The contents and distribution of iron in natural colloids
- 海洋环境－已发表论文 
In traditional oceanography research, colloids were usually studied together with the dissolved phase, which made the recognizing of the biogeochemistry cycle and the biological availability of elements deflected to some extent. Actually colloids can easily absorb some radioactive isotopes, trace elements and organic compounds to its surface. As a result, they play a significant role in the presentation and transportation of elements in the ocean. In this paper, the contents and distribution of iron in two fractions (<10kDa and 10kDa similar to 0.22 mu m) were studied in the water from Jiulongjiang River, Jiulongjiang River estuary and south Xiamen Bay of China during Apr.2004 and Mar.2005. The result showed that concentrations of Fe3+ in absolutely dissolved phase varied from 2.8 similar to 31.9 mu g/L and that of Fe 21 was below detection limit(<0.5 mu g/L) to 8.6 mu g/L, Fe3+ and Fe 21 in colloidal phase were <2.5 mu g/L similar to 10.0 mu g/L and <0.5 mu g/L similar to 50.4 mu g/L, respectively. It was found that Fe 31 mainly distribute in absolutely dissolved phase and the majority of colloidal phase was Fe. Moreover, the concentrations of total iron in all phases were highest in samples from estuarine water. Fe2+ which is thought to be used directly by algae was very few in August in both natural colloids phase and absolutely dissolved phase during the blooms of phytoplankton.