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2008/FWG-MRCWG/004 Agenda item: 3

Ocean Ecosystem Consequences of Climate Change

Purpose: Information Submitted by: Lead Shepherd

7th Joint Session of the Fisheries and Marine Resource Conservation Working Groups

Piura, Peru18 April 2008

Ocean Ecosystem Consequences Ocean Ecosystem Consequences of Climate Changeof Climate Change

Francisco ChavezFrancisco ChavezSenior ScientistSenior Scientist

Monterey Bay Aquarium Research Institute Monterey Bay Aquarium Research Institute (MBARI)(MBARI)

APEC Piura April 2008APEC Piura April 2008

How does APEC define Climate How does APEC define Climate Change?Change?

•• GLOBEC scientists define it to include any GLOBEC scientists define it to include any change in climate, be it due to nature or change in climate, be it due to nature or man, on any scale (e.g. man, on any scale (e.g. interannualinterannual to to centennial or longer)centennial or longer)

National Academies Report 2006

Little Ice Age

What about Global Change?What about Global Change?

•• Here I define it as any environmental Here I define it as any environmental change associated with human activitychange associated with human activity

•• The most debated is global warming but The most debated is global warming but there are many others such as ocean there are many others such as ocean acidification, pollution (nutrients, metals, acidification, pollution (nutrients, metals, etc.), etc.), overfishingoverfishing, etc., etc.

The role of the ocean in moderating the atmospheric CO2 increase has been recognized (by scientists) for a very long time. Revelle and Suess (1957) first explicitly calculated the partitioning of CO2released to the atmosphere between air and sea and estimated that ~ 40% of the gas would quickly be absorbed by the surface ocean, with the remainder building up in the atmosphere and changing climate.

While the climate impacts of increasing atmospheric CO2 levels have received great attention, the direct effects of the enormous CO2enrichment of the upper ocean have had little discussion. That is about to change, for ocean chemistry is being altered on a scale not seen for millions of years, and there are very basic questions on the impact on ecosystems and biogeochemical cycles to which we simply do not yet have answers. The oceanic invasion rate of fossil fuel CO2 must now be close to 1 million tons CO2 per hour.

Ocean Acidification

During the 5 days of the APEC During the 5 days of the APEC meeting in Piura the ocean will meeting in Piura the ocean will

have absorbed about 125 million have absorbed about 125 million tons of COtons of CO22

There could be many biological There could be many biological impacts but the most obvious is impacts but the most obvious is on organisms with calcareous or on organisms with calcareous or aragoniticaragonitic shells, these include:shells, these include:

•• CoralsCorals•• CoccolithophoridsCoccolithophorids•• PteropodsPteropods –– apparently the preferred first apparently the preferred first

food of pink salmonfood of pink salmon

But what about Climate Change?But what about Climate Change?

•• Where are we on long term changes in the Where are we on long term changes in the oceanocean

•• What are the sources of natural variabilityWhat are the sources of natural variability•• What will the future bringWhat will the future bring

Natural Versus Anthropogenic Natural Versus Anthropogenic Climate ChangeClimate Change

•• Natural cycles fluctuate between two or Natural cycles fluctuate between two or more states, typically warm versus coldmore states, typically warm versus cold

•• Anthropogenic unidirectional unless Anthropogenic unidirectional unless measures are taken to reverse trend measures are taken to reverse trend (Hudson estuary example of reversal)(Hudson estuary example of reversal)

•• Natural and anthropogenic may interact Natural and anthropogenic may interact differently and unpredictably (warm PDO, differently and unpredictably (warm PDO, global warming, cool PDO, global warming)global warming, cool PDO, global warming)

The “classic” food chain

(P. Cury)

Small pelagic fish are central and drive variations up and down

(P. Cury)

Small Pelagics

Fisheries

Ocean Thermal Dynamics and

Circulation

Atmosphere and Climate

Macronutrients plus iron

Zooplankton

Primary Productivity

Freshwater fluxes

Surface Warming

Precipitation, wind, dust supply

Recruitment

Mortalityand

Predation

Habitat and distribution

Climate Change and the Abundance of Small Pelagic Fish

El Niño is most well known ocean-driven climate change

Upwelling regions account for 1% of the ocean but ~50% of the global fish production

El Viejo La Vieja

El Viejo

La Vieja

It is a familiar storyChildEl Niño La Niña

Parent

1900 to 2000

Once ever 3-8 years

Once ever 25-40 years

SoSo--called regime shift, what is it?called regime shift, what is it?•• Depends on who you ask!Depends on who you ask!

• Associated with global and synchronous anchovy and sardine alternations

• Term first used by Isaacs (1975) in discussing the increase in anchovy off California following the famous collapse of the sardine population in the 1940s.

• Ocean ecosystem changes that persist for long periods (decades)

• Best documented is a 1976 shift in the North Pacific

In the Pacific thought to be driven by the ocean overturning meridional circulation

Why are they importantWhy are they important

•• Affect commercially important speciesAffect commercially important species•• They are natural experiments that can be They are natural experiments that can be

used to understand how ocean used to understand how ocean ecosystems are organizedecosystems are organized

•• They provide a window into what can be They provide a window into what can be expected from anthropogenic influences expected from anthropogenic influences and a changing climateand a changing climate--they also make it they also make it difficult to determine human influencesdifficult to determine human influences

North Pacific regime shift North Pacific regime shift –– Hare and Hare and Mantua (2000)Mantua (2000)

Beaugrand & Ibanez (in press, MEPS)

-2.4-2

-1.6-1.2-0.8-0.4

00.40.81.21.6

2

1958

1960

1962

1964

1966

1968

1970

1972

1974

1976

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

Stan

dard

dev

iate

Calanoid copepods

-2-1.6-1.2-0.8-0.4

00.40.81.21.6

1958

1960

1962

1964

1966

1968

1970

1972

1974

1976

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

Stan

dard

dev

iate Cala noid copepods (17 indicato rs)

Fish total biomass (5 species)

Beaugrand G (2004) Progress in Oceanography

One thought is that there are two “stable” or regime states (North Atlantic)

1925 1950 1975 2000

Japan

California

Peru and Chile

South Africa

Sardine Landings

1925 1950 1975

Alternations of anchoviesand sardines

When will El Viejo return and what will be the effects of global change?

Oxy

gen

1950 1960 1970 1980 1990 2000

Export production

Oxygen at 150 m

Gutierrez et al. - Paleopeces

Longer Centennial changes

Processes responsible for low Processes responsible for low oxygenoxygen

•• Ventilation (and age), primary driver of Ventilation (and age), primary driver of large scale oxygen patterns (in eastern large scale oxygen patterns (in eastern Pacific)Pacific)

•• Primary productivity and export, primary Primary productivity and export, primary driver at local scales (i.e. Oregon and driver at local scales (i.e. Oregon and BenguelaBenguela))

The low oxygen expanded The low oxygen expanded southward in to Chile, what about southward in to Chile, what about the recent record (~50 years)the recent record (~50 years)

•• CaliforniaCalifornia•• PeruPeru

Long-Term Trends in Dissolved Oxygen off California-2.1 μmol/kg/y

ΔZmean = -41 m ΔZmax = -92 m

Expansion of Low-Oxygen Habitat

In situ oceanographic data off Peru shows thatocean losing nitrate (oxygen is zero so nitrate

electron donor)

It appears as if the eastern It appears as if the eastern Pacific low oxygen regions Pacific low oxygen regions

reformed after the Little Ice reformed after the Little Ice Age and continue to expand Age and continue to expand

todaytoday

Are there biological indicators of Are there biological indicators of this expansion?this expansion?

The Hake off Peru has retreated and gotten more concentrated

1966-19771978-1987

1988-1995 1996-2001

02000

40006000

800010000

1200014000

1600018000

20000

1991 1993 1995 1997 1999 2001 2003 2005 2007

Hake inEcuador Merluza durante La Niña (1996)

05

10

1520

25

3035

40

4550

1967

1969

1971

1973

1975

1977

1979

1981

1983

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007Catchability (F/f)

Index of hake concentración

JUMBO FLYING SQUID LANDINGS 1980 - 2000

0

20000

40000

60000

80000

100000

120000

140000

160000

180000

200000

80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00

Years

Tons

PERU MEXICO

A large Humboldt squid caught offshore from Sitka in October 2004 is among numerous sightings of a species seen for the first time in waters of the Far North

July 2005Tracy Arm (Sitka), AK

Post 1997/98 expansion of Dosidicus gigas range

British ColumbiaSept. 2005

1984

Long Beach, WAOct 2004

2004Outer Coast, BC

La Jolla Cove, CA.July, 2002

2001

2004

SummarySummary•• Low oxygen in eastern Pacific as we know Low oxygen in eastern Pacific as we know

today reformed after the Little Ice Agetoday reformed after the Little Ice Age•• Expansion continues today?Expansion continues today?•• Low oxygen=low pHLow oxygen=low pH•• Anthropogenic influences pushing in the Anthropogenic influences pushing in the

same direction (i.e. warming, stratification same direction (i.e. warming, stratification reducing ventilation, CO2 absorption < reducing ventilation, CO2 absorption < pH)pH)

•• Peru and Chile, a window into the future?Peru and Chile, a window into the future?

Effects will not be uniformly distributed

pH at 50 m

How will a warmer world How will a warmer world change atmospheric forcing and change atmospheric forcing and

ocean circulation and ocean circulation and productivity? First guessesproductivity? First guesses

•• It may drive stronger coastal upwelling by It may drive stronger coastal upwelling by increasing the land sea temperature increasing the land sea temperature gradientgradient

•• It may weaken the trade winds by It may weaken the trade winds by weakening the high to low latitude weakening the high to low latitude temperature gradienttemperature gradient

ContinuedContinued

•• It will create stronger stratification that It will create stronger stratification that will:will:

•• Reduce primary production in the open Reduce primary production in the open oceanocean

•• Create stronger gradients in Create stronger gradients in upwelling/mixing regionsupwelling/mixing regions

•• Favor Favor dinoflagellatesdinoflagellates??

TwoPrimaryStates

Change?

Varia-bility

The northwest African margin is a coastal upwelling system. Sea surface temperature (SST) records from Moroccan sediment cores, extending back 2500 years, reveal anomalous and unprecedented cooling during the 20th century, which is consistent with increased upwelling. Upwelling-driven SSTs vary out of phase with millennial-scale changes in Northern Hemisphere temperatureanomalies (NHTAs) and show relatively warm conditions during the Little Ice Age and relatively cool conditions during the Medieval Warm Period. These results suggest that coastal upwelling may continue to intensify as global warming and atmospheric CO2 levels increase.

McGregor, Dima, Fischer, Mulitza Science, 2/2/2007

Weakening of tropical Pacific atmospheric circulation due to

anthropogenic forcing driven by stronger warming at poles

Gabriel A. Vecchi, Brian J. Soden, Andrew T. Wittenberg, Isaac M. Held, Ants Leetmaa & Matthew J. Harrison in Nature 2006

Monterey Bay Time Series- El Niños during 92-93 and 97-98- Transition from El Viejo to La Vieja- The age of dinoflagellates?

1990 1995 2000 2005

What about models; can they What about models; can they be used to study the impacts be used to study the impacts

of climate change on of climate change on fisheries?fisheries?

Utilizing increased computer power

Development of CCSM-4

Improved Simulation of Physical Climate

(From Jim Hurrell)

Realist Model of the Pacific at 12.5 km resolution - SST

Yi Chao, JPL

Yamanaka et al. (2005)

NEMURO.NEMURO.FISHFISHNEMURO.NEMURO.FForor IIncluding ncluding SSauryaury and and HHerringerring

General Hypothesis :General Hypothesis :Ecosystem Change Associated with Global WarmingEcosystem Change Associated with Global Warming

Ocean Acidification

Decrease inCaCO3 Producerby the Lower PH

(This process is not included in this model)

Climate Change forcing scenarios and predictive planktonic ecosystem responses

Couple the shelf seas to the global ocean

Model pelagic/ benthic dynamics as driven by regional hydrodynamics

Abu n

danc

e

Body mass

TEPPR

1ary Production

A Dream?A Dream?•• In 5 years*In 5 years*††:: BGCs and ecological models will BGCs and ecological models will

be integrated in be integrated in ““weatherweather--toto--climateclimate”” modelsmodels•• In 10 years:In 10 years: we will begin to we will begin to seamlesslyseamlessly bridge bridge

the BGC and ecological questions in an Earth the BGC and ecological questions in an Earth System framework (fluxes System framework (fluxes →→ populations populations →→fluxes)fluxes)

•• In 15 years:In 15 years: we will be able to provide we will be able to provide quantitative predictions of marine systems quantitative predictions of marine systems [path: regional climate models to global [path: regional climate models to global models]models]

* 5 years = 1 generation of PhDs† time scales affected by feedback from management/societal goals

Where climate meets the global economy

Global Climate

GlobaleconomySmall Pelagic Fish

AquacultureHogs

Poultry

6Mt Fishmeal + 1.2 Mt Fish oil(from 30 Mt fish or 25 % Global catch)

Impacts and Consequences of Global Environmental Change on the fishmeal-based global food markets

Future vulnerability of national economies and global fishmeal and food markets to effects of climate change and other drivers on fisheries

Implications for aquaculture via feed substitution

Bio-economic modelsExposure (E)

Sensitivity (S)

Adaptive Capacity (AC)

Potential Impacts (PI)

+

VULNERABILITYV =f ( PI, AC)

=

Conclusions/thoughtsConclusions/thoughts

•• Ocean drives natural climate change which Ocean drives natural climate change which in turn has strong impacts on ocean physics, in turn has strong impacts on ocean physics, marine ecosystems and biogeochemical marine ecosystems and biogeochemical cyclingcycling

•• The effects are both negative and positiveThe effects are both negative and positive•• HumanHuman--induced climate change will also induced climate change will also

have strong impactshave strong impacts•• Natural variability confuses global warming Natural variability confuses global warming

climate impacts but also may provide lessons climate impacts but also may provide lessons and particularly surprisesand particularly surprises

•• As with natural variability global warming As with natural variability global warming effects will not be uniformeffects will not be uniform

Adaptive managementAdaptive management•• Information on climate change has not Information on climate change has not

been typically used for management of been typically used for management of exploited populationsexploited populations

•• At the same time we continue to be At the same time we continue to be surprised by naturesurprised by nature

•• We cannot always use the natural climate We cannot always use the natural climate system as an analog (i.e. El Nisystem as an analog (i.e. El Niñño and o and global warming)global warming)

•• How do we include climate change in the How do we include climate change in the (ecosystem(ecosystem--based) management of based) management of ecosystems with this in mind?ecosystems with this in mind?