Isotope Tracer Methods for Studies of the Marine Nitrogen Cycle

摘要: This chapter covers improvements in tracer methods as applied to pelagic marine over the past decade and attempts point out promising new directions for future. Applicable from large literature on benthic nitrogen cycling studies are highlighted. The focus is rather than ecological or physiological applications of methods, covered other chapters this volume. However, salient will be mentioned provide context why one might want isolate analyze isotopic composition a particular analyte. review begins with major changes years, discusses basic experimental design experiments, then analytical separation different constituents cycle, concludes 15 N analysis itself interpretation resulting isotope data using various models. Two developments chemistry have greatly enhanced ability conduct analyses ocean; actual instrumentation analysis, advances chemical detection that an more accurately measure low concentrations ammonium nitrate. Coupling mass spectrometers CHN (carbon, hydrogen, nitrogen) analyzers, combined computers permitted extensive automation, has opened up field far wider range practitioners well vast expansion speed can completed.