SESSION 7
UNIFYING CONCEPTS IN COASTAL ECOLOGY AND
MANAGEMENT
European Land-Ocean Interaction Studies
4th ELOISE Conference
5-7 September 2001, Rende, Italy
SESSION 7
158
Oral Presentation
European Land-Ocean Interaction Studies
4th ELOISE Conference
5-7 September 2001, Rende, Italy
F-ECTS: OVERALL SUMMARY OF THE PROJECT
A. Bergamasco
IST, National Research Council, Spianata S. Raineri, 98122, Messina, Italy
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4th ELOISE Conference
5-7 September 2001, Rende, Italy
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Oral Presentation
European Land-Ocean Interaction Studies
4th ELOISE Conference
5-7 September 2001, Rende, Italy
1. F-ECTS - MONITORING
THE CONCEPTUAL SCHEMATIZATION OF AN ESTUARINE SYSTEM FOR
THE INVESTIGATION OF THE INTERACTIONS AMONG PHYSICAL AND
ECOLOGICAL PROCESSES
Bergamasco A.1, L. De Nat2, K. Millard3, M. Flindt4, C. Amos5 , P. Ciavola6
(1)
(2)
(3)
(4)
(5)
(6)
IST, National Research Council, Spianata S. Raineri, 98122, Messina, Italy
Thetis SpA, Castello 2737/f, 30122 Venice, Italy
HR Wallingford, Wallingford, England
Biological Institute, SDU, University of Odense, Campusvej 55, DK-5230, Odense,
Denmark
SOC, University of Southampton, Empress Dock, Southampton, SO143ZH, UK
Dipartimento di Scienze della Terra, Università di Ferrara, C.so E. I d’Este 32, 44100,
Ferrara, Italy
A CONTRIBUTION FROM THE ELOISE PROJECT: F-ECTS
F-ECTS main focus is the interdisciplinary investigation of the ecosystem loops in
estuarine environments involving phytobentos communities, hydrodynamics, nutrient
cycling and sediment transport. The Lagoon of Venice (Italy) was considered as the
pilot site for the in-situ investigation of the above phenomena through the carrying out
of two seasonal field campaigns, aiming at the parameterization of the main physical
and biological processes of the ecosystem. Following such investigation, a mathematical
model of the feed-back links between phytobenthos and sediment transport was to be
produced improving and putting together existing hydrodynamic, phytobenthos growth
and sediment transport modules. To support this research flow and as a first step
towards modelling, a provisional state-of-the-art conceptual scheme describing the
structure of an estuarine ecosystem and its functioning was set up at the beginning of
the project, according to the present knowledge of biogeochemical and physical
phenomena, and tailored to the Lagoon of Venice. This also in order to drive the
identification of the key parameters to be measured during the field campaigns.
Following a preliminary analysis of the new experimental data sets, the provisional
conceptual scheme of the Lagoon of Venice ecosystem set up at the beginning of the
project has been reviewed in detail in the light of the new experimental findings and
adjusted/modified to produce the extended conceptual scheme of the Lagoon of Venice
ecosystem which has been used as a basis for the development of the new model. The
paper describes such conceptual scheme and discuss the possibility to extend its
adoption to approach the study of other estuarine ecosystems.
SESSION 7
161
Oral Presentation
European Land-Ocean Interaction Studies
4th ELOISE Conference
5-7 September 2001, Rende, Italy
FEEDBACK MECHANISMS BETWEEN HYDRAULICS, NUTRIENT EFFLUX
AND BENTHIC MICROBIAL ACTIVITY
M.R. Flindt 1, C. Amos 2, A Bergamasco 3 and C. B. Pedersen 4
(1)
(2)
(3)
(4)
Biological Institute, SDU, University of Odense, Campusvej 55, DK-5230, Odense,
Denmark, e-mail: mrf@biology.sdu.dk
SOC, University of Southampton, Empress Dock, Southampton, SO143ZH, UK
Thetis SpA, Castello 2737/f, 30122 Venice, Italy
Freshwater Biological Laboratory, University of Copenhague, Helsingørsgade 51, dk-3400
Hillerød, Denmark
A CONTRIBUTION FROM THE ELOISE PROJECT: F-ECTS
In the context of the F-ECTS fieldwork in the Lagoon of Venice 20 stations of
varying bed properties (grain size, water content, organic content, dissolved inorganic
profiles and macrophyte composition, and biomass) were occupied by the benthic flume
Sea Carousel. Current speed was increased in increments of 10 cm s-1 within the flume.
At each increment, water samples were collected through pumping while measures of
turbidity, turbulence, and mean flow were made.
Thus, it was possible to determine the hydrodynamic effect on the efflux of dissolved
inorganic nutrients measured in pumped samples as well as the benthic bacterial activity
and benthic diatom production.
Effluxes of ammonia, nitrate, nitrite, phosphate, and dissolved organic carbon from
the sediment porewater were measured through increases in water column
concentration.
As well, the benthic heterotrophic bacterial activity was measured by adding INT
pumped samples. The bacterial respiration was terminated after 30 minutes by addition
of H2SO4.
Benthic diatom production was measured traditionally by the addition of 14C;
incubations were also halted after 30 minutes by addition of H2SO4. The bed shear
stress was strongly reduced by the presence of rooted vegetation (Cymodocea sp. and
Zostera marina), and it was not possible to resuspend the underlying sediment.
By contrast, beds free of vegetation or colonised by macroalgae were much easier to
erode. The highest increases in absolute and specific activity of bacteria and algae were
also measured at these sites. Epiphytes on the leaves of the rooted vegetation were
sloughed at high flows and contributed to the measurements of carbon. Bacterial
activity and benthic microalgae production increased with water velocity over bare
bottoms.
The increase ranged from 2 to 20 times the still water condition, and resulted mainly
from resuspension of biomass. Normalising for changes in biomass showed that the
specific activities also increased.
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4th ELOISE Conference
5-7 September 2001, Rende, Italy
These were from 2 to 7 times higher than the still water condition. Where the highest
specific rates occurred, the benthic microalgae were growth limited by light and PO 4
and the benthic bacteria were limited by easily degradable carbon sources (DOC). So
resuspension and the resulting effluxes of nutrients and dissolved organic carbon
stimulated the enhanced benthic biological activities.
SESSION 7
163
Oral Presentation
European Land-Ocean Interaction Studies
4th ELOISE Conference
5-7 September 2001, Rende, Italy
MEASUREMENTS OF MACROPHYTE GROWTH AND LOSS RATES AND
NUTRIENT FLUXES IN A SUMMER AND A WINTER FIELD CAMPAIGN IN
THE LAGOON OF VENICE
Pedersen C.B.1, M.R. Flindt2, M. Pardal3, J. Neto3, A. Bergamasco4
(1)
Freshwater Biological Laboratory, University of Copenhague, Helsingørsgade 51, dk-3400
Hillerød, Denmark
(2)
Biological Institute, SDU, University of Odense, Campusvej 55, DK-5230, Odense,
Denmark
(3)
IMAR, Zoological Department, University of Coimbra, Portugal
(4)
Thetis SpA, Castello 2737/f, 30122 Venice, Italy
A CONTRIBUTION FROM THE ELOISE PROJECT: F-ECTS
At nine stations in the Lagoon of Venice measurements of plant growth and loss
rates were done together with nutrient fluxes between the sediment and water column.
The measured fluxes included: Ammonia, nitrate, nitrite, dissolved organic nitrogen,
dissolved organic carbon, phosphate and oxygen. The stations varied with respect to
sediment properties (grain size, water content, pools of carbon, nitrogen and
phosphorus) and dominating plant species (Cymodocea sp., Zostera marina, Zostera
noltii, and Ulva sp.). The measured plant loss rates included grazing, sporulation and
advective transport. Macrophyte growth rates varied between 0.02-0.18 d-1, while loss
rates by grazing ranged from 0.02 to 0.05 d-1 and sporulation ranged from 0.00 to 0.17
d-1. In the summer campaign the net loss rates exceeded the growth rates at several
stations especially during spring tide periods where rooted vegetation sloughed leaves
do to high current velocities while unattached opportunistic macroalgae were
resuspended and transported away. Sediment oxygen dynamic varied between daytime
oxygen production of 40 mg O2 m-2 h-1 and nighttime oxygen consumption of 200 mg
O2 m-2 h-1. The sediment ammonia fluxes varied from -2 mg NH4-N h-2 d-1 to 18 mg
NH4-N m-2 h-1, while phosphate fluxes varied between -0.25 mg PO4-P m-2 h-1 to 1 mg
PO4-P m-2 h-1. Summer nitrification and denitrification were closely related to the
biomass of rooted vegetation. Net mass balances at the stations showed huge variation
in the nutrient pathways. Some stations were dominated by the heterotrophic processes
resulting in huge nutrient effluxes, while other stations were dominated by nutrient
uptake by macrophytes and relatively small effluxes. In general, stations dominated by
rooted macrophyte released less nutrients than stations without, and the oxygen
dynamics were much more balanced.
SESSION 7
164
Oral Presentation
European Land-Ocean Interaction Studies
4th ELOISE Conference
5-7 September 2001, Rende, Italy
PLANT BOUND NUTRIENT TRANSPORT – A NEGLECTED PART OF THE
NUTRIENT MASS BALANCE – IN ESTUARIES
Flindt M.R 1, C. B. Pedersen 2 , M. Pardal 3 , A Bergamasco 4 , C. Amos 5
(1)
Biological Institute, SDU, University of Odense, Campusvej 55, DK-5230, Odense,
Denmark (mrf@biology.sdu.dk)
(2)
Freshwater Biological Laboratory, University of Copenhague, Helsingørsgade 51, dk-3400
Hillerød, Denmark
(3)
IMAR, Zoological Department, University of Coimbra, Portugal
(4)
Thetis SpA, Castello 2737/f, 30122 Venice, Italy
(5)
SOC, University of Southampton, Empress Dock, Southampton, SO143ZH, UK
A CONTRIBUTION FROM THE ELOISE PROJECT: F-ECTS
A major observation has been that nutrient export from estuaries during the growth
season takes place as drifting macro algae and macro detritus. During a summer
campaign in the Lagoon of Venice more than 90% of the nutrient export (nitrogen and
phosphorus) was bound in plant material, while about 20-30% of the nutrient export
from the Danish Roskilde Fjord was linked to plant transport. Even in the winter season,
the plant and macro detritus associated nutrient export accounted for about 25% of the
total nutrient export. The transport patterns of different plants vary. Some plants were
transported as bedload (Chaetomorpha sp.) while other species were transported either
in the water column (Ulva sp.) or floating at the surface (leaves from the rooted
vegetation).
Measurements at the outer boundary verified that less than 20 % of the exported
plant matter returned to the Lagoon of Venice and in most cases it was even less than 5
%. High settling rates of 500-2000 md-1 explained why only small amounts of plant
material returned to the Lagoon as they settle to the bed of the inner Adriatic Sea at the
end of the ebb tide. In conclusion, this extra nutrient transport mechanism has an impact
on the mass balance calculations in coastal areas, which sometimes may have been
underestimated.
SESSION 7
165
Oral Presentation
European Land-Ocean Interaction Studies
4th ELOISE Conference
5-7 September 2001, Rende, Italy
THE ROLE OF MACROPHYTE DEBRIS MOVING AS BEDLOAD ON THE
BENTHIC FLUX – TWO FEEDBACK MECHANISMS IN A SEASONALLY
CONTROLLED BALANCE
Amos C.1., M.R. Flindt2, A. Bergamasco3 A. Levy4
(1)
(2)
(3)
(4)
School of Ocean and Earth Science, Southampton Oceanography Centre, Empress Dock,
Southampton, UK (cla8@soc.soton.ac.uk)
Biological Institute, SDU, University of Odense, Campusvej 55, DK-5230, Odense,
Denmark
Thetis SpA, Castello 2737/f, 30122 Venice, Italy
Department of Biology, Acadia University, Wolfville, Nova Scotia, Canada
A CONTRIBUTION FROM THE ELOISE PROJECT: F-ECTS
Two intensive field campaigns within Venice Lagoon were carried out within the
EU-funded F-ECTS project (Amos et al., 2000). Two in situ benthic flumes (Sea
Carousel and Mini Flume) were used to simulate resuspension of organic matter,
sediment and nutrients under controlled conditions of flow. Fast settling organic matter
was ubiquitous and exhibited threshold velocities for motion of 0.02 m/s. This material
contributed substantially to the benthic flux through the solid-transmitted stresses
caused by saltation. Further laboratory experimentation in a laboratory equivalent of Sea
Carousel were carried out using the macrophyte Ulva sp. These results showed
increases in erosion rate by a factor of 20 over the fluid-induced erosion rates; a much
lower threshold for the onset of resuspension was found than was the case for a purely
fluid-transmitted stress (Levy, 2000). Furthermore, the erosion began at the onset of
motion of the macroalgae. This threshold was largely dependent on the sinking rate of
the organic debris, and, surprisingly, independent of the properties of the bed. The rate
of erosion was dependent on the area concentration of material over the bed, and
appeared to be independent of shape or size of the plant material (Cosette, 2000). This
mechanism was the dominant control of the benthic flux when area concentration of
debris exceeded 5%. Thus we may conclude that below 5% cover, the fluid-transmitted
stress prevails and the properties of the bed are important: above 5% debris cover the
solid-transmitted stress prevails and the properties of the debris are important. The
important sediment-macrophyte feedback mechanisms evident from this work are as
follows: fixed macrophytes grow on the muddy substrate of Venice Lagoon (barene);
the macrophytes stabilise the bed through sheltering (the first feedback mechanism);
macrophyte debris is sloughed by wind-wave-current erosion; the debris enhances the
efficiency of bed/macrophyte erosion (the second feedback mechanism); decreases in
macrophyte cover reduces the solid-transmitted stresses thereby establishing a dynamic
balance which is probably seasonally controlled.
SESSION 7
166
Oral Presentation
European Land-Ocean Interaction Studies
4th ELOISE Conference
5-7 September 2001, Rende, Italy
References
Amos, C.L., Cloutier, D., Cristante, S. and Cappucci, S. 2000. The Venice Lagoon
Study (F-ECTS), Field Results – February, 1999. Geological Survey of Canada Open
File Report 3904.
Levy, A. 2000. The role of mobile macroalgae on the erosion of cohesive sediments.
Unpublished M.Sc. Thesis, Acadia University, Wolfville: 137p.
SESSION 7
167
Oral Presentation
European Land-Ocean Interaction Studies
4th ELOISE Conference
5-7 September 2001, Rende, Italy
IN-SITU ASSESSMENT OF SEDIMENT STABILITY IN INTERTIDAL
AREAS: MEASUREMENT OF BIO-DEPENDENT BED PARAMETERS AS A
PROXY TOOL
Ciavola P.1, P. Friend2, S. Cappucci2, and C. Amos2
(1)
Dipartimento di Scienze della Terra, Università di Ferrara, C.so E. I d’Este 32, 44100,
Ferrara, Italy (cvp@unife.it)
(2)
SOC, University of Southampton, Empress Dock, Southampton, SO143ZH, UK
A CONTRIBUTION FROM THE ELOISE PROJECT: F-ECTS
The assessment of critical erosion thresholds in intertidal areas is of extreme
importance for studies of the feed-back mechanisms between biostabilisation of
sediment and current regimes, at estuarine sites.
The feed-back process has practical implications for the artificial recreation of
mudflats using dredged material, and for the evaluation of habitat loss following
accidental pollution events.
As part of the F-ECTS Project, within the ELOISE framework, a field study of these
mechanisms was undertaken in the Lagoon of Venice in northern Italy. Two campaigns
were conducted, in summer 1998 and in winter 1999, in which the annular flumes, SeaCarousel and Mini Flume, were deployed from a movable jack-up barge.
In order to have a comprehensive view of the small-scale variability in erosion
thresholds at an intertidal site (Palude della Centrega), a portable instrument, the
Cohesive Strength Meter (CSM), was also used. There was close agreement between the
results obtained using Sea Carousel and those from Mini Flume; biostabilisation and
erosion thresholds in the summer were greater, by almost a factor of two, compared
with winter values. Biostabilisation at the Centrega site was due mainly to a biofilm of
filamentous brown algae present at the edge of a main channel. Spatial variability
studies using the CSM on the mudflat, identified that sediment stability was directly
related to elevation; stability was higher at the edge of tidal creeks than within sea-grass
communities living on the lower mudflat.
In order to test the exportability of the results obtained from the fieldwork in Venice,
two further sets of experiments were undertaken in September 2000 and March 2001 in
the Ria Formosa Lagoon, in southern Portugal. On these occasions, the CSM was the
only erosion device to be deployed; this choice was dictated by its relative ease of
transportation, as well as its widespread usage elsewhere in other sedimentological and
ecological field studies, including the EU funded projects, INTRMUD, BIOPTIS,
ECOFLAT. The site selected was a mixed habitat, intertidal site near the Ramalhete
Channel, in the western part of the lagoon; here, a total of 32 stations were sampled in
four cross-shore transects. A strong relationship was found between habitat type and
erosion threshold; and between colloidal carbohydrate and chlorophyll a content, and (to
a lesser extent) bed elevation.
SESSION 7
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European Land-Ocean Interaction Studies
4th ELOISE Conference
5-7 September 2001, Rende, Italy
Generally, erosion thresholds decreased seawards, reflecting a change in habitat type
from cyanobacterial mats in the upper shore, through Spartina then Zostera beds, to a
silty/sandy substrate of the main channel sides. In the first campaign, filamentous
cyanobacteria were the dominant microphytobenthic stabilisers of sediment. HPLC
analysis of the sediments, showed the increasing presence towards the lower shore, and
particularly on the channel sides, of diatoms.
However, any stabilising effect by the diatoms was insignificant, compared with that
of the cyanobacterial mats. The sandy channel sides appeared to become more stable,
after the passage of a high-energy wind (and wave) event, possibly due to an increase in
epipelic diatom activity. In the second campaign, cyanobacterial activity was low.
Instead, a filamentous Enteromorpha spp. had apparently replaced the cyanobacterial
mats as the main sediment stabiliser; this process has not been observed previously.
Statistical relationships between erosion thresholds, bed level elevation, colloidal
carbohydrate and chlorophyll a will be presented from the two sites and their possible
exportability to other locations and habitats will be discussed.
SESSION 7
169
Oral Presentation
European Land-Ocean Interaction Studies
4th ELOISE Conference
5-7 September 2001, Rende, Italy
CUSTOMIZED, LOW-COST AND HIGH RESOLUTION SPECTRAL DATA
FOR MODELLING IN THE COASTAL ZONE
Millard K.1, J. Monk 2, A. Brady 1
(1)
(2)
HR Wallingford, Wallingford, England
University of Dundee, Dundee, Scotland
A CONTRIBUTION FROM THE ELOISE PROJECT: F-ECTS
Many scientists and engineers working in the field of environmental management
have realised the benefits of using remote sensing techniques for providing wide-area
spatial data. The increases over recent years in both the spectral and spatial resolution of
available data has resulted in remote sensing techniques being clearly demonstrated as
offering the potential to effectively support environmental management. Coastal Zone
Management however remains one area where this promise is yet to be fully
realised.Coastal Zone Management (CZM) requires data of both high spatial resolution
and high spectral resolution. This data also needs to be provided at low-cost. Satellite
data on the most part can meet this low-cost and high-spectral resolution demands, but
the requirement of high spectral and spatial resolution can only be offered at present by
airborne instruments such as CASI. These sophisticated techniques are expensive to
commission and require specialist aircraft to operate. Accordingly they tend to be
operated by government agencies and national environmental bodies.There is a demand
therefore for low cost remotely sensed data of both high spatial and spectral resolution
that can be collected to solve particular management issues or scientific research in the
coastal zone. This paper presents the results of the practical application of one such
approach using an instrument known as VIFIS.
SESSION 7
170
Oral Presentation
European Land-Ocean Interaction Studies
4th ELOISE Conference
5-7 September 2001, Rende, Italy
This instrument is based on commercial video-camera technology and can be used on
most aircraft platforms, collecting data at a much lower costs than instruments such as
CASI.This paper describes applying VIFIS to collect data on suspended particulate
matter (SPM) and chlorophyl-a in the Venice Lagoon for the purpose of numerical
modelling. The aim of the numerical modelling is to better understand the relationship
between sediment transport and phytobenthic growth in the region.
This paper explains the processing involved from data collection to the delivery of
processed data suitable for use in a particular numerical model. Particular attention is
made to analysis of the costs incurred during this process compared to the value of the
data as input to the numerical modelling processes and in understanding the SPM and
phytobenthic regimes in the Venice Lagoon.
SESSION 7
171
Oral Presentation
European Land-Ocean Interaction Studies
4th ELOISE Conference
5-7 September 2001, Rende, Italy
2. F-ECTS - MODELING
THE SPM PHYTOBENTHOS-REACTION MODEL FOR ESTUARINE
ECOSYSTEMS AND ITS APPLICATION TO THE VENICE LAGOON PILOT
SITE
Rolinski S.1, G. Umgiesser 2, M. Flindt3 and C. Amos 4
(1)
(2)
(3)
(4)
Instituti fuer Meereskunde, University of Hamburg, Germany,
ISDGM, National Research Council, Venice, Italy
Biological Institute, SDU, University of Odense, Campusvej 55, DK-5230, Odense,
Denmark
SOC, University of Southampton, Empress Dock, Southampton, SO143ZH, UK
A CONTRIBUTION FROM THE ELOISE PROJECT: F-ECTS
Feedbacks between estuarine circulation and transport of sediments on phytobentos
are the main focus of the F-ECTS project in the framework of the European MAST III
Programme. Modelling the hydrodynamics and the transport of suspended particulate
matter (SPM) in the Venice Lagoon was to be combined with simulations of the
dynamics of phytobenthic algae. The 3D finite element hydrodynamical model of
Venice Lagoon uses real-time forcing for tidal elevation and atmospheric data,
producing mass, current, salinity and temperature fields for the subsequent simulation of
the transport of SPM. A newly conceived interpolation mechanism transforms the
relevant parameters from the irregular finite element grid on to a regular finite
difference grid, on which the SPM model is formulated. Mass consistency between the
resulting transport and water elevation fields is guaranteed. Particulate material
originating both from mineral and organic origin are traced following the Lagrangian
concept. Besides the transport due to advection, diffusion and sinking, exchange of
material with the sediment is implemented in terms of erosion and deposition. Benthic
organisms are assumed to redistribute fine grains in the sediment and thus, influence
erodibility of sediments. The dynamics of biological components such as algae (Ulva
Sp.) and detritus and a dissolved nutrient are simulated according to the well-known
concept of three components ecological models. Physical and biological processes are
linked by two mechanism. Turbidity due to SPM concentrations reduces the available
light for photosynthesis of algae so that their growth decreases. On the other hand,
abundance of algae influences the formulation of erosion. The actual depth, into which
the erosion event reaches, decreases where algae are numerous. Results of simulations
during the summer campaign in August 1998, comparing runs with the physical and
biological modules separately and combined, are discussed.
SESSION 7
172
Oral Presentation
European Land-Ocean Interaction Studies
4th ELOISE Conference
5-7 September 2001, Rende, Italy
EXPORTING THE PHYTOBENTHOS-REACTION MODELING APPROACH:
ROSKILDE FJORD CASE STUDY
Umgiesser G.1, M. Flindt2, C. Amos3 and A. Bergamasco4
(1)
(2)
(3)
(4)
ISDGM, National Research Council, Venice, Italy (georg@isdgem.ve.cnr.it)
Biological Institute, SDU, University of Odense, Campusvej 55, DK-5230, Odense,
Denmark
SOC, University of Southampton, Empress Dock, Southampton, SO143ZH, UK
Thetis SpA, Castello 2737/f, 30122 Venice, Italy
A CONTRIBUTION FROM THE ELOISE PROJECT: F-ECTS
A finite element hydrodynamic model has been applied in the framework of the
European project F-ECTS to the Roskilde Fjord in Denmark. The fjord is a bay about 35
km long and about 10 meters deep. Along its coast numerous cities are situated and
various touristic and commercial activities are going on. The hydrodynamic model is
the same as the one used in the study for the Venice Lagoon. The model uses linear
triangular elements in the horizontal and fixed layers (z-coordinates) in the vertical. The
time-integration is accomplished by a semi-implicit method that allows for longer time
steps that are not constrained by the gravity wave stability criterion. The hydrodynamic
model solves also the transport and diffusion equation. This module is used for physical
quantities such as temperature and salinity and the ecological state variables that are
solved in parallel with the physical quantities and are fully integrated into the code of
the hydrodynamic model. In this way the feedback of the physical quantities (sediment
concentration) can be accounted for in the ecological model (light shading on benthic
vegetation).The ecological model contains 23 state variables that simulates the carbon,
nitrogen and phosphorus forcing, pools, processes and dynamics. The model has been
developed independently in the computer language PowerSim. From the PowerSim
printout a Fortran version has been produced with the help of Perl and Python modules.
This Fortran version has been directly included into the hydrodynamic code of the
Roskilde model.The model has been run for one whole year to reproduce the interannual variability. Real forcings have been prescribed for the hydrology, meteorology
and water quality. Results of the ecological model are presented.
SESSION 7
173
Oral Presentation
European Land-Ocean Interaction Studies
4th ELOISE Conference
5-7 September 2001, Rende, Italy
ARE ALL THE INTERTIDAL FLATS IN VENICE LAGOON DISAPPEARING?
Cappucci S.1, C. Amos1 and G. Umgiesser2
(1)
School of Ocean and Earth Science, Southampton Oceanography Centre, Empress Dock,
Southampton, UK SO14 3ZH (sc14@soc.soton.ac.uk)
(2)
ISDGM, National Research Council, S. Polo 1364, 30125 Venice, Italy
A CONTRIBUTION FROM THE ELOISE PROJECT: F-ECTS
The diverse and fertile tidal flats fringing Venice Lagoon have been in chronic
decline over the last 100 years. If this continues, the tidal flats will disappear by 2040.
This study has attempted to examine the potential factors responsible for habitat loss
through a study, which couples field measurements over a period of 2 years with a 1-D
numerical simulation of tidal flat evolution. The questions we were attempting to
answer were: (1) to what extent does river inflow impact the observed sedimentation
trends , and (2) to what extent are these trends influenced by (i) storms, (ii) vegetation
cover, (iii) residence times of sediment within the Lagoon, and (iv) sediment stability
(v) and inundation depth (subsidence / sea level rise). The study was undertaken within
the EU project F-ECTS the objectives of which were to examine the role of macrophyte
distribution and species on tidal flat evolution. The work presented here is focussed on
an intertidal mudflat to the north of Venice (Palude della Centrega). The site is one of
the few in accretion within the Lagoon (1.6 cm/year). The net changes in bed level were
measured at 13 sites across the tidal flats which vary in elevation, physical properties
and cover of the sea grass during Summer time. As well, the erosion thresholds, erosion
rates, minimum shear stress for deposition and deposition rates were evaluated using in
situ benthic flumes (Mini Flume) coupled with laboratory experiments. Chlorophyll and
carbohydrate contents were measured along with bulk density, sediment grain size and
organic content in an attempt to adequately characterise each site. The sensitivity
analysis of the model showed that the combined effect of shear stress reduction (by sea
grass) and input of sediment dominate the observed deposition trends on the tidal flat.
SESSION 7
174
Oral Presentation
European Land-Ocean Interaction Studies
4th ELOISE Conference
5-7 September 2001, Rende, Italy
SIMPLIFIED MODELING APPROACHES TO SUPPORT THE EVALUATION
OF SITE-SPECIFIC RELEVANT PROCESSES: RIA FORMOSA CASE STUDY
Silva A.1, J. Leitão1, R. Santos2, P. Ciavola3
(1)
Hidromod Modelacao em Engenharia, Portugal
(2)
UCTRA, Universidade do Algarve, Campus de Gambelas, 8000 Faro, Portugal
(3)
Dipartimento di Scienze della Terra, Università di Ferrara, C.so E. I d’Este 32, 44100,
Ferrara, Italy
A CONTRIBUTION FROM THE ELOISE PROJECT: F-ECTS
Ria Formosa lagoon (Southern Portugal) covers a region about 55 km long
corresponding to the limits of five barrier islands that protect the lagoon against the
direct action of the sea. In the framework of Mast III F-ECTS project, Ria Formosa
lagoon was selected as specific investigation sites to evaluate the exportability of some
major results concerning the feed-backs that couple the establishment of phytobenthic
communities and the physical parameters, obtained for the pilot project site: the Venice
lagoon. To support these actions, a limited field-work activity concerning the
characterization of the local currents, the macrophyte distribution, leaf release and
transport rates and bed erodibility was carried out. An hydrodynamic model and a
lagrangian transport model of Ria Formosa lagoon were set up in order to enable the
integration of the field-data and the interpretation of the local transport processes. The
model resulted from an implementation of the MOHID modelling system. The
hydrodynamic model was calibrated using the currents and the water levels field data.
The lagrangian transport model was used to follow the macrophyte paths and to
evaluate the macrophyte mass exported outside the lagoon, taking into consideration
different tide and wind conditions. In this paper the results of Ria Formosa lagoon
hydrodynamic and lagrangian transport models will be presented and compared with the
available field data concerning the hydrodynamics and the macrophyte distribution.
SESSION 7
175
Oral Presentation
European Land-Ocean Interaction Studies
4th ELOISE Conference
5-7 September 2001, Rende, Italy
3. F-ECTS - TOOLS FOR MANAGEMENT
MAPPING THE “ECOLOGICAL SUITABILITY” WITHIN AN ESTUARY
Bergamasco A.1, L. De Nat2, M. Flindt3, S. Rolinski4, G. Umgiesser5, C. Amos6
(1)
(2)
(3)
(4)
(5)
(6)
IST, National Research Council, Spianata S. Raineri, 98122 Messina, Italy
Thetis SpA, Castello 2737/f, 30122 Venice, Italy
Biological Institute, SDU, University of Odense, Campusvej 55, DK-5230, Odense, Denmark
Institut fuer Meereskunde, University of Hamburg, Germany
ISDGM, Natrional Research Council, S.Polo 1364, 30125 Venice, Italy
SOC, University of Southampton, Empress Dock, Southampton, SO143ZH, UK
A CONTRIBUTION FROM THE ELOISE PROJECT: F-ECTS
Feed-backs between estuarine circulation and transport of sediments on phytobentos
are the main focus of the F-ECTS project in the framework of the European MAST III
Programme. One of the main goals of the project was to demonstrate the combined use
of in-situ measurements and model results in the context of a GIS-based application and
its transfer into a practical tool for supporting the evaluation of CZM actions in complex
systems such as estuarine areas. The experience and methodologies achieved during FECTS in setting up a procedure for the comparison of different scenarios suggest that
central in this evaluation process is the possibility to map the changes of the “ecological
suitability” within the estuary with respect to the presence and/or the development of
phytobenthos. To address this issue the main requirement is the possibility to classify
the environment according to the persistence of a given “state” resulting from the
combination of several forcing processes, both physical and ecological. Examples of
these classification criteria are: duration of submersion versus emersion phases;
overshooting of the local erosion threshold and duration of the erosive phase in a tidal
cycle; persistence of SPM and/or nutrients above or below a fixed threshold. A synthetic
description of the newly developed GIS-based tools is presented and evaluated through
a Venice Lagoon case study. In particular management questions such as (i) “Where
and how long does the current velocity overcome local erosion threshold ? Is this
pattern related to grain size or phytobenthos distribution?” or (ii) “Where and how long
is light climate the limiting factor for the phytobenthos growth?” or (iii) “To what extent
are released dissolved inorganic nutrients becoming assimilated or dispersed around in
the estuary?” can be specifically addressed.
SESSION 7
176
Oral Presentation
European Land-Ocean Interaction Studies
4th ELOISE Conference
5-7 September 2001, Rende, Italy
BOOKLET PART I: GUIDELINES FOR INTEGRATED MODEL-ORIENTED
MONITORING OF ESTUARINE ECOSYSTEMS
Bergamasco A.1, L. De Nat2, M. Flindt3, S. Rolinski4, G. Umgiesser5, C. Amos6
(1)
(2)
(3)
(4)
(5)
(6)
IST, National Research Council, Spianata S. Raineri, 98122 Messina, Italy
Thetis SpA, Castello 2737/f, 30122 Venice, Italy
Biological Institute, SDU, University of Odense, Campusvej 55, DK-5230, Odense,
Denmark
Institut fuer Meereskunde, University of Hamburg, Germany
ISDGM, Natrional Research Council, S.Polo 1364, 30125 Venice, Italy
SOC, University of Southampton, Empress Dock, Southampton, SO143ZH, UK
A CONTRIBUTION FROM THE ELOISE PROJECT: F-ECTS
The specific experience developed in the context of the project F-ECTS concerning
the interdisciplinary approach to the study of an estuarine ecosystem has been translated
into a Booklet of integrated guidelines. In particular Part I of the Guidelines describes
this approach relying on a three-pier architecture: (1) the conceptualisation of the
system to be studied, mainly focusing to the feed-backs between the physical subsystem
and the ecological one, (2) the monitoring activity, specifically oriented to selectively
generate field data able to support (3) the joint dynamical modelling of hydrodynamic,
sediment transport and ecological processes. The main requirements of the monitoring
programme to be set up are identified and described on the basis of a generalized
conceptual scheme, developed and refined for the Lagoon of Venice. The essential links
and processes recognized through the preliminary screening of the system are taken into
account, such as basic hydrographic forcings, external loadings, internal nutrient
loadings and dynamics, SPM concentration, erosion/deposition thresholds, status of the
biological structures; requirements and constraints depending both on the using of these
data for modelling purposes and on field-related aspects are highlighted. The basic
assumptions of the suggested modelling approach to be adopted are presented in detail,
with particular reference to the selection of the scenarios to be modelled. Criteria to
select boundary conditions, duration of simulations, parameters to be followed with
respect to the target of the analyses will be presented and discussed.
SESSION 7
177
Oral Presentation
European Land-Ocean Interaction Studies
4th ELOISE Conference
5-7 September 2001, Rende, Italy
BOOKLET PART II: SCIENTIFICALLY-BASED GUIDELINES TO SUPPORT
MANAGEMENT STRATEGIES IN ESTUARIES
Bergamasco A.1, L. De Nat2, M. Flindt3, S. Rolinski4, G. Umgiesser5, C. Amos6
(1)
(2)
(3)
(4)
(5)
(6)
IST, National Research Council, Spianata S. Raineri, 98122 Messina, Italy
Thetis SpA, Castello 2737/f, 30122 Venice, Italy
Biological Institute, SDU, University of Odense, Campusvej 55, DK-5230, Odense,
Denmark
Institut fuer Meereskunde, University of Hamburg, Germany
ISDGM, Natrional Research Council, S.Polo 1364, 30125 Venice, Italy
SOC, University of Southampton, Empress Dock, Southampton, SO143ZH, UK
A CONTRIBUTION FROM THE ELOISE PROJECT: F-ECTS
The know-how developed in the context of the project F-ECTS concerning the
evaluation of the feed-back mechanisms involving hydrodynamics, phytobenthos
communities, nutrient cycling and sediment transport within an estuary has been
translated into a Booklet of integrated guidelines to support the selection and assessment
of different management strategies in these ecosystems. The aim of Part II is to
demonstrate that this evaluation approach can be synthesized in the following
“(Monitoring+Modeling)and GIS  Management”. First of all, based on the active role
the estuarine phytobenthic communities can have, the main mechanisms and processes
responsible for the back- and forward- mediation of the human activities on the
estuaries are identified and described. Furthermore Part II deals with (i) the application
of empirical modelling from in-situ data and/or GIS analyses to support the production
of highly-aggregated information in form of time series or spatial distribution of key
parameters and (ii) the demonstration of possible benefits for managers, environment
operators and engineers dealing with the set up of strategies or the planning, the design
and the comparison of specific management actions in estuarine areas such as wetland
restoration, dredging and port operations, fishing activities, transports. In this context
scientifically-based criteria to evaluate the “environmental quality” within an estuary in
terms of its suitability to sustain the natural ecosystem and the development of human
activities are proposed and illustrated for specific case studies.
SESSION 7
178
Oral Presentation
European Land-Ocean Interaction Studies
4th ELOISE Conference
5-7 September 2001, Rende, Italy
A GENERIC DECISION SUPPORT SYSTEM FOR THE EVALUATION OF
POLICIES TO REDUCE NITROGEN INPUTS TO WATER
Grimvall, A, Forsman, Å. and Wittgren, H.-B.
Department of Mathematics, Linkoping University, Sweden
Decision support systems (DSSs) for the evaluation of environmental policies have
two important functions: to predict how the studied policies influence the behaviour of
important groups of actors and to predict the impact of a given set of actions on the
environment and other sectors. So far, almost all attempts to construct DSSs for
environmental management have focused on one subtask, i.e. to assess the
environmental impact of a given set of actions. In this article, we describe the generic
structure of a DSS that enables a more complete evaluation of regional or national
policies to reduce nitrogen inputs to water. In particular, we describe the principles of
linking economic models of agricultural production at the farm level to catchment-scale
models of the transport and transformation of nitrogen in soil and water. A strict
definition of system boundaries for nitrogen fluxes through the agricultural sector and
the ambient environment form the basis of the model integration. Thereafter, we show
how different modules operating on different temporal and spatial scales can be linked
to each other by using generic procedures for upscaling, downscaling, extrapolation and
conditional simulation. Finally, we demonstrate how statistical emulators or
metamodels can be derived to facilitate simulation of the nitrogen transport from land to
water for a representative set of weather conditions and realistic spatial distributions of
crops, fertiliser application and other characteristics of the cropping systems. In
particular, we show when and how the temporal or spatial resolution of model inputs
can be lowered without significantly influencing annual nitrogen fluxes on the scale of
catchments.
SESSION 7
179
Oral Presentation