Nitrogen IsotopesTrichechus manatusCarbon IsotopesIsotopesIsotope LabelingCarbonOxygen IsotopesZinc IsotopesDeuteriumCarbon DioxideMass SpectrometryIron IsotopesSulfur IsotopesNitrogen FixationEcosystemCarbon MonoxideProteomicsIndicator Dilution TechniquesNitrogen CompoundsNanotubes, CarbonGas Chromatography-Mass SpectrometryChromatography, LiquidFood ChainTandem Mass SpectrometryRadioisotope Dilution TechniqueMolecular Sequence DataProteomeNitrogen CycleStrontium IsotopesKineticsSoilAmino AcidsBiomassNitrogen DioxideBlood Urea NitrogenNitrogenGeologic SedimentsBacteriaSeawaterMethaneBiodiversity