Climate Change Impacts on West Coast Marine Ecosystems

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Climate Change Impacts on West Coast Marine
Ecosystems

• Nate Mantua, Ph.D.
• University of Washington
• Climate Impacts Group
• School of Aquatic and Fishery Sciences
• For the San Juan County MRC
• Friday Harbor, June 18, 2008

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The University of Washingtons Climate Impacts
Group
A NOAA-funded research and education team at the
University of Washington
cses.washington.edu/cig
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My short list of key issues for the future of PNW
marine ecosystems

• Variability in winds
• Ocean temperatures
• Ocean acidification
• Declines in dissolved oxygen
• Sea level rise
• I wont talk about diseases or invasive species,
  but they probably belong here too

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Fickle winds can cause large changes in upwelling
habitat on short time-space scales
Stonewall Banks Buoy SST June 18 - August 2 2005
17.5C on July 14
11C on July 20
August
June
July
Buoy SST plot courtesy of Pete Lawson
20 July 2005 SST NOAA CoastWatch image
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The California Current Ecosystem is dynamic
because Pacific winds vary greatly from year to
year
Sept 1997 El Niño
Sept 1998 La Niña
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Exotic Species Sightings off the BC Coast During
1983, an extreme El Niño year (J. Fulton, P.B.S.)
Slide provided by Kim Hyatt, DFO
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upwelling food webs in our coastal ocean
Cool water, weak stratification high nutrients, a
productive subarctic food-chain with abundant
forage fish and few warm water predators
Warm stratified ocean, few nutrients, low
productivity subtropical food web, a lack of
forage fish and abundant predators
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supercharged upwelling in 2006
Equatorward, Upwelling favorable

• In the summer of 2005, upwelling winds started
  late, but were then very from late July through
  August
• In 2006, upwelling was intense beginning in May
  and persisting through August

Cumulative wind stress since Spring Transition
Barth/Pierce (OSU)
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In the summer of 2006, severe hypoxia on the
continental shelf was widespread off the
Washington/Oregon coast
September 20-28, 2006 BPA and PISCO cruises
(Figure Courtesy Bill Peterson, Cheryl Morgan
NOAA)
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Is hypoxia/anoxia a normal feature of the Oregon
shelf?
DO (ml l-1)
Depth (m)
1950 to 1999 Hypoxia rare, no sign of
anoxia 2000 to 2005 Increase severity and
prevalence of hypoxia 2006 Appearance of
inner-shelf anoxia
National Oceanographic Data Center, NOAA, OSU
Archives, GLOBEC LTOP, NOAA, PISCO Chan et al.
2008 Science
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Sea Surface Temperature (Race Rocks lighthouse,
Victoria)
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Race Rocks Salinity and Temperature
Annual mean SST and SSS phase diagram for Race
Rocks lighthouse show trends toward warmer and
fresher surface waters at Race Rocks
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21st Century PNW Temperature Change Scenarios
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(No Transcript)
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Future warming will increase stratification

• Observations of the past 50 years show that most
  of the warming of the global oceans is
  concentrated in the upper few hundred meters
• Projections for the future point to more of the
  same -- upper ocean warming and increased
  stratification
• This will likely impact the ability to supply
  nutrients to the photic zone and impact the
  timing, duration and intensity of plankton blooms

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Window for accelerated growth of HABs in Puget
Sound
Rising water temperatures alone may promote
earlier and longer lasting blooms of harmful
algae (like Alexandrium catenella, which causes
psp in Puget Sound). Stephanie Moore, NOAA/NWFSC
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A Changing Chemical Regime for Marine Ecosystems
Ocean Acidification That other CO2 problem
pH
CO32-
CO2(aq)
Estimated aragonite saturation states of the
surface ocean for the years 1765, 1995, 2040, and
2100 (Feely et al., submitted), based on the
modeling results of Orr et al. (2005) and a
business-as-usual CO2 emissions scenario.
Wolf-Gladrow et al., 1999
As ocean calcium carbonate saturation state
decreases, a concomitant reduction in
calcification rates by marine organisms can
occur. - reduced extension rates - weaker
skeletons/shells
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Ocean Acidification of the North American
Continental Shelf
NACP Coastal Survey Cruise 11 May - 14 June 2007
Distribution of the depths of the corrosive water
(aragonite saturation lt 1.0 pH lt 7.75) on the
continental shelf of western North America from
Queen Charlotte Sound, Canada to San Gregorio
Baja California Sur, Mexico. On transect lines
5 and 6 the corrosive water reaches all the way
to the surface in the inshore waters near the
coast.
Depth of corrosive waters
Feely et al. 2008 Science Express
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PNW sea level rise Mote et al 2008
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A timely report from the National Wildlife
Federation

• The Sea Level Affecting Marshes Model (SLAMM) is
  used to project the impacts of sea level rise on
  Northwest coastal habitats

http//www.nwf.org/sealevelrise
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Projected Changes for a 27 slr (NWF 2007)

• Habitat will be converted!
• beaches to tide flats tide flats to shallow
  water
• Freshwater marsh to saltwater marsh

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• Nearshore habitat has already undergone extreme
  changes due to land use (image reproduced from
  Sound Science 2007)

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CO2 and Climate Change will play an important
role in West Coast Marine Ecosystems

• Natural patterns of variability (the annual
  cycle, El Niño, PDO, etc.) coordinate broad-scale
  changes in habitat, some aspects of which are
  predictable
• Global warming is likely to cause many direct and
  indirect ecosystem impacts
• Biogeographic shifts match-mismatch between
  predators and prey top-down, bottom-up,
  middle-out impacts changes in dissolved oxygen
  concentrations
• changing winds a major factor and a key source of
  uncertainty
• Ocean acidification due to increasing
  concentrations of atmospheric CO2 poses
  potentially large threats to west coast food
  webs, but those threats are currently not well
  understood
• Other issue I havent mentioned invasive
  species, diseases

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Studies have shown that the shells of living
pteropods begin to dissolve at elevated CO2 levels
Whole shell Clio pyramidata
Prismatic layer (1 µm) peels back
Arag. rods exposed
Limacina helicina
Aperture (7 µm) advanced dissolution
Normal shell unexposed to undersaturated water
C. pyramidata
Orr et al., (2005)
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• Since the beginning of the industrial age, the pH
  and CO2 chemistry of the oceans (ocean
  acidification) have been changing because of the
  uptake of anthropogenic CO2 by the oceans.
• Decrease in pH 0.1 over the last two centuries
• 30 increase in acidity decrease in carbonate
  ion of about 16

These changes in pH and carbonate chemistry may
have serious impacts on open ocean and coastal
marine ecosystems.
http//www.biol.tsukuba.ac.jp/inouye
Photo Missouri Botanical Gardens
Calcareous Plankton
Corals
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For more information

• The Intergovernmental Panel on Climate Change
• http//www.ipcc.ch
• The UW Climate Impacts Group
• http//cses.washington.edu/cig
• RealClimate -- a no spin zone on climate
  science
• http//realclimate.org