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Gerard Kiely - One of the best experts on this subject based on the ideXlab platform.
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Meteorological and functional response partitioning to explain interannual variability of CO2 exchange at an Irish Atlantic Blanket Bog
Agricultural and Forest Meteorology, 2014Co-Authors: Philip Mcveigh, Matteo Sottocornola, Nelius Foley, Paul Leahy, Gerard KielyAbstract:This study aims to develop models to describe CO2 fluxes in terms of environmental and meteorological variables and their variation over an Atlantic Blanket Bog in Glencar, southwest Ireland. Ten full years (September 2002–August 2012) of data were included in the assessment of CO2 flux and micro-meteorological data. Models were based on non-gapfilled growing season data, using complete calendar years for annual models, and the entire time-series for weekly models, whilst taking interaction between variables into account for increased model accuracy. This was to determine which environmental variables were most influential in directly controlling CO2 exchange on a long- and short-term basis. A homogeneity of slopes (HOS) model was used to determine if there was any ecosystem response to indirect effects (functional response) of environmental or meteorological interannual variation. This model uses multiple regression analysis to determine if the ecosystem response can be better predicted as a linear function of the variables using a single slope model for all years, or a separate slopes model for each year. The separate slopes model gave a different (and improved) outcome for both daytime and night-time CO2 fluxes, and so functional responses were deemed to have occurred. The contribution to variation of day and night-time net ecosystem exchange (NEEday and NEEnight respectively) was then separated into four components: indirect functional responses, direct interannual meteorological variability, direct week to week meteorological variability, and random error, which identified 13.8%, 36.6%, 28.2% and 21.4% respectively of the variation in NEEday, as well as 23.4%, 24.4%, 22.2% and 30% respectively of the variation in NEEnight. Water table level (WTL) had the greatest influence upon functional variation of NEE at the Glencar Blanket peatland, and comparisons of modelled NEEday with leaf area index (LAI) measurements verified the estimate of functional contribution using the separate slopes model. The significance of interannual variation (IAV) and functional responses on NEE at Glencar suggests that it is a resilient ecosystem which might be able to adapt to environmental or climatic changes, although given current climate change predictions, it is likely to have a reduced carbon dioxide sink status in the future.
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How strong is the current carbon sequestration of an Atlantic Blanket Bog
Global Change Biology, 2010Co-Authors: Ann-kristin Koehler, Matteo Sottocornola, Gerard KielyAbstract:Although northern peatlands cover only 3% of the land surface, their thick peat deposits contain an estimated one-third of the world's soil organic carbon (SOC). Under a changing climate the potential of peatlands to continue sequestering carbon is unknown. This paper presents an analysis of 6 years of total carbon balance of an almost intact Atlantic Blanket Bog in Glencar, County Kerry, Ireland. The three components of the measured carbon balance were: the land-atmosphere fluxes of carbon dioxide (CO 2 ) and methane (CH 4 ) and the flux of dissolved organic carbon (DOC) exported in a stream draining the peatland. The 6 years C balance was computed from 6 years (2003-2008) of measurements of meteorological and eddy-covariance CO 2 fluxes, periodic chamber measurements of CH 4 fluxes over 3.5 years, and 2 years of continuous DOC flux measurements. Over the 6 years, the mean annual carbon was —29.7 ± 30.6 (± 1 SD) g C m -2 yr -1 with its components as follows: carbon in CO 2 was a sink of - 47.8 ± 30.0 g C m -2 yr -1 ; carbon in CH 4 was a source of 4.1 ± 0.5 g C m -2 yr -1 and the carbon exported as stream DOC was a source of 14.0 ± 1.6 g C m -2 yr -1 . For 2 out of the 6 years, the site was a source of carbon with the sum of CH 4 and DOC flux exceeding the carbon sequestered as CO 2 . The average C balance for the 6 years corresponds to an average annual growth rate of the peatland surface of 1.3 mm yr -1 .
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Energy fluxes and evaporation mechanisms in an Atlantic Blanket Bog in southwestern Ireland
Water Resources Research, 2010Co-Authors: Matteo Sottocornola, Gerard KielyAbstract:[1] Water and energy fluxes control the development of northern peatlands and influence their carbon budget. Blanket Bogs are peatlands that occur in temperate maritime regions where precipitation is much greater than evapotranspiration (ET). In this paper, five years (October 2002–September 2007) of ET and energy fluxes derived from eddy-covariance measurements were analyzed in the context of the predicted climate change for Ireland. Monthly ET at the Glencar Atlantic Blanket Bog varied little, ranging between a minimum of 12 mm month−1 and a maximum of 56 mm month−1 over the five years, resulting in an annual ET average of 394 mm, with typical highest daily values of 2.5–3.0 mm. Compared to other peatland types, Glencar had lower summer ET and a lower ET/potential ET ratio, despite having higher precipitation and water table. The ET was limited not only by the low vapor pressure deficit and cool summer temperatures but also by the low cover of vascular plants and mosses (essential for transpiration). The energy budget was similar to other peatland types in terms of net radiation and sensible heat fluxes, but had lower latent and higher ground heat fluxes. A comparison among the five years suggests that the predicted climate change (greater winter precipitation, lower summer precipitation, and higher all year round temperatures) will probably increase winter ET, while the summer energy flux patterns will not be profoundly affected. However, if the frequency of summer rain events should diminish, the moss component of these ecosystems may become water stressed, ultimately leading to lower evapotranspiration.
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Hydro-meteorological controls on the CO2 exchange variation in an Irish Blanket Bog
Agricultural and Forest Meteorology, 2010Co-Authors: Matteo Sottocornola, Gerard KielyAbstract:Abstract Northern peatlands contain an estimated 1/3 of the world's soil carbon pool. This large carbon pool is of concern due to its uncertain future in a changing climate. Blanket Bogs are peatlands that occur in temperate maritime regions where precipitation is much greater than evapotranspiration. We describe five years (1 October 2002 to 30 September 2007) of eddy-covariance (EC) carbon dioxide (CO 2 ) flux measurements in an Atlantic Blanket Bog in Ireland. The measured net ecosystem CO 2 exchange (NEE) was partitioned into its components of ecosystem respiration (ER) and gross ecosystem production (GEP). The inter-annual variation of the CO 2 fluxes was investigated using correlation coefficient analyses with measured hydro-meteorological parameters. The annual NEE was negative for all five years (thus the peatland was a sink of CO 2 ), ranging between −16.5 ± 5.1 and −96.5 ± 23.2 g C-CO 2 m −2 (average of −54.9 ± 15.6 g C-CO 2 m −2 ). During the study period, NEE was negative for the same five months in each year (May–September). NEE showed the highest CO 2 uptake (due to the highest GEP) in the summer with intermediate rather than extreme meteorological conditions, thus with low vapour pressure deficit, intermediate soil water content, air temperature and light radiation, which might be partly explained by the role of the bryophyte community. Under climate change predictions of higher temperature, the inter-annual variation analysis suggests that ER might increase in winter. Furthermore, the predicted lower precipitation and higher temperature in the summer are expected to lead to lower GEP. The resulting increase in NEE (thus lower CO 2 uptake) will be partly compensated by a higher GEP in warmer winters and in dryer autumns. Moreover, the CO 2 uptake will benefit by a longer growing season, while wetter conditions will likely lower the ecosystem respiration in the spring. The length of the growing season was found to be driven by warmer winter and September soil temperatures.
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seasonal variation of doc concentration and annual loss of doc from an atlantic Blanket Bog in south western ireland
Biogeochemistry, 2009Co-Authors: Ann-kristin Koehler, Gerard Kiely, Kilian Murphy, Matteo SottocornolaAbstract:This paper represents the first continuous dissolved organic carbon (DOC) record, measured in a stream draining an Atlantic Blanket Bog in South West Ireland for the calendar year 2007. At 30-min intervals, the DOC concentration was automatically measured using an in-stream spectroanalyser whose variation compared well with laboratory analysed samples taken by a 24-bottle auto-sampler. The concentration of DOC ranged from 2.7 to 11.5 mg L−1 with higher values during the summer and lower values during the winter. A simple linear regression model of DOC concentration versus air temperature of the previous day was found, suggesting that temperature more than discharge was controlling the DOC concentration in the stream. The change in DOC concentration with storm events showed two patterns: (1) in the colder period: the DOC concentration seemed to be independent of changes in stream flow; (2) in the warmer period: the DOC concentration was found to rise with increases in stream flow on some occasions and to decrease with increasing stream flow on other occasions. The annual export of DOC for 2007 was 14.1 (±1.5) g C m−2. This value was calculated using stream discharge data that were determined by continuously recorded measurements of stream height. The flux of DOC calculated with the 30-min sampling was compared with that calculated based on lower sampling frequencies. We found that sampling frequency of weekly or monthly were adequate to calculate the annual flux of DOC in our study site in 2007.
Eeva-stiina Tuittila - One of the best experts on this subject based on the ideXlab platform.
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Vegetation and environmental variation in an Atlantic Blanket Bog in South-western Ireland
Plant Ecology, 2008Co-Authors: Matteo Sottocornola, Kenneth A Byrne, Anna M. Laine, Gerard Kiely, Eeva-stiina TuittilaAbstract:A vegetation survey was carried out in a relatively intact Atlantic Blanket Bog in Southwest Ireland to study the vegetation patterns in relation to environmental variation, and to quantify the effect of artificial and natural borders on compositional variation. The data were analysed using canonical correspondence analysis. In terms of both vegetation and water chemistry, the study site can be categorized as typical of Atlantic Blanket Bogs in the maritime regions of North-western Europe. The distribution of plant species was explained mainly by depth of the water table. The distribution of bryophytes was secondarily explained by the pH of the Bog water, while the distribution of vascular plants was secondarily explained by concentrations of ammonia. The vegetation distribution exhibited little variation between the central sector of the peatland and its disturbed edges (hill-grazing and restoration areas), but a substantial variation was observed between the area along a natural edge (stream) and the areas close to the other peatland borders or centre. Similarly, the internal variation within each sector (centre, hill-grazing edge and restoration area edge) was small, but substantial vegetation variation was observed within the area located along the stream. The area along the stream was associated with relatively deep water table, shallow peat depth, high water colour, pH and NH4+ concentrations, and low Cl− concentrations in the Bog water. Our results suggest the existence of strong centre-natural margin gradients, as in raised Bogs, and indicate that human or animal disturbance do not give rise to the marked transition zones that often characterize natural margins of mire systems. This indicates that even small areas and remnants of Atlantic Blanket Bogs are worthy of conservation and that their conservation value would benefit from the inclusion of sectors close to the natural peatland borders, which would increase the plant biodiversity of the conserved area.
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Patterns in Vegetation and CO_2 Dynamics along a Water Level Gradient in a Lowland Blanket Bog
Ecosystems, 2007Co-Authors: Anna Laine, Kenneth A Byrne, Gerard Kiely, Eeva-stiina TuittilaAbstract:The surface of Bogs is commonly patterned and composed of different vegetation communities, defined by water level. Carbon dioxide (CO_2) dynamics vary spatially between the vegetation communities. An understanding of the controls on the spatial variation of CO_2 dynamics is required to assess the role of Bogs in the global carbon cycle. The water level gradient in a Blanket Bog was described and the CO_2 exchange along the gradient investigated using chamber based measurements in combination with regression modelling. The aim was to investigate the controls on gross photosynthesis (P_G), ecosystem respiration (R_E) and net ecosystem CO_2 exchange (NEE) as well as the spatial and temporal variation in these fluxes. Vegetation structure was strongly controlled by water level. The species with distinctive water level optima were separated into the opposite ends of the gradient in canonical correspondence analysis. The number of species and leaf area were highest in the intermediate water level range and these communities had the highest P_G. Photosynthesis was highest when the water level was 11 cm below the surface. Ecosystem respiration, which includes decomposition, was less dependent on vegetation structure and followed the water level gradient more directly. The annual NEE varied from −115 to 768 g CO_2 m^−2, being lowest in wet and highest in dry vegetation communities. The temporal variation was most pronounced in P_G, which decreased substantially during winter, when photosynthetic photon flux density and leaf area were lowest. Ecosystem respiration, which is dependent on temperature, was less variable and wintertime R_E fluxes constituted approximately 24% of the annual flux.
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Patterns in Vegetation and CO2 Dynamics along a Water Level Gradient in a Lowland Blanket Bog
Ecosystems, 2007Co-Authors: Anna M. Laine, Kenneth A Byrne, Gerard Kiely, Eeva-stiina TuittilaAbstract:The surface of Bogs is commonly patterned and composed of different vegetation communities, defined by water level. Carbon dioxide (CO2) dynamics vary spatially between the vegetation communities. An understanding of the controls on the spatial variation of CO2 dynamics is required to assess the role of Bogs in the global carbon cycle. The water level gradient in a Blanket Bog was described and the CO2 exchange along the gradient investigated using chamber based measurements in combination with regression modelling. The aim was to investigate the controls on gross photosynthesis (PG), ecosystem respiration (RE) and net ecosystem CO2 exchange (NEE) as well as the spatial and temporal variation in these fluxes. Vegetation structure was strongly controlled by water level. The species with distinctive water level optima were separated into the opposite ends of the gradient in canonical correspondence analysis. The number of species and leaf area were highest in the intermediate water level range and these communities had the highest PG. Photosynthesis was highest when the water level was 11 cm below the surface. Ecosystem respiration, which includes decomposition, was less dependent on vegetation structure and followed the water level gradient more directly. The annual NEE varied from −115 to 768 g CO2 m−2, being lowest in wet and highest in dry vegetation communities. The temporal variation was most pronounced in PG, which decreased substantially during winter, when photosynthetic photon flux density and leaf area were lowest. Ecosystem respiration, which is dependent on temperature, was less variable and wintertime RE fluxes constituted approximately 24% of the annual flux.
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Estimating net ecosystem exchange in a patterned ecosystem : Example from Blanket Bog
Agricultural and Forest Meteorology, 2006Co-Authors: Anna M. Laine, Kenneth A Byrne, Matteo Sottocornola, Gerard Kiely, David Wilson, Eeva-stiina TuittilaAbstract:Abstract Net ecosystem exchange (NEE) was measured in a patterned peatland with eddy covariance (EC) and chamber methods during a 12-month period. The peatland surface was composed of microforms characterized by a difference in water level and vegetation composition. The distribution of microforms varied spatially within the peatland. To achieve correspondent half-hourly EC and chamber NEE estimates, we modelled microform level chamber fluxes, estimated them at each instance of weather recordings and integrated them over the year. We then scaled the fluxes up to the EC footprint. On a half-hourly time scale the correlation coefficient ( R ) of the NEE between the methods was 0.80 and the slope of regression 0.91. Measurements made in summer and during daylight were more highly correlated than measurements made in winter and during darkness. When integrated on a monthly time scale the methods agreed better, with R of 0.98 and slope of regression 1.00. The annual NEE for the EC and chamber methods were 206 and 242 g(CO 2 ) m −2 , respectively. The study confirmed that the surface pattern of the EC footprint in the Blanket Bog was sufficiently homogeneous, that the changing wind direction did not influence the half-hourly NEE. However, the chamber estimates found that the annual NEE of the driest area within the footprint was 130% larger than that in the wettest area, indicating that large spatial variation can be found in NEE.
Lorraine Wilson - One of the best experts on this subject based on the ideXlab platform.
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Ditch blocking, water chemistry and organic carbon flux: Evidence that Blanket Bog restoration reduces erosion and fluvial carbon loss
The Science of the total environment, 2011Co-Authors: Lorraine Wilson, Jared Wilson, Ian Johnstone, Joseph Holden, Alona Armstrong, Michael MorrisAbstract:The potential for restoration of peatlands to deliver benefits beyond habitat restoration is poorly understood. There may be impacts on discharge water quality, peat erosion, flow rates and flood risk, and nutrient fluxes. This study aimed to assess the impact of drain blocking, as a form of peatland restoration, on an upland Blanket Bog, by measuring water chemistry and colour, and loss of both dissolved (DOC) and particulate organic carbon (POC). The restoration work was designed to permit the collection of a robust experimental dataset over a landscape scale, with data covering up to 3 years pre-restoration and up to 3 years post-restoration. An information theoretic approach to data analyses provided evidence of a recovery of water chemistry towards more 'natural' conditions, and showed strong declines in the production of water colour. Drain blocking led to increases in the E4:E6 ratio, and declines in specific absorbance, suggesting that DOC released from blocked drains consisted of lighter, less humic and less decomposed carbon. Whilst concentrations of DOC showed slight increases in drains and streams after blocking, instantaneous yields of both DOC and POC declined markedly in streams over the first year post-restoration. Attempts were made to estimate total annual fluvial organic carbon fluxes for the study site, and although errors around these estimates remain considerable, there is strong evidence of a large reduction in aquatic organic carbon flux from the peatland following drain-blocking. Potential mechanisms for the observed changes in water chemistry and organic carbon release are discussed, and we highlight the need for more detailed information, from more sites, to better understand the full impacts of peatland restoration on carbon storage and release.
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The effect of Blanket Bog drainage on habitat condition and on sheep grazing, evidence from a Welsh upland Bog
Biological Conservation, 2011Co-Authors: Lorraine Wilson, Jared Wilson, Ian JohnstoneAbstract:There has been increasing interest in potential benefits to be gained by restoring damaged peatlands, with the majority of funding currently being driven by the recovery of protected habitats. However, few data are available linking vegetation community declines with peatland drainage, and so the potential for recovery remains difficult to predict. Surprisingly, there is a similar paucity of research demonstrating the extent of drainage impacts on grazing conditions for livestock, despite this being a priority amongst land managers. We attempt to address these two knowledge gaps, first by investigating whether ditches in Blanket Bog habitat have improved or increased grazing for sheep, and second by assessing the impact of ditches on the condition of vegetation communities. At an extensively drained upland Blanket Bog in Wales, currently undergoing ditch blocking restoration, we collected vegetation and sheep occurrence data across five catchments and over 2 years. We present evidence that drained areas had remained relatively wet and were less preferred by sheep. Furthermore, our results show that while sheep preferred graminoid-rich areas, drainage did not increase the abundance of this species group. Drainage at the site has, however, resulted in some degradation in Blanket Bog vegetation adjacent to ditches; although at the landscape scale, historic high grazing levels appear to explain much of the current poor ecological condition of the site. We conclude that drain-blocking restoration should not reduce sheep grazing conditions beyond their current relatively poor state, and thus in this respect may not represent a threat to hill farming productivity.
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Recovery of water tables in Welsh Blanket Bog after drain blocking: Discharge rates, time scales and the influence of local conditions
Journal of Hydrology, 2010Co-Authors: Lorraine Wilson, Jared Wilson, Ian Johnstone, Joseph Holden, Alona Armstrong, Michael MorrisAbstract:Peatland practitioners and scientists have increasingly recognised the damage resulting from various management methods, and the need to restore peatlands to achieve several potential benefits. Many of the hoped-for benefits of peatland restoration, such as Carbon storage, biodiversity conservation and water quality improvements, are thought to depend on a reinstatement of high water tables that had been reduced by drainage. Despite the current emphasis on restoring drained peatlands, many of the predicted responses to restoration are still not adequately proven and the mechanisms behind them still uncertain. This study reports on water table and discharge responses to drain blocking restoration of a degraded Welsh upland Blanket Bog. Restoration work and monitoring were designed to permit a novel catchment scale control-intervention experimental design. An information theoretic approach to examining the data provided evidence of increases in water retention and water tables within the Bog after restoration. But the study also demonstrated the importance of small and large scale topography in determining the degree of these responses. The increases in water storage after restoration produced lower discharge rates observable at the level of both drains and hill streams; as well as greater water table stability, reduction in peak flows and increases in water residency after rainfall. Crucially, this study showed strong catchment scale differences in response, and a very gradual recovery of water tables, both of which highlight the need for more studies to be carried out at the landscape scale and over longer time periods.
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Recovery of water tables in Welsh Blanket Bog after drain blocking: Discharge rates, time scales and the influence of local conditions
Journal of Hydrology, 2010Co-Authors: Lorraine Wilson, Jared Wilson, Ian Johnstone, Joseph Holden, Alona Armstrong, Michael MorrisAbstract:Peatland practitioners and scientists have increasingly recognised the damage resulting from various management methods, and the need to restore peatlands to achieve several potential benefits. Many of the hoped-for benefits of peatland restoration, such as Carbon storage, biodiversity conservation and water quality improvements, are thought to depend on a reinstatement of high water tables that had been reduced by drainage. Despite the current emphasis on restoring drained peatlands, many of the predicted responses to restoration are still not adequately proven and the mechanisms behind them still uncertain. This study reports on water table and discharge responses to drain blocking restoration of a degraded Welsh upland Blanket Bog. Restoration work and monitoring were designed to permit a novel catchment scale control-intervention experimental design. An information theoretic approach to examining the data provided evidence of increases in water retention and water tables within the Bog after restoration. But the study also demonstrated the importance of small and large scale topography in determining the degree of these responses. The increases in water storage after restoration produced lower discharge rates observable at the level of both drains and hill streams; as well as greater water table stability, reduction in peak flows and increases in water residency after rainfall. Crucially, this study showed strong catchment scale differences in response, and a very gradual recovery of water tables, both of which highlight the need for more studies to be carried out at the landscape scale and over longer time periods. (c) 2010 Elsevier B.V. All rights reserved
Matteo Sottocornola - One of the best experts on this subject based on the ideXlab platform.
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Low impact of dry conditions on the CO2 exchange of a Northern-Norwegian Blanket Bog
Environmental Research Letters, 2015Co-Authors: Magnus Lund, Matteo Sottocornola, Jarle W. Bjerke, Bert G. Drake, Ola Engelsen, Georg Hansen, Frans-jan W. Parmentier, Thomas L. Powell, Hanna Silvennoinen, Hans TømmervikAbstract:Northern peatlands hold large amounts of organic carbon (C) in their soils and are as such important in a climate change context. Blanket Bogs, i.e. nutrient-poor peatlands restricted to maritime climates, may be extra vulnerable to global warming since they require a positive water balance to sustain their moss dominated vegetation and C sink functioning. This study presents a 4.5 year record of land-atmosphere carbon dioxide (CO2) exchange from the Andoya Blanket Bog in northern Norway. Compared with other peatlands, the Andoya peatland exhibited low flux rates, related to the low productivity of the dominating moss and lichen communities and the maritime settings that attenuated seasonal temperature variations. It was observed that under periods of high vapour pressure deficit, net ecosystem exchange was reduced, which was mainly caused by a decrease in gross primary production. However, no persistent effects of dry conditions on the CO2 exchange dynamics were observed, indicating that under present conditions and within the range of observed meteorological conditions the Andoya Blanket Bog retained its C uptake function. Continued monitoring of these ecosystem types is essential in order to detect possible effects of a changing climate. (Less)
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Meteorological and functional response partitioning to explain interannual variability of CO2 exchange at an Irish Atlantic Blanket Bog
Agricultural and Forest Meteorology, 2014Co-Authors: Philip Mcveigh, Matteo Sottocornola, Nelius Foley, Paul Leahy, Gerard KielyAbstract:This study aims to develop models to describe CO2 fluxes in terms of environmental and meteorological variables and their variation over an Atlantic Blanket Bog in Glencar, southwest Ireland. Ten full years (September 2002–August 2012) of data were included in the assessment of CO2 flux and micro-meteorological data. Models were based on non-gapfilled growing season data, using complete calendar years for annual models, and the entire time-series for weekly models, whilst taking interaction between variables into account for increased model accuracy. This was to determine which environmental variables were most influential in directly controlling CO2 exchange on a long- and short-term basis. A homogeneity of slopes (HOS) model was used to determine if there was any ecosystem response to indirect effects (functional response) of environmental or meteorological interannual variation. This model uses multiple regression analysis to determine if the ecosystem response can be better predicted as a linear function of the variables using a single slope model for all years, or a separate slopes model for each year. The separate slopes model gave a different (and improved) outcome for both daytime and night-time CO2 fluxes, and so functional responses were deemed to have occurred. The contribution to variation of day and night-time net ecosystem exchange (NEEday and NEEnight respectively) was then separated into four components: indirect functional responses, direct interannual meteorological variability, direct week to week meteorological variability, and random error, which identified 13.8%, 36.6%, 28.2% and 21.4% respectively of the variation in NEEday, as well as 23.4%, 24.4%, 22.2% and 30% respectively of the variation in NEEnight. Water table level (WTL) had the greatest influence upon functional variation of NEE at the Glencar Blanket peatland, and comparisons of modelled NEEday with leaf area index (LAI) measurements verified the estimate of functional contribution using the separate slopes model. The significance of interannual variation (IAV) and functional responses on NEE at Glencar suggests that it is a resilient ecosystem which might be able to adapt to environmental or climatic changes, although given current climate change predictions, it is likely to have a reduced carbon dioxide sink status in the future.
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How strong is the current carbon sequestration of an Atlantic Blanket Bog
Global Change Biology, 2010Co-Authors: Ann-kristin Koehler, Matteo Sottocornola, Gerard KielyAbstract:Although northern peatlands cover only 3% of the land surface, their thick peat deposits contain an estimated one-third of the world's soil organic carbon (SOC). Under a changing climate the potential of peatlands to continue sequestering carbon is unknown. This paper presents an analysis of 6 years of total carbon balance of an almost intact Atlantic Blanket Bog in Glencar, County Kerry, Ireland. The three components of the measured carbon balance were: the land-atmosphere fluxes of carbon dioxide (CO 2 ) and methane (CH 4 ) and the flux of dissolved organic carbon (DOC) exported in a stream draining the peatland. The 6 years C balance was computed from 6 years (2003-2008) of measurements of meteorological and eddy-covariance CO 2 fluxes, periodic chamber measurements of CH 4 fluxes over 3.5 years, and 2 years of continuous DOC flux measurements. Over the 6 years, the mean annual carbon was —29.7 ± 30.6 (± 1 SD) g C m -2 yr -1 with its components as follows: carbon in CO 2 was a sink of - 47.8 ± 30.0 g C m -2 yr -1 ; carbon in CH 4 was a source of 4.1 ± 0.5 g C m -2 yr -1 and the carbon exported as stream DOC was a source of 14.0 ± 1.6 g C m -2 yr -1 . For 2 out of the 6 years, the site was a source of carbon with the sum of CH 4 and DOC flux exceeding the carbon sequestered as CO 2 . The average C balance for the 6 years corresponds to an average annual growth rate of the peatland surface of 1.3 mm yr -1 .
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Energy fluxes and evaporation mechanisms in an Atlantic Blanket Bog in southwestern Ireland
Water Resources Research, 2010Co-Authors: Matteo Sottocornola, Gerard KielyAbstract:[1] Water and energy fluxes control the development of northern peatlands and influence their carbon budget. Blanket Bogs are peatlands that occur in temperate maritime regions where precipitation is much greater than evapotranspiration (ET). In this paper, five years (October 2002–September 2007) of ET and energy fluxes derived from eddy-covariance measurements were analyzed in the context of the predicted climate change for Ireland. Monthly ET at the Glencar Atlantic Blanket Bog varied little, ranging between a minimum of 12 mm month−1 and a maximum of 56 mm month−1 over the five years, resulting in an annual ET average of 394 mm, with typical highest daily values of 2.5–3.0 mm. Compared to other peatland types, Glencar had lower summer ET and a lower ET/potential ET ratio, despite having higher precipitation and water table. The ET was limited not only by the low vapor pressure deficit and cool summer temperatures but also by the low cover of vascular plants and mosses (essential for transpiration). The energy budget was similar to other peatland types in terms of net radiation and sensible heat fluxes, but had lower latent and higher ground heat fluxes. A comparison among the five years suggests that the predicted climate change (greater winter precipitation, lower summer precipitation, and higher all year round temperatures) will probably increase winter ET, while the summer energy flux patterns will not be profoundly affected. However, if the frequency of summer rain events should diminish, the moss component of these ecosystems may become water stressed, ultimately leading to lower evapotranspiration.
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Hydro-meteorological controls on the CO2 exchange variation in an Irish Blanket Bog
Agricultural and Forest Meteorology, 2010Co-Authors: Matteo Sottocornola, Gerard KielyAbstract:Abstract Northern peatlands contain an estimated 1/3 of the world's soil carbon pool. This large carbon pool is of concern due to its uncertain future in a changing climate. Blanket Bogs are peatlands that occur in temperate maritime regions where precipitation is much greater than evapotranspiration. We describe five years (1 October 2002 to 30 September 2007) of eddy-covariance (EC) carbon dioxide (CO 2 ) flux measurements in an Atlantic Blanket Bog in Ireland. The measured net ecosystem CO 2 exchange (NEE) was partitioned into its components of ecosystem respiration (ER) and gross ecosystem production (GEP). The inter-annual variation of the CO 2 fluxes was investigated using correlation coefficient analyses with measured hydro-meteorological parameters. The annual NEE was negative for all five years (thus the peatland was a sink of CO 2 ), ranging between −16.5 ± 5.1 and −96.5 ± 23.2 g C-CO 2 m −2 (average of −54.9 ± 15.6 g C-CO 2 m −2 ). During the study period, NEE was negative for the same five months in each year (May–September). NEE showed the highest CO 2 uptake (due to the highest GEP) in the summer with intermediate rather than extreme meteorological conditions, thus with low vapour pressure deficit, intermediate soil water content, air temperature and light radiation, which might be partly explained by the role of the bryophyte community. Under climate change predictions of higher temperature, the inter-annual variation analysis suggests that ER might increase in winter. Furthermore, the predicted lower precipitation and higher temperature in the summer are expected to lead to lower GEP. The resulting increase in NEE (thus lower CO 2 uptake) will be partly compensated by a higher GEP in warmer winters and in dryer autumns. Moreover, the CO 2 uptake will benefit by a longer growing season, while wetter conditions will likely lower the ecosystem respiration in the spring. The length of the growing season was found to be driven by warmer winter and September soil temperatures.
Michael Morris - One of the best experts on this subject based on the ideXlab platform.
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Ditch blocking, water chemistry and organic carbon flux: Evidence that Blanket Bog restoration reduces erosion and fluvial carbon loss
The Science of the total environment, 2011Co-Authors: Lorraine Wilson, Jared Wilson, Ian Johnstone, Joseph Holden, Alona Armstrong, Michael MorrisAbstract:The potential for restoration of peatlands to deliver benefits beyond habitat restoration is poorly understood. There may be impacts on discharge water quality, peat erosion, flow rates and flood risk, and nutrient fluxes. This study aimed to assess the impact of drain blocking, as a form of peatland restoration, on an upland Blanket Bog, by measuring water chemistry and colour, and loss of both dissolved (DOC) and particulate organic carbon (POC). The restoration work was designed to permit the collection of a robust experimental dataset over a landscape scale, with data covering up to 3 years pre-restoration and up to 3 years post-restoration. An information theoretic approach to data analyses provided evidence of a recovery of water chemistry towards more 'natural' conditions, and showed strong declines in the production of water colour. Drain blocking led to increases in the E4:E6 ratio, and declines in specific absorbance, suggesting that DOC released from blocked drains consisted of lighter, less humic and less decomposed carbon. Whilst concentrations of DOC showed slight increases in drains and streams after blocking, instantaneous yields of both DOC and POC declined markedly in streams over the first year post-restoration. Attempts were made to estimate total annual fluvial organic carbon fluxes for the study site, and although errors around these estimates remain considerable, there is strong evidence of a large reduction in aquatic organic carbon flux from the peatland following drain-blocking. Potential mechanisms for the observed changes in water chemistry and organic carbon release are discussed, and we highlight the need for more detailed information, from more sites, to better understand the full impacts of peatland restoration on carbon storage and release.
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Recovery of water tables in Welsh Blanket Bog after drain blocking: Discharge rates, time scales and the influence of local conditions
Journal of Hydrology, 2010Co-Authors: Lorraine Wilson, Jared Wilson, Ian Johnstone, Joseph Holden, Alona Armstrong, Michael MorrisAbstract:Peatland practitioners and scientists have increasingly recognised the damage resulting from various management methods, and the need to restore peatlands to achieve several potential benefits. Many of the hoped-for benefits of peatland restoration, such as Carbon storage, biodiversity conservation and water quality improvements, are thought to depend on a reinstatement of high water tables that had been reduced by drainage. Despite the current emphasis on restoring drained peatlands, many of the predicted responses to restoration are still not adequately proven and the mechanisms behind them still uncertain. This study reports on water table and discharge responses to drain blocking restoration of a degraded Welsh upland Blanket Bog. Restoration work and monitoring were designed to permit a novel catchment scale control-intervention experimental design. An information theoretic approach to examining the data provided evidence of increases in water retention and water tables within the Bog after restoration. But the study also demonstrated the importance of small and large scale topography in determining the degree of these responses. The increases in water storage after restoration produced lower discharge rates observable at the level of both drains and hill streams; as well as greater water table stability, reduction in peak flows and increases in water residency after rainfall. Crucially, this study showed strong catchment scale differences in response, and a very gradual recovery of water tables, both of which highlight the need for more studies to be carried out at the landscape scale and over longer time periods.
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Recovery of water tables in Welsh Blanket Bog after drain blocking: Discharge rates, time scales and the influence of local conditions
Journal of Hydrology, 2010Co-Authors: Lorraine Wilson, Jared Wilson, Ian Johnstone, Joseph Holden, Alona Armstrong, Michael MorrisAbstract:Peatland practitioners and scientists have increasingly recognised the damage resulting from various management methods, and the need to restore peatlands to achieve several potential benefits. Many of the hoped-for benefits of peatland restoration, such as Carbon storage, biodiversity conservation and water quality improvements, are thought to depend on a reinstatement of high water tables that had been reduced by drainage. Despite the current emphasis on restoring drained peatlands, many of the predicted responses to restoration are still not adequately proven and the mechanisms behind them still uncertain. This study reports on water table and discharge responses to drain blocking restoration of a degraded Welsh upland Blanket Bog. Restoration work and monitoring were designed to permit a novel catchment scale control-intervention experimental design. An information theoretic approach to examining the data provided evidence of increases in water retention and water tables within the Bog after restoration. But the study also demonstrated the importance of small and large scale topography in determining the degree of these responses. The increases in water storage after restoration produced lower discharge rates observable at the level of both drains and hill streams; as well as greater water table stability, reduction in peak flows and increases in water residency after rainfall. Crucially, this study showed strong catchment scale differences in response, and a very gradual recovery of water tables, both of which highlight the need for more studies to be carried out at the landscape scale and over longer time periods. (c) 2010 Elsevier B.V. All rights reserved