scholarly journals RADIOCARBON DATING OF PRECIOUS CORALS OFF THE SOUTHWEST COAST OF KOCHI PREFECTURE, SOUTHWEST JAPAN

Radiocarbon ◽  
2020 ◽  
pp. 1-18
Author(s):  
Tomoyo Okumura ◽  
Fujio Kumon ◽  
Hidekazu Tokuyama
Keyword(s):  
Historical Background ◽  
Additional Time ◽  
Last Glacial Period ◽  
Southwest Coast ◽  
Coral Colony ◽  
Fossil Resource ◽  
Sustainable Fishery ◽  
Kochi Prefecture ◽  
Destructive Fishing ◽  
The Last Glacial

ABSTRACT Radiocarbon (14C) dating was performed for various types of precious coral colony fragments collected from the Ashizuri fishing field, around 100–200 m deep, off the southwest coast of Kochi Prefecture, Japan, to understand the historical background of one of the largest precious coral fishing fields in Japan. The 14C ages of the 55 specimens range from ~7500 years ago to the modern. Most of the measured samples were older than 1871, when fishing activities of precious corals began in Kochi Prefecture. These results suggest that most of the deaths of the precious coral colonies were due to natural causes, such as natural mortality, predation, or various forms of environmental degradation, and not strictly related to destructive fishing practices. Additionally, precious corals started inhabiting the study area at least ~7500 years ago, when the marine condition became similar to that of today after the Last Glacial Period. This study is the first to focus on the age of dead precious coral fragments and has revealed that they might be an important fossil resource that could lengthen the timespan of precious coral fishery. This additional time may enable us to establish reasonable and effective regulations for sustainable fishery.

scholarly journals Post-depositional manganese mobilization during the last glacial period in sediments of the eastern Clarion-Clipperton Zone, Pacific Ocean

2020 ◽  
Vol 532 ◽  
pp. 116012 ◽  
Author(s):  
Jessica B. Volz ◽  
Bo Liu ◽  
Male Köster ◽  
Susann Henkel ◽  
Andrea Koschinsky ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Glacial Period ◽  
Last Glacial Period ◽  
Last Glacial ◽  
The Last Glacial

scholarly journals <i>δ</i><sup>13</sup>C decreases in the upper western South Atlantic during Heinrich Stadials 3 and 2

2017 ◽  
Vol 13 (4) ◽  
pp. 345-358 ◽  
Author(s):  
Marília C. Campos ◽  
Cristiano M. Chiessi ◽  
Ines Voigt ◽  
Alberto R. Piola ◽  
Henning Kuhnert ◽  
...  
Keyword(s):  
Climate Change ◽  
South Atlantic ◽  
Meridional Overturning Circulation ◽  
Glacial Period ◽  
Last Deglaciation ◽  
Last Glacial Period ◽  
Last Glacial ◽  
Change Events ◽  
The Last Glacial ◽  
Millennial Scale

Abstract. Abrupt millennial-scale climate change events of the last deglaciation (i.e. Heinrich Stadial 1 and the Younger Dryas) were accompanied by marked increases in atmospheric CO2 (CO2atm) and decreases in its stable carbon isotopic ratios (δ13C), i.e. δ13CO2atm, presumably due to outgassing from the ocean. However, information on the preceding Heinrich Stadials during the last glacial period is scarce. Here we present δ13C records from two species of planktonic foraminifera from the western South Atlantic that reveal major decreases (up to 1 ‰) during Heinrich Stadials 3 and 2. These δ13C decreases are most likely related to millennial-scale periods of weakening of the Atlantic meridional overturning circulation and the consequent increase (decrease) in CO2atm (δ13CO2atm). We hypothesise two mechanisms that could account for the decreases observed in our records, namely strengthening of Southern Ocean deep-water ventilation and weakening of the biological pump. Additionally, we suggest that air–sea gas exchange could have contributed to the observed δ13C decreases. Together with other lines of evidence, our data are consistent with the hypothesis that the CO2 added to the atmosphere during abrupt millennial-scale climate change events of the last glacial period also originated in the ocean and reached the atmosphere by outgassing. The temporal evolution of δ13C during Heinrich Stadials 3 and 2 in our records is characterized by two relative minima separated by a relative maximum. This w structure is also found in North Atlantic and South American records, further suggesting that such a structure is a pervasive feature of Heinrich Stadial 2 and, possibly, also Heinrich Stadial 3.

Global population divergence of the sea star Hippasteria phrygiana corresponds to the onset of the last glacial period of the Pleistocene

2013 ◽  
Vol 160 (5) ◽  
pp. 1285-1296 ◽  
Author(s):  
D. W. Foltz ◽  
S. D. Fatland ◽  
M. Eléaume ◽  
K. Markello ◽  
K. L. Howell ◽  
...  
Keyword(s):  
Population Divergence ◽  
Glacial Period ◽  
Sea Star ◽  
Last Glacial Period ◽  
Last Glacial ◽  
Global Population ◽  
The Last Glacial

scholarly journals South Pole glacial climate reconstruction from multi-borehole laser particulate stratigraphy

2013 ◽  
Vol 59 (218) ◽  
pp. 1117-1128 ◽  
Author(s):  
Keyword(s):  
Particle Physics ◽  
Volcanic Ash ◽  
Ice Core ◽  
Hot Water ◽  
Radiometric Dating ◽  
South Pole ◽  
Last Glacial Period ◽  
Annual Layer ◽  
Paleoclimate Records ◽  
The Last Glacial

AbstractThe IceCube Neutrino Observatory and its prototype, AMANDA, were built in South Pole ice, using powerful hot-water drills to cleanly bore >100 holes to depths up to 2500 m. The construction of these particle physics detectors provided a unique opportunity to examine the deep ice sheet using a variety of novel techniques. We made high-resolution particulate profiles with a laser dust logger in eight of the boreholes during detector commissioning between 2004 and 2010. The South Pole laser logs are among the most clearly resolved measurements of Antarctic dust strata during the last glacial period and can be used to reconstruct paleoclimate records in exceptional detail. Here we use manual and algorithmic matching to synthesize our South Pole measurements with ice-core and logging data from Dome C, East Antarctica. We derive impurity concentration, precision chronology, annual-layer thickness, local spatial variability, and identify several widespread volcanic ash depositions useful for dating. We also examine the interval around ∼74 ka recently isolated with radiometric dating to bracket the Toba (Sumatra) supereruption.

scholarly journals Deep Ocean storage of heat and CO2 in the Fram Strait, Arctic Ocean during the last glacial period

2021 ◽  
Author(s):  
Mohamed M. Ezat ◽  
Tine L. Rasmussen ◽  
Mathis P. Hain ◽  
Mervyn Greaves ◽  
James W B Rae ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Deep Ocean ◽  
Fram Strait ◽  
Glacial Period ◽  
Last Glacial Period ◽  
Last Glacial ◽  
The Last Glacial
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