海水中的氮化合物,已知包括无机的及有机的两大部分。前者主要是NO_3~-、NO_2~-及NH_4~+,后者主要是从蛋白质到氨基酸、脲等的一系列有机含氮化合物,按其形态的不同,而又区分为粒状有机氮及溶解有机氮。 NO_3~-、NO_2~-、NH_4~+及有机氮化合物,在海洋中的分布是具有明显规律性的。而它们的时间变化及循环,则更是复杂而有趣的、。无机氮作为浮游植物的养分而被吸收,并合成为有机氮。而浮游植物又作为浮游动物等的饵料,并两者在排泄或死亡分解时,则释出有机氮。后者经过细菌的分解作用,而 Nitrogen compounds in seawater are known to include both inorganic and organic components. The former is mainly NO_3 ~ -, NO_2 ~ - and NH_4 ~ +, the latter mainly from the protein to amino acids, urea and a series of organic nitrogen compounds, according to their morphological differences, but also divided into granular organic nitrogen and dissolved organic nitrogen. The distribution of NO_3 ~ -, NO_2 ~ -, NH_4 ~ + and organic nitrogen compounds in the ocean is obviously regular. Their time changes and cycles are even more complicated and interesting. Inorganic nitrogen is absorbed as a nutrient in phytoplankton and synthesized as organic nitrogen. Phytoplankton, on the other hand, act as bait for zooplankton and others, and both excrete organic nitrogen when they are excreted or die. The latter after bacterial decomposition, and