J. L. Espinar
L. Serrano
M. Reina
2006
<p>We have studied the effect of the presence of emergent macrophytes on the sediment phosphate composition of a eutrophic shallow marsh on the NE margin of Doñana (SW Spain). Top sediment and water samples were collected from both the open-water and the vegetated sites at three areas covered by different plant species: <i>Scirpus maritimus</i>, <i>Juncus subulatus</i> and <i>Phragmites australis</i>. The concentration of organic matter was significantly higher in the top sediment of sites covered by vegetation than in their adjacent open-water sites at the three vegetation areas. The P-fractional composition showed that the sediment was dominated by the inorganic P-fractions in all cases, reaching the highest concentration in the Ca-bound P-fraction (281–372 μg g<sup>−1</sup> d.w.). The sum of all P-fractions was significantly higher in the top sediment of the sites covered by <i>J. subulatus</i> and <i>S. maritimus</i> than in their adjacent open-water sites, and so were the org-P fraction extracted by hot NaOH and the concentration of phytate within this fraction. Deposition of plant material on the top sediment of areas vegetated by <i>J. subulatus</i> and <i>S. maritimus</i> explains these differences. The P-fractional composition of the seeds from <i>J. subulatus</i> showed that they contained a large proportion of organic P-fractions, particularly of the fraction extracted by hot NaOH (1868 μg g<sup>−1</sup> d.w., 85% of which was phytate). The presence of emergent macrophytes, therefore, influenced the distribution of P-fractions in the sediment depending on plant species. The P-bioavailability of shallow aquatic systems must be fully understood if wetlands are to be protected from further eutrophication.</p>
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10.1016/j.watres.2006.01.031
en
Elsevier
Sediment phosphate composition in relation to emergent macrophytes in the Doñana Marshes (SW Spain)
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