232
M. Bartoli et al.
sediment was incubated in parallel with Ruppia
colonised sediment (data not shown). Oxygen
and DIN fluxes were strongly affected by the
presence of Ruppia and exchange rates were up
to 10-15 fold higher. No significant differences
were found comparing denitrification rates with
or without macrophytes probably because of the
extremely low N0 3 - concentrations in the water
column and the absence of 02 in the rhizosphere
(Barbanti et al. 1997).
Overall, comparison of the three sites indicates the effects of the dominant primary producers on the balance between N -assimilation
and denitrification. The seagrasses control the
N-cyde throughout the year, whereas Ulva controls processes during the spring growth phase
and in the early decomposition period. At the
microalgal site rates have a high variability due
to the low and rapidly changing biomass of the
microalgae and the inherently high variability of
physicochemical parameters and macrofaunal
populations.
Acknowledgements. This research has been jointly supported
by the EU projects NICE (contract MAS3-CT96-0048) and
ROBUST (contract ENV4-CT96-0218).
References
Barbanti A, Bartoli M, Cavicchini F, Giordani G, Viaroli P, Varallo
G, (1997) Nictemeral changes of redox equilibrium at the
sediment-water interface of a Ruppia cirrhosa meadow
determined by in situ microprofiling.In: VIII Congr Ital Soc
EcolAtti,pp 501-505
Bartoli M (1996) Nitrogen and phosphorus benthic fluxes in
coastal environments characterised by different communities of primary producers (in italian). PhD thesis,
Department of Environmental Sciences, Parma University,
Italy
Borum J (1996) Shallow waters and land/sea boundaries. In:
Jorgensen BB, Richardson K (eds) Eutrophication in coastal
marine ecosystems. (Coastal and Estuarine Studies) Am
Geophys Union 52. pp 179-203
Caffrey J. Kemp WM (1992) Influence of the submerged plant,
Potamogeton Perjoliatis, on nitrogen cycling in estuarine
sediments. Limnol Oceanogr 37: 1483-1495
Castaldelli G (1998) Nitrification and ammonium pools in the
sediments of the Sacca di Goro, Po River Delta (in italian).
PhD thesis, Department of Environmental Sciences, Parma
University, Italy
Christensen PH, Revsbech NP, Sand-Jensen K (1994) Microsensor
analysis of oxygen in the rhizosphere of the aquatic macrophyte Littorella uniflora (1.) ascherson. Plant Physiol lOS:
847-852
Dalsgaard T (ed.) (1999). Protocol handbook for NICE (nitrogen
cycling in estuaries). NICE contract MAS3-CT96-0048,
Comm Eur Communities DC XII, Bruxelles, Appendix 25
Focht DD, Verstraete V (1977) Biochemical ecology of nitrification and denitrification. Mv Microbio! Eco! I: 135-214
Giordani G (1997) Sulphide speciation and inorganic phosphorus
mobility in relation to iron availability in sediments of mstrophic lagoon environments (in italian). PhD thesis,
Department of Environmental Sciences, Parma University,
Italy
Henriksen K. Kemp W (1988) Nitrification in estuarine and
coastal marine sediment. In: Blackburn TH, Sorensen J (eds)
Nitrogen cycling in coastal marine environments. John
Wiley and Sons, New York, pp 210-249
Henriksen K, Jensen A, Rasmussen MB (1984) Aspects of nitrogen
and phosphorus mineralization and recycling in the northern part of the Danish Wadden Sea. Neth Inst Sea Res Publ
Ser 10: Sl-69
Kristensen E (1984). Effect of natural concentrations on nutrient
exchange between a polychaete burrow in estuarine sediment and the overlying water. J Exp Mar BioI Eco175: 171-90
Naldi M (1994) Benthic macroalgae and nutrient cycles in a
lagoon of the Po River Delta (Sacca di Goro) (in italian). PhD
thesis, Department of Environmental Sciences, Parma
University, Italy
Nielsen LP (1992) Denitrification in sediment determined from
nitrogen isotope pairing. PEMS Microbiol Ecol 86: 357-362
Nielsen LP, Sloth NP (1994) Denitrification, nitrification and
nitrogen assimilation in photosynthetic microbial mats. In:
Stahl LJ, Coumette P (eds) Microbial mats, structure, development and environmental significance. (NATO ASI Ser G
Ecol Sci, vo13S) Springer Verlag. Berlin Heidelberg New York
Tokyo, pp 319-324
Nielsen LF, Christensen PB, Revsbech NP, Sorensen J (1990)
Denitrification and photosynthesis in stream sediment
studied with microsensor and whole-core technique. Limnol
Oceanogr. 35: 1135-1144.
Orlandi S (1998) Nutrient loads and restoration perspectives in a
coastal lagoon of the Po River Delta (in italian). Bachelor
thesis, Dep Environ Sci Univ Parma
Pedersen MF, Borum J (1992) Nitrogen dynamics of eelgrass during late summer period of high growth and low nutrient
availability. Mar Ecol Prog Ser 80: 65-73
Rasmussen MB, Henriksen K. Jensen A (1983) Possible causes of
temporal fluctuations in primary production of the microphytobenthos in the Danish Wadden Sea. Mar BioI 73: 109114
Revsbech NP, Jorgensen BB, Brix 0 (1981) Primary production of
microalgae in sediments measured by oxygen microprofile,
Hl4(;O, fixation, and oxygen exchange methods. Limnol
Oceanogr 26: 717-730
Risgaard-Petersen N, Jensen K (1997) Nitrification and denitrification in the rhizosphere of the aquatic macrophyte Lobelia
Dortmanna L. Limnol Oceanogr 42: 529-S37
Rysgaard S, &isgurd-Petersen N, Sloth NP (1996) Nitrification.
denitrification and nitrate ammonification in two coastal
lagoons in Southern France. In: Coumette P, Castel J, Herbert
R (eds) Coastal lagoon eutrophication and anaerobic
processes. Kluwer, Amsterdam, pp 133-144
Sand-Jensen K, Borum J (1991) Interactions among phytoplankton, periphyton, and macrophytes in temperate freshwaters
and estuaries. Aquat Bot 41: 137-175
Sand-Jensen K, Prahl C (1982) Oxygen exchange with the lacunae
and across leaves and roots of the submerged vascular
macrophyte, Lobelia Dortmanna 1. New P.hytologist 91: 103120
Sondergaard M (1983) Heterotrophic utilization and decomposition of extracellular carbon released by the aquatic
angiosperm Littorella uniflora (L.) Aschers. Aquat Bot Mar
27;547-555
M. Bartoli et al.
sediment was incubated in parallel with Ruppia
colonised sediment (data not shown). Oxygen
and DIN fluxes were strongly affected by the
presence of Ruppia and exchange rates were up
to 10-15 fold higher. No significant differences
were found comparing denitrification rates with
or without macrophytes probably because of the
extremely low N0 3 - concentrations in the water
column and the absence of 02 in the rhizosphere
(Barbanti et al. 1997).
Overall, comparison of the three sites indicates the effects of the dominant primary producers on the balance between N -assimilation
and denitrification. The seagrasses control the
N-cyde throughout the year, whereas Ulva controls processes during the spring growth phase
and in the early decomposition period. At the
microalgal site rates have a high variability due
to the low and rapidly changing biomass of the
microalgae and the inherently high variability of
physicochemical parameters and macrofaunal
populations.
Acknowledgements. This research has been jointly supported
by the EU projects NICE (contract MAS3-CT96-0048) and
ROBUST (contract ENV4-CT96-0218).
References
Barbanti A, Bartoli M, Cavicchini F, Giordani G, Viaroli P, Varallo
G, (1997) Nictemeral changes of redox equilibrium at the
sediment-water interface of a Ruppia cirrhosa meadow
determined by in situ microprofiling.In: VIII Congr Ital Soc
EcolAtti,pp 501-505
Bartoli M (1996) Nitrogen and phosphorus benthic fluxes in
coastal environments characterised by different communities of primary producers (in italian). PhD thesis,
Department of Environmental Sciences, Parma University,
Italy
Borum J (1996) Shallow waters and land/sea boundaries. In:
Jorgensen BB, Richardson K (eds) Eutrophication in coastal
marine ecosystems. (Coastal and Estuarine Studies) Am
Geophys Union 52. pp 179-203
Caffrey J. Kemp WM (1992) Influence of the submerged plant,
Potamogeton Perjoliatis, on nitrogen cycling in estuarine
sediments. Limnol Oceanogr 37: 1483-1495
Castaldelli G (1998) Nitrification and ammonium pools in the
sediments of the Sacca di Goro, Po River Delta (in italian).
PhD thesis, Department of Environmental Sciences, Parma
University, Italy
Christensen PH, Revsbech NP, Sand-Jensen K (1994) Microsensor
analysis of oxygen in the rhizosphere of the aquatic macrophyte Littorella uniflora (1.) ascherson. Plant Physiol lOS:
847-852
Dalsgaard T (ed.) (1999). Protocol handbook for NICE (nitrogen
cycling in estuaries). NICE contract MAS3-CT96-0048,
Comm Eur Communities DC XII, Bruxelles, Appendix 25
Focht DD, Verstraete V (1977) Biochemical ecology of nitrification and denitrification. Mv Microbio! Eco! I: 135-214
Giordani G (1997) Sulphide speciation and inorganic phosphorus
mobility in relation to iron availability in sediments of mstrophic lagoon environments (in italian). PhD thesis,
Department of Environmental Sciences, Parma University,
Italy
Henriksen K. Kemp W (1988) Nitrification in estuarine and
coastal marine sediment. In: Blackburn TH, Sorensen J (eds)
Nitrogen cycling in coastal marine environments. John
Wiley and Sons, New York, pp 210-249
Henriksen K, Jensen A, Rasmussen MB (1984) Aspects of nitrogen
and phosphorus mineralization and recycling in the northern part of the Danish Wadden Sea. Neth Inst Sea Res Publ
Ser 10: Sl-69
Kristensen E (1984). Effect of natural concentrations on nutrient
exchange between a polychaete burrow in estuarine sediment and the overlying water. J Exp Mar BioI Eco175: 171-90
Naldi M (1994) Benthic macroalgae and nutrient cycles in a
lagoon of the Po River Delta (Sacca di Goro) (in italian). PhD
thesis, Department of Environmental Sciences, Parma
University, Italy
Nielsen LP (1992) Denitrification in sediment determined from
nitrogen isotope pairing. PEMS Microbiol Ecol 86: 357-362
Nielsen LP, Sloth NP (1994) Denitrification, nitrification and
nitrogen assimilation in photosynthetic microbial mats. In:
Stahl LJ, Coumette P (eds) Microbial mats, structure, development and environmental significance. (NATO ASI Ser G
Ecol Sci, vo13S) Springer Verlag. Berlin Heidelberg New York
Tokyo, pp 319-324
Nielsen LF, Christensen PB, Revsbech NP, Sorensen J (1990)
Denitrification and photosynthesis in stream sediment
studied with microsensor and whole-core technique. Limnol
Oceanogr. 35: 1135-1144.
Orlandi S (1998) Nutrient loads and restoration perspectives in a
coastal lagoon of the Po River Delta (in italian). Bachelor
thesis, Dep Environ Sci Univ Parma
Pedersen MF, Borum J (1992) Nitrogen dynamics of eelgrass during late summer period of high growth and low nutrient
availability. Mar Ecol Prog Ser 80: 65-73
Rasmussen MB, Henriksen K. Jensen A (1983) Possible causes of
temporal fluctuations in primary production of the microphytobenthos in the Danish Wadden Sea. Mar BioI 73: 109114
Revsbech NP, Jorgensen BB, Brix 0 (1981) Primary production of
microalgae in sediments measured by oxygen microprofile,
Hl4(;O, fixation, and oxygen exchange methods. Limnol
Oceanogr 26: 717-730
Risgaard-Petersen N, Jensen K (1997) Nitrification and denitrification in the rhizosphere of the aquatic macrophyte Lobelia
Dortmanna L. Limnol Oceanogr 42: 529-S37
Rysgaard S, &isgurd-Petersen N, Sloth NP (1996) Nitrification.
denitrification and nitrate ammonification in two coastal
lagoons in Southern France. In: Coumette P, Castel J, Herbert
R (eds) Coastal lagoon eutrophication and anaerobic
processes. Kluwer, Amsterdam, pp 133-144
Sand-Jensen K, Borum J (1991) Interactions among phytoplankton, periphyton, and macrophytes in temperate freshwaters
and estuaries. Aquat Bot 41: 137-175
Sand-Jensen K, Prahl C (1982) Oxygen exchange with the lacunae
and across leaves and roots of the submerged vascular
macrophyte, Lobelia Dortmanna 1. New P.hytologist 91: 103120
Sondergaard M (1983) Heterotrophic utilization and decomposition of extracellular carbon released by the aquatic
angiosperm Littorella uniflora (L.) Aschers. Aquat Bot Mar
27;547-555