Preface This publication presents the Proceedings of the 4th International Symposium on phosphate in sediments held at Carmona (Spain) from 9 to 12 Sept. 2003.
These P-symposia are the spin-off of the first symposium “Interactions between sediments and fresh water”, held at Amsterdam, 6 – 10 Sept. 1976. The proceedings of that symposium were edited by Golterman, 1976. The second sediment symposium was held in Kingston, Canada, 1981 and the third in Geneva in 1984.
During the Amsterdam meeting a group of scientists concentrating their work on phosphate in sediments decided that it would be useful to have a meeting dedicated to this subject only. In Geneva it was decided to have the first symposium on Phosphate in Sediments, which was finally organized in the Department of Limnology, University of Vienna; the proceedings were edited by Psenner & Gunatilaka (1988).
The second symposium was organized in the Laboratory of Limnology of the University of Uppsala (Sweden) in 1988. No proceedings were published; a short report is published by Enell et al., 1989. The third one was held at Woudschoten (Netherlands) in 1991. The proceedings were published by Boers et al. (1993).
The fourth symposium was organized by the Department of Plant Biology and Ecology of the University of Sevilla with cooperation of the Instituto del Agua, Universidad de Granada. It took place in the splendid environment of the Parador of Carmona. The main themes were:

1) Exchange and release processes (7 lectures; Chairman: C. Bonetto) In this session the following papers or posters were read: G. Bally et al., J. Borovec, A. Maine et al. (2 papers), A. Mitchell et al., G. Nürnberg & H. Cyr, L. Serrano et al.

2) Vertical distribution in sediment; P-Composition & Availability (6 lectures; chairman: M. A. Maine) In this session the following papers were read: A. deVicente et al., W. Eckert & A. Nishri, A. Maine et al., A. Jorcin et al., B. Ruiz, et al., M. T. Barral et al.

3) Methodology (5 lectures; chairman: P. Ekholm) In this session the following papers were read: P. Ekholm, H. Jensen, M. K. Leivuori et al., C. Orona et al., K. Reitzel.

4) P-transformations (3 lectures; chairman: A. Kleeberg) In this session the following papers were read: R. Gilbin et al., B. Grüneberg et al., H. Mugni & C. Bonetto.

5) P-Transport and Fluxes (5 lectures; Chairman: F. Ø. Andersen) In this session the following papers were read: M. Alvarez et al., M. Flindt, J. Lewandoski, H. Mugni et al., H. Golterman.

6) Miscellaneous topics (8 lectures; chairman: D. Baldwin) In this session the following papers were read: A. Kleeberg et al., D. R. Thomsen et al., G. Wauer et al., D. Baldwin, U. Selig et al., K. B. Nielsen & F. Ø. Andersen, M. E. Jacobson-Meyers et al., Shigeo Tsujimura.

Furthermore there was ample time for discussions, stimulated by the atmosphere and splendour of the Parador. Not all papers were submitted for publication.
We shall not follow the habit of trying to synthesize the lectures – they are before you and we think it is better to read them yourselves, and not a short synthesis. To stimulate this we add the reports of the chairmen. But we like to point out the area’s where more research appears to be needed. Without the sequence giving a suggestion of priority, these were:
– The chemical composition of organic phosphates, especially the humic bound phosphate.
– The separation between phytate phosphates and polyphosphates.
– The release of phosphate especially following the onset of anoxic conditions.
– The diffusion of phosphate from interstitial water into the overlying water layer
– The measurement of interstitial phosphate concentrations by using ‘peepers’, cores or (micro) electrodes.
– Determination of potentially bioavailable phosphate
– Phosphates in very acid environments.
We want to thank all participants for their enthusiastic cooperation and the authors for their contributions and their
confidence in the editors.

The editors: Dr Laura Serrano & Dr Han Golterman
Sevilla/Arles, November 2004


Preface vii

A note on the use of abbreviations and acronyms xi
Acknowledgement xiii
Opening lecture
Chemistry and limnology: A marriage de raison?
Han L. Golterman 1

Section 1. Exchange and release processes Dialysis porewater sampler: a strategy for time equilibration optimisation
Gabriel Bally, V. Mesnage, R. Verney, O. Clarisse, J.-P. Dupont, B. Ouddanne & R. Lafite 9
Phosphate and metal retention in a small-scale constructed wetland for waste-water treatment
Alejandra Maine, N. Suñe, H. Hadad,, G. Sánchez & C. Bonetto .. 21
Spatial variation of phosphate distribution in the sediments of an artificial wetland
Alejandra Maine, N. Suñe, H. Hadad & G. Sánchez .. 33
Alterations to potential phosphorus release from anaerobic freshwater sediments with additions of different species of labile carbon
Alison M. Mitchell, D. S. Baldwin & G. N. Rees .. 43
Methodological biasis in phosphate adsorption experiments
Hélène Cyr & G. K. Nürnberg . 55
Phosphate release from sediments in highly eutrophic coastal lagoons of southern Spain
Laura Serrano, I. de Vicente, M. Reina, J. Toja & L. Cruz-Pizarro .. 67

Section 2.Vertical distribution in sediment/Composition/Availability
Phosphate distribution in the sediments along a cascade of reservoirs (Paranapanema River, SE, Brazil)
Adriana Jorcin & Marcos G. Nogueira .. 77
Spatial and temporal variability of particulate phosphorus fractions in seston and sediments of Lake Kinneret
under changing loading scenario (Abstract only)
Werner Eckert & A. Nishri ... 87
Vertical distribution of P, C, N and S in sediment cores from the Anllons River (NW Spain) (Abstract only)
M.T. Barral, B. Ruiz, M. Ruiz & F. Díaz-Fierros .. 88
Phosphorus in sediment of the Anllons river (Galicia, NW Spain). (Abstract only)
B. Ruiz, M.T. Barral, M. Ruiz & F. Díaz-Fierros 88

Section 3. Methodology
Reflections on the determination of the potential availability of phosphate to algae
Petri Ekholm, Jouni Lehtoranta & Han Golterman .. 89
Phosphate concentration and association as revealed by sequential extraction and microprobe analysis. The case
of sediments from two Argentinean dams. (Abstract only)
L. Borgnino, C. Oroná, M. Avena , M. A. Maine, A. Rodriguez & C.P. De Pauli .. 98
Humic-bound phosphorus in soils and sediment
Henning S. Jensen, Nina Caraco, Jonas Hansen & Kasper K. Christensen 99
Sequential extraction studies on sediment phosphorus at the Gulf of Finland (Abstact only)
Mirja Leivuori & Kaarina Lukkari 108
Separation of aluminum bound phosphate from iron bound phosphate in freshwater sediments by
a sequential extraction procedure
Kasper Reitzel . 109

Section 4. Transformations
Macroalgal decomposition and phosphate behaviour in sediment of coastal brackish lagoons:
A laboratory study under oxic and anoxic conditions
E. Gomez, R. Gilbin, D. Rosain & B. Picot 119
Benthic phosphorus forms and transformations during neutralization of acid mining lakes
B. Grüneberg & A. Kleeberg ... 127
Phosphate and nitrogen transformations in a large floodplain river
H. Mugni, A. Maine & C. Bonetto .. 139

Section 5. Transport and fluxes
Carbon, nitrogen and phosphorus sediment fluxes in Venice Lagoon. Dependency on current velocity
and plant coverage and dynamics (Abstract only)
M.R. Flindt, J. Neto, M.A. Pardal, C.L. Amos, C.B. Pedersen & A. Bergamasco .. 150
What happens after phosphate is released from the sediment in stratifying lakes?
M. Alvarez-Cobelas & E. Piña ... 151
Phosphate and nitrogen compounds in streams of Pampean Plain areas under intensive cultivation
(Buenos Aires, Argentina).
H. Mugni, S. Jergentz, R. Schulz, A. Maine & C. Bonetto .. 163
Impact of macrozoobenthos on two-dimensional small-scale heterogeneity of pore water phosphorus
concentration in lake sediments (Abstract only)
J.Lewandowski & M. Hupfer ... 171
Section 6. Miscellaneous
Interactions of the macrophyte Littorella uniflora with sediment phosphate in three oligotrophic
Danish lakes
K.B. Nielsen & F. Ø. Andersen ... 173
Variation in sediment phosphate along an estuarine salinity gradient on the Baltic Sea
U. Selig, S. Berghoff, G. Sclungbaum & H. Schubert 185
Is exudation of organic acids by Littorella uniflora a mechanism for sediment phosphate dissolution?
D.R. Thomsen, K. B. Nielsen & F. Ø. Andersen .. 195
P-immobilisation and phosphatase activities in lake sediment following treatment with nitrate
and iron (Abstract only)
Gerlinde Wauer, Thomas Gonsiorczyk, Peter Casper & Rainer Koschel 201
Water management in Lake Yogo targeting on internal phosphorus loading released from sediment
(Abstract only)
Shigeo Tsujimura . 202