BERAC subcommittee review of Free Air CO2 Enrichment (FACE)

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BERAC subcommittee review of Free Air CO2
Enrichment (FACE) Open Top Chamber (OTC)
elevated CO2 projects in the DOE Program October
8-9, 2006
Richard Birdsey, USFS Reinhart Ceulemans,
Antwerp, Belgium James Ehleringer, Univ Utah,
Chair Jerry Melillo, Marine Biology Lab Josef
Nösberger, ETH, Switzerland Walter Oechel, San
Diego State Univ Susan Trumbore, UC Irvine
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What is an open top chamber (OTC) experiment?
smaller size altered microclimate requires
less CO2
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What is a free air CO2-enrichment experiment
(FACE)?
larger size realistic microclimate uses
much more CO2
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Rhinelander, deciduous forest
Duke, coniferous forest
Oak Ridge, deciduous forest
Nevada, desert shrub
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Where are the DOE-sponsored OTC experiments?
SI, salt marsh, MD
SI, scrub oak, FL
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There are additional FACE and OTC experiments
nationally that receive partial support from DOE,
but that were not part of this review.
DOE funds can be broadly divided into several
categories
Infrastructure support Carbon dioxide gas
Site management Research
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The distribution of FACE sites globally (gt 8 m
ring)
http//www.bnl.gov/face/Research_Sites.asp
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BERAC Subcommittee Review of DOE-Funded FACE and
Related Experiments

• Context for review
• DOE is funding trace gas enrichment experiments
  in two separate programs (Terrestrial Carbon
  Processes Program and Ecosystem Functioning and
  Response Program)
• Recent BERAC review of DOEs Terrestrial Carbon
  Processes Program did not review FACE experiments
  but raised questions about them How long should
  current sites/experiments remain operational?
  Where might new sites/experiments best be
  established?
• Recommended that
• 1) review be undertaken to assess existing
  scientific information and potential for new
  findings at each DOE FACE experiment
• 2) DOE periodically evaluate when a site has
  reached a point of diminishing scientific return
• Use review procedure to produce recommendations
  concerning which current DOE FACE
  sites/experiments should be either maintained or
  phased out, and where new ones should or might be
  established.

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BERAC Subcommittee Review of DOE-Funded FACE and
Related Experiments

• Specifics of Charge
• Focused review on the charges in the letter
• Review/assess information from existing DOE
  experiments (What has been learned?)
• Assess their potential to yield new findings, if
  continued
• Provide recommendations on whether existing
  experiments have reached or are reaching point of
  diminishing scientific return
• Provide recommendations on which experiments
  should be maintained or discontinued, and where
  new ones might be established to address
  programmatic goals requiring such experiments

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BERAC Subcommittee Review of DOE-Funded FACE and
Related Experiments

• Specifics of charge (cont.)
• Assess
• Escalating costs of FACE experiments and how such
  costs might be reduced
• Scientific need and technical feasibility of
  modifying FACE experimental approaches to
  consider other greenhouse gases or climatic
  influences on carbon cycle processes, and
  functioning and response of terrestrial
  ecosystems
• Alternative approaches for conducting FACE-type
  experiments that offer significant cost
  advantages

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• The review of FACE/OTC projects in DOE is based
  on
• presentations and documents from DOE managers
• responses from DOE managers on specific questions
  related to the charge of the subcommittee
• responses from project PIs on specific questions
  related to the charge of the subcommittee
  (transmitted via DOE managers)
• open scientific literature
• previous BERAC reports

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• The subcommittee consisted of
• individuals with expertise in
• carbon cycle science and policy
• physiology to ecosystems scales
• agriculture, forestry, and ecology
• temperate, tropical, and arid lands
• soil carbon
• global change
• experimental to modeling
• FACE experience (operating and decommissioning)

Richard Birdsey, USFS, PA Reinhart Ceulemans,
Antwerp James Ehleringer, Univ Utah, Chair Jerry
Melillo, Marine Biology Lab Josef Nösberger, ETH,
Zurich Walter Oechel, San Diego State Susan
Trumbore, UC Irvine
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• Findings
• The DOE has been the lead federal agency in
  ecosystem climate change experiments, pioneering
  the required technology necessary to predict how
  ecosystems will respond to future CO2
  environments. The continued DOE role as the
  leader in this area is absolutely critical if we
  are to develop the knowledge base and models of
  how ecosystems will respond to future
  environments and to the release of anthropogenic
  CO2.
• FACE studies have achieved the most realistic
  elevated CO2 (eCO2) environment for ecosystem
  studies of all experimental approaches to date.
• FACE-scale studies of ecosystem processes have
  been quite productive by any metric, and have
  produced fundamental new insights into carbon
  dynamics that were not predictable from pot- and
  greenhouse-scale studies.
• In many cases, generalities about processes
  relevant to the ecosystem scale have emerged,
  allowing for progress in the development of
  models to predict carbon dynamics at multiple
  scales. Applications of the models are important
  to forming climate policy at national and global
  scales.

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Examples from cross-site comparisons
Elevated CO2 did not have a detectable effect on
N mineralization, suggesting progressive N
limitation on ecosystems.
Net primary production enhanced across sites,
with the effect greatest in high-productivity
ecosystems
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• Findings (continued)
• Surprises from FACE studies have also emerged,
  such as the importance of belowground processes,
  their influence on the carbon cycle, and on
  turnover processes under elevated CO2.

Fine root turnover (3-9 yr) is far slower than
earlier predictions (1 yr), with clear
implications for carbon sequestration.
The stable isotope tracer associated with the
eCO2 is used to follow carbon.
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• Findings (continued)
• Another surprise is the interactive importance
  other factors, such as moisture, trace gases, and
  nutrients in moderating, enhancing, or
  diminishing the effects of eCO2 on enhancing
  carbon fixation.

Elevated O3 concentration (partly) counteracts
benefits of elevated CO2 concentration.
Standing biomass after 6 years ( differences
relative to ambient plots)
Community? Treatment ? CO2 O3 CO2 O3
Aspen stands 35 26 4 ( 4)
Aspen-birch stands 66 10 24 ( 28)
Aspen-maple stands 74 8 38 ( 33)
"CO2, ozone, and species" interactions were part
of the design of the Rhinelander FACE, whereas
other eCO2 experiments appear to have
incorporated additional factors subsequently.
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• Findings (continued)
• Another surprise is the interactive importance
  other factors, such as moisture, trace gases, and
  nutrients in moderating, enhancing, or
  diminishing the the effects of eCO2 on enhancing
  carbon fixation.

After 7 years of experimental treatment Soil T
reatment respiration Elevated CO2 26 Elevate
d O3 8 Elevated CO2 and O3 39
Soil respiration
"CO2, ozone, and species" interactions were part
of the design of the Rhinelander FACE, whereas
other eCO2 experiments appear to have
incorporated additional factors subsequently.
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• Findings (continued)
• Given the significance of microbial processes
  under elevated CO2, FACE studies would benefit
  from more significant interactions between DOE's
  Terrestrial Carbon Processes and Genomics GTL
  Programs.
• The current FACE design and plot sizes impose
  constraints on the experimental sampling of
  aboveground and belowground materials, leading to
  a useful life expectancy of only 10-12 years per
  experiment.
• Harvesting plans of an eCO2 project were not
  described nor explicitly defined in any of the
  provided documents for FACE or OTC projects.
• Harvesting of eCO2 sites is a critical and
  productive phase of an eCO2 experiment life
  cycle harvesting of the above- and below-ground
  components will yield some of the most useful
  samples for future research, analyses, and
  insights.
• Earlier recommendations from the last review
  regarding data sharing policies and data
  archiving protocols should be more fully
  implemented.

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(No Transcript)
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• Recommendations
• During FY07 enter into the harvesting phase of an
  eCO2 experiment life cycle for several current
  projects.
• For the remaining, existing eCO2 projects, enter
  into the harvesting phase by FY10 at the latest.
• Immediately plan and initiate a workshop(s) to
  plan the next generation eCO2 experiments,
  incorporating multiple interacting factors and
  potentially different eCO2 designs and/or
  technologies elaborated on later slide
• We recommend that no new eCO2 projects be
  initiated until after workshop decisions on the
  future design of eCO2 experiments to address
  multiple interacting factors. It is clear now
  that single factor approaches are limited.
• We recommend that funding for any new or renewal
  research proposals at FACE/OTC projects be
  considered in the context of the schedule for
  harvesting a site.
• As soon as harvesting is determined, we recommend
  workshops at FACE/OTC projects to plan for the
  harvesting phase of the project.
• We recommend that funding be provided after
  "turning off the eCO2" to allow publishing of
  original research, within-site syntheses, and
  cross-site syntheses.

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What are the factors contributing to a limited
lifetime for any eCO2 project?
original project objective(s) completed
technical constraints in continuing the
operations at a site (e.g. pipe height
limits, reduced-height buffer effects) site
trampling, oversampling of soil and vegetation
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A decision flowchart for guidance on when
existing FACE/OTC projects should enter the
harvesting phase of their life cycle
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A decision flowchart for guidance on when
existing FACE/OTC projects should enter the
harvesting phase of their life cycle
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Recommended guidance on when existing FACE/OTC
projects should enter the harvesting phase of
their life cycle
Site Harvesting year
Nevada, desert shrub FY 07
Maryland, salt marsh FY 07
Florida, oak scrub FY 07 or FY 10
Oak Ridge, deciduous forest no later than FY 10
Duke, coniferous forest no later than FY 10
Rehinelander, deciduous forest no later than FY 10
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• What is the potential to yield new insights if
  continued?
• The potential for multi-factorial eCO2 studies to
  yield new insights into the capacity of
  ecosystems to take up and sequester C is
  extremely high.
• Regarding the specific proposals under
  consideration, this is a decision for the DOE and
  its external review process and guided by the
  principles outlined here
• the subcommittee did not have access to
  individual proposals
• the subcommittee was not asked to review
  individual proposals
• the subcommittee was addressing programmatic
  issues and not specific proposals

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Elements in the harvesting of an eCO2 experiment

• As soon as the harvesting decision is determined,
  we recommend workshops at FACE/OTC projects to
  plan for the turning off the eCO2.
• Model simulations to identify data gaps, and
  short-term experiments should be components of
  the pre- and post-harvesting process.
• Short-term experiments should be identified that
  are to be conducted in the transition period
  associated with turning off the eCO2.
• The harvesting of aboveground and belowground
  materials for analyses should be planned, with a
  portion of the materials archived for future
  investigations by all interested investigators.
• A plan should be developed for the long-term
  archiving and public access to experimental
  treatment data, process data results, and other
  parameters measured and models produced in the
  experiment.
• Consideration should be given to setting aside of
  a portion of the experimental plot for future
  studies (whether supported by DOE or other
  funding sources).

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Planning now for future critically needed eCO2
experiments
multi-factorial
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• Elaboration of recommendation 3
• Convene a workshop(s) to plan for the next
  generation of eCO2 ecosystem experiments that
  will incorporate multiple-level CO2 treatments
  and multiple "drivers" (temperature, nutrients,
  moisture, and bio-complexity).
• Following the workshop(s), we recommend a pilot
  study(ies) of alternatives to the current FACE
  (ring) approach that would allow for
  consideration of

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Sufficiently detailed information was not
supplied by each of the PIs in order for the
subcommittee to determine the costs of the eCO2
experiments. Thus, the committee was not able to
respond to that point of the charge at this point
in time. However, from the information provided
it is clear that CO2 is an ever increasing
component of the budget.
For future eCO2 experiments We note that
significant budgetary savings could be achieved
simply through the sighting of new eCO2
experiments near CO2 production facilities,
thereby reducing or possibly eliminating
transportation costs and perhaps also assisting
that industry with its CO2-disposal needs.
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• Restatement of recommendations
• During FY07 enter into the harvesting phase of
  several eCO2 projects.
• For the remaining, existing eCO2 projects, enter
  into the harvesting phase by FY10 at the latest.
• Immediately plan and initiate a workshop(s) to
  plan the next generation eCO2 experiments.
• We recommend that no new eCO2 projects be
  initiated until after workshop decisions on the
  future design of eCO2 experiments to address
  multiple interacting factors.
• We recommend that funding for any new or renewal
  research proposals at FACE/OTC projects be
  considered in the context of the schedule for
  harvesting a site.
• As soon as harvesting is determined, we recommend
  workshops at FACE/OTC projects to plan for the
  harvesting phase of the project.
• We recommend that funding be provided after
  "turning off the eCO2" to allow publishing of
  original research, within-site syntheses, and
  cross-site syntheses.