Chemical Stoichiometry of Logoonal Metabolism: Preliminary Report on an Environmental Chemistry Survey of Christmas Island, Kiribati

摘要

The mass balance of carbon, silicon, nitrogen, and phosphorus in the lagoon of Christmas Island has been calculated. There is no net silicon flux, consistent with the composition of coral reef systems. Dissolved organic nitrogen is released by the lagoonal system and exported. Carbon, phosphorus, and inorganic nitrogen are all slowly taken up by the system. The ratio of net inorganic N:P uptake matches the compositional ratio of incoming water and is very low in comparison with the compositional ratio of benthic plants. The observed patterns of carbon, nitrogen, and phosphorus flux can be explained by a relatively simple model. Net metabolism of this system -- and that of other confined water bodies -- is limited by the availability of phosphorus. Just sufficient nitrogen is fixed to use the available phosphorus. Export of dissolved organic nitrogen simply removes a largely unutilized by-product of the nitrogen fixation.