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Full-Text Articles in Life Sciences
Mg/Ca-Temperature Calibration Of Polar Benthic Foraminifera Species For Reconstruction Of Bottom Water Temperatures On The Antarctic Shelf, Elaine M. Mawbey, Katharine R. Hendry, Mervyn J. Greaves, Claus-Dieter Hillenbrand, Gerhard Kuhn, Charlotte L. Spencer-Jones, Erin L. Mcclymont, Kara J. Vadman, Amelia E. Shevenell, Patrycja E. Jernas, James A. Smith
Mg/Ca-Temperature Calibration Of Polar Benthic Foraminifera Species For Reconstruction Of Bottom Water Temperatures On The Antarctic Shelf, Elaine M. Mawbey, Katharine R. Hendry, Mervyn J. Greaves, Claus-Dieter Hillenbrand, Gerhard Kuhn, Charlotte L. Spencer-Jones, Erin L. Mcclymont, Kara J. Vadman, Amelia E. Shevenell, Patrycja E. Jernas, James A. Smith
Marine Science Faculty Publications
Benthic foraminifera Mg/Ca is a well-established bottom water temperature (BWT) proxy used in paleoclimate studies. The relationship between Mg/Ca and BWT for numerous species has been determined using core-top and culturing studies. However, the scarcity of calcareous microfossils in Antarctic shelf sediments and poorly defined calibrations at low temperatures has limited the use of the foraminiferal Mg/Ca paleothermometer in ice proximal Antarctic sediments. Here we present paired ocean temperature and modern benthic foraminifera Mg/Ca data for three species, Trifarina angulosa, Bulimina aculeata, and Globocassidulina subglobosa, but with a particular focus on Trifarina angulosa. The core-top data from several …
Diverse And Highly Recombinant Anelloviruses Associated With Weddell Seals In Antarctica, Elizabeth Fahsbender, Jennifer M. Burns, Stacy Kim, Simona Kraberger, Greg Frankfurter, Mya Breitbart
Diverse And Highly Recombinant Anelloviruses Associated With Weddell Seals In Antarctica, Elizabeth Fahsbender, Jennifer M. Burns, Stacy Kim, Simona Kraberger, Greg Frankfurter, Mya Breitbart
Marine Science Faculty Publications
The viruses circulating among Antarctic wildlife remain largely unknown. In an effort to identify viruses associated withWeddell seals (Leptonychotes weddellii) inhabiting the Ross Sea, vaginal and nasal swabs, and faecal samples were collectedbetween November 2014 and February 2015. In addition, a Weddell seal kidney and South Polar skua (Stercorariusmaccormicki) faeces were opportunistically sampled. Using high throughput sequencing, we identified and recovered 152anellovirus genomes that share 63–70% genome-wide identities with other pinniped anelloviruses. Genome-wide pairwisecomparisons coupled with phylogenetic analysis revealed two novel anellovirus species, tentatively named torque tenoLeptonychotes weddellii virus (TTLwV) -1 and -2. TTLwV-1 (n¼133, genomes encompassing 40 genotypes) is …
Sub-Ice Shelf Sediment Geochronology Utilizing Novel Radiocarbon Methodology For Highly Detrital Sediments, C. Subt, H. I. Yoon, K. C. Yoo, J. I. Lee, A. Leventer, Eugene W. Domack, Brad E. Rosenheim
Sub-Ice Shelf Sediment Geochronology Utilizing Novel Radiocarbon Methodology For Highly Detrital Sediments, C. Subt, H. I. Yoon, K. C. Yoo, J. I. Lee, A. Leventer, Eugene W. Domack, Brad E. Rosenheim
Marine Science Faculty Publications
Sub-ice shelf sediments near Larsen C ice shelf (LIS-C) show fine-scale rhythmic laminations that could provide a near-continuous seasonal-resolution record of regional ice mass changes. Despite the great potential of these sediments, a dependable Late Quaternary chronology is difficult to generate, rendering the record incomplete. As with many marginal Antarctic sediments, in the absence of preserved carbonate microfossils, the reliability of radiocarbon chronologies depends on presence of high proportions of autochthonous organic carbon with minimized detrital organic carbon. Consequently, acid insoluble organic (AIO) 14C dating works best where high productivity drives high sediment accumulation rates, but can be problematic …
Validation Of The Diurnal Cycles In Atmospheric Reanalyses Over Antarctic Sea Ice, Esa-Matti Tastula, Timo Vihma, Edgar L. Andreas, Boris Galperin
Validation Of The Diurnal Cycles In Atmospheric Reanalyses Over Antarctic Sea Ice, Esa-Matti Tastula, Timo Vihma, Edgar L. Andreas, Boris Galperin
Marine Science Faculty Publications
The diurnal cycles of near-surface meteorological parameters over Antarctic sea ice in six widely used atmospheric reanalyses are validated against observations from Ice Station Weddell. The station drifted from February through May 1992 and provided the most extensive set of meteorological observations ever collected in the Antarctic sea ice zone. For the radiative and turbulent surface fluxes, both the amplitude and shape of the diurnal cycles vary considerably among different reanalyses. Near-surface temperature, specific humidity, and wind speed in the reanalyses all feature small diurnal ranges, which, in most cases, fall within the uncertainties of the observed cycle. A skill …
Middle Miocene Ice Sheet Dynamics, Deep‐Sea Temperatures, And Carbon Cycling: A Southern Ocean Perspective, Amelia E. Shevenell, James P. Kennett, David W. Lea
Middle Miocene Ice Sheet Dynamics, Deep‐Sea Temperatures, And Carbon Cycling: A Southern Ocean Perspective, Amelia E. Shevenell, James P. Kennett, David W. Lea
Marine Science Faculty Publications
Relative contributions of ice volume and temperature change to the global ∼1‰ δ18O increase at ∼14 Ma are required for understanding feedbacks involved in this major Cenozoic climate transition. A 3‐ma benthic foraminifer Mg/Ca record of Southern Ocean temperatures across the middle Miocene climate transition reveals ∼2 ± 2°C cooling (14.2–13.8 Ma), indicating that ∼70% of the increase relates to ice growth. Seawater δ18O, calculated from Mg/Ca and δ18O, suggests that at ∼15 Ma Antarctica's cryosphere entered an interval of apparent eccentricity‐paced expansion. Glaciations increased in intensity, revealing a central role for internal climate …
Antarctic Sediment Chronology By Programmed-Temperature Pyrolysis: Methodology And Data Treatment, Brad E. Rosenheim, Mary Beth Day, Eugene Domack, Heather Schrum, Albert Benthien, John M. Hayes
Antarctic Sediment Chronology By Programmed-Temperature Pyrolysis: Methodology And Data Treatment, Brad E. Rosenheim, Mary Beth Day, Eugene Domack, Heather Schrum, Albert Benthien, John M. Hayes
Marine Science Faculty Publications
We report a detailed programmed-temperature pyrolysis/combustion methodology for radiocarbon (14C) dating of Antarctic sub-ice shelf sediments. The method targets the autochthonous organic component in sediments that contain a distribution of acid-insoluble organic components from several sources of different ages. The approach has improved sediment chronology in organic-rich sediments proximal to Antarctic ice shelves by yielding maximum age constraints significantly younger than bulk radiocarbon dates from the same sediment horizons. The method proves adequate in determining isotope ratios of the pre-aged carbon end-member; however, the isotopic compositions of the low-temperature measurements indicate that no samples completely avoided mixing with some proportion …