Abstract:

WT5BZ] During the first Chinese scientific expedition to the Arctic in July-September, 1999, a simple nutrient enrichment incubation experiment was carried out in the Bering Sea. The incubated water was taken from 10 m at station B2 1. The experiment began on 23th July and ended on 5th August. The nutrient concentration was enriched to 2, 4 and 8 times of the initial concentration of phosphate and nitrate respectively. Two controls were set up. The incubation bottles were incubated in a water flow temperature controlled incubator on board the R.V. “Xuelong”. After 5 days of incubation, chlorophyll a concentration increased to the 3.5-4.5 fold of the initial concentration (0.55 μg·l -1 ) in the control and nutrient enriched bottles. No obvious difference showed up at this time. At the tenth day of the incubation, the chlorophyll a concentration in the nitrate enriched bottles, phosphate enriched bottles and the controls were 17.6-24.0, 9.3-11.4 and 7.6-9 μg·l -1 respectively. The chlorophyll a concentrations in all the bottles decreased at the end of the incubation. The result of the incubation showed that nitrate was the potential limitation nutrient. The concentration of the nutrient did not affect the phytoplankton growth obviously. It was the absolute amount of nutrient absorbed by the phytoplankton that limited their growth. [WT5HZ]