1. Department of Environmental Sciences, Jiquan Chen & Johan F. Gottgens
Contribution of methane and lateral carbon fluxes in a temperate freshwater marsh
Housen Chu
Ph.D. candidate
Department of Environmental Sciences,
University of Toledo
Jiquan Chen & Johan F. Gottgens

2. Acknowledgements Post-doc/Graduate/Undergraduate
Mike Deal, Jianye Xu, Orrin Babcok, Cory Becher
Zutao Ouyang, Changliang Shao, Yahn-Jauh Su, Jing Xie, Jennifer Teeple
Logistic & infrastructure assistance
John Simpson, Walter Butch Berger
Faculty
Richard Becker, Ankur Desai, Ge Sun,
Timothy Fisher, James Martin-Hayden, Kevin P. Czajkowski,
Donald R Cahoon, Karen Roderick-Lingema, Thomas Bridgeman
Winous Point
Marsh Conservancy

3. Background Detroit Lake Erie Toledo Cleveland Offshore Nearshore
Marshland site, Winous Point (ML)
Detroit
Lake Erie
Marsh
Woodland
Cropland
Suburban
Nearshore
Offshore
Toledo
Cleveland
Satellite image of 2011 bloom (Credit: MERIS/NASA; processed by NOAA/NOS/NCCOS )

4. C Background Importance of inland water ecosystems
Neutral pipes ?? (Cole et al., 2007)
Sedimentation
CO2 evasion
Anaerobic condition
Methanogenesis – CH4 emission
25 × global warming potential than CO2 C
Land
Rivers, Lakes, Wetlands
Ocean
(Aufdenkampe et al. 2011)

5. C budget in a freshwater marsh ecosystem
Objectives
CO2
CH4
Dissolved Organic Carbon (DOC)
DOC
Particulate Organic Carbon (POC)
POC
Ecosystem Respiration
(ER)
Methane Emission
(FCH4)
Gross Ecosystem Production
(GEP)
C budget in a freshwater marsh ecosystem
Quantify the contribution of CH4 & lateral C fluxes
Examine their response to climate variability (extreme climate)

6. Winous Point North Marsh
Vegetation: open water/ emergent vegetation / woody plants
Hydrology: nearly hydrologically-isolated
129 ha, with ~900 ha agricultural watershed
Surface water level managed 0.1 ~ 0.7 m
The target marsh is winous point north marsh, which has been managed by the winous point marsh conservancy for 150 years.
Currently, this marsh consists of areas of emergent vegetation, open water and woody plant on the dikes.
The dominant plant species in the open water area are water lily, american lotus and pickerel weeds. The dominant emergent species is narrow-leaved cattail.
We choose this marsh as the research site because of its relatively isolated hydolody.

7. Research site – Winous Point North Marsh
Tower
Outflow
Inflow 3
Inflow 2
Inflow 1
Sandusky Bay
Hydrological C flux
(Every 2-3 weeks, Mar/ Nov/2013)
POC / DOC: Weight loss on ignition
Discharge: Water level + Portable velocity flow meter

8. Environmental factors & phenology
CO2 & CH4 eddy flux
(Mar/2011-Dec/2013)
Ultrasonic Anemometer CSAT3, Campbell
Open path CO2 / H2O Infrared Gas Analyzer LI-7500, LICOR
Open path CH4 Gas Analyzer LI-7700, LICOR
Met, soil & water
Net radiation, PAR
Wind speed, Friction velocity
Precipitation, Humidity
Air temp, Water temp, Soil temp
Soil water content, Ground water level
CDOM
Phenology
MODIS – NDVI, EVI

9. Preliminary Result Preliminary Result 2011: wet year
2012: dry/warm year
– the 1st wettest year over 118 yrs
– the 12nd hottest year (0.9°C higher)
– the 2nd hottest year (1.9°C higher)
– the 16th drier summer and fall

10. Phenology
155 days
162 days
Month

11. Atmospheric CO2 Exchange: GEP and ER
2012 – dry/warm year
Shift in growing season
7% increase in annual ER
5% decrease in annual GEP
Not statistically significant
Month

12. Atmospheric CH4 Exchange
2012 – dry/warm year
Quick rising in early spring
Significantly higher throughout the spring-early summer
Sensitive to short-period of hot events
Increase ~34% in 2012
Month

13. + : Flow in - : Flow out Hydrological DOC and POC Flux General Pattern
Peak inflow in spring
Short period / large flow of outflow – flush out
DOC ~ 10 × POC
Annual Inflow > outflow
2011 – wet year
Peak inflow in spring / fall
30-day outflow flush out ~45% of the imported DOC & POC
- : Flow out
2012 – dry/warm year
Earlier peak inflow in spring
Reverse flow in late summer-fall
Both inflow/outflow reduce ~80%

14. Annual C Budget 2011 – wet year 2012 – dry/warm year
Flux: g C m-2 yr-1
581.7 ±39.3
( 100% )
2012 – dry/warm year
±5.4
( -8% )
±71.3
( -101% ) 88
(14%)
- 40
(-7%)
Near C neutral: -5.8
±70.7
(-113%)
±7.2
( -11% ) 14
(3%)
- 9
(-2%)
Net C loss:
608.6 ±37.6 ( 100% )
1394
Carbon budget, normalized by GEP ….
1. Underestimated Inflow, Uncertainty needs quantified.
2. Sedimentation rate
12164
Sedimentation rate ~ 170 g C m-2 yr-1
, Pb210 dating (Gottgens & Liptak, 1998)
Pool: g C m-2
Flux: g C m-2 y-r1

15. Summary The Winous Point North Marsh isn’t a neutral pipe
Inflow C >? outflow C
ER & CH4 emission > GEP
High CH4 emissions in the marsh
~30% in terms of the gas C loss
Plant modulated gas flow (pressurized ventilation)
High inter-annual variation in CH4 & lateral C fluxes
Sensitive to inter-annual climate
Early warm-up didn’t enhance annual production