Biological Ramifications of Climate-Change Mediated Oceanic Multi-Stressors !

Scott Doney Woods Hole Oceanographic Institution

Phil Boyd (U. Tasmania), Sinikka Lennartz (GEOMAR), & David Glover (WHOI)

Supported by:

Southern Ocean Dynamics & Biogeochemistry

Workshop Caltech, Feb. 2015

Climate Change Drivers!

Plankton Response to Multiple Environmental Drivers!

Boyd & Hutchins, Mar. Ecol. Prog. Series, 2012

Talk Outline!Earth System Model Projections: •  multiple stressor trends •  regional variability

Guide design & interpretation of field/lab manipulation studies

Surface Warming!

Ensemble of CMIP5 Coupled Climate-Carbon Models Bopp et al. Biogeosciences 2013

ΔSST

0.0

2.0

-1.0

4.0

1900 2000 2100

CESM1(BGC) Δ (2100 – 2000)

Moore et al., J. Climate 2013 Boyd et al., Nature Climate Change 2015

Physical Drivers!

Δ 2100 - 2000

CESM1(BGC)

Moore et al., J. Climate 2013 Boyd et al., Nature Climate Change 2015

Biogeochemical Drivers!

Δ 2100 - 2000

CESM1(BGC)

Moore et al., J. Climate 2013 Boyd et al., Nature Climate Change 2015

Present-Day Southern Ocean Iron Budget Terms!

Misumi et al. Biogeosciences 2014

Divergence/Convergence terms for: •  Horizontal

advection •  Vertical

advection •  Mixing •  External

forcing dust & sediments

Positive is net source

Net Primary Productivity!

Bopp et al. Biogeosciences 2013

ΔNPP

1900 2000 2100

0%

20%

8%

10%

Δ NPP

Declining Seasonal Sea-ice along Peninsula!

Sharon Stammerjohn U Colorado Boulder

Stammerjohn et al. Geophysical Research Letters 2012

3.3 months shorter

2.6 months longer

(1979/80 – 2010/11)

Decadal Change in Surface Chlorophyll

Montes et al. Science (2009)

Ecological Changes to Retreating Sea-Ice!

Courtesy Zina Deretsky, NSF

-Sea ice melt stabilizes upper ocean and fosters phytoplankton growth -Long sea ice duration acts as a barrier to light penetration and prevents growth

Effects on Growth & Community Structure!Small Phytoplankton

Growth Rate Diatom

Growth Rate

Marinov et al. Global Biogeochemical Cycles 2013

Ocean Acidification!

Bopp et al. Biogeosciences 2013

Δsurface pH

0.0

-0.4

0.1

1900 2000 2100

-0.2

CESM1(BGC) Δ (2100 – 2000)

Moore et al., J. Climate 2013 Boyd et al., Nature Climate Change 2015

Ocean Acidification!

CESM1(BGC)

Moore et al., J. Climate 2013 Boyd et al., Nature Climate Change 2015

Boyd, Lennartz, Glover & Doney Nature Climate Change 2015

Regional Climate Signals: “Climate Clusters”!

Global Trends vs. Regional Variation!

ΔSST ΔSST

ΔSST ΔSST

ΔFe

ΔSi(OH)4 ΔNO3

ΔpH

Nutrients log10([X])

global trend

Surface Stratification Factor (20%)

Nutrient Factor (26%)

T S MLD

PO4 NO3

Fe

Principal Component Analysis (PCA)!

Temperature-Growth Curves!

Boyd et al. PLoS One 2013

Interactive Effects of Multiple Environmental Drivers!

Rose et al. Biogeosciences 2009

Days

Boyd, Lennartz, Glover & Doney Nature Climate Change 2015

ΔpH <-0.35

ΔNPP <-100 mgC m-2 y-1 ΔSST >3.5 K O2 <50 mmol m-3

ΔO2 <-50 mmol m-3

Regional Variation in Multiple Stressors!

<-20 <50

Bopp et al. Biogeosciences 2013

Talk Outline!Earth System Model Projections: •  multiple stressor trends •  regional variability

Guide design & interpretation of field/lab manipulation studies