Controls%20on%20carbon%20and%20energy%20exchanges%20between%20a%20mangrove%20forest%20and%20the%20atmosphere

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Controls on carbon and energy exchanges between a
mangrove forest and the atmosphere
Contributors Jose D. Fuentes, Jordan G. Barr,
Jay C. Zieman University of Virginia Vic Engel
U.S. National Park Service Dan Childers, Florida
International University
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Ideas to discuss

• Characteristics of mangrove forests in the
  Florida coastal Everglades
• Challenges of establishing research platforms in
  coastal ecosystems, particularly in those regions
  impacted by tropical storms
• Sample results Exchanges of carbon and energy
• Benefits of long-term studies in coastal
  ecosystems

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Mangrove distribution in Florida Everglades
Figure developed by Mike Rugge, Florida
International University
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Dwarf mangroves in eastern Florida Everglades
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Tall mangroves in the western Florida Everglades
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Tower construction Elevated boardwalk
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Tower construction Anti-sinking design
4x4x12 feet long
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Tower construction Anti-sinking design
Planks
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Tower construction Anti-sinking design
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Tower construction Guy wire anchoring
12 Turnbuckle
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Tower construction solar panels and batteries
power instruments
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Tower construction Need Nixalite to protect
instruments from birds
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Tower construction Need to heavily protect
instruments from lightning
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Tower construction Data loggers and laptop
computers acquire data
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Research objectives

• Determine mangrove physiological attributes and
  incorporate these attributes and local climate
  forcings into a new biophysical model.

• Investigate the patterns of surface energy
  partitioning.

• Quantify seasonal amounts of and controls on
  ecosystem-level carbon dioxide assimilation rates.

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Leaf physiological responses to local climate
Red mangrove foliage
Model prediction
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Leaf physiological responses to local climate
Stomatal conductance regression (revised
algorithm)
Sample PAR response curve

• New stomatal conductance algorithm needed
• Quantum use efficiencies are large (0.4)

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Energy balance of a coastal ecosystem
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Surface energy partitioning
10 January 2004
High tide
Short-lived spike in LE as incoming tide wets the
surface
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Surface energy partitioning
During 07 March 2004, H LE under normal
neotropical flows
During 28 February 2004, H 2LE with passage of
a cold front.
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Surface energy partitioning
August 2005
During the summertime, there is a net export of
energy to the estuary due to tidal activity. On
average, the sum of sensible and laten heat
fluses amount to 70 percent of Rnet-Gsoil.
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Seasonal differences in C assimilation
Reduced nighttime respiration and maximum midday
photosynthesis
Greater nighttime respiration and midday
photosynthesis deactivation
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Influence of clouds on carbon uptake
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Seasonal carbon assimilation
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Seasonal carbon assimilation
For 2004 the mangrove forest assimilated 770 g m-2
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C assimilation compared to FluxNet sites
From Baldocchi et al. 2001
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New Science

• Mangrove physiological characteristics (Jmax,
  Vcmax, etc.) exhibit different patterns compared
  to terrestrial plants.
• Though inundated by tides twice daily, mangrove
  forests partition more available energy towards
  sensible than latent heating. This phenomenon is
  normally exhibited mostly in semi-arid
  environments.
• Everglades mangroves assimilated atmospheric
  carbon dioxide at the rates of 7-9 t C ha-1
  during 2004-2005 seasons.
• Carbon assimilation in mangrove ecosystems is
  largely controlled by temperature, with extreme
  events resulting in a lag of assimilation
  recovery.
• Diffuse PAR results in elevated light use
  efficiencies and increased resistance to
  photosynthesis saturation in mangrove canopies.
• Trends in carbon assimilation over the course of
  the year may also be controlled by variations in
  salinity.

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Benefits of long-term studies in coastal
ecosystems
Seasonal responses of ecosystem functioning, in
response to disturbances such as hurricanes, can
be investigated using tower-based observing
systems. Tower-based observing systems allow us
to investigate trace gas exchange processes
across a spectrum of temporal and space
scales. Continuous field observations permit us
to investigate the ecosystem response to on-going
climate change, sea level rise, and land
use. With continuous and long-term data sets, we
can test and validate mechanistic models. Such
models can be applied to test research hypotheses.
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Disturbances such as the one caused by hurricane
Wilma
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On 24 October 2005 hurricane Wilma passed over
tower site
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Hurricane Wilma destroyed nearly 30 percent of
trees
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Current and future studies in Florida Everglades
mangroves
Quantify the diurnal and seasonal response of the
mangrove forest to hurricane Wilma. Investigate
the carbon dioxide assimilation rates and other
eco-physiological characteristics of mangrove
foliage in response to ecosystem drivers such as
salinity levels, hydroperiod and
nutrients. Quantify the allocation of
mangrove-fixed carbon and translocation of
mangrove-derived organic material. Quantify the
lateral organic carbon exchange between the
mangrove wetland and the adjacent estuary in
response to tidal variations and seasonal
hydrology.
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Funding Sources

• The U.S. National Aeronautics and Space
  Administration
• The U.S. National Science Foundation (through the
  Florida Coastal Everglades Long-Term Ecological
  Research program)
• The U.S. National Park Service
• The Jones Everglades Research Fund
• The Barley Scholars Program