Elizabeth Ryder Elvira de Eyto Mary Dillane Russell Poole Suzanne Linnane and Eleanor Jennings 2 nd of March 2012 Annual Meeting of Freshwater Biologists Trinity College Dublin ID: 269925
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Slide1
Impact of climate on export of DOC from a peatland catchment.
Elizabeth Ryder, Elvira de Eyto, Mary Dillane, Russell Poole, Suzanne Linnane and Eleanor Jennings. 2nd of March 2012Annual Meeting of Freshwater BiologistsTrinity College Dublin. Slide2
Introduction
Sources of carbonSite DescriptionDrivers of carbonExamples. Slide3
Sources of carbon
Two main sources of carbon, specifically dissolved organic carbon (DOC) in aquatic ecosystemsTerrestrial (Allochthonous carbon)Primary production (Autochthonous carbon).Slide4
Sources of carbon
Organic carbon content (%) in topsoils (0–30cm) in Europe. Peatlands are those with organic content of greater than 25% (Montanarella et al. (2006).
Worldwide peatlands cover 500 million hectare of land.Most extensive in Europe and North America
.
Peatlands or bogs are one of the largest stores of carbon in the world. Slide5
Glenamong sub-catchment
GG Rain Gauge GG Rain Gauge
GG Rain Gauge
GG Rain Gauge
GG Rain Gauge
ARMS
(Temperature, Conductivity, pH, DO, CDOM fluorometer, nephelometer) and water level recorder
Catchment Area 1821 ha.
Forested area 408 ha = 22%
Annual rainfall = 2000mmSlide6
CDOM fluorometer
: Chromophoric Dissolved Organic Matter is the light absorbing component of dissolved organic matter. After initial corrections and calibrationsCDOM fluorescence (mV) temperature corrected.CDOM fluorescence (mV) was converted into QSUCDOM fluorescence can be used as a proxy for dissolved organic carbon (DOC). Water Colour is also a proxy for
DOC.Slide7
Mean daily DOC export from the GG catchment
Annual DOC export 9.87
tC km2Slide8
DOC Drivers
TemperatureSoil moisture (Impact on decomposition processes)Precipitation (variation in timing and intensity)Glenamong DOC export 2010-2011Slide9
Temperature
Soil organic matter decomposition in response to temperatureTemperature effect on decomposition rates vary due to different soil moisture content leading to differences in aerobic and anaerobic decompositionSlide10
Temperature
How will global warming affect these carbon pools?Air temperature trends globally, in Ireland and in Burrishoole Fealy et al. RESCALE project final report 2010
Mean annual air temperature in
Burrishoole
increased significantly by 1.48
o
CSlide11
Soil Moisture
Production of DOC have been shown to be correlated with low soil moisture over time.Decomposition rates of peatlands are very sensitive to changes in soil moisture, particularly in soils that are generally water logged.Decrease in water table, allowing oxygen into anoxic layers and lead to increase in aerobic decomposition of peatSlide12
PrecipitationSlide13
Low soil moisture + high precipitationSlide14
Drought/Precipitation eventSlide15
Drought/Precipitation eventSlide16
After the autumn DOC flux,
DOC concentrations remain comparatively low irrelevant to storm eventsPrecipitationSlide17
Seasonality of DOC
export may result in an over estimation of DOC fluxes during winter/spring load estimates.Slide18
Glenamong
Janurary 2010
Glenamong
September
2010
Glenamong June 2010
Glenamong August
2010
Emission-Excitation Matrix Scans (
EEM’s
) for Glenamong
River.
The EEM scan enables a detailed characterisation of the organic matter and can discriminate between humic and fulvic-like acid.
CDOM Fluorometers, under estimate the carbon exported from the catchment.
Full excitation emission plots
Black square = where field
instrument
measures
370 – 440nm