NORTHEAST PACIFIC SEAWATER RADIOCARBON RECORDED IN ABALONE SHELLS OBTAINED FROM OTSUCHI BAY, JAPAN

Radiocarbon ◽  
2019 ◽  
pp. 1-10 ◽  
Author(s):  
Kosuke Ota ◽  
Yusuke Yokoyama ◽  
Yosuke Miyairi ◽  
Jun Hayakawa ◽  
Naomi Satoh ◽  
...  
Keyword(s):  
Ocean Circulation ◽  
Large Scale ◽  
Dissolved Inorganic Carbon ◽  
Coastal Ecosystems ◽  
Coastal Regions ◽  
Otsuchi Bay ◽  
The Pacific ◽  
Abalone Shell ◽  
The Relationship ◽  
Northern Japan

ABSTRACTReconstructing past ocean currents in the coastal regions is necessary to better understand the relationship between oceanographic changes and coastal ecosystems. It is known that variations have occurred with large-scale climate changes such as ENSO (El Niño Southern Oscillations) and PDO (Pacific Decadal Oscillations). Thus, reconstruction of past seawater conditions in coastal regions is needed to better understand the relationship between oceanographic changes and coastal ecosystems. Seawater radiocarbon is a unique proxy to understand the properties of water masses. Reef-building corals have been employed extensively and successfully in conducting this type of research into past ocean circulation histories. However, their distribution is limited to the low latitudes and hence alternative archives are required for studies in mid to high-latitude locations. Here, we use abalone shell samples obtained from Otsuchi Bay located in the Tohoku region on the Pacific coast of Northern Japan. Radiocarbon in abalone shells was compared with dissolved inorganic carbon in two-year-long records of river water as well as seawater. The data indicate that abalone shells can be used to reconstruct past seawater radiocarbon variations in northern Japan where coral skeletons are not available for ocean mixing studies.

scholarly journals Can seafloor voltage cables be used to study large-scale circulation? An investigation in the Pacific Ocean

Ocean Science ◽  
2021 ◽  
Vol 17 (1) ◽  
pp. 383-392
Author(s):  
Jakub Velímský ◽  
Neesha R. Schnepf ◽  
Manoj C. Nair ◽  
Natalie P. Thomas
Keyword(s):  
Pacific Ocean ◽  
Flow Velocity ◽  
Ocean Circulation ◽  
Large Scale ◽  
Eastern Pacific ◽  
Low Flow ◽  
Large Scale Circulation ◽  
Numerical Predictions ◽  
The Pacific ◽  
The Pacific Ocean

Abstract. Marine electromagnetic (EM) signals largely depend on three factors: flow velocity, Earth's main magnetic field, and seawater's electrical conductivity (which depends on the local temperature and salinity). Because of this, there has been recent interest in using marine EM signals to monitor and study ocean circulation. Our study utilizes voltage data from retired seafloor telecommunication cables in the Pacific Ocean to examine whether such cables could be used to monitor circulation velocity or transport on large oceanic scales. We process the cable data to isolate the seasonal and monthly variations and then evaluate the correlation between the processed data and numerical predictions of the electric field induced by an estimate of ocean circulation. We find that the correlation between cable voltage data and numerical predictions strongly depends on both the strength and coherence of the model velocities flowing across the cable, the local EM environment, as well as the length of the cable. The cable within the Kuroshio Current had good correlation between data and predictions, whereas two of the cables in the Eastern Pacific Gyre – a region with both low flow speeds and interfering velocity directions across the cable – did not have any clear correlation between data and predictions. Meanwhile, a third cable also located in the Eastern Pacific Gyre showed good correlation between data and predictions – although the cable is very long and the speeds were low, it was located in a region of coherent flow velocity across the cable. While much improvement is needed before utilizing seafloor voltage cables to study and monitor oceanic circulation across wide regions, we believe that with additional work, the answer to the question of whether or not seafloor voltage cables can be used to study large-scale circulation may eventually be yes.

scholarly journals A synthesis of marine sediment core δ<sup>13</sup>C data over the last 150 000 years

2010 ◽  
Vol 6 (5) ◽  
pp. 645-673 ◽  
Author(s):  
K. I. C. Oliver ◽  
B. A. A. Hoogakker ◽  
S. Crowhurst ◽  
G. M. Henderson ◽  
R. E. M. Rickaby ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Carbon Storage ◽  
Ocean Circulation ◽  
Marine Sediment ◽  
Large Scale ◽  
Dissolved Inorganic Carbon ◽  
Deep Ocean ◽  
Global Ocean ◽  
Last Interglacial ◽  
Basin Scale

Abstract. The isotopic composition of carbon, δ13C, in seawater is used in reconstructions of ocean circulation, marine productivity, air-sea gas exchange, and biosphere carbon storage. Here, a synthesis of δ13C measurements taken from foraminifera in marine sediment cores over the last 150 000 years is presented. The dataset comprises previously published and unpublished data from benthic and planktonic records throughout the global ocean. Data are placed on a common δ18O age scale suitable for examining orbital timescale variability but not millennial events, which are removed by a 10 ka filter. Error estimates account for the resolution and scatter of the original data, and uncertainty in the relationship between δ13C of calcite and of dissolved inorganic carbon (DIC) in seawater. This will assist comparison with δ13C of DIC output from models, which can be further improved using model outputs such as temperature, DIC concentration, and alkalinity to improve estimates of fractionation during calcite formation. High global deep ocean δ13C, indicating isotopically heavy carbon, is obtained during Marine Isotope Stages (MIS) 1, 3, 5a, c and e, and low δ13C during MIS 2, 4 and 6, which are temperature minima, with larger amplitude variability in the Atlantic Ocean than the Pacific Ocean. This is likely to result from changes in biosphere carbon storage, modulated by changes in ocean circulation, productivity, and air-sea gas exchange. The North Atlantic vertical δ13C gradient is greater during temperature minima than temperature maxima, attributed to changes in the spatial extent of Atlantic source waters. There are insufficient data from shallower than 2500 m to obtain a coherent pattern in other ocean basins. The data synthesis indicates that basin-scale δ13C during the last interglacial (MIS 5e) is not clearly distinguishable from the Holocene (MIS 1) or from MIS 5a and 5c, despite significant differences in ice volume and atmospheric CO2 concentration during these intervals. Similarly, MIS 6 is only distinguishable from MIS 2 or 4 due to globally lower δ13C values both in benthic and planktonic data. This result is obtained despite individual records showing differences between these intervals, indicating that care must be used in interpreting large scale signals from a small number of records.

scholarly journals Is Blocking a Circulation Regime?

2007 ◽  
Vol 135 (6) ◽  
pp. 2406-2413 ◽  
Author(s):  
Cristiana Stan ◽  
David M. Straus
Keyword(s):  
Large Scale ◽  
Temperature Anomaly ◽  
Potential Temperature ◽  
Weather Extremes ◽  
Large Scale Circulation ◽  
The Pacific ◽  
Tightly Coupled ◽  
Constant Potential ◽  
The Relationship ◽  
Blocking Index

Abstract The relationship between Pacific blocking and large-scale circulation regimes is investigated. The large-scale circulation regimes are obtained by cluster analysis using the k-means method and tested against significance and reproducibility. Pacific blocking is described using two different methods. In a direct approach, blocking is described by a recently developed blocking index, which is defined in terms of potential temperature anomaly on a surface of constant potential vorticity. In an indirect approach, the occurrence of extreme events is used as a proxy for blockings. Between the two methods there is a causal relationship; the direct one is an indication of the occurrence of the blocking, while the indirect one is a measure of some of the effects caused by the blocking. The results indicate that large-scale circulation regimes are related to but not necessarily tightly coupled to blocking and weather extremes in the Pacific–North America region.

Can seafloor voltage cables be used to study large scale transport? An investigation in the Pacific Ocean.

2020 ◽  
Author(s):  
Neesha Schnepf ◽  
Manoj Nair ◽  
Jakub Velimsky ◽  
Natalie Thomas
Keyword(s):  
Pacific Ocean ◽  
Ocean Circulation ◽  
Large Scale ◽  
Eastern Pacific ◽  
Clear Correlation ◽  
Numerical Predictions ◽  
Main Challenge ◽  
The Pacific ◽  
The Pacific Ocean ◽  
Oceanic Transport

&lt;p&gt;Marine electromagnetic (EM) signals largely depend on three factors: oceanic transport (i.e., depth-integrated flow), the local main magnetic field, and the local seawater conductivity (which depends on the local temperature and salinity). Thus, there is interest in using seafloor telecommunication cables to isolate marine EM signals and study ocean processes because these cables measure voltage differences between their two ends. Data from such cables can provide information on the depth-integrated transport occurring in the water column above the cable. However, these time-varying data are a superposition of all EM fields present at the observatory, no matter what source or process created the field. The main challenge in using such submarine voltage cables to study ocean circulation is properly isolating its signal.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;Our study utilizes voltage data from retired seaoor telecommunication cables in the Pacific Ocean to examine whether such cables could be used to monitor transport on large-oceanic scales. We process the cable data to isolate the seasonal and monthly variations, and evaluate the correlation between the processed data and numerical predictions of the electric field induced by ocean circulation. We find that the correlation between cable voltage data and numerical predictions strongly depends on both the strength and coherence of the transport owing across the cable. The cable within the Kuroshio Current had the highest correlation between data and predictions, whereas two of the cables in the Eastern Pacific gyre (a region with both low transport values and interfering transport signals across the cable) did not have any clear correlation between data and predictions. Meanwhile, a third cable also located in the Eastern Pacific gyre did have correlation between data and predictions, because although the transport values were low, it was located in a region of coherent transport flow across the cable. While much improvement is needed before utilizing seafloor voltage cables to study and monitor oceanic transport across wide oceanic areas, we believe that the answer to our title's questions is yes: seafloor voltage cables can eventually be used to study large-scale transport.&lt;/p&gt;

scholarly journals Modulation of ocean acidification by decadal climate variability in the Gulf of Alaska

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Claudine Hauri ◽  
Rémi Pagès ◽  
Andrew M. P. McDonnell ◽  
Malte F. Stuecker ◽  
Seth L. Danielson ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Ocean Circulation ◽  
Large Scale ◽  
Dissolved Inorganic Carbon ◽  
Model Simulation ◽  
Gulf Of Alaska ◽  
Sea Surface Height ◽  
Sea Surface ◽  
Global Ocean ◽  
Wind Stress Curl

AbstractUptake of anthropogenic carbon dioxide from the atmosphere by the surface ocean is leading to global ocean acidification, but regional variations in ocean circulation and mixing can dampen or accelerate apparent acidification rates. Here we use a regional ocean model simulation for the years 1980 to 2013 and observational data to investigate how ocean fluctuations impact acidification rates in surface waters of the Gulf of Alaska. We find that large-scale atmospheric forcing influenced local winds and upwelling strength, which in turn affected ocean acidification rate. Specifically, variability in local wind stress curl depressed sea surface height in the subpolar gyre over decade-long intervals, which increased upwelling of nitrate- and dissolved inorganic carbon-rich waters and enhanced apparent ocean acidification rates. We define this sea surface height variability as the Northern Gulf of Alaska Oscillation and suggest that it can cause extreme acidification events that are detrimental to ecosystem health and fisheries.

scholarly journals A simple nutrient-dependence mechanism for predicting the stoichiometry of marine ecosystems

2015 ◽  
Vol 112 (27) ◽  
pp. 8199-8204 ◽  
Author(s):  
Eric D. Galbraith ◽  
Adam C. Martiny
Keyword(s):  
Ocean Circulation ◽  
Large Scale ◽  
Phytoplankton Community ◽  
Simple Relationship ◽  
Low Latitude ◽  
Average Composition ◽  
Biogeochemical Models ◽  
The Relationship ◽  
Globally Distributed

It is widely recognized that the stoichiometry of nutrient elements in phytoplankton varies within the ocean. However, there are many conflicting mechanistic explanations for this variability, and it is often ignored in global biogeochemical models and carbon cycle simulations. Here we show that globally distributed particulate P:C varies as a linear function of ambient phosphate concentrations, whereas the N:C varies with ambient nitrate concentrations, but only when nitrate is most scarce. This observation is consistent with the adjustment of the phytoplankton community to local nutrient availability, with greater flexibility of phytoplankton P:C because P is a less abundant cellular component than N. This simple relationship is shown to predict the large-scale, long-term average composition of surface particles throughout large parts of the ocean remarkably well. The relationship implies that most of the observed variation in N:P actually arises from a greater plasticity in the cellular P:C content, relative to N:C, such that as overall macronutrient concentrations decrease, N:P rises. Although other mechanisms are certainly also relevant, this simple relationship can be applied as a first-order basis for predicting organic matter stoichiometry in large-scale biogeochemical models, as illustrated using a simple box model. The results show that including variable P:C makes atmospheric CO2 more sensitive to changes in low latitude export and ocean circulation than a fixed-stoichiometry model. In addition, variable P:C weakens the relationship between preformed phosphate and atmospheric CO2 while implying a more important role for the nitrogen cycle.

Experiments on spin-up and spin-down on a β-plane

1994 ◽  
Vol 271 ◽  
pp. 153-172 ◽  
Author(s):  
W. J. Jillians ◽  
T. Maxworthy
Keyword(s):  
Ocean Circulation ◽  
Large Scale ◽  
Flow Characteristics ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Homogeneous Fluid ◽  
Video Record ◽  
Homogeneous Models ◽  
The One ◽  
The Relationship

Here we study the spin-up and spin-down of a homogeneous fluid with a free surface on an experimental ‘β-plane’ and describe the important features for both cases over a range of parameters. Quantitative values are found for the velocity fields using a new image processing technique that analyses a video record of particle motion and stores the results digitally. Streamlines, pressure fields and vorticity values are found by interpolation techniques and result in a complete description of the flow characteristics. We discuss the relationship between the results of these experiments and those observed in large-scale homogeneous models of ocean circulation, e.g. Moore (1963). This study extends the work of van Heijst et al. (1990) to the case of spin-up in a rectangular container but of non-uniform depth and we note the differences to and similarities with their observations. It is related, also, to more recent results of Maas et al. (1992), who considered spin-up on a β-plane but in a tank of very different proportions to the one considered here.

The areal typology of western Middle and South America: Towards a comprehensive view

Linguistics ◽  
2019 ◽  
Vol 57 (6) ◽  
pp. 1403-1463
Author(s):  
Matthias Urban ◽  
Hugo Reyes-Centeno ◽  
Kate Bellamy ◽  
Matthias Pache
Keyword(s):  
South America ◽  
Present Article ◽  
Large Scale ◽  
Pacific Coast ◽  
The Pacific ◽  
Language Areas ◽  
The Relationship ◽  
Geographical Space ◽  
General Cluster ◽  
Language Sample

Abstract Against a multidisciplinary background this contribution explores the areal typology of western Middle and South America. Based on a new language sample and a typological questionnaire that is specifically designed to bring some of the poorly documented and extinct languages into the debate, we explore the areal distribution of 77 linguistic traits in 44 languages. While one of the goals of the present article is to provide a general up-to-date view of the areal patterning of these traits on a large scale, we also explore a number of specific questions in more detail. In particular, we address the relationship between known language areas like Mesoamerica and the Central Andes with their respective peripheries, the possibility of detecting an areal-typological signal that predates the rise of these linguistic areas, and, finally, the question of linguistic convergence along the Pacific coast. We find that, while the languages of the Mesoamerican periphery are rather diffuse typologically, the structural profiles of the Central Andean languages are embedded organically into a more general cluster of Andean typological affinities that alters continuously as one moves through geographical space. In different ways, the typological properties of the peripheral languages may reflect a situation that goes back to time depths which are greater than that of the emergence of the Mesoamerican and Central Andean linguistic areas. Finally, while we can confirm typological affinities with Mesoamerica for some languages of coastal South America, we do not find support for large-scale linguistic convergence on the Pacific coast.

scholarly journals Decadal Changes in Bomb-Produced Radiocarbon in the Pacific Ocean from the 1990s to 2000s

Radiocarbon ◽  
2013 ◽  
Vol 55 (3) ◽  
pp. 1641-1650 ◽  
Author(s):  
Yuichiro Kumamoto ◽  
Akihiko Murata ◽  
Takeshi Kawano ◽  
Shuichi Watanabe ◽  
Masao Fukasawa
Keyword(s):  
Pacific Ocean ◽  
Ocean Circulation ◽  
Dissolved Inorganic Carbon ◽  
World Ocean ◽  
Temporal Changes ◽  
Turnover Time ◽  
Subtropical Region ◽  
The North ◽  
The Pacific ◽  
The Pacific Ocean

In the 2000s, radiocarbon in dissolved inorganic carbon was measured during 7 revisit cruises along the lines of the World Ocean Circulation Experiment in the Pacific Ocean. Comparison of 14C data along these lines from the 1990s and 2000s revealed decadal changes of 14C concentration in the thermocline, most of which were due to temporal changes in the bomb-produced 14C. Vertical profiles and vertical-integrated inventories of the bomb 14C in the subarctic and equatorial regions did not change appreciably. In the southern subtropical region, 14C decreased in the upper thermocline from the surface to ∼500 m depth. In contrast, 14C increased in the lower thermocline below ∼500 m depth. The opposing directions in 14C change resulted in small temporal changes in the total inventory of bomb 14C. On the other hand, the water-column inventory significantly decreased in the northwestern subtropical region due to the 14C decrease in the upper thermocline. These decadal changes in bomb 14C indicate that the turnover time of thermocline circulation in the northwestern subtropical region is faster than that in the southern subtropical region, and imply an interbasin transport of bomb 14C from the North Pacific to other basins.

scholarly journals Long-Period Tides in an Atmospherically Driven, Stratified Ocean

2015 ◽  
Vol 45 (7) ◽  
pp. 1917-1928 ◽  
Author(s):  
Rui M. Ponte ◽  
Ayan H. Chaudhuri ◽  
Sergey V. Vinogradov
Keyword(s):  
Ocean Circulation ◽  
General Circulation ◽  
Large Scale ◽  
Equation Model ◽  
The Arctic ◽  
Hudson Bay ◽  
Tidal Period ◽  
Long Period ◽  
The Pacific ◽  
Stratified Ocean

AbstractLong-period tides (LPT) are studied using a stratified, primitive equation model on a global domain and in the presence of a fully developed, atmospherically forced ocean general circulation. The major LPT constituents, from termensual to nodal (18.6 yr) periods, are examined. Ocean circulation variability can overwhelm the longest tide signals and make inferring LPT from data difficult, but model results suggest that bottom pressure offers cleaner signal-to-noise ratios than sea level, particularly at low latitudes where atmospherically driven variability is substantially stronger at the surface than at the bottom. Most tides exhibit a significant large-scale dynamic response, with the tendency for weaker nonequilibrium signals in the Atlantic compared to the Pacific as seen in previous studies. However, across most tidal lines, the largest dynamic signals tend to occur in the Arctic and Nordic Seas and also in Hudson Bay. Bathymetry and coastal geometry contribute to the modeled nonequilibrium behavior. Baroclinic effects tend to increase with the tidal period. Apart from short spatial-scale modulations associated with topographic interactions, the excitation of various propagating baroclinic wave modes is clearly part of the modeled LPT, particularly at tropical latitudes, for fortnightly and longer-period tides.

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