity of upward movement at 600 hPa during the summer. Precipitation in East Asia has a significant negative correlation (The correlation coefficient exceeds −0.463 and confidence level is greater than 99%) with the vertical motion of air over the Tibetan Plateau and the North Pacific during both the winter and summer. There is also a negative correlation of precipitation in the region south of the Yangtze River with the vertical motion of air over the Tibetan Plateau in winter, whereas the area of negative correlation to the vertical motion of air over the North Pacific in winter is located to the east of the Tibetan Plateau and the Yangtze–Huaihe river basin. The research results provide a climatic framework for the vertical motion of air over both the Tibetan Plateau and the North Pacific.

scholarly journals Quantifying the influence of CO<sub>2</sub> seasonality on future aragonite undersaturation onset

2015 ◽  
Vol 12 (20) ◽  
pp. 6017-6031 ◽  
Author(s):  
T. P. Sasse ◽  
B. I. McNeil ◽  
R. J. Matear ◽  
A. Lenton
Keyword(s):  
Ocean Acidification ◽  
North Pacific ◽  
Dissolved Inorganic Carbon ◽  
Marine Ecosystem ◽  
Global Ocean ◽  
Saturation State ◽  
The North ◽  
Data Limitations ◽  
The Future ◽  
The North Pacific

Abstract. Ocean acidification is a predictable consequence of rising atmospheric carbon dioxide (CO2), and is highly likely to impact the entire marine ecosystem – from plankton at the base of the food chain to fish at the top. Factors which are expected to be impacted include reproductive health, organism growth and species composition and distribution. Predicting when critical threshold values will be reached is crucial for projecting the future health of marine ecosystems and for marine resources planning and management. The impacts of ocean acidification will be first felt at the seasonal scale, however our understanding how seasonal variability will influence rates of future ocean acidification remains poorly constrained due to current model and data limitations. To address this issue, we first quantified the seasonal cycle of aragonite saturation state utilizing new data-based estimates of global ocean-surface dissolved inorganic carbon and alkalinity. This seasonality was then combined with earth system model projections under different emissions scenarios (representative concentration pathways; RCPs 2.6, 4.5 and 8.5) to provide new insights into future aragonite undersaturation onset. Under a high emissions scenario (RCP 8.5), our results suggest accounting for seasonality will bring forward the initial onset of month-long undersaturation by 17 ± 10 years compared to annual-mean estimates, with differences extending up to 35 ± 16 years in the North Pacific due to strong regional seasonality. This earlier onset will result in large-scale undersaturation once atmospheric CO2 reaches 496 ppm in the North Pacific and 511 ppm in the Southern Ocean, independent of emission scenario. This work suggests accounting for seasonality is critical to projecting the future impacts of ocean acidification on the marine environment.

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