Portal de Periódicos da CAPES

Vertex: phytoplankton/iron studies in the Gulf of Alaska

1989; Pergamon Press; Volume: 36; Issue: 5 Linguagem: Inglês

10.1016/0198-0149(89)90144-1

1878-2477

John H. Martin, R. Michael Gordon, Steve E. Fitzwater, William W. Broenkow,

Mercury impact and mitigation studies

VERTEX studies were performed in the Gulf of Alaska in order to test the hypothesis that iron deficiency was responsible for the phytoplankton's failure to remove major plant nutrients from these waters. In view of the observed Fe distributions and the results of phytoplankton Fe enrichment experiments, it was concluded that Gulf of Alaska atmospheric Fe input rates are sufficient to support moderately high rates of primary productivity; however, not enough Fe is available to support the high growth rates that would lead to normal major nutrient depletion. Enhanced Fe input does occur along the Alaska continental margin, where normal NO3 surface depletion is observed. Coccolithophorids appear to be best able to cope with low Fe conditions; however, they cannot compete with diatoms when Fe is readily available. Iron may be more important than available N in determining global rates of phytoplankton new production. Offshore Pacific Ocean water, replete with major nutrients, appears to be infertile without supplemental iron from the atmosphere or continental margin.