• Nitrate
  • 2015. Nitrogen cycling in the subsurface biosphere: Nitrate isotopes in porewaters underlying the oligotrophic North Atlantic. (whoi.edu)
  • The isotope biogeochemical modeling also yielded estimates for the δ15N and δ18O of newly produced nitrate (δ15NNTR (NTR, referring to nitrification) and δ18ONTR), as well as the isotope effect for denitrification (15ϵDNF) (DNF, referring to denitrification), parameters with high relevance to global ocean models of N cycling. (whoi.edu)
  • Denitrification is a microbially facilitated process where nitrate is reduced and ultimately produces molecular nitrogen (N2) through a series of intermediate gaseous nitrogen oxide products. (wikipedia.org)
  • The preferred nitrogen electron acceptors in order of most to least thermodynamically favorable include nitrate (NO3−), nitrite (NO2−), nitric oxide (NO), nitrous oxide (N2O) finally resulting in the production of dinitrogen (N2) completing the nitrogen cycle. (wikipedia.org)
  • analyses
  • Dual stable isotope analyses (delta 13C and delta 15N) of fiddler crabs from a forest-fringed, land-locked lagoon in Puerto Rico indicated the differential assim- ilation of material from ingested sediments. (upenn.edu)
  • In 2007 Jennifer Leonard undertook a study of the genetic, morphology, and stable isotope analyses of seventy-four Beringian wolf specimens from Alaska and the Yukon that revealed the genetic relationships, prey species, and feeding behavior of prehistoric wolves, and supported the classification of the Beringian wolf as C. lupus. (wikipedia.org)
  • uptake
  • Long distance types are associated with increased levels of organic nitrogen uptake compared to other exploration types and are thought to be less competitive in disturbed systems in contrast to short distance types which are able to regenerate more efficiently after a disturbance event. (wikipedia.org)
  • Fixation
  • Our findings indicate that the production of organic matter by in situ autotrophy (e.g., nitrification, nitrogen fixation) supplies a large fraction of the biomass and organic substrate for heterotrophy in these sediments, supplementing the small organic-matter pool derived from the overlying euphotic zone. (whoi.edu)
  • organism
  • For best result the researcher would need to know the original levels, or an estimation thereof, of isotopes in the organism at the time of its death. (wikipedia.org)
  • transformations
  • In the organic-lean sediment porewaters underlying the oligotrophic ocean, where low levels of microbial activity persist despite limited organic matter delivery from overlying water, the extent and modes of nitrogen transformations have not been widely investigated. (whoi.edu)
  • 15N tracing has been applied to quantify rates of nitrogen transformations in soil and to distinguish the sources of the greenhouse gas nitrous oxide under different environmental conditions. (wikipedia.org)
  • The amendment of additional nitrogen can also be a bias by changing natural nitrogen transformations. (wikipedia.org)
  • A way to calculate nitrogen transformation rates in soil can be achieved by numerical approximation that takes different, simultaneous nitrogen transformations into account. (wikipedia.org)
  • measurements
  • This report presents (1) methodology and data on mercury, methylmercury, stable isotopes, and (2) other ecologically relevant measurements in biological tissues of periphyton, invertebrates, forage fish, and predator fish. (usgs.gov)
  • The planned experiments are expected to advance our understanding of N and O isotope signatures of anammox in natural environments, as well as to verify the use of NOx N and O isotope measurements for process control during autotrophic nitrogen removal in wastewater treatment systems. (umd.edu)
  • experience with DIN isotope measurements will be an asset. (umd.edu)
  • Abrantes KG, Semmens JM, Lyle JM, Nichols PD (2011) Normalisation models for accounting for fat content in stable isotope measurements in salmonid muscle tissue. (springer.com)
  • variations
  • The precision of the isotope abundances and atomic mass is limited through variations. (wikipedia.org)
  • It is also important for the researcher to know the variations of isotopes within individuals, between individuals, and over time. (wikipedia.org)
  • analysis
  • Analysis of media isotope enrichment during substrate depletion revealed relationships between net discrimination and external N concentration. (springer.com)
  • Brooks PD, Stark JM, McInteer BB, Preston T (1989) Diffusion method to prepare soil extracts for automated nitrogen-15 analysis. (springer.com)
  • Stable isotope analysis is often used to investigate the trophic ecology of marine systems. (springer.com)
  • Isotope analysis has widespread applicability in the natural sciences. (wikipedia.org)
  • Isotope analysis has been particularly useful in archaeology as a means of characterization. (wikipedia.org)
  • Particularly in the Bronze Age Mediterranean, lead isotope analysis has been a useful tool for determining the sources of metals and an important indicator of trade patterns. (wikipedia.org)
  • Analysis of bones from Alaska showed high concentrations of nitrogen-15, a stable nitrogen isotope accumulated by meat-eaters, with no evidence of ingestion of vegetation. (wikipedia.org)
  • sulfur
  • The death of the salmon has important consequences, since it means significant nutrients in their carcasses, rich in nitrogen, sulfur, carbon and phosphorus, are transferred from the ocean to terrestrial wildlife such as bears and riparian woodlands adjacent to the rivers. (wikipedia.org)
  • The nitrogen, sulfur, and noble gas abundances in Jupiter's atmosphere exceed solar values by a factor of about three. (wikipedia.org)
  • despite
  • Despite the different weights, 15N is involved in the same chemical reactions as the more abundant 14N and is therefore used to trace and quantify conversions of one nitrogen compound to another. (wikipedia.org)
  • archaeology
  • Judith Sealy is a Professor and South Africa Research Chairs Initiative Research Chair in Archaeology and Paleoenvironmental Studies and director of the Stable Light Isotope Lab in the Department of Archaeology at University of Cape Town. (wikipedia.org)
  • atmosphere
  • Some kinds of cosmic radiation cause a nuclear reaction with nitrogen-14 in the upper atmosphere of the Earth, creating carbon-14, which decays back to nitrogen-14 with a half-life of 5,730±40 years. (wikipedia.org)
  • water
  • The work is part of several subprojects of the SFB754 with the aim to decipher nitrogen pathways in the water column and in the benthic boundary layer of the eastern tropical South Pacific and tropical Atlantic Oceans. (ocean-partners.org)
  • data
  • Interpretation of lead isotope data is, however, often contentious and faces numerous instrumental and methodological challenges. (wikipedia.org)