Biogeochemical consequences of interannual to multidecadal variability

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Biogeochemical consequences of interannual to
multidecadal variability

• Francisco Chavez, Monterey Bay Aquarium Research
  Institute
• Credits R.T. Barber, D.M. Karl, J.T. Pennington,
  R. Michisaki, J.P. Ryan

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El Viejo
La Vieja
Do productivity increases in cold areas balance
decreases in warm areas?
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Carbon cycle variability drivers

• Equatorial Pacific upwelling
• Coastal upwelling circulation
• Gyre circulation changes
• Balance between denitrification and nitrogen
  fixation
• Iron deposition/coastal source
• Bifurcation of subarctic current/Potential
  experiment

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Sardine Landings
Japan
California
Peru
South Africa
1925 1950 1975
1925 1950 1975
2000
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El Viejo
El Viejo
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El Viejo
La Vieja
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Coastal upwelling system
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A global warming story?
Still may be but ..
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Never average, either warm or cool
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• Chlorophyll, pheophytin and primary production
  have all increased 3-5 fold since 1970, but with
  different temporal patterns
• Pheo increase is most dramatic
• Pheo is actually chlorophyll b
  (Prochlorococcus)

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Natural iron fertilization Large coastal source
(10x atmospheric deposition) no negative
impacts (i.e. N2O) Possible source of
variability
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NSF Ocean Observatory Initiative (OOI)

• To create new research infrastructure (observing
  systems) One package containing
• Coastal
• Relocatable Globa buoys
• Cabled Plate
• Coastal (ca. 50M over 5 yr for equipment)
• Two workshops defined possibilities
• Imagine the 1 month Monterey Bay effort this
  summer extending spatially and going on for
  several years.
• ORION workshop (Jan 04) meeting critical
• Support of coastal component specifically, and
• Overall initiative. (Congress will make the final
  decision)
• Research Community support critical. What
  compelling science questions can be addressed?
  Does anyone care?

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OOI Pioneer Array Concept
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Experimental Concept for integrating
Global Regional and Coastal
Q What are the effects of ENSO and PDO on the
speed and wobble of the NPSG and the biological
dynamics therein? - Oxygen decreases -
Nitrification/Denitrification -
Correlation/Decorrelation length scales for
global network and models. - Source waters
Each Mooring Array - 0-1000m focus - 100-200km
spacing - Intermediate complexity (profiling) -
supplemented by 20 Gliders 10 day synoptic
coverage - Lagrangian floats - 5-6 year
deployment balance between events (ENSO/PDO/St
orms) - sensor suit addressing questions
Coast
500km
1000km
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Conclusions

• El Niño and El Viejo are pervasive in the Pacific
• They have strong impact on climate, ocean
  physics, marine ecosystems and biogeochemical
  cycling
• Natural variability confuses the global warming
  issue (is it occurring and what are the impacts?)
• The next twenty years might tell the story (La
  Viejacool but if warming continues)
• Highlights the need for a global (and integrated)
  ocean observing system for ocean physics AND
  marine ecology and biogeochemistry
• Need to consider these phenomena in our
  experimental design

Analysis of fish scale records in the sediments
hint at 100 year cycles