Effects of flow and sediments on
sessile marine invertebrates in the light
of marine renewable energy
Marie-Lise Schläppy
University of the Highlands and Islands
@mlschlappy
merikafp7.eu
[email protected]
@mlschlappy
The MERIKA Project has received funding from the European Union Seventh
Framework Programme (FP7/2007-2013) under grant agreement n° 315925.
Sponge
death
Equipment
acquired
MERIKA
start
M-L start
Jan 2014
July 2014 Summer 2015
merikafp7.eu
[email protected]
@mlschlappy
First
measurements
with sensor
and flumes
April 2016
5 expt
MERIKA
end
August 2016 March 2014
2 MERIKA partners
Effects of flow and sediments on
sponge oxygenation and
morphological plasticity
1) Sediment transport variability
due to the Waveroller device
and its effect on a nearby
Sabellid reef
2) 2) effects of ambient flow on
sponge morphological plasticity
merikafp7.eu
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@mlschlappy
Sediment transport variability
due to the Waveroller device
and its effect on a nearby
Sabellid reef
merikafp7.eu
[email protected]
@mlschlappy
Sediment transport variability
due to the Waveroller device
and its effect on a nearby
Sabellid reef
http://www.bbc.co.uk/
Sabellid reef. ©Sue Scott/SNH
http://www.cornwallwildlife.org.uk/wildlife/habitats/biogenic-reefs
merikafp7.eu
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@mlschlappy
Sediment transport variability
due to the Waveroller device
and its effect on a nearby
Sabellid reef
Hypotheses:
• The waveroller changes the local sediment transport regime in
the area beyond the natural variation of the system
• The change of sediment regime in the region of the wave
roller leads to a change of the sediment/Sabellid ratio on
nearby Sabellid reefs
merikafp7.eu
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@mlschlappy
Initial field work design
With Wave roller
Spring 2015
Autumn 2015
Spring 2016
Autumn 2016
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@mlschlappy
No
Waveroller
Sabellid reef
Current status
With Wave roller
Spring 2015
Autumn 2015
Spring 2016
Autumn 2016
merikafp7.eu
[email protected]
@mlschlappy
No
Waveroller
Sabellid reef
• Weather
conditions
• WavEc
availability
for field
work
Methods
Sabellid reef. ©Sue Scott/SNH
WavEc
http://www.bbc.co.uk/
Camera at right angle to the substratum
Transects – stratified haphazard, georeferenced
Video transects analysis using 1) visual analysis 2) mosaic
• features on sand (near Waveroller)
• % cover of Sabellid
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@mlschlappy
Mosaics
•
•
•
•
Compress the full transect into a mosaic
Make a set of colour palettes unique to a feature
Extract the number of pixels belonging to each palette
Derive % cover of each feature
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@mlschlappy
Effects of flow on sponges
in situ
Mixed X
Turbulent X
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X
Unidirectional
2 data sets for effects of flow on
sponges in situ - Berlengas
1. Transects - % cover of sponges + sponge morphology
2. 3D reconstructions (Amy Scott-Murray/Aberdeen)sponge morphology
Hypothesis: ambient flow shapes the morphology of sponges
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@mlschlappy
Transects in Berlengas
Turbulent
Autumn 2016
Spring 2017 ?
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Mixed
Unidirectional
Methods - transects
Diver-held camera at right angle to the substratum
Transects – stratified haphazard transect start identified by
underwater features
Video transects analysis using 1) visual analysis 2) mosaic
• % cover of sponges
• Sponge morphological characteristics (orientation of
oscules, encrusting vs erect forms)
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@mlschlappy
Methods – 3D models
2 sets of photos per sponge
• Top circle (20 photos)
• Bottom circle (40 photos)
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@mlschlappy
Methods – 3D models
In situ photography 20 min per
sponge
Turbulent
Autumn 2016
Spring 2017 ?
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@mlschlappy
Unidirectional
In summary
• Waveroller and Sabellid reef (ROV transects)
• Sponge morphology due to flow (divers transects + 3D)
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@mlschlappy
Effects of flow and sediments on sponge
1. oxygenation
2. morphological plasticity
3. respiration rates
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@mlschlappy
Rationale for research on sponge oxygenation
• Flow alterations due to MRE (local or regional)
• Sedimentation is linked to flow
• In corals, sedimentation can cause tissue necrosis
Weber et al. (2012) PNAS, (109) 24, 1-10.
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Microbes that a sponge
has to contend with
Sediments
Food
Associated (some phototrophs)
What we know: food bacteria
• Food bacteria and associated bacteria are not the same
• Food bacteria can become invasive
What we know: associated
bacteria
• Associated bacteria are passed on from mother to
daughter
• Associated bacteria are very diverse
• Some phyla are only found in sponge: e.g Poribacteria
Temporal fluctuations in oxygen
Low oxygen lasting up to 1h
Schläppy et al. (2010) Limnology and Oceanography
55 (3): 1289–1300
Bacteria in sediments on top
of sponge: unknown
• In corals, nutrient-rich sediments can accumulate on top the coral tissue
• Sulphate reducers make sulphide under anoxic conditions
• Sulphide can lead to tissue lesion over time
Weber et al. (2012) PNAS, (109) 24, 1-10.
Microbial processes in sponges
• Nitrification
• Denitrification
• Anammox
+
Hoffmann et al. 2006 Marine Biotechnology 8: 373-379
• Sulphate reduction
@mlschlappy
http://wiki.biomine.skelleftea.se/wiki/index.php/Sulfate_reducing_bacteria
Research questions
Are the oxygen conditions at the sponge surface
1. stable enough to sustain aerobic and anaerobic microbial
processes?
2. determined by the presence or absence of sediment/flow?
Study species
Pachymatisma johnstonii
Dysidea fragilis
Flume set up
F
S
S
F
S
F
F
S
Fast: 17.7 l/min-1
Slow: 8.6 l/min-1
2 positions in flume:
• Turbulent
• Linear
• 8 sponges per flume
Flume set up
Hobo flow meter
Turbulent
Linear
Natural seawater
• 2 positions in flume
• 8 sponges per flume (4 of each species)
Methods/results
Exposed to natural sediments
for 3 weeks
Microprofiling at locations with/out sediments
1/32 showed some discolouration
Influence of sediment on surface
oxygenation in P. johnstonii
@mlschlappy
Sediments create a reduction of oxygen in the water
column above the sponge (~ 1mm)
Influence sediment
surface oxygenation
of D. fragilis
@mlschlappy
Sediments create a reduction of oxygen in the water
column above the sponge (~ 1mm)
Influence of sediments on
oxygenation D. fragilis
Sediment
No sediment
Sponge pumping behaviour alters the outcome of
sediment presence/absence
Morphological plasticity of
sponges in relation to flow
Hypotheses
Why? Because anoxia in sponge is related to
• Ambient flow (Schläppy et al. 2007)
• Sponges’ morphology is partially due to ambient flow (3 months, 3 weeks,
• Sponge pumping activity
and 24h experiments)
Experiments:
• 1 x 24 may
h experiment
(photo
record,
every
• Changes
not be visible
to the
naked
eye2h)
(3D)
• 1x 3D models of sponges -method testing (cut sponges)
• Flow regime (turbulent vs unidirectional has an effect on sponge
• 1x 3D models of sponge exposed to 2 flow regimes in flumes
morphology)
• 1x respiration experiments
•
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Sponge
respiration
@mlschlappy
rate are different after exposure to sediments
Methods – 3D models
2 sets of photos per sponge
• Top circle (20 photos)
• Bottom circle (40 photos)
merikafp7.eu
[email protected]
@mlschlappy
Sponge morphological
plasticity
Method testing with cut sponges (n=10)
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@mlschlappy
Sponge morphological
plasticity
3D of sponge before and after flume treatment
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@mlschlappy
Sponge morphological
plasticity
3D of sponge before and after flume
treatment
merikafp7.eu
[email protected]
@mlschlappy
Sponge respiration
32 sponges tested before
and after exposure to
sediments for 3 weeks
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@mlschlappy
In summary
• Combined effects of flow and sedimentation on sponges in flumes
• Effects of flow on sponge morphological plasticity (photos record, 3D)
• Respiration rates in sponges before /after exposure to sediments
merikafp7.eu
[email protected]
@mlschlappy
Thank you
merikafp7.eu
[email protected]
@mlschlappy