Primary amines in California coastal waters: Utilization by phytoplankton1

Abstract

A new reagent, fluorescamine, provides a simple, rapid fluorometric measurement of primary amino compounds in seawater. The reagent detects as little as 0.2 µ M (glycine equivalents) directly in 2 ml of seawater. Fluorescamine‐positive primary amines in the region of Newport Bay, California, range from about 0.3 µ M in nearshore waters to 14 µ M in bay sediments. About half the fluorescamine‐positive material in Newport Bay water can be taken up rapidly by phytoplankton, and thus, may be an important nitrogen source. The half not taken up probably occurs as peptides. Fluorescamine should be invaluable for studies on microbial nutrition and cycling of organic matter in aquatic ecosystems.