43.—The Water Volume in Oceans and Seas.

1972 ◽  
Vol 72 (1) ◽  
pp. 429-431
Author(s):  
Eugenie Lisitzin
Keyword(s):  
Sea Water ◽  
Water Cycle ◽  
Water Volume ◽  
Roman Poet ◽  
De Rerum Natura ◽  
Last Glacial Period ◽  
Special Cases ◽  
Principal Factors ◽  
Inland Ice ◽  
The Last Glacial

Oceanography, as is well known, is considered a young science, lacking in old traditions. Nevertheless, the interest in oceans and seas may in some special cases be traced back as far as the centuries before the beginning of the Christian era. Reference may be made, for instance, to the Roman poet Lucretius, who in his work De rerum natura expressed astonishment that the amount of water in the seas does not augment in spite of the fact that the discharge of all the rivers in the world gathers there. Lucretius considered the effect of evaporation a possible explanation for this fact, thus mentioning one of the principal factors which determine the water cycle in nature, at least during periods in which average climatological conditions prevail. During periods characterised by more pronounced climatological deviations the equilibrium of the water cycle may be greatly disturbed. As an interesting example it may be mentioned that during the last glacial period considerable quantities of sea water were transformed into inland ice. It has been estimated that the water level in the oceans and seas at that epoch was approximately 100 metres lower than at the present time.

scholarly journals Quantifying molecular oxygen isotope variations during a Heinrich stadial

2015 ◽  
Vol 11 (11) ◽  
pp. 1527-1551 ◽  
Author(s):  
C. Reutenauer ◽  
A. Landais ◽  
T. Blunier ◽  
C. Bréant ◽  
M. Kageyama ◽  
...  
Keyword(s):  
Isotope Fractionation ◽  
Water Cycle ◽  
Atmospheric Oxygen ◽  
Dominant Role ◽  
Climatic Conditions ◽  
Fractionation Factor ◽  
Last Glacial Period ◽  
Main Driver ◽  
The Last Glacial

Abstract. δ18O of atmospheric oxygen (δ18Oatm) undergoes millennial-scale variations during the last glacial period, and systematically increases during Heinrich stadials (HSs). Changes in δ18Oatm combine variations in biospheric and water cycle processes. The identification of the main driver of the millennial variability in δ18Oatm is thus not straightforward. Here, we quantify the response of δ18Oatm to such millennial events using a freshwater hosing simulation performed under glacial boundary conditions. Our global approach takes into account the latest estimates of isotope fractionation factor for respiratory and photosynthetic processes and make use of atmospheric water isotope and vegetation changes. Our modeling approach allows to reproduce the main observed features of a HS in terms of climatic conditions, vegetation distribution and δ18O of precipitation. We use it to decipher the relative importance of the different processes behind the observed changes in δ18Oatm. The results highlight the dominant role of hydrology on δ18Oatm and confirm that δ18Oatm can be seen as a global integrator of hydrological changes over vegetated areas.

scholarly journals Quantifying molecular oxygen isotope variations during a Heinrich Stadial

2015 ◽  
Vol 11 (3) ◽  
pp. 2281-2339
Author(s):  
C. Reutenauer ◽  
A. Landais ◽  
T. Blunier ◽  
C. Bréant ◽  
M. Kageyama ◽  
...  
Keyword(s):  
Water Cycle ◽  
Atmospheric Oxygen ◽  
Dominant Role ◽  
Climatic Conditions ◽  
Water Isotopes ◽  
Fractionation Factor ◽  
Last Glacial Period ◽  
Main Driver ◽  
The Last Glacial

Abstract. δ18O of atmospheric oxygen (δ18Oatm) undergoes millennial scale variations during the last glacial period, and systematically increases during Heinrich Stadials (HS). Changes in δ18Oatm combine variations in biospheric and water cycle processes. The identification of the main driver of the millennial variability of δ18Oatm is thus not straightforward. Here, we quantify the response of δ18Oatm to such millennial events using a freshwater hosing simulation (HS_exp) performed under glacial boundary conditions. Our global approach takes into account the latest estimates of isotope fractionation factor for respiratory and photosynthetic processes and make use of atmospheric water isotopes and vegetations changes. Our modeling approach allows to reproduce the main observed features of a HS in terms of climatic conditions, vegetation distribution and δ18O of precipitation. We use it to decipher the relative importance of the different processes behind the observed changes in δ18Oatm. The results highlight the dominant role of hydrology on δ18Oatm and confirm that δ18Oatm can be seen as a global integrator of hydrological changes over vegetated areas.

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 Site information and initial results from deep ice drilling on Law Dome, Antarctica

1997 ◽  
Vol 43 (143) ◽  
pp. 3-10 ◽  
Author(s):  
V.I. Morgan ◽  
C.W. Wookey ◽  
J. Li ◽  
T.D. van Ommen ◽  
W. Skinner ◽  
...  
Keyword(s):  
Ice Core ◽  
Ice Sheet ◽  
High Accumulation ◽  
Ice Flow ◽  
Ice Cap ◽  
Basal Ice ◽  
Inland Ice ◽  
The Last Glacial Maximum ◽  
Initial Results ◽  
The Last Glacial

AbstractThe aim of deep ice drilling on Law Dome, Antarctica, has been to exploit the special characteristics of Law Dome summit, i.e. low temperature and high accumulation near an ice divide, to obtain a high-resolution ice core for climatic/environmental studies of the Holocene and the Last Glacial Maximum (LGM). Drilling was completed in February 1993, when basal ice containing small fragments of rock was reached at a depth of 1196 m. Accurate ice dating, obtained by counting annual layers revealed by fine-detail δ18О, peroxide and electrical-conductivity measurements, is continuous down to 399 m, corresponding to a date of AD 1304. Sulphate concentration measurements, made around depths where conductivity tracing indicates volcanic fallout, allow confirmation of the dating (for Agung in 1963 and Tambora in 1815) or estimates of the eruption date from the ice dating (for the Kuwae, Vanuatu, eruption ~1457). The lower part of the core is dated by extrapolating the layer-counting using a simple model of the ice flow. At the LGM, ice-fabric measurements show a large decrease (250 to 14 mm2) in crystal size and a narrow maximum in c-axis vertically. The main zone of strong single-pole fabrics however, is located higher up in a broad zone around 900 m. Oxygen-isotope (δ18O) measurements show Holocene ice down to 1113 m, the LGM at 1133 m and warm (δ18O) about the same as Holocene) ice near the base of the ice sheet. The LGM/Holocene δ18O shift of 7.0‰, only ~1‰ larger than for Vostok, indicates that Law Dome remained an independent ice cap and was not overridden by the inland ice sheet in the 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.

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