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THE EBB TIDAL DELTA OF AMELAND
Harriëtte Holzhauer
A SEAWAD-phd-projectSuzanne Hulscher – 1st promotor, Twente UniversityPeter Herman – 2nd promotor, Deltares, Delft UniversityBas Borsje – Daily supervisor, Twente University, DeltaresKathelijne Wijnberg, Twente University
A FIRST VIEW UNDERWATER
Introduction Research aim
Measuring benthic species at the ebb tidal delta Ameland ebb tidal delta Grouping analysis Habitats and sample locations
Measurements Field approach A first look
Upcoming activities
CONTENT
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Gain a better understanding of the combination and dynamics of interacting environmental parameters relevant for steering the benthic species distribution in the coastal zone.
Benthic species are an important food source for higher trophic species such as birds and fish.
Benthic species live in the sediment and are largely impacted by changes in morphology and hydrodynamics
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RESEARCH AIMENVIRONMENTAL PROCESSES DETERMINING BENTHIC SPECIES DISTRIBUTION NEAR
THE COAST
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THE EBB TIDAL DELTA OF AMELAND
Benthic species distribution over the ebb tidal delta is steered by the variance in environmental conditions.
Defining habitats based on morphology, hydrodynamics and sediment composition With the use of a grouping analysis in the GIS package ARCgis10.4.1
Randomized samples in the habitats
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MEASURING BENTHIC SPECIES AT THE EBB TIDAL DELTAWHERE TO SAMPLE?
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GROUPING ANALYSISINPUT PARAMETERS
Bathymetry
Slope
Slope direction
Sedimentation- erosion
Sedimentcompositon
Bed shear stress
Input parameters on a 20x20 grid No spatial constrains Evaluation of the optimal number
of groups
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GROUPING ANALYSIS
= Bathymetry + slope + direction + sedimentation/erosion
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HABITATS
Sample locations randomly placed within each habitat
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SAMPLE LOCATIONS
166 samples
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THE FIELD
Vessels
BoxcoreDepth: 30 cm Opp: 0.078 m2
1 mm sieve Small coreDepth: 30 cmDiam: 3cm
WR82 max draught 0.50 cm
Terschellingmax draught 3m
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THE SAMPLESA FIRST LOOK
East side >-8 m NAP
West side >-8 m NAP
Habitat Sediment Benthic species
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THE SAMPLESA FIRST LOOK
Delta erosion
Habitat Sediment Benthic species
Delta sedimentation
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THE SAMPLESA FIRST LOOK
Channel inlet
Slope channel Slope
delta
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THE SAMPLESA FIRST LOOK
Habitat Sediment Benthic species
Offshore
Flat
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A FIRST LOOK
spisula rich
(ensis spisula)
richmud layer
Species distribution at the ebb tidal delta based on the lab results
Multivariate analysis to detect relations between the species distribution and the combination of abiotic parameters of the ebb tidal delta.
Investigate the interaction of environmental parameters (hydrodynamic, morphodynamic in combination with meteorological conditions) with the help of existing numerical models (such as Delft3D, and Xbeach)
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UPCOMING ACTIVITIES
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