SESSION 4
NUTRIENTS IN TERRESTRIAL, ATMOSPHERIC,
RIVERINE, ESTUARINE AND COASTAL COMPARTMENTS
European Land-Ocean Interaction Studies
4th ELOISE Conference
5-7 September 2001, Rende, Italy
ATMOSPHERIC INPUT OF NITROGEN INTO THE NORTH SEA: ANICE
RESULTS
De Leeuw G.1, G. J. Kunz1, L.H. Cohen1, M. Moerman1, G. Geernaert2, O. Hertel2, L.M. Frohn2, C. A. Skjøth2, B. Pedersen2, B. Jensen2, L.-L. Sorensen3, S. Lund3, K.
Heinke Schlünzen4, L. Klein4, K. von Salzen4a, Tim Jickells5, L. Spokes5, M. Schulz6, S.
Tamm6, E. Vignati7
(1)
TNO Physics and Electronics Laboratory, The Hague, The Netherlands
National Environmental Research Institute, Roskilde, Denmark
(3)
Risø National Laboratory, Roskilde, Denmark
(4)
Meteorologisches Institut, Univ. Hamburg, Germany
(5)
School of Environmental Sciences, University of East Anglia, Norwich Norfolk, UK
(6)
Inst. Fuer Angew. Und Anorg. Chemie, Univ. Hamburg, Germany
(7)
Joint Research Centre, Environment Institute, TP 460, 21020 Ispra, Italy
(a)
Current address: Canadian Centre for Climate Modelling and Analysis, Univ. Victoria,
Canada
(2)
A CONTRIBUTION FROM THE ELOISE PROJECT: ANICE
The aim of the ANICE (Atmospheric Nitrogen Inputs into the Coastal Ecosystem)
project is to improve transport-chemistry models that estimate nitrogen deposition to the
sea. To achieve this, experimental and modelling work is undertaken which aims at
improving the understanding of the processes involved in the chemical transformation,
transport and deposition of atmospheric nitrogen compounds.
Of particular emphasis within ANICE is the influence of coastal zone processes.
The improved transport-chemistry models will be used to assess the atmospheric
inputs of nitrogen compounds into the European regional seas (the North Sea is studied
as a prototype). The experimental results show the large spatial and temporal variability
in the concentrations of gaseous nitrogen compounds, and their influences on fluxes.
Model calculations show the strong variation of both concentrations and gradients of
nitric acid at fetches of up to 25 km.
Aerosol concentrations also show high temporal variability and experimental
evidence for the reaction between nitric acid and sea salt aerosol is provided by sizesegregated aerosol composition measured at both sides of the North Sea.
In several occasions throughout the experimental period, air mass back trajectory
analysis showed connected flow between the two sampling sites (the Weybourne
Atmospheric Observatory on the North Norfolk coast of the UK and Meetpost
Noordwijk, a research tower at 9 km off the Dutch coast).
Results from the METRAS/SEMA mesoscale chemistry transport model system for
one of these cases are presented.
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4th ELOISE Conference
5-7 September 2001, Rende, Italy
Measurements of aerosol and rain chemical composition, using equipment mounted
on a commercial ferry, show variations in composition across the North Sea. These
measurements have been compared to results obtained with the transport chemistry
model ACDEP which calculates the atmospheric inputs into the whole North Sea area.
SESSION 4
108
Oral Presentation
European Land-Ocean Interaction Studies
4th ELOISE Conference
5-7 September 2001, Rende, Italy
NUTRIENT DYNAMICS MEDIATED THROUGH TURBULENCE AND
PLANKTON INTERACTIONS
Marrasé Cèlia1, John Dolan2, Harry Havskum3, Atle Lohrmann4, Tim Pedley5, Francesc
Peters1 and Frede Thingstad6
(¹) Institut de Ciències del Mar (CSIC), Passeig Joan de Borbo s/n, 08039 Barcelona, Spain
(celia@icm.csic.es)
(²) Station Zoologique. BP 28. F 06230 Villefranche-Sur-Mer France
(³) Marine Biological Laboratory, Zoological Institute, University of Copenhagen.
Strandpromenaden, 5. 3000 Helsingoer, Denmark
(4) NORTEK AS, Industriveien, 33, N-1337 Sandvika, Norway
(5) University of Cambridge, Department of Applied Mathematics and Theoretical Physics,
Silver Street, CB39EW Cambridge, United Kingdom
(6) University of Bergen, Department of Microbiology, Jahnebakken 5, N-5020 Bergen, Norway
A CONTRIBUTION FROM THE ELOISE PROJECT: NTAP
Turbulence effects on plankton can strongly modulate nutrient and organic matter
dynamics in coastal areas. However, data at present show that effects may be nonlinear,
depend on initial environmental conditions, and/or may be specific to certain sizes of
organisms or specific taxa.
In models of marine systems, turbulence is accounted for as affecting the transport of
chemicals and organisms, but rarely as affecting biological processes, since biological
effects appear complex and little is known about their dynamics. The overall objective
is to provide a unified conceptual framework for nutrient dynamics as modulated by the
interaction of turbulence and plankton and to use this information to aid in
implementing and modifying legislation on coastal water quality and management. The
specific objectives are a) to build a database on turbulence effects by gathering existing
scattered data, b) to produce experimental data on key organisms, interactions and mass
transfer rates, c) to develop a sensor for laboratory measurement of small-scale
turbulence, and d) to produce a dynamical model at community level with exploratory
and predictive capabilities. The research strategy for fulfilling the specific objectives as
well as building the overall framework consists of using multi-level approaches and
levels of observation. Existing data from both experiments and field observations is
analysed to guide the design of new experiments and preliminary modelling efforts.
New experimental data on the effects of turbulence on plankton, ranging from organism
to net community responses, is produced. A microsensor to measure flow in small
containers is developed to overcome current size constraints. Modelling efforts are
conducted to incorporate small-scale turbulence effects into a microbial food web
model. Project output will permit improved assessment of nutrient and mass transfer
behaviour and variability in coastal pelagic communities and thus be of value to
environmental managers and in the formulation of water quality regulations.
SESSION 4
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European Land-Ocean Interaction Studies
4th ELOISE Conference
5-7 September 2001, Rende, Italy
Figure: Simplified scheme of plankton trophic interactions. The “T” indicates the fluxes that
can be affected by turbulence
SESSION 4
110
Oral Presentation
European Land-Ocean Interaction Studies
4th ELOISE Conference
5-7 September 2001, Rende, Italy
MONITORING LONG-TERM TRENDS IN EUTROPHICATION
NUTRIENTS IN THE COASTAL ZONE (MOLTEN)
AND
Conley Daniel J 1, Steve Juggins 2, Atte Korhola 3, N. John Anderson 4, Victor N. de
Jonge 5, Elinor Andrén 6
(1)
Dept. Of Marine Ecology, National Environmental Research Institute, DK-4000, Roskilde,
Denmark (dco@dmu.dk)
(2)
University of Newcastle upon Tyne, Newcastle upon Tyne, NE1 7RU, UK
(3)
Dept. Of Ecology and Systematics, Division of Hydrobiology/ECRU, University of Helsinki,
Helsinki, Finland
(4)
Institue of Geography, University of Copenhagen, DK-1350 Copenhagen, Denmark
(5)
National Institute for Coastal and Marine Management, RIKZ, The Netherlands
(6)
Dept. Of Earth Sciences, Uppsala University, Uppsala, Sweden
A CONTRIBUTION FROM THE ELOISE PROJECT: MOLTEN
MOLTEN is using the high resolution record of environmental changes recorded in
coastal sediments to reconstruct, or hindcast, the long-term (100-150 years) changes in
nutrient (N and P) concentrations that have taken place in four representative European
coastal basins (Mariager Fjord, Denmark; Himmerfjärden, Sweden; Laajalahti, Finland;
and the Elms-Dollard Estuary, The Netherlands). We use novel approaches to
reconstruct historical nutrient concentrations using the recently developed technique of
diatom-based transfer functions. A harmonised transfer function will be developed in
order to provide a general tool that can be applied at the European scale. In addition,
we will establish long-term historical trends in biological and chemical parameters from
sediment records at four coastal sites. This multi-proxy palaeoecological work will
provide insights into changes in structure of various parts of the ecosystem
(phytoplankton, littoral macrophytes, zoobenthos). A system will be developed for
coastal managers to evaluate the effectiveness of policies to reduce nutrient loads by
using the palaeoecological data for the period 1850-1900 to establish reference
ecological and chemical conditions for each basin under minimal human impact; will
compare time-series of biological and geochemical proxies and nutrient reconstructions
with these reference conditions to assess ecological change in terms of departure from
baselines; will determine the reduction in nutrient loading necessary to bring about a
return to reference conditions; will evaluate the effectiveness of the different
palaeoecological records for assessing the ecological status of coastal waters and to
derive a minimum, parsimonious sampling strategy appropriate to provide a cost
effective tool for addressing the key points of the Water Framework Directive in a
standardised way across a large part of the European coastal zone.
SESSION 4
111
Oral Presentation
European Land-Ocean Interaction Studies
4th ELOISE Conference
5-7 September 2001, Rende, Italy
MODEL SYSTEM FOR THE MANAGEMENT OF NITROGEN LEACHING AT
THE SCALE OF RIVER BASINS AND REGIONS
Wendland, F.1, R. Kunkel 1, A. Grimvall 2, B. Kronvang 3 and D.I. Müller-Wohlfeil 3
(1)
(2)
(3)
Research Centre Jülich, Systems Analysis and Technology Evaluation (STE), Jülich, D
Department of Mathematics, Division of Statistics, Linköping University, Linköping, S
National Environmental Research Institute (NERI), Vejlsøvej 25, DK-8600 Silkeborg, DK
A CONTRIBUTION FROM THE ELOISE PROJECT: RANR
In the framework of the EU-project RANR (Regional analysis of subsurface nitrogen
retention and its impact on the nitrogen export from land to sea: Grimvall et al., 2000) a
model system was developed to estimate groundwater-borne nitrogen inputs into river
systems.
The core of this model system is composed of a soil nitrogen leaching model (SOILN: Johnsson et al., 1987), a runoff model (GROWA98: Kunkel & Wendland, 1999) and
a groundwater residence time/denitrification model (WEKU: Kunkel & Wendland,
1997; 1999).
The application of the model system was carried out for the study catchment areas of
the Uecker basin (ca. 2400 km2, Germany) and the Gjern basin (ca. 200 km2, Denmark).
For both catchment areas, the modelled average nitrogen loads leached into the
groundwater were about 40 kg N/ha a, while the remaining groundwater-borne nitrogen
intake to rivers was quantified to an average of about 2 kg/ha a.
The comparision with observed groundwaterborne riverine nitrogen loads showed a
very good agreement. With regard to the generalisation and transfer of the SOILN/GROWA98-WEKU model we propose the model to be applied for the analysis of the
interaction between water balance and nitrate balance at the scale of mesoscale to
macroscale river basins.
References
Grimvall, A., Forsman, A., Kronvang, B., Kunkel, R., Müller-Wohlfeil, D.I., &
Wendland, F. (2000, in press). Regional Analysis of subsurface retention of nitrogen
and the impact of such retention on the export of nitrogen from land to sea. Schriften
des Forschungszentrums Jülich Reihe Umwelt/Environment, Jülich, Germany.
Johnsson P.O., Bergström, H.L., & Jansson, P.-E. (1987). Simulated nitrogen dynamics
and losses in a layered agricultural soil. Agriculture, Ecosystems and Environment, 18,
333-356.
Kunkel, R. & Wendland, F. (1999). Der Landschaftswasserhaushalt
Flußeinzugsgebiet der Elbe. HW 43, H.5, 226 - 233.
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Oral Presentation
European Land-Ocean Interaction Studies
4th ELOISE Conference
5-7 September 2001, Rende, Italy
Kunkel, R. & Wendland, F. (1997). WEKU – a GIS supported stochastic model of
groundwater residence times in upper aquifers for the supraregional groundwater
management. Envir. Geol., 30(1/2), 1-9.
Kunkel, R. & Wendland, F. (1999). Das Weg-/Zeitverhalten der unterirdischen
Abflusskomponente im Elbeeinzugsgebiet. Schriften des Forschungszentrum Jülich,
Reihe Umwelt/Environment, 19, Jülich, Germany.
Kunkel, R., Wendland, F., & Albert, H. (1999). Zum Nitratabbauvermögen im Grundwasser.
Wasser & Boden, 51/9, 16–19.
SESSION 4
113
Oral Presentation
European Land-Ocean Interaction Studies
4th ELOISE Conference
5-7 September 2001, Rende, Italy
AN INVESTIGATION OF THE STRUCTURE AND DYNAMICS OF WATER
BLOOMS OF CYANOBACTERIA IN THE BALTIC SEA – RESPONSES TO A
CHANGING ENVIRONMENT
Stal Lucas J.
Netherlands Institute of Ecology, P.O.Box 140, 4400 AC Yerseke, Netherlands
A CONTRIBUTION FROM THE ELOISE PROJECT: BASIC
The blooms of cyanobacteria that develop each summer in the Baltic Sea are
composed of two functional groups, namely the small-sized picocyanobacteria
(Synechococcus spp.) and the larger, colony-forming, filamentous N2-fixing
cyanobacteria. The former encompassed both red (phycoerythrin-rich) and blue-green
(phycocyanin-rich) species.
The majority of the picocyanobacteria measured less than 1 m and this size-fraction
comprised as much as 80% of the total cyanobacterial biomass and contributed as much
as 50% of the total primary production of a cyanobacterial bloom.
The picocyanobacteria are incapable of fixing N2, do not possess gas vesicles and are
not toxic. The larger cyanobacteria may form surface scum due to the fact that they
possess gas vesicles that make them buoyant.
Although their biomass was less than the picocyanobacteria, they were the more
conspicuous and nuisance part of the bloom. This functional group was composed of
mainly three different species: Nodularia spumigena, Aphanizomenon flos-aquae and
Anabaena sp. They all belong to the heterocystous, N2-fixing cyanobacteria and form
gas vesicles. N. spumigena and A. flos-aquae were the dominant species and formed
colonies. Of the three species, only N. spumigena has been shown to be toxic.
Although Nodularia occurred in different phenotypes that have been assigned to
different species, it was demonstrated that they all belong to one species that exchange
genetic information. N. spumigena and A. flos-aquae revealed differences with respect
to their photosynthetic and N2-fixing potentials.
Depending on the prevailing environmental conditions, these differences would
promote the proliferation of one species over the other and hence would determine the
toxicity of a bloom.
Overall, it was demonstrated that light rather than temperature was the factor that
determined the formation of a bloom. During such a bloom, the diazotrophic
cyanobacteria fixed N2 10-20% in excess of their own demand. This nitrogen was
transferred to the picocyanobacteria as was shown by 15N incorporation.
During bloom conditions, the diazotrophic cyanobacteria covered about 50% of the
N-demand of the total cyanobacterial community.
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4th ELOISE Conference
5-7 September 2001, Rende, Italy
The other 50% was probably provided by internal recycling. The picocyanobacteria
were predominantly N-limited. The diazotrophic cyanobacteria were iron limited. These
findings are important to understand the formation of toxic cyanobacterial blooms and
to develop tools to predict them.
SESSION 4
115
Oral Presentation
European Land-Ocean Interaction Studies
4th ELOISE Conference
5-7 September 2001, Rende, Italy
EUROTROPH : NUTRIENTS CYCLING AND THE TROPHIC STATUS OF
COASTAL ECOSYSTEMS
Frankignoulle M.1, J.P. Vanderborght 2, J. Middelburg 3, J.P. Gattuso 4, N. Iversen 5, C.
Duarte6, M. Elliot7 and Roland Wollast2
(1)
(2)
(3)
(4)
(5)
(6)
(7)
Unité d'Oceanographie Chimique, Univerité de Liege, Sart Tilman, Belgium
Laboratoire d'Oceanographie Chimique et Geochimie des Eaux, Université Libre de
Bruxelles, Bruxelles, Belgium
Centre for Estuarine and Coastal Ecology, NIOO - CEMO, Yerseke, The Netherlands
Observatoire Oceanologique de Villafrance-sur mer, Villafranche-sur-mer, France
Aalborg Universitet, Aalborg, Denmark
Instituto Mediterraneo de Estudios Avanzados, CSIC-Univ. Illes Balears, Palma de Mallorca,
Spain
Institute of Estuarine and Coastal Studies, Dept. Of Biological Sciences,University of Hull,
Hull, UK
A CONTRIBUTION FROM THE ELOISE PROJECT: EUROTROPH
The project aims to improve our knowledge of the metabolic state of coastal
ecosystems, which is fundamental in terms of nutrients and carbon cycling/storage. The
trophic status will be determined in diverse ecosystems using simultaneously different
methods at various time scales. The effect of nutrients speciation and organic carbon
fractionation will be studied in systems of various eutrophication levels. A model will
be implemented to estimate transfer and fluxes of carbon/nitrogen and to forecast the
impact of human intervention on trophic status change. Results will be translated into
management criteria and directives for monitoring procedures to assess the trophic
status of coastal ecosystems. Dissemination will be organized at several levels, from
general public to policy makers and environmental organisations.
SESSION 4
116
Oral Presentation
European Land-Ocean Interaction Studies
4th ELOISE Conference
5-7 September 2001, Rende, Italy
EFFECTS OF NUTRIENT ENRICHED SEAWATER ON ROCKY SHORE
ECOSYSTEMS (EULIT)
Bokn Tor L. et Al.
Norwegian Institute For Water Research (Niva) Oslo, Norway (tor.bokn@niva.no)
A CONTRIBUTION FROM THE ELOISE PROJECT: EULIT
The response of rocky shore ecosystems to increased nutrient availability was
examined in eight land-based mesocosms designed for hard-bottom littoral communities
built at Marine Research Station Solbergstrand (Norway). The average seawater volume
in each basin was 9 m3 with an average water residence time of about 2 hours. A tidal
regime resembling that in the fjord was maintained in the basins, and waves were
generated regularly. NH4NO3 and H3PO4, at a constant molar NP ratio of 16:1, was
added into 6 basins at concentrations 1, 2, 4, 8, 16, 32 µmol DIN l -1 above the
background DIN concentration during 28 months. Two mesocosms were kept as control
treatment. Marine communities were introduced into the basins two years prior the start
of nutrient dosage.
The effects of nutrient enrichment were few and only marginal during the first year
of nutrient addition, while some effects became more obvious during the second year.
The growth rate of the periphyton and fast-growing macroalgae communities was
stimulated by nutrient enrichment, while the response was less evident among the
perennial fucoids. The structure of the macroalgal communities, however, did not
change during 28 months measurements. In contrast, growth on artificial rock substrates
during the same period of time revealed intensive growth of the fast-growing Ulva
lactuca in high dosed basins compared with low dosed and control basins, which were
dominated by the fucoid Fucus serratus. The biomass settled on granite chips during
three growth seasons was significantly higher in low dosed and control basins than in
the higher dosed basins. The fauna communities exhibited only minor response to
nutrient treatment. The common periwinkle Littorina littorea, however, appeared with
increased abundance in the high dosed basins. The total system metabolism tended to
increase slightly, but not significantly, with increased nutrient loading.
SESSION 4
117
Oral Presentation
European Land-Ocean Interaction Studies
4th ELOISE Conference
5-7 September 2001, Rende, Italy
SIGNATURE OF C AND N STABLE ISOTOPES IN EUTROPHIED RIVERS
DRAINING INTO THE BALTIC SEA
Maren Voss1, Constanze Stegemann2, Marianna Pastuczak3, Iris Helling 1
(1)
(2)
(3)
Baltic Sea Research Institute, Seestr. 15, 18119 Rostock, Germany
University of Bochum, Universitätsstr. 150, 44780 Bochum, Germany
Morski Institut Rydbacki, Kollatahja 1, 81-332 Gdynia, Poland
A CONTRIBUTION FROM THE ELOISE PROJECT: SIGNAL
The use of stable nitrogen and carbon isotopes as indicator of eutrophication has
found wide application during the last years [1,2]. Nitrogen isotopes have been found be
related to the sewage input [3] that is of course related to the human population in the
drainage area of the rivers. In the Baltic Sea drainage area which is four times as big as
the sea surface area the population has drastically increased during the last century and
is now around 85 million. This has clear consequences especially along the coast where
anoxia occur more frequently and the organic matter content in sediments has
drastically increased. Sediment data from dated cores indicated the time period when
excess nitrogen input started. This coincided with the increased use of fertilizer for
farming [4]. Even in the depositional basins of the Baltic Proper first signs of
anthropogenic nitrogen input is indicated by slightly elevated nitrogen isotope values in
the upper sediment layers [5]. A detailed study of the riverine nitrogen input through
some major and few small rivers and the modification of the isotope signal in the river
plum is currently carried out in the framework of an EU funded project. Biweekly
sampling in two major Baltic Sea rivers the Oder and the Vistula river are carried out
15
N signals in nitrate. The Oder river has a mean runoff of
16*109 m³ yr-1 with 42,000t NO3 yr-1 and drains into a lagoon with only narrow outlets
into the Baltic Sea, the major one carrying 70% of the water is the Swina Canal. The
variable residence time of river water in the lagoon allow nutrient uptake and
denitrification processes to reduce the concentration. Both processes also have for the
nitrogen isotope data of nitrate and for the nitrate to phosphate ratios. The Vistula River
is the largest single nitrogen source for the Baltic with 59,300t NO3 yr-1. Both rivers,
their nutrient load and nutrient isotope data from summer 2000 to spring 2001 will be
discussed in the broader context of the river data from preceding years and the
modification of the signal after it entered the Baltic Sea.
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European Land-Ocean Interaction Studies
4th ELOISE Conference
5-7 September 2001, Rende, Italy
References
[1] Cabana, G. and Rasmussen, J.B. (1996) Proc. Natl. Acad. Sci. USA 93, 1084410847.
[2] Fry, B., Bern, A.L., Ross, M.S. and Meeder, J.F. (2000) Estuarine, Coastal and Shelf
Science 50, 291-296.
[3] McClelland, J.W. and Valiela, I. (1998) Marine Ecology Progress Series 168, 259271.
[4] Voss, M., Larsen, B., Leivuori, M. and Vallius, H. (2000) Journal of Marine
Systems (Special Issue) 25, 287-298.
[5] Struck, U., Emeis, K.-C., Voss, M., Christiansen, C. and Kunzendorf, H. (2000)
Marine Geology 164, 157-171.
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