metabolic constraints on marine habitat and its climatic changes

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Metabolic Constraints on Marine Habitat and its Climatic Changes Curtis Deutsch University of California, Los Angeles In collaboration with: Aaron Ferrel, Taka Ito, Hartmut Frenzel And funded by:

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Metabolic Constraints on Marine Habitat and its Climatic Changes. Curtis Deutsch University of California, Los Angeles. In collaboration with: Aaron Ferrel, Taka Ito, Hartmut Frenzel. And funded by:. 2) Microbes (biogeochemistry). 1) Macrofauna (ecology). 1.0. - PowerPoint PPT Presentation

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Page 1: Metabolic Constraints  on Marine Habitat  and its Climatic Changes

Metabolic Constraints on Marine Habitat

and its Climatic Changes

Curtis DeutschUniversity of California, Los Angeles

In collaboration with: Aaron Ferrel, Taka Ito, Hartmut Frenzel

And funded by:

Page 2: Metabolic Constraints  on Marine Habitat  and its Climatic Changes

Oxygen and marine ecosystems

Low O2 restricts habitat of aerobic macrofauna. - anaerobic metabolism - mortality

2) Microbes (biogeochemistry)

NO

2 (m

ol/li

ter)

0 2 4 6 8 10 12 14 16 18

O2 ()

1) Macrofauna (ecology)1.0

0.8

0.6

0.4

0.2

0

Fra

ctio

n S

peci

es H

abita

bilit

y

50% lethalityO2~ 50 M “Hypoxia”

O2 ()0 60 120 180 240 300

Vacquer-Sunyer and Duarte [2008] Devol [1978]

Low O2 creates habitat for anaerobic microbes. - denitrification, annamox - widespread N limitation

Onset of denitrificationO2~ 5 M “Suboxia”

Page 3: Metabolic Constraints  on Marine Habitat  and its Climatic Changes

Biogeochemical ChangesO

2 cy

cle

N c

ycle

Simulations (GCM) Observations (CalCOFI)

Deutsch et al. [2011]

Page 4: Metabolic Constraints  on Marine Habitat  and its Climatic Changes

log(VO2/VO2)

Hypoxic sensitivity

VO2 =∂VO2

∂O2crit ΔO 2 The sensitivity of

hypoxic volumes can be predicted from data alone.

It increases rapidly with decreasing O2 threshold.

Model simulations (dots) consistent with this simple prediction.

Global O2 anomaly(assumed)

Derivative of histogram(observed)

Change in volume(predicted)

100%

30%10%

300%

Normalized change in hypoxic volume (VO2/VO2)

Deutsch et al. [2011]

Page 5: Metabolic Constraints  on Marine Habitat  and its Climatic Changes

Goals of this Study

Question:

How does climate warming change the aerobic habitat of marine species?

Strategy:

Integrate laboratory, demographic, and climate data to map the metabolic scope of diverse marine species across their geographic range.

Page 6: Metabolic Constraints  on Marine Habitat  and its Climatic Changes

A General Framework

Φ =O2 Supply

O2 Demand= Ao *

[O2 ]

B 3/4 exp(−Eo /kBT )

Gas Transfer

Metabolic Rate

Ferrel and Deutsch [in review]

Problem: Index depends (invisibly) on many physiological factors. Solution: Estimate coefficients (Eo, Ao) using laboratory data.

Alternate interpretation: Φ is the ratio of potential metabolic rate to minimum rate for survival, i.e. a non-dimensional measure of metabolic scope [Fry, 1947; Hochachka, 1990].

Page 7: Metabolic Constraints  on Marine Habitat  and its Climatic Changes

Laboratory dataUse published laboratory experiments on hypoxic tolerance (O2

crit) measured as onset of anaerobic metabolism and increased mortality (LC50)

Φ(O2crit) = 1

Estimate parametersAo (intercept)Eo (slope)

Mass and temperature account for ~70% of variance.

Ferrel and Deutsch [in review]

Problem: Laboratory tanks are not the real world!Solution: Map Φ alongside species distribution data.

Page 8: Metabolic Constraints  on Marine Habitat  and its Climatic Changes

Φ =1.6

Distribution data: Cod

Cod Characteristics:

Depth of habitat0-400m

Mass at maturity500-1500g

Range of Φcrit

1.3-2.6

Page 9: Metabolic Constraints  on Marine Habitat  and its Climatic Changes

Φ =1.6

Western PopulationMigrates From ~37oN in winterTo ~41oN in summer

Eastern PopulationMigrates Surface in spring/winterTo ~250 m in summer/fall

Seasonal Migration

Page 10: Metabolic Constraints  on Marine Habitat  and its Climatic Changes

Annual PopulationsAnnual Populations

Φmax=2.4 Φmin=2.4

Seasonal populations

Annual populations

Species Distribution: Rock Crab

Crab Characteristics:

Depth of habitat0-400m (benthic)

Mass (larval)1.25-5 x10-4

Range of Φcrit

1.8-4.1

Page 11: Metabolic Constraints  on Marine Habitat  and its Climatic Changes

Φ =2.2

Species Distribution: Seabream

Seabream Characteristics:

Depth of habitat0-60m

Mass at maturity300-900g

Range of Φcrit

1.6-4.0

Page 12: Metabolic Constraints  on Marine Habitat  and its Climatic Changes

Φ =1.9

Species Distribution: Eelpout

Eelpout Characteristics:

Depth of habitat0-40m

Mass at maturity100-300g

Range of Φcrit

1.4-3.3

Page 13: Metabolic Constraints  on Marine Habitat  and its Climatic Changes

Comparison to Terrestrial Taxa

Peterson, Nagy, Diamond [1990]

Ratio of Field to Resting Metabolic Rates:

Birds, mammals, lizards 1.5-5 (max 7)

Marine fish/crabs 1.3-4.1 (1.6-2.4)

Humans 1.4-5.6

Page 14: Metabolic Constraints  on Marine Habitat  and its Climatic Changes

A B

T (oC) O2 (M)

Climate ProjectionsProjected T, O2 changes in 2071-2100, 0-400m

IPCC Earth System Model mean, RCP8.5 scenario

Warming is global, deoxygenation is extra-tropical.

Page 15: Metabolic Constraints  on Marine Habitat  and its Climatic Changes

Declining Metabolic IndexProjected change in Φ in 2071-2100, 0-400m

IPCC Earth System Model mean, RCP8.5 scenario

Global meanDecrease ~20%

Northern High Latitudes ~40%

Page 16: Metabolic Constraints  on Marine Habitat  and its Climatic Changes

Φ %) Φ %)

A B

Temperature vs OxygenOxygen contribution Temperature contribution

Globally, warming and deoxygenation contribute ~15% and 5% reduction of metabolic index, respectively. The role of O2 is greater in the Pacific, where O2 is already lower.

Page 17: Metabolic Constraints  on Marine Habitat  and its Climatic Changes

Habitat Loss

Habitat Loss(slope, annual)

Metabolic Habitat Loss

Cod-24%

Seabream-14%

Eelpout-26%

Rock Crab-22%

Relative change in habitable thickness (%)

Page 18: Metabolic Constraints  on Marine Habitat  and its Climatic Changes

Integrated Habitat Loss

Loss of metabolic habitat is generally greater than theloss of thermal habitat (Tmax), but not always.

The loss of O2 contributes ~25% of the metabolic habitat loss. Its role in the Pacific is likely to be even greater.

Page 19: Metabolic Constraints  on Marine Habitat  and its Climatic Changes

Conclusions– The ratio of O2 supply to demand - an index of metabolic

scope – can be mapped using laboratory, demographic, and climate data.

– Species with diverse thermal and hypoxic tolerances are limited at the equatorward edge of their geographic range by a similar metabolic scope, consistent with that of terrestrial taxa.

– Metabolic habitat is projected to contract rapidly due to the synergistic impacts of anthropogenic warming (~75%) and the associated loss of oxygen (~25%).

Page 20: Metabolic Constraints  on Marine Habitat  and its Climatic Changes
Page 21: Metabolic Constraints  on Marine Habitat  and its Climatic Changes

Figure S5A

B C

Page 22: Metabolic Constraints  on Marine Habitat  and its Climatic Changes
Page 23: Metabolic Constraints  on Marine Habitat  and its Climatic Changes

A

B

Page 24: Metabolic Constraints  on Marine Habitat  and its Climatic Changes

Changes in Metabolic Index