temperate seagrass bed metabolism and carbon ocb 2019 ...€¦ · 2 buried carbon particulate...
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Amelie Berger, Peter Berg, Karen McGlathery, Lillian Aoki,
Matthew Oreska, Marie Lise Delgard
Temperate seagrass bed metabolism and carbon
sequestration
OCB 2019 Summer
Workshop
Slime moldwasting disease
VCR loss due to pandemic wasting disease and “Great
Storm” of 1933CheapeakeBay
VCR
Atlantic Ocean
OCB 2019 Summer
Workshop
Landscape-scale restorationseeds
Orth Lab, VIMS; The Nature Conservancy
500 acres seeded70 million seeds6200 acres meadow
= 25 km2
OCB 2019 Summer
Workshop
South BaySouth Bay0.5 – 1 acre plots100k seeds acre-1
http://web.vims.edu/bio/sav/
Landscape-scale restoration
OCB 2019 Summer
Workshop
Long-term seagrass study
2014
2015
2017
2016
High temperatures in June 2015 caused large-scale die-off
Meadow development
Mature meadow
Die-off Parti
al re
cove
ry
OCB 2019 Summer
Workshop
VCR
Atlantic Ocean
Photo: AWI Sea Ice Physics group
Aquatic eddy covariance technique
OCB 2019 Summer
Workshop
Aquatic eddy covariance technique
Berger et al. (in review)
OCB 2019 Summer
Workshop
Aquatic eddy covariance technique
24 hours
Berger et al. (in review)
• R = !"# ∑ flux%&'( + ∑flux*+,-
h*+,- h./012
• GPP = !"# ∑ flux./012 +
∑flux*+,-h*+,- h./012
Hume et al. (2011) L&O
• R = !"# ∑ flux%&'( + ∑flux*+,-
h*+,-h./012
• GPP = !"# ∑ flux./012 +
∑flux*+,-h*+,- h./012
OCB 2019 Summer
Workshop
2015
2014
Highly dynamic, but overall balanced seagrass metabolism
Berger et al. (in review)
heterotrophic
autotrophic
OCB 2019 Summer
Workshop
Long-term record of seagrass metabolism
2015
2014
Berger et al. (in review)Hume et al. 2011 Rheuban et al. 2014
OCB 2019 Summer
Workshop
2015
2014 NEM = 1.0 mmol O2 m-2 d-1
Highly dynamic, but overall balanced seagrass metabolism
Berger et al. (in review)
OCB 2019 Summer
Workshop
Annual carbon budget
Berger et al. (in review)
OCB 2019 Summer
Workshop
Restoration reinstates C storage in sediments
0
100
200
300
400
500
600
700
0 2 4 6 8 10 12 14
Density
(sho
otsm
-2)
MeadowAge(yr)
• Within 12 years, C burial within range of natural systems
• ~half seagrass C; half algal C produced in situ
CO2
Buried Carbon
ParticulateOrganic C
Greiner et al. 2013, Greiner et al. 2016, Oreska et al. 2017a,b
Meadow development
Mature meadow
050100150200250300350400450500
0 9-14 15 16 17
BulkC(gm
-2)
Meadowage(y)
050
100150200250300350400450500
0 9-14 15 16 17
BulkC(gm
-2)
Meadowage(y)
Restoration reinstates C sequestration in plant biomass
Berger et al. (in review)
OCB 2019 Summer
Workshop
Disturbance caused a shift in trophic status
Berger et al. (in review)
Trophic status: balanced
2014
OCB 2019 Summer
Workshop
Disturbance caused a shift in trophic status
Berger et al. (in review)
2014
2015
Trophic status: heterotrophic
OCB 2019 Summer
Workshop
Disturbance caused a shift in trophic status
Berger et al. (in review)2017
2016
2014
2015
Trophic status: autotrophic
OCB 2019 Summer
Workshop
050
100150200250300350400450500
0 9-14 15 16 17
Carbon
storage(gm
-2)
Meadowage(y)
Seagrass loss affects C storage
Nice to meet you. I’m a Zostera.Nice to meet you. I’m a Zostera.Nice to meet you. I’m a Zostera.Nice to meet you. I’m a Zostera.
Restor
ation Loss
Nice to meet you. I’m a Zostera.
Nice to meet you. I’m a Zostera.Nice to meet you. I’m a Zostera.
Nice to meet you. I’m a Zostera.Nice to meet you. I’m a Zostera.Nice to meet you. I’m a Zostera.
Recovery
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Workshop
0
50
100
150
200
250
300
350
400
450
NearInlet Mid-meadow
Carbon
storage(gm
-2)
2013
2017
2018
2017
Landscape-scale variation affects C loss
No carbon loss near inlet
Near Inlet
Mid-meadow
Link to exposure to temperature stress
High flushing,Short
residence time
Higher resilience
+
Berger et al. (in prep)
OCB 2019 Summer
Workshop
bathymetry
Limitation by low CO2 or high O2?
Berg et al. (2019) L&O
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Workshop
bathymetry
No limitation by low CO2 or high O2
Berg et al. (2019) L&O
OCB 2019 Summer
Workshop
• Restoration reinstates C storage and sequestration
• Sediment C stocks are vulnerable to shoot losses fromtemperature stress
• Seagrass loss and recovery causes shifts in trophicstatus, but the meadow is metabolically balanced overallà most C retention = in sediment
• Meadows are resilient at the landscape scale
• No stimulation of photosynthesis at high CO2concentrations
Conclusions
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Dieback and C loss is patchy at plot scale
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50
100
150
200
250
300
Seagrass Bare
C (g
/m2)
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Workshop