Periodic Reporting for period 1 - CReScenDo (Combining Remote Sensing Technologies for Peatland Detection and Characterization)
Okres sprawozdawczy: 2017-06-01 do 2019-05-31
Peatlands hide a treasure in their soils. It is the enormous amount of organic carbon that is stored belowground and preserved by the constant or cyclical presence of water. The source of carbon is the mixture of organic material that is produced by wetland plants and that is left in the wet soil as they die. The presence of water slows down the oxidation of dead and decaying plant material, leading, over time, to the accumulation of peat. This mechanism is so efficient that peatlands are among the most carbon-dense environments in the world, storing up to 70 kg of carbon per cubic meter. Peatlands continue to extract carbon dioxide from the atmosphere and to store it unless the water is removed and the soil is drained. Unfortunately this is an extremely common practice, mainly related to land reclamation for agricultural purposes. Once water is drained, aerobic microorganisms attack the organic matter in the soil and quickly decompose it, releasing carbon dioxide. Land reclamation is just part of the problem: the degradation of peatlands is currently accelerating due to the higher frequency of droughts caused by global warming and to natural and man-induced fire events. Unfortunately, the speed at which peat is degrading is alarming. It is estimated that the total emissions from degraded peatlands and peat fires correspond to about 2 billion tons of carbon dioxide equivalent per year, which is about 6% of total anthropogenic greenhouse gasses emissions.
The conservation of peatlands is one of the main measures indicated by the Intergovernmental Panel on Climate Change (IPCC) to mitigate climate change. The European Commission has recently added the preservation of carbon-rich soils such as peatlands and wetlands among the environmental objectives of the future CAP (Common Agricultural Policy, 2019). This type of actions necessarily needs a precise assessment of the avoided potential emissions linked to conservation strategies and accurate methods to monitor peatland changes over time. Hence, a precise map of peatlands at the regional scale is urgently needed. However, the identification of the territories with the presence of peatlands is not sufficient for a proper quantification of the carbon stored in these systems. We need to determine how thick peatland soils are in order to quantify their volume and the amount of organic carbon they store.
This was the main objective of CReScenDo: quantifying the extent and thickness of peat deposits, from the local to the regional scale, to accurately define their importance in the global carbon cycle. In the process, the project developed a radically new observational methodology making use of remote sensing and airborne geophysical sensors.
The conservation of peatlands is one of the main measures indicated by the Intergovernmental Panel on Climate Change (IPCC) to mitigate climate change. The European Commission has recently added the preservation of carbon-rich soils such as peatlands and wetlands among the environmental objectives of the future CAP (Common Agricultural Policy, 2019). This type of actions necessarily needs a precise assessment of the avoided potential emissions linked to conservation strategies and accurate methods to monitor peatland changes over time. Hence, a precise map of peatlands at the regional scale is urgently needed. However, the identification of the territories with the presence of peatlands is not sufficient for a proper quantification of the carbon stored in these systems. We need to determine how thick peatland soils are in order to quantify their volume and the amount of organic carbon they store.
This was the main objective of CReScenDo: quantifying the extent and thickness of peat deposits, from the local to the regional scale, to accurately define their importance in the global carbon cycle. In the process, the project developed a radically new observational methodology making use of remote sensing and airborne geophysical sensors.
CReScenDo started June 1st 2017. The two-year project included activities performed at three study sites located in different countries, Indonesia, Norway, and Italy, with different ecological conditions: peatlands developing in the Indonesian tropical climate, high-latitude Norwegian bogs in pristine conditions, and a reclaimed peatland that underwent intensive agricultural practices in Italy.
The Norwegian study site is located south of Lillehammer, near the Brottum village. The area is characterized by the presence of forested land on frequent bedrock depressions, bogs and fens, at 300-400 m asl. A field survey was performed at this study site in August 2017. An Airborne Electromagnetic (AEM) dataset was already available and kindly made available by the National Norwegian Railroad Authorities. The analyses of the AEM data were performed in collaboration with Aarhus Geofisica (Pisa, IT) during the MSC fellow’s training (i.e. Secondment). The MSC fellow worked also in collaboration with the Norwegian Geotechnical Institute, where she performed the lab analyses of the peat samples.
The Indonesian study site is located in Kubu Raya District, West Kalimantan (Borneo). The study site covers an area of about 230 sq km and is characterized by the presence of large oil palms plantations. AEM data were collected in November 2017; 110 parallel flight lines were collected for a total length of 827 km with a system named SkyTEM. The campaign included several ancillary activities for the acquisition of ground-based geophysical data and peat thickness measurements through coring. Peat samples were collected and analyzed in the lab.
The Italian study site is located south of the Venice lagoon, in a basin named Zennare. Also in this case, the field campaigns (performed in fall 2018/spring 2019) included the collection of peat thickness measurements through coring and the acquisition of ground-based geophysical data. At this location also a contact-less frequency domain electro-magnetometer method was also used.
The analyses carried out in CreScenDo showed that the integration of AEM data with remote sensing, field measurements and lab analyses is the most robust and accurate approach for peat volume mapping across large peatland areas, and allows to accurately estimate their carbon stock. The results revealed that there are two main limitations to the applicability of this methodology: the high operational costs and the limited sensitivity of AEM to thin peat layers (order of 1-1.5 m). In order to overcome these issues, an alternative approach based on the use of a portable geophysical instruments (i.e. a contact-less frequency domain electro-magnetometer - FDEM) has been successfully tested at one of the study sites, providing reliable and rapid quantification of peat thickness over very thin peat layers. The methodology developed during the project has been applied to the three selected study sites, but can be applied to other areas around the world, allowing a precise assessment of peat deposits, which is the first essential step needed to implement conservation policies at the national and international level.
CreScenDo results have been presented at 7 scientific conferences. Three press releases were circulated (see for example https://www.nature.com/naturejobs/2017/171102/pdf/nj7678-129a.pdf?foxtrotcallback=true) and one interview on an on-line radio (http://www.radiobue.it/tag/sonia-silvestri/). Moreover, the researcher organized a public event on climate change and peatlands at the Museum of Natural History in Venice (Italy) (https://msn.visitmuve.it/it/eventi/archivio-eventi/cambiamenti-climatici/2018/03/19107/come-sara-la-nostra-vita-tra-50-anni/).
The Norwegian study site is located south of Lillehammer, near the Brottum village. The area is characterized by the presence of forested land on frequent bedrock depressions, bogs and fens, at 300-400 m asl. A field survey was performed at this study site in August 2017. An Airborne Electromagnetic (AEM) dataset was already available and kindly made available by the National Norwegian Railroad Authorities. The analyses of the AEM data were performed in collaboration with Aarhus Geofisica (Pisa, IT) during the MSC fellow’s training (i.e. Secondment). The MSC fellow worked also in collaboration with the Norwegian Geotechnical Institute, where she performed the lab analyses of the peat samples.
The Indonesian study site is located in Kubu Raya District, West Kalimantan (Borneo). The study site covers an area of about 230 sq km and is characterized by the presence of large oil palms plantations. AEM data were collected in November 2017; 110 parallel flight lines were collected for a total length of 827 km with a system named SkyTEM. The campaign included several ancillary activities for the acquisition of ground-based geophysical data and peat thickness measurements through coring. Peat samples were collected and analyzed in the lab.
The Italian study site is located south of the Venice lagoon, in a basin named Zennare. Also in this case, the field campaigns (performed in fall 2018/spring 2019) included the collection of peat thickness measurements through coring and the acquisition of ground-based geophysical data. At this location also a contact-less frequency domain electro-magnetometer method was also used.
The analyses carried out in CreScenDo showed that the integration of AEM data with remote sensing, field measurements and lab analyses is the most robust and accurate approach for peat volume mapping across large peatland areas, and allows to accurately estimate their carbon stock. The results revealed that there are two main limitations to the applicability of this methodology: the high operational costs and the limited sensitivity of AEM to thin peat layers (order of 1-1.5 m). In order to overcome these issues, an alternative approach based on the use of a portable geophysical instruments (i.e. a contact-less frequency domain electro-magnetometer - FDEM) has been successfully tested at one of the study sites, providing reliable and rapid quantification of peat thickness over very thin peat layers. The methodology developed during the project has been applied to the three selected study sites, but can be applied to other areas around the world, allowing a precise assessment of peat deposits, which is the first essential step needed to implement conservation policies at the national and international level.
CreScenDo results have been presented at 7 scientific conferences. Three press releases were circulated (see for example https://www.nature.com/naturejobs/2017/171102/pdf/nj7678-129a.pdf?foxtrotcallback=true) and one interview on an on-line radio (http://www.radiobue.it/tag/sonia-silvestri/). Moreover, the researcher organized a public event on climate change and peatlands at the Museum of Natural History in Venice (Italy) (https://msn.visitmuve.it/it/eventi/archivio-eventi/cambiamenti-climatici/2018/03/19107/come-sara-la-nostra-vita-tra-50-anni/).
Our ability of accurately estimating the volume of peat at the regional to the global scale is of key importance for the correct implementation of conservation policies that aim at mitigate climate change. For countries that are extremely rich in peatlands, as for example Indonesia and Norway, a precise assessment of the carbon stock is fundamental for implementing conservation policies at the national level, a key aspect to mitigate climate change. For countries where peatlands have been reclaimed, the restoration may represent a valuable alternative to current uses and an efficient way to preserve the peat still present. The CreScenDo project produced an important advancement in our ability of assessing peatland quantification at the regional scale, providing society with a concrete solution to the problem of quantifying peat volume and the associated carbon pool.