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  • 1
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    PANGAEA
    In:  Supplement to: McClintock, James B; Angus, Robert A; Mcdonald, Michelle R; Amsler, Charles D; Catledge, Shane A; Vohra, Yogesh K (2009): Rapid dissolution of shells of weakly calcified Antarctic benthic macroorganisms indicates high vulnerability to ocean acidification. Antarctic Science, 21(5), 449-456, https://doi.org/10.1017/S0954102009990198
    Publication Date: 2024-03-15
    Description: Antarctic calcified macroorganisms are particularly vulnerable to ocean acidification because many are weakly calcified, the dissolution rates of calcium carbonate are inversely related to temperature, and high latitude seas are predicted to become undersaturated in aragonite by the year 2100. We examined the post-mortem dissolution rates of aragonitic and calcitic shells from four species of Antarctic benthic marine invertebrates (two bivalves, one limpet, one brachiopod) and the thallus of a limpet shell-encrusting coralline alga exposed to acidified pH (7.4) or non-acidified pH (8.2) seawater at a constant temperature of 4 C. Within a period of only 14-35 days, shells of all four species held in pH 7.4 seawater had suffered significant dissolution. Despite calcite being 35% less soluble in seawater than aragonite, there was surprisingly, no consistent pattern of calcitic shells having slower dissolution rates than aragonitic shells. Outer surfaces of shells held in pH 7.4 seawater exhibited deterioration by day 35, and by day 56 there was exposure of aragonitic or calcitic prisms within the shell architecture of three of the macroinvertebrate species. Dissolution of coralline algae was confirmed by differences in weight loss in limpet shells with and without coralline algae. By day 56, thalli of the coralline alga held in pH 7.4 displayed a loss of definition of the conceptacle pores and cracking was evident at the zone of interface with limpet shells. Experimental studies are needed to evaluate whether there are adequate compensatory mechanisms in these and other calcified Antarctic benthic macroorganisms to cope with anticipated ocean acidification. In their absence, these organisms, and the communities they comprise, are likely to be among the first to experience the cascading impacts of ocean acidification.
    Keywords: Alkalinity, total; Animalia; Antarctic; Aragonite saturation state; Benthic animals; Benthos; Bicarbonate ion; Brachiopoda; Calcification/Dissolution; Calcite saturation state; Calculated; Calculated using seacarb after Nisumaa et al. (2010); Carbon, inorganic, dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Coast and continental shelf; DATE/TIME; EPOCA; EUR-OCEANS; European network of excellence for Ocean Ecosystems Analysis; European Project on Ocean Acidification; Experiment day; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Laboratory experiment; Laternula elliptica; Laternula elliptica, weight; Liothyrella uva; Liothyrella uva, weight; Mettler AJ100 balance (Mettler-Toledo); Mollusca; Nacella concinna; Nacella concinna, weight; OA-ICC; Ocean Acidification International Coordination Centre; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); pH; pH meter (Fisher Model AB15); Polar; Salinity; Sample ID; Single species; Temperature, water; Titration; Yoldia eightsi; Yoldia eightsi, weight
    Type: Dataset
    Format: text/tab-separated-values, 5342 data points
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  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 58 (1987), S. 1887-1890 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The wiggler provides a substantially higher flux of photons through a given collimator at high energies than is available from the bending magnet at the Cornell High Energy Synchrotron Source. This opens a new dimension in ultrapressure x-ray diffraction studies. Examples are shown in which a good diffraction pattern of gold at 112 GPa (1.12 Mbar) was obtained in 13 s and in which the diffraction pattern for primitive hexagonal silicon at 35 GPa using the beam from the wiggler contains twice as many peaks as is the case for the beam from the bending magnet.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 55 (1989), S. 232-234 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Synthetic type 1B yellow diamonds containing nitrogen in single substitutional form, with extremely low birefringence, were used as anvils in a diamond anvil cell. The diamonds were well characterized by infrared and visible absorption spectra. Sensitive spectroscopic methods along with mechanical chopping techniques were used to record ruby fluorescence to 250–300 GPa, a pressure equal to or exceeding that attained with natural diamonds. Nitrogen platelets are not essential to attaining multimegabar pressures.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 94 (1990), S. 1117-1122 
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 73 (1998), S. 181-183 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The thickness and surface roughness of diamond films grown on a Ti–6Al–4V alloy in a microwave plasma reactor was measured in situ using optical pyrometry. The growing film results in oscillations of the apparent temperature with time, which can be explained by interference effects caused by reflections from the film/air and film/substrate interfaces. The equation governing the transmittance of the diamond/metal system has been derived by taking into account the complex index of refraction of an absorbing substrate. The apparent temperature was modeled using this relation for the transmittance in order to extract the time dependence of film thickness, surface roughness, and the true temperature of the substrate. The growth rate was observed to exhibit two regimes: an initial period of slowly increasing growth followed by a growth rate that was about 50% higher. The surface roughness increased at a nearly uniform rate but quickly reached a saturation roughness for long deposition times (high surface roughness). The limitation of the model for films in the high surface roughness regime is discussed. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 64 (1994), S. 3386-3388 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report ultrahigh pressure calibration and fluorescence intensity measurements of Sm:YAG to 180 GPa in a diamond anvil cell at room temperature. Several fluorescence emission bands excited by argon ion laser were followed with increasing pressure and it was observed that Y4 band was the most intense in the pressure regime of 100–180 GPa. The Y4 band is calibrated against the R band of ruby to 180 GPa. Irreversible changes in the line intensities above 100 GPa were observed in Sm:YAG and quenched to ambient pressure. Linewidths of the fluorescence bands of the quenched phase indicate structural disorder. In contrast to ruby pressure sensor, the Y4 emission band of Sm:YAG is easily detectable at ultrahigh pressures.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 7978-7982 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report photoluminescence and x-ray-diffraction studies on Sm-doped yttrium aluminum garnet (YAG) to ultrahigh pressures of 338 GPa in a diamond-anvil cell at room temperature. Photoluminescence spectra from Sm:YAG could be clearly identified with increasing pressures to 304 GPa. The rapidly shifting fluorescence from diamond anvil obscures the Sm:YAG emission spectra above 300 GPa. We provide the shift of the Y4 emission band of Sm:YAG to 304 GPa and give its pressure coefficients as referenced to the ruby standard to 180 GPa and platinum standard to 304 GPa. We present possible structural disorder mechanisms in Sm:YAG above 100 GPa which give rise to the line broadening and changes in intensities of various photoluminescence bands. The application of Sm:YAG as an optical pressure sensor in the ultrahigh-pressure regime is also discussed. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 84 (1998), S. 6469-6471 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A new regime is reported for synthesis of nanostructured diamond films on Ti–6Al–4V alloy and molybdenum substrates using microwave plasma chemical vapor deposition (CVD) at high pressure (125 Torr) and high methane feed-gas concentration (5%–15% in a balance of hydrogen). These films are shown to be predominantly comprised of diamond nanocrystallites in a matrix of tetrahedral amorphous carbon. In contrast to standard CVD conditions, the high density plasma results in adhered films on the metal substrates even at substrate temperatures of 850 °C. These films are also significantly smoother than conventionally processed CVD diamond films and have a rms surface roughness of about 50 nm. The average grain size of these nanocrystalline diamond films is 13 nm as determined from x-ray diffraction data and the hardness of the films as determined from nanoindentation data is 90% that of natural diamond. Micro-Raman studies using 458 and 647.1 nm excitation indicate an increasing tetrahedral amorphous carbon content with increasing methane feed-gas concentration. The adhesion and mechanical properties of these films makes them attractive for a variety of tribological applications. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 83 (1998), S. 198-204 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Microwave plasma-enhanced chemical vapor deposition was used to grow diamond films on Ti–6Al–4V alloy using various gas phase precursors. The results of four types of experiments with different gas mixtures are compared: (1) 2% CH4 in H2; (2) initial saturation of 5% CH4 in H2 followed by 2% CH4 in H2; (3) a CO-rich mixture with a CO:H2 ratio of 8; and (4) a hybrid mixture of 2% CH4 in H2 followed by a CO:H2 ratio of 8. The substrate temperature during deposition with CH4/H2 mixtures was between 715 and 810 °C, and was between 550 and 600 °C when CO/H2 mixtures were used. Optical emission spectroscopy was used to monitor the excited gas-phase species in the plasma. The films were characterized by micro-Raman spectroscopy, glancing-angle x-ray diffraction, and nanoindentation. The films grown with the type (1) mixture often exhibited good quality with high hardness (70 GPa) but suffered from poor adhesion to the substrate. The films grown with the type (2) mixture were of slightly lower quality and hardness (58 GPa) but exhibited better adhesion. The films produced from the type (3) mixture were adhered, but exhibited very low growth rates and low hardness (18 GPa). Finally, the films produced from the hybrid type (4) mixture were of poor quality and suffered from poor adhesion to the substrate. The differences in interfacial phases and mechanical properties for each film are discussed and the usefulness of each gas mixture for the diamond growth is evaluated. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 78 (1995), S. 7053-7058 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: High density plasma processing of diamond films on titanium was carried out by microwave plasma chemical vapor deposition. The deposited films were characterized by Raman spectroscopy and thin film x-ray diffraction. We measure a residual compressive stress of 3.5±1.0 GPa which is lower than that obtained in previous studies. A measure of the film adherence to the titanium substrates was obtained by examining micro-Raman spectra near Brale C indentations. Using a model for biaxially stressed polycrystalline diamond films, it is determined that as much as 7.8 GPa can be sustained in the film before delamination occurs. Our experimental results are compared to earlier adhesion data of diamond on titanium. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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