A5041144000- Isotope Analysis in Ecology
- Geology and Paleoclimatology Research
- Marine and coastal ecosystems
- Groundwater and Isotope Geochemistry
- Atmospheric and Environmental Gas Dynamics
- Marine Biology and Ecology Research
- Atmospheric Ozone and Climate
- Paleontology and Stratigraphy of Fossils
- Photosynthetic Processes and Mechanisms
- Cryospheric studies and observations
- Aquatic Ecosystems and Phytoplankton Dynamics
- Archaeology and ancient environmental studies
- Marine and environmental studies
- Ocean Acidification Effects and Responses
- Fish Ecology and Management Studies
- Oceanographic and Atmospheric Processes
- Plant Water Relations and Carbon Dynamics
- Microbial Community Ecology and Physiology
- Climate change and permafrost
- Physiological and biochemical adaptations
- Algal biology and biofuel production
- Pleistocene-Era Hominins and Archaeology
- Geological formations and processes
- Mitochondrial Function and Pathology
- Marine Bivalve and Aquaculture Studies
McMaster University
2025
Hebrew University of Jerusalem
2011-2024
Lamont-Doherty Earth Observatory
1994
Columbia University
1994
Brown University
1973
We have optimized the method of water fluorination using solid reagent CoF3 to produce O2. This allows isotope ratio measurements by dual-inlet mass spectrometry with very high precision 0.01 0.03/1000 for both delta17O and delta18O. Using this method, delta18O atmospheric O2 were determined as 12.08 23.88/1000 vs. VSMOW, respectively. Likewise, GISP -13.12 -24.73/1000, SLAP they -29.48 -55.11/1000 Analysis these data in a ln(delta17O + 1) ln(delta18O plot yields line regression coefficient...
Measurements of δ(17)O and δ(18)O values tropospheric CO(2) are great importance. However, to be useful, such measurements must an order magnitude more precise than in current published literature. With this purpose we developed a new method for high-precision mass spectrometric (17)O/(16)O (18)O/(16)O ratios CO(2), which is presented study.The based on isotopic exchange equilibration between H(2)O sealed glass ampoules followed by water fluorination produce O(2). Dual inlet isotope ratio...
Plant production in the sea is a primary mechanism of global oxygen formation and carbon fixation. For this reason, also because ocean major sink for fossil fuel dioxide, much attention has been given to estimating marine production. Here, we describe an approach photosynthetic oxygen, based on isotopic composition dissolved seawater. This method allows estimation integrated oceanic productivity time scale weeks.
We have determined the isotope effects of (17)O and (18)O substitution (16)O in H(2)O on molecular diffusivities water vapor air by use evaporation experiments. The derived diffusion fractionation coefficients (17)alpha(diff) (18)alpha(diff) are 1.0146 +/- 0.0002 1.0283 0.0003, respectively. also determined, for first time, ratio ln((17)alpha(diff))/ln((18)alpha(diff)) as 0.5185 0.0002. This ratio, which is excellent agreement with theoretical value 0.5184, significantly smaller than...
We measured δ 17 O and 18 in recent Antarctic snow down the Vostok ice core calculated excess of with respect to VSMOW. The magnitude Holocene last interglacial is ∼45 per meg, it remains constant a transect from coast continental interior. Analysis data shows that O‐excess not sensitive temperature variations over continent. There are significant shifts low values glacial high times. observed suggest higher normalized relative humidity and/or wind speeds source oceanic regions
Oxygen isotopic, elemental, and X-ray data are presented for a suite of 24 fossil horse teeth from Nebraska ranging in age 18.2 to 8.5 Ma, test the use δ18O enamel phosphate (δ18OP04) as quantitative record continental climate. Modern equid were analyzed estimate relationship between δ8OP04 environment water. Multiple samples seven different species Burge Quarry, ∼ 12 Ma attritional deposit, indicate diagenetic overprints exist but can be detected by decreased P concentration increased...
Abstract The triple isotope composition (δ 17O and δ 18O) of dissolved O2 in the ocean ice cores was recently used to assess primary productivity over broad spatial temporal scales. However, assessment with aid this method must rely on accurate measurements 17O/16O versus 18O/16O relationship each main oxygen-producing -consuming reactions. Data obtained here showed that cleavage water photosystem II did not fractionate oxygen isotopes; 18O evolved were essentially identical those substrate...
Recently, an excess of 17 O ( O‐excess) has been demonstrated in meteoric water and ice cores. Based on theory experiments, it suggested that this originates from evaporation ocean into under‐saturated air. However, there never direct demonstration marine vapor. Here, we present results the first measurements δ 18 vapor samples collected over South Indian Southern Oceans. Our data show existence O‐excess also clear negative correlation between relative humidity. Thus, is useful for...
Abstract A method for high‐precision and high‐accuracy mass spectometric measurements of the ratios among three oxygen isotopes, O 2 /Ar ratio, is presented. It involves separation ‐Ar mixture from air includes a fully automated system that ensures highly reliable sample processing. Repeated atmospheric yield repeatability (±SE × t, standard error mean (n = 12) multiplied by Student's t‐factor 95% confidence limit) 0.004, 0.003 0.2‰ δ 18 O, 17 /Ar, respectively. Copyright © 2003 John Wiley...