SIBER

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SIBER

• Sustained Indian Ocean Biogeochemical and
  Ecological Research

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Acknowledgements

• IndoUS Science and Technology Forum
• Organizers
• NASA and NSF
• Slides from
• Raleigh Hood (University of Maryland)
• Oscar Schofield (Rutgers University)

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Workshop in Goa in October 3-6, 2006
Workshop Goals

• Review the state of our knowledge of the
  biogeochemical and ecological dynamics of the IO
• Identify prominent gaps
• Formulate a plan for future international
  research
• Implement parallel program to CLIVAR/GOOS and CO2
  surveys
• focused on biogeochem. and ecology

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Motivation

• Promote interdisciplinary collaboration and
  research in
• the Indian Ocean
• Leverage planned CLIVAR/GOOS Indian Ocean
  mooring array
• Develop a new, parallel program in the IO
  focused on
• biogeochemical and ecological research
• The Indian Ocean is interesting and different
• It is one of the last great frontiers for ocean
  biogeochemical
• and ecological research
• Good News we are just starting and have a
  chance to get on with the physical measurements /
  Bad News great paucity of measurements

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Time Series Locations for OceanSITES
OceanSITES Science Team has used
multi-disciplinary site selection

Yellow dots represent Argo float
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ORION PROPOSED GLOBAL SITES BASED ON COMMUNITY
WORKSHOP IN SALT LAKE CITY (MARCH 2006)
White questions 12 (biogeochem, ecology,
biodiversity), Yellow question 3 (ridge and
subduction sites) Pink question 4 (seismic
studies of earth structure), Green question 5
(air-sea flux) Question 6 All
Phase A WHITE, Phase B YELLOW, Phase C RED
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Insufficient data to fully characterize CO2
exchange
air-sea pCO2 gradient (µatm)

• IO is a source of CO2 to the
• atmosphere but also responsible
• for 20 of global CO2 uptake
• (Takahashi et al., 2002)
• Large seasonal changes in ?pCO2
• -In southern IO linked to temp.
• -In northern IO linked to
• upwelling and summer monsoons
• Need to better characterize
• spatial and seasonal patterns and
• particularly air-sea flux on
• regional scales
• Need to better understand
• linkages to wind, temperature,
• upwelling and biogeochemical
• cycles

From Takahashi et al. 2002, courtesy of B.
Tilbrook
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Systematic warming - unknown biogeochemical
response
The Indian Ocean has warmed over the 20th century
more than any other ocean basin
From Levitus et al. 2000
From Meyers et al. 2005 IOP Report

• How are biogeochemical processes and the carbon
  cycle being impacted
• by this warming?
• Increased SST is known to reduce CO2 uptake.
• How will this impact the role of the Indian
  Ocean in the global C cycle?
• Is the IO a preview of global oceanic warming
  biogeochemical response?

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The Indian Ocean is very different from the
Atlantic and the Pacific
Winds
Circulation
Chlorophyll
Jan/Feb
Jul/Aug
From Schott and McCreary, 2001
From Wiggert et al. 2006

• Bounded to the north
• (no T-cline ventilation)
• Low-lat. Opening to east (ITF)
• Annual Monsoon cycle
• - Seasonal reversal of winds
• (extending to 10o South)
• - Strong seasonal precipitation
• (especially in east and BOB)

• Strongly seasonal circulation (e.g.)
• - South Equatorial Counter Current
• - Somali Current
• - India Coastal Currents
• - Wyrtki Jets (intermonsoon periods)
• Warmest temps and deepest thermocline in the
  east
• Strongly seasonal upwelling and biogeochemical
  response
• No equatorial upwelling or biogeochemical
  response!

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The Arabian Sea versus the Bay of Bengal - two
dramatically different basins
Arabian Sea
Bay of Bengal

• Intense upwelling and mesoscale variability
• High productivity, highly seasonal
• Net evaporation with high salinity sources
• Strongly seasonal Fe and dust deposition
• Deep open ocean OMZ and oxygen depletion
• Substantial open ocean denitrification
• Significant open ocean N2-fixation
• Strong source of carbon to the atmosphere

• Weaker upwelling
• Modest productivity, less seasonality
• Very significant freshwater/nutrient sources
• Deep open ocean OMZ, but not depletion
• Broad shelves
• High rates of shelf denitrification
• Significant open ocean N2-fixation
• Weak sink (or source) of C to the atmosphere

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New findings and uncertainties on Fe limitation
What is the extent and role of Fe limitation in
the IO?

• Traditional view is that Arabian Sea is Fe
  replete
• New evidence suggests possibility of seasonal Fe
  limitation in the Arabian Sea associated with
  upwelling waters with low FeN (Wiggert et al.,
  2006 Naqvi et al. 2006)
• IO sector of the Southern Ocean is strongly Fe
  limited (Gervais et al., 2002)
• Models suggest large areas of persistent Fe
  limitation in tropical and subtropical waters

Red N-limitation
Blue Fe-limitation
From Wiggert et al. (2006)
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New findings and uncertainties on Fe limitation
How does dust and Fe deposition influence the
carbon cycle?
from www.igbp.kva.se/cgi-bin/php/sciencehistory.sh
ow.php

• A linkage between eastward propagating
  atmospheric dust and offshore carbon sink regions
  between 30o and 50o S has been suggested (Piketh
  et al., 2000)
• What about further north, e.g., in the Arabian
  Sea?

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SIBER Steering Committee

• India
• Wajih Naqvi (co-chair)
• National Institute of Oceanography
• Satish Shetye
• National Institute of Oceanography
• V. S. N. Murty
• National Institute of Oceanography
• Prasanna Kumar
• National Institute of Oceanography
• Dileep Kumar
• National Institute of Oceanography

• United States
• Raleigh Hood (chair)
• University of Maryland
• Lou Codispoti
• University of Maryland
• Jay McCreary
• University of Hawaii
• Jerry Wiggert
• Old Dominion University
• Ajit Subramaniam
• Lamont-Doherty Earth Observatory

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SIBER Invited Participants (targets)

• 20 United States
• 20 India
• 20 International
• 100 maximum

SIBER Products

• An international SSC
• A plan for future international research
• A symposium volume

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SIBER Website http//ian.umces.edu

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SIBER and Indoflux Complimentary and Synergistic
Global Partnerships
Is the Indian coast net heterotrophic or
autotrophic
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ORION WATER COLUMN
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Moorings Ocean Equivalents of Flux Towers
BTM 1994- Present Also, HALE-ALOHA HOT
site Ongoing
Autosub
Dickey et al., 2001
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Aerosol Sampler with IMET on BTM Ed Sholkovitz,
Bob Weller, Dave Hosom, et al., WHOI
Fe Al Mn P Ca
African Dust Event
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MITESS Fe Time Series from BTM Ed Boyle, MIT
MITESS Fe Time Series
Osmoanalyzer Hans Jannasch, MBARI
Eddy
OPL Optics
TS-SID Craig Taylor, WHOI
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BRING ON THE ROBOTS
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Multi- Platform Approach
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Bay of Bengal Algorithms to derive proxies to
feed models Are nepheloid layers dominated by the
minerogenics? By organics?
A) Salinity
B) bb(650) (m-1)
D) bb(650) / c(650)
C) c(650) (m-1)
Hudson River plume
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Some random thoughts

• Study the effect of eutrophication and river
  outflow on marine ecosystem
• Study CO2 drawdown and outgassing in the ocean
• N2O release on coastal western shelf due to
  denitrification
• SST impact on rainfall
• Harmful algal blooms
• Potential for instrument development and training

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