Values of isotopic enrichment
were calculated, and first-order and zero-order rate constants were calculated, for each test.
To assess both the isotopic enrichment
and the individual fatty acid concentrations (both unlabeled and [1.-sup.13]C-labeled) in the same GC/MS analysis, we designed a dual acquisition program in single-ion monitoring (SIM) mode.
We use the isotopic enrichment
of PON as a proxy for phytoplankton (using appropriate scaling functions) because our data set for [[N.sup.15].sub.t]-PON is far more extensive than for [[N.sup.15].sub.t]-phytoplankton.
in different particle sizes of a surficial sediment sample was measured to assess the availability of labeled, deposited PON to benthic primary consumers.
of water in the "woody" tissues of plants: implications for plant water source, water uptake, and other studies which use the stable isotopic composition of cellulose.
Physiological ecologists can greatly contribute to progress in isotopic ecology by providing a quantitative description of the fates of amino acids in different tissues, by "calibrating" the isotopic enrichment
of different tissues during starvation, and by providing the mechanisms that give rise to this enrichment (see Millward 1979, 1989).
Calibration of isotopic enrichments
to VPDB standard is based on daily analysis of NBS-19 (National Bureau of Standards) powdered carbonate and the analytical precision is better than 0.1% for both [[delta].sup.13]C and [[delta].sup.18]O values.