Nitrogen isotopic composition of marine and freshwater invertebrates

Nitrogen and carbon isotopic composition of bone collagen from marine and terrestrial animals

The stable nitrogen and carbon isotope ratios of bone collagen prepared from more than 100 animals representing 66 species of birds, fish, and mammals are presented. The b15N values of bone collagen from animals that fed exclusively in the marine environment are, on average, 9% more positive than those from animals that fed exclusively in the terrestrial environment; ranges for the two groups o...

Factors Controlling the Stable Nitrogen Isotopic Composition (δ15N) of Lipids in Marine Animals

Lipid extraction of biomass prior to stable isotope analysis is known to cause variable changes in the stable nitrogen isotopic composition (δ15N) of residual biomass. However, the underlying factors causing these changes are not yet clear. Here we address this issue by comparing the δ15N of bulk and residual biomass of several marine animal tissues (fish, crab, cockle, oyster, and polychaete),...

Utilization of Organic Nitrogen Compounds by Marine and Freshwater Bacteria

Reduced nitrogen species represent the largest pool of nitrogen in many aquatic systems, yet little is known about the chemical composition of this pool and the metabolic pathways required for its remineralization. The long residence time of this material in aquatic systems suggests that it is very refractory and relatively resistant to degradation by direct metabolism or extra-cellular enzymat...

Dispersal in freshwater invertebrates

Stable nitrogen isotopic composition of amino acids reveals