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- Info
Can urbanization limit iron availability to estuarine algae?
| Author: |
Kawaguchi, Tomohiro; Lewitus, Alan J.; Aelion, C. Marjorie; McKellar, Henery N. |
| Date: |
1997 |
| Periodical: |
Journal of Experimental Marine Biology and Ecology |
| Abstract: |
Bioavailable forms of iron are highly unstable in oxygenated saline water, but one way in which iron bioavailability to algae can be enhanced is by chelation to dissolved organic matter (DOM). We hypothesized that urbanization-associated deforestation in Murrells Inlet, South Carolina caused a reduction of iron bioavailability to estuarine phytoplankton by decreasing the supply of forest-derived DOM (i.e., the iron chelation source). Bioassay experiments were conducted comparing the potential for iron depletion by phytoplankton in natural populations and Cylindrotheca closterium (Ehr.) Reimann et Lewin cultures, transferred to Murrells Inlet and North Inlet (an undeveloped estuary) water. Chelated iron addition to incubated natural populations transferred to Murrells Inlet water resulted in increased abundances of phototrophic microplankton (accounted for by Cylindrotheca), nanoplankton, and picoplankton (dominated by Synechococcus spp.). In North Inlet water, iron enrichment to natural populations only enhanced Synechococcus growth, but this stimulation was much less than that in Murrells Inlet water. The effect of iron on Synechococcus growth in Murrells Inlet was striking (up to 34-fold greater abundance in iron-enriched treatment), suggesting that estuarine Synechococcus may be sensitive to iron stress. The results indicate that iron could be depleted much more readily in Murrells Inlet water, and suggest that iron availability to estuarine phytoplankton may be reduced by urbanization-related practices such as coastal forest clear-cutting. |
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