Morel François M M
Department of Geosciences, Princeton University, Princeton, NJ 08544, USA.
Geobiology. 2008 Jun;6(3):318-24. doi: 10.1111/j.1472-4669.2008.00144.x.
The composition of the oceans and of its biota have influenced each other through Earth's history. Of all the biologically essential elements, nitrogen is the only one whose seawater concentration is clearly controlled biologically; this is presumably the main reason why the stoichiometry of nitrogen (defined as its mol ratio to phosphorus), but not that of the trace nutrients manganese, iron, cobalt, nickel, copper, zinc and cadmium, is the same in seawater and in the plankton. Like the major nutrients, the trace nutrients are depleted in surface seawater as a result of quasi-complete utilization by the biota. This is made possible in part by the ability of marine phytoplankton to replace one trace metal by another in various biochemical functions. This replacement also results in an equalization of the availability of most essential trace metals in surface seawater. The difference in the stoichiometric composition of the plankton and of deep seawater, which is the dominant source of new nutrients to the surface, indicates that some nutrients are likely recycled with different efficiencies in the photic zone. The difference in the composition of the ocean and its biota provides insight into the coupling of biochemistry and biogeochemistry in seawater.
在地球历史进程中，海洋及其生物群的组成相互影响。在所有对生物至关重要的元素中，氮是唯一一种其海水浓度明显受生物控制的元素；这大概是海水和浮游生物中氮的化学计量比（定义为其与磷的摩尔比）相同，而微量营养元素锰、铁、钴、镍、铜、锌和镉的化学计量比不同的主要原因。与主要营养元素一样，由于生物群几乎完全利用，表层海水中的微量营养元素会被消耗。这在一定程度上是由于海洋浮游植物在各种生化功能中能用一种微量金属替代另一种微量金属的能力。这种替代还导致表层海水中大多数必需微量金属的可利用性趋于均衡。浮游生物与深层海水（表层新营养物质的主要来源）的化学计量组成差异表明，某些营养物质在光合层中可能以不同效率循环利用。海洋及其生物群组成的差异为深入了解海水中生物化学与生物地球化学的耦合提供了线索。
