Publish in OALib Journal
APC: Only $99
A major limitation in the use of stable isotope of water in ecological studies is the time that is required to extract water from soil and plant samples. Using vacuum distillation the extraction time can be less than one hour per sample. Therefore, assembling a distillation system that can process multiple samples simultaneously is advantageous and necessary for ecological or hydrological investigations. Presented here is a vacuum distillation apparatus, having six ports, that can process up to 30 samples per day. The distillation system coupled with the Los Gatos Research DLT-100 Liquid Water Isotope Analyzer is capable of analyzing all of the samples that are generated by vacuum distillation. These two systems allow larger sampling rates making investigations into water movement through an ecological system possible at higher temporal and spatial resolution.
used to determine the authenticity of artifacts that compares the oxygen
isotopic composition of speleothems to the carbonate included within the patina
of unprovenanced artifacts is of questionable value. The unprovenanced Jehoash
Inscription Tablet and James Ossuary are of potentially immense historical and
cultural importance. Nevertheless, they
both were rejected by workers based on the oxygen isotope technique which provided the major foundational
evidence of forgery in the longest running archaeological trial in Israel.
Nevertheless, both these artifacts were determined not to be forged. The initial incongruence between the oxygen
isotopes of the speleothems of the Soreq cave (Israel) purported to represent
the unique composition of Jerusalem rainfall, and the patina on the artifacts,
can be readily explained by the accretion of materials and geo-biochemical
processes expected in normal patina formation in the Jerusalem region. The
patina formation involves sporadic events in disequilibrium kinetic processes
that are opposed to the equilibrium formation of
speleothems in a sealed cave. Moreover, 23 of 56 patina samples (41%) on well-documented
ancient artifacts from Israel yielded oxygen isotope values greater or lower
than the expected speleothem values of -4 δ18O ‰ [PDB] to -6 δ18O ‰ [PDB].
Thus, the speleothem-patina correlation is invalid and the applied oxygen
isotopes technique for determining the authenticity of patinas on artifacts is
not a useful tool in the authentication of artifacts.
Speleothems from Nerja Cave in southern Spain provide a record during interglacial period MIS5a. Period of speleothem deposition occurred from 70,000 90,000 yr ago. Oxygen (δ18O) and hydrogen (δD) isotope ratios of speleothem and fluid inclusions enable the reconstruction of climatic variability in this region of southern Spain. Fluid inclusions trapped in speleothems represent samples of drip water from which the speleothems grew. The isotopic compositions of cave dripwaters approximate average annual δ18O and δD of precipitation, therefore δ18O can be calculated from D/H of inclusion water using the MWL relationship δD = 8δ18O + 10. The measurements of the δD values of fluid-inclusion water and δ18O values from speleothems have been applied to paleoclimate reconstruction in Southern Spain indicating a colder condition than at present.
Microcosm experiments were
conducted to determine the fractionation of stable carbon isotopes during
biodegradation of naphthalene. The microcosms were performed under aerobic
conditions, anaerobic (amended with sulfate, amended with nitrate and with no
amendments) and sterile controls. The liquid phase was analyzed to determine
naphthalene concentration and stable carbon isotope signature. Aerobic
microcosm showed that naphthalene degraded aerobically within 60 hours. The δ13C increased from -25.5‰ to -25.1‰ (enrichment of 0.4‰ ± 0.08‰) in a single sample in which 95% of the
naphthalene was biodegraded. Anaerobic microcosms show that after 288 days, the
microcosms with no amendments, amended with nitrate and amended with sulfate
had consumed respectively 30%, 50% and 60% of naphthalene on average, compared
to control microcosms. Under the denitrifying conditions, the δ13C of
naphthalene increased from -25.2‰ to -23.9‰ (enrichment of 1.3‰ ± 0.3‰)
after a 95% of naphthalene biodegradation. For the unamended microcosms, a
slight enrichment on δ13C
napththalene was detected, from -25.2‰ to -24.5‰ (enrichment of 0.7‰ ± 0.3‰)
after a biodegradation of approximately 65% of naphthalene (after 288 days).
For sulfate reducing microcosms, no significant changes were detected on the δ13C during naphthalene