Foi apresentado um sistema automatizado para monitorar fluxos de metano (CH4) e do dióxido de carbono (CO2) na relação da água/ar de ecossistemas aquáticos. Consiste em uma série de câmaras flutuantes dinâmicas acopladas a um analisador photo acústico infravermelho de gás. Associado os outros sensores atmosféricos e de qualidade da água, foi possível identificar os fatores atmosféricos, hidrológico e biológico que afetam emissões de CH4 e de CO2 no reservatório de Corumbá (estado de Goiás), uma terra inundada antropogenica de savana. O estudo realizado em novembro 2004 e em março/agosto 2005 permitiu uma inter-correlação desobstruídos de estabelecimento da câmara, embora relações ligadas da profundidade-fluxo. Os fluxos de CH4 borbulhando médios em novembro 2004, em março e em agosto 2005 eram respectivamente 0.05 ± 2.19, 4 ± 45 e 505 o ± 1192 mg/m2/d. Para os mesmos meses, as emissões de CH4 difusivo médias foram 17 o ± 6, 37 ± 9 e 69 o ± 28 mg/m2/d, visto que os fluxos difusivo do CO2 foram respectivamente 59 o ± 398, 385 ± 629 e o ± 1466 1223 mg/m2/d. Um aspecto interessante de bolhas de CH4 é a liberação repentina e grande em locais rasos e liberação do escoamento em locais profundos. Em uma base diária, a freqüência e o valor de bolhas de CH4 são condicionados à oxidação durante períodos da flutuação do lago, e às mudanças totais da pressão exercidas no sedimento. Em escalas de tempo sazonal, a intensidade de bolhas de CH4 é condicionada principalmente pela disponibilidade da carcaça ao metanogeneses. As frentes frias são responsáveis pela a ruptura da estratificação (misturar), favorecendo emissões do CO2 depois da oxidação CH4. As emissões do CO2 puderam também ser acopladas ao diel metanotrófico. Nossos resultados sugerem que as emissões de gás do efeito estufa de Corumbá estão controladas pela maior parte pelo nível de água e pela luz solar. / It was present an automated system for monitoring methane (CH4) and carbon dioxide (CO2) fluxes at the water/air interface of aquatic ecosystems. It consists of a series of floating dynamic chambers coupled to an infrared photo acoustic gas analyzer. Associated to other atmospheric and water quality sensors, it was possible to identify atmospheric, hydrologic and biological factors affecting CH4 and CO2 emissions at Corumbá reservoir (State of Goiás), a savanna anthropogenic flooded land. The study carried out in November 2004 and March/August 2005 allowed establishing clear chamber inter-correlations, although intricate depth-flux relations. Mean CH4 bubbling fluxes in November 2004, March and August 2005 were respectively 0.05 ± 2.19, 4 ± 45 and 505 ± 1192 mg/m2/d. For the same months, mean CH4 diffusive emissions were 17 ± 6, 37 ± 9 and 69 ± 28 mg/m2/d, whereas CO2 diffusive fluxes were respectively 59 ± 398, 385 ± 629 and 1466 ± 1223 mg/m2/d. An interesting aspect of CH4 bubbling is the sudden and large release at shallow sites and seepage release at deep sites. On a daily basis, the frequency and magnitude of CH4 bubbling is conditioned to oxidation during overturn periods, and to the total pressure changes exerted on the sediment. At seasonal time scales, CH4 bubbling intensity is mainly conditioned by substrate availability to methanogenesis. Cold fronts are responsible for stratification rupture (mixing), favoring CO2 emissions following CH4 oxidation. CO2 emissions might also be coupled to diel methanotrophy. Our results suggest that greenhouse gas emissions from Corumbá are largely controlled by water level and sunlight.

No description available.

In an interdisciplinary study requiring the synergistic association of historical evidence and chemical and biochemical analyses, this thesis investigates the properties and characteristics of historically modified soils known as anthrosols. These soils, developed through the anthropogenic addition of high volumes of organic-rich municipal waste materials to land, including human and animal waste, as part of the waste management practices in medieval urban communities in Scotland at St Andrews, Roxburgh and Elgin, offer an insight to the state and dynamics of these organic material. Soil is one of the most sensitive environmental domains to transformation. These transformations are visible from the alterations to the physical and chemical properties of soil. Anthropogenic activities may leave behind signatures in the soil in the form of artefacts, ecofacts, elemental enrichment or depletion, enhancement in soil magnetic properties and organic matter content. In the historical dimension of this study, the observable features and measurable properties of soil profiles are exploited to reveal past organisation and functions of cultural landscapes by carefully studying the stratigraphic units of soil profile, and examining the association of each unit with settlement artefacts and soil properties. Through comparison with historical records of past events on the respective study sites, the relationship between the soils record of past human activities is observed through physical, chemical and biochemical properties. The historical record is used to assess if such evidence can be used reliably to develop the account of site use for the medieval burghs of Scotland. In the environmental aspect, investigation focuses on the physical and chemical conditions of these soils in terms of their carbon content, composition, residence time estimates and their role in global C cycle and terrestrial carbon budgeting. Past investigations of anthopogenically-deepened soils have been interpreted with respect to historical site use, however, the environmental implications of the resultant accumulated organic material or residue have not previously been considered in much detail. A particular novelty of this aspect of the project is that it is an in-depth examination of anthropogenic soils with known histories extending into the medieval period. This time-depth allows a new understanding of the processes and products of decomposition of known organic materials that were added to soil. The biophysicochemical data obtained from these soils such as their extant organic carbon content and variability with depth, the composition of the various carbon species that together constitute soil organic matter, and biological community and activity (microorganisms and enzymes) provides critical information on the relative recalcitrance, state of decomposition, and the mechanism of stabilisation of these materials in the soil.

The objectives of this research were to develop and evaluate a field method for in situ measurement of soil properties using visible near-infrared reflectance spectroscopy (Vis-NIRS). A probe with an independent light source for acquiring soil reflectance spectra from soil cores was developed around an existing portable field spectrometer (ASD FieldSpecPro, Boulder, CO, USA; 350-2500 nm). Initial experiments tested the ability of the acquired spectra to predict plant root density, an important property in soil carbon dynamics. Reflectance spectra were acquired from soil containing ryegrass roots (Lolium multiflorum) grown in Allophanic and Fluvial Recent soils in a glasshouse pot trial. Differences in root density were created by differential nitrogen and phosphorus fertilization. Partial least squares regression (PLSR) was used to calibrate spectral data (pre-processed by smoothing and transforming spectra to the first derivative) against laboratory-measured root density data (wet-sieve technique). The calibration model successfully predicted root densities (r2 = 0.85, RPD = 2.63, RMSECV = 0.47 mg cm-3) observed in the pots to a moderate level of accuracy. This soil reflectance probe was then tested using a soil coring system to acquire reflectance spectra from two soils under pasture (0-60 mm soil depths) that had contrasting root densities. The PLSR calibration models for predicting root density were more accurate when soil samples from the two soils were separated rather than grouped. A more accurate prediction was found in Allophanic soils (r2 = 0.83, RPD = 2.44, RMSECV = 1.96 mg g-1) than in Fluvial Recent soils (r2 = 0.75, RPD = 1.98, RMSECV = 5.11 mg g-1). The Vis-NIRS technique was then modified slightly to work on a soil corer that could be used to measure root contents from deeper soil profiles (15- 600 mm depth) in arable land (90-day-old maize crop grown in Fluvial Recent soils). PLSR calibration models were constructed to predict the full range of maize root densities (r2 = 0.83, RPD = 2.42, RMSECV = 1.21 mg cm-3) and also soil carbon (C) and nitrogen (N) concentrations that had been determined in the laboratory (LECO FP- 2000 CNS Analyser; Leco Corp., St Joseph, MI, USA). Further studies concentrated on improving the Vis-NIRS technique for prediction of total C and N concentrations in differing soil types within different soil orders in the field. The soil coring method used in the maize studies was evaluated in permanent and recent pastoral soils (Pumice, Allophanic and Tephric Recent in the Taupo-Rotorua Volcanic Zone, North Island) with a wide range of soil organic matter contents resulting from different times (1-5 years) since conversion from forest soils. Without any sample preparation, other than the soil surface left after coring, it was possible to predict soil C and N concentrations with moderate success (C prediction r2 = 0.75, RMSEP = 1.23%, RPD = 1.97; N prediction r2 = 0.80, RMSEP = 0.10%, RPD = 2.15) using a technique of acquiring soil reflectance spectra from the horizontal cross-section of a soil core (H method). The soil probe was then modified to acquire spectra from the curved vertical wall of a soil core (V method), allowing the spectrometer’s field of view to increase to record the reflectance features of the whole soil sample taken for laboratory analysis. Improved predictions of soil C and N concentrations were achieved with the V method of spectral acquisition (C prediction r2 = 0.97, RMSECV = 0.21%, RPD = 5.80; N prediction r2 = 0.96, RMSECV = 0.02%, RPD = 5.17) compared to the H method (C prediction r2 = 0.95, RMSECV = 0.27%, RPD = 4.45; N prediction r2 = 0.94, RMSECV = 0.03%, RPD = 4.25). The V method was tested for temporal robustness by assessing its ability to predict soil C and N concentrations of Fluvial Recent soils under permanent pasture in different seasons. When principal component analysis (PCA) was used to ensure that the spectral dimensions (which were responsive to water content) of the data set used for developing the PLSR calibration model embraced those of the “unknown” soil samples, it was possible to predict soil C and N concentrations in “unknown” samples of widely different water contents (in May and November), with a high level of accuracy (C prediction r2 = 0.97, RMSEP = 0.36%, RPD = 3.43; N prediction r2 = 0.95, RMSEP = 0.03%, RPD = 3.44). This study indicates that Vis-NIRS has considerable potential for rapid in situ assessment of soil C, N and root density. The results demonstrate that field root densities in pastoral and arable soil can be predicted independently from total soil C, which will allow researchers to predict C sequestration from root production. The recommended “V” technique can be used to assess spatial and temporal variability of soil carbon and nitrogen within soil profiles and across the landscape. It can also be used to assess the rate of C sequestration and organic matter synthesis via root density prediction. It reduces the time, labour and cost of conventional soil analysis and root density measurement.

The objectives of this research were to develop and evaluate a field method for in situ measurement of soil properties using visible near-infrared reflectance spectroscopy (Vis-NIRS). A probe with an independent light source for acquiring soil reflectance spectra from soil cores was developed around an existing portable field spectrometer (ASD FieldSpecPro, Boulder, CO, USA; 350-2500 nm). Initial experiments tested the ability of the acquired spectra to predict plant root density, an important property in soil carbon dynamics. Reflectance spectra were acquired from soil containing ryegrass roots (Lolium multiflorum) grown in Allophanic and Fluvial Recent soils in a glasshouse pot trial. Differences in root density were created by differential nitrogen and phosphorus fertilization. Partial least squares regression (PLSR) was used to calibrate spectral data (pre-processed by smoothing and transforming spectra to the first derivative) against laboratory-measured root density data (wet-sieve technique). The calibration model successfully predicted root densities (r2 = 0.85, RPD = 2.63, RMSECV = 0.47 mg cm-3) observed in the pots to a moderate level of accuracy. This soil reflectance probe was then tested using a soil coring system to acquire reflectance spectra from two soils under pasture (0-60 mm soil depths) that had contrasting root densities. The PLSR calibration models for predicting root density were more accurate when soil samples from the two soils were separated rather than grouped. A more accurate prediction was found in Allophanic soils (r2 = 0.83, RPD = 2.44, RMSECV = 1.96 mg g-1) than in Fluvial Recent soils (r2 = 0.75, RPD = 1.98, RMSECV = 5.11 mg g-1). The Vis-NIRS technique was then modified slightly to work on a soil corer that could be used to measure root contents from deeper soil profiles (15- 600 mm depth) in arable land (90-day-old maize crop grown in Fluvial Recent soils). PLSR calibration models were constructed to predict the full range of maize root densities (r2 = 0.83, RPD = 2.42, RMSECV = 1.21 mg cm-3) and also soil carbon (C) and nitrogen (N) concentrations that had been determined in the laboratory (LECO FP- 2000 CNS Analyser; Leco Corp., St Joseph, MI, USA). Further studies concentrated on improving the Vis-NIRS technique for prediction of total C and N concentrations in differing soil types within different soil orders in the field. The soil coring method used in the maize studies was evaluated in permanent and recent pastoral soils (Pumice, Allophanic and Tephric Recent in the Taupo-Rotorua Volcanic Zone, North Island) with a wide range of soil organic matter contents resulting from different times (1-5 years) since conversion from forest soils. Without any sample preparation, other than the soil surface left after coring, it was possible to predict soil C and N concentrations with moderate success (C prediction r2 = 0.75, RMSEP = 1.23%, RPD = 1.97; N prediction r2 = 0.80, RMSEP = 0.10%, RPD = 2.15) using a technique of acquiring soil reflectance spectra from the horizontal cross-section of a soil core (H method). The soil probe was then modified to acquire spectra from the curved vertical wall of a soil core (V method), allowing the spectrometer’s field of view to increase to record the reflectance features of the whole soil sample taken for laboratory analysis. Improved predictions of soil C and N concentrations were achieved with the V method of spectral acquisition (C prediction r2 = 0.97, RMSECV = 0.21%, RPD = 5.80; N prediction r2 = 0.96, RMSECV = 0.02%, RPD = 5.17) compared to the H method (C prediction r2 = 0.95, RMSECV = 0.27%, RPD = 4.45; N prediction r2 = 0.94, RMSECV = 0.03%, RPD = 4.25). The V method was tested for temporal robustness by assessing its ability to predict soil C and N concentrations of Fluvial Recent soils under permanent pasture in different seasons. When principal component analysis (PCA) was used to ensure that the spectral dimensions (which were responsive to water content) of the data set used for developing the PLSR calibration model embraced those of the “unknown” soil samples, it was possible to predict soil C and N concentrations in “unknown” samples of widely different water contents (in May and November), with a high level of accuracy (C prediction r2 = 0.97, RMSEP = 0.36%, RPD = 3.43; N prediction r2 = 0.95, RMSEP = 0.03%, RPD = 3.44). This study indicates that Vis-NIRS has considerable potential for rapid in situ assessment of soil C, N and root density. The results demonstrate that field root densities in pastoral and arable soil can be predicted independently from total soil C, which will allow researchers to predict C sequestration from root production. The recommended “V” technique can be used to assess spatial and temporal variability of soil carbon and nitrogen within soil profiles and across the landscape. It can also be used to assess the rate of C sequestration and organic matter synthesis via root density prediction. It reduces the time, labour and cost of conventional soil analysis and root density measurement.

The objectives of this research were to develop and evaluate a field method for in situ measurement of soil properties using visible near-infrared reflectance spectroscopy (Vis-NIRS). A probe with an independent light source for acquiring soil reflectance spectra from soil cores was developed around an existing portable field spectrometer (ASD FieldSpecPro, Boulder, CO, USA; 350-2500 nm). Initial experiments tested the ability of the acquired spectra to predict plant root density, an important property in soil carbon dynamics. Reflectance spectra were acquired from soil containing ryegrass roots (Lolium multiflorum) grown in Allophanic and Fluvial Recent soils in a glasshouse pot trial. Differences in root density were created by differential nitrogen and phosphorus fertilization. Partial least squares regression (PLSR) was used to calibrate spectral data (pre-processed by smoothing and transforming spectra to the first derivative) against laboratory-measured root density data (wet-sieve technique). The calibration model successfully predicted root densities (r2 = 0.85, RPD = 2.63, RMSECV = 0.47 mg cm-3) observed in the pots to a moderate level of accuracy. This soil reflectance probe was then tested using a soil coring system to acquire reflectance spectra from two soils under pasture (0-60 mm soil depths) that had contrasting root densities. The PLSR calibration models for predicting root density were more accurate when soil samples from the two soils were separated rather than grouped. A more accurate prediction was found in Allophanic soils (r2 = 0.83, RPD = 2.44, RMSECV = 1.96 mg g-1) than in Fluvial Recent soils (r2 = 0.75, RPD = 1.98, RMSECV = 5.11 mg g-1). The Vis-NIRS technique was then modified slightly to work on a soil corer that could be used to measure root contents from deeper soil profiles (15- 600 mm depth) in arable land (90-day-old maize crop grown in Fluvial Recent soils). PLSR calibration models were constructed to predict the full range of maize root densities (r2 = 0.83, RPD = 2.42, RMSECV = 1.21 mg cm-3) and also soil carbon (C) and nitrogen (N) concentrations that had been determined in the laboratory (LECO FP- 2000 CNS Analyser; Leco Corp., St Joseph, MI, USA). Further studies concentrated on improving the Vis-NIRS technique for prediction of total C and N concentrations in differing soil types within different soil orders in the field. The soil coring method used in the maize studies was evaluated in permanent and recent pastoral soils (Pumice, Allophanic and Tephric Recent in the Taupo-Rotorua Volcanic Zone, North Island) with a wide range of soil organic matter contents resulting from different times (1-5 years) since conversion from forest soils. Without any sample preparation, other than the soil surface left after coring, it was possible to predict soil C and N concentrations with moderate success (C prediction r2 = 0.75, RMSEP = 1.23%, RPD = 1.97; N prediction r2 = 0.80, RMSEP = 0.10%, RPD = 2.15) using a technique of acquiring soil reflectance spectra from the horizontal cross-section of a soil core (H method). The soil probe was then modified to acquire spectra from the curved vertical wall of a soil core (V method), allowing the spectrometer’s field of view to increase to record the reflectance features of the whole soil sample taken for laboratory analysis. Improved predictions of soil C and N concentrations were achieved with the V method of spectral acquisition (C prediction r2 = 0.97, RMSECV = 0.21%, RPD = 5.80; N prediction r2 = 0.96, RMSECV = 0.02%, RPD = 5.17) compared to the H method (C prediction r2 = 0.95, RMSECV = 0.27%, RPD = 4.45; N prediction r2 = 0.94, RMSECV = 0.03%, RPD = 4.25). The V method was tested for temporal robustness by assessing its ability to predict soil C and N concentrations of Fluvial Recent soils under permanent pasture in different seasons. When principal component analysis (PCA) was used to ensure that the spectral dimensions (which were responsive to water content) of the data set used for developing the PLSR calibration model embraced those of the “unknown” soil samples, it was possible to predict soil C and N concentrations in “unknown” samples of widely different water contents (in May and November), with a high level of accuracy (C prediction r2 = 0.97, RMSEP = 0.36%, RPD = 3.43; N prediction r2 = 0.95, RMSEP = 0.03%, RPD = 3.44). This study indicates that Vis-NIRS has considerable potential for rapid in situ assessment of soil C, N and root density. The results demonstrate that field root densities in pastoral and arable soil can be predicted independently from total soil C, which will allow researchers to predict C sequestration from root production. The recommended “V” technique can be used to assess spatial and temporal variability of soil carbon and nitrogen within soil profiles and across the landscape. It can also be used to assess the rate of C sequestration and organic matter synthesis via root density prediction. It reduces the time, labour and cost of conventional soil analysis and root density measurement.

Orientador: Alan Rodrigo Panosso / Resumo: As emissões de CO2 do solo (FCO2) tem sido correlacionadas aos atributos do solo que, por sua vez, são fortemente influenciadas pelo uso manejo agrícola. Além disso, a temperatura do solo, a umidade e a relação entre ambos os atributos são as principais variáveis que regem o FCO2. Nesse sentido, este trabalho deve fornecer um conhecimento importante sobre o meca-nismo que regula o padrão FCO2 em sistemas de manejos agrícolas, uma vez que as áreas foram convertidas de Cerrado para usos distintos há trinta anos. O objetivo do trabalho foi foi avaliar a influência dos usos: cerrado nativo (CE), floresta de eucalipto (EU), floresta de pinus (PI) e sistema silvopastoril (SI) sobre o a dinâmica do carbono do solo, bem como sua relação com o HLIFS (Grau de humificação de matéria orgânica) e o EC (estoque de carbono do solo) de um latosolo na região do baixo Cerrado de Selvíria - MS. Dentre os manejos avaliados, o CE foi o que obteve as maiores emissões (4,55 µmol m-2 s-1) em contraste com o PI que exibiu as menores (2,98 µmol m-2 s-1). O EC e HLIFS apresentaram valores divergentes entre os manejos, como exemplo, o SI atingiu os maiores valores de EC (17 t ha-1), enquanto que, o HLIFS desse manejo alcançou as menores taxas, portanto, menos humificado. De modo contrário, o PI obteve os menores valores de EC (11,5 t ha -1) e maiores de HLIFS. Os resultados das variáveis EC, HLIFS, constante de decaimento do carbono (k), estoque de nitrogênio do solo (EN) e relação CN do solo evidenciam... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Soil CO2 emissions (FCO2) has been correlated to soil atributtes, and are strongly influenced by agricultural use and management. Furthermore, soil temperature, humidity and the relationship between both attributes are the main variables that govern FCO2. In this way, this work should provide an important knowledge about the mechanism that regulates the FCO2 standard in dif-ferents management agriculture systems, since the areas were converted from Cerrado to diffe-rent agricultural management for thirty years. The objective of the study was to evaluate the influence of five land use: native vegetation (CE), eucalypt forest (EU), pine forest (PI) and silvopastoral system (SI) on soil carbon dynamic, as well as effects (FCO2), as well as its relation with degree of humification of organic matter (HLIFS) and soil carbon stock (EC) in a oxisol in the Cerrado region of Mato Grosso do Sul. Among the managements evaluated, EC was the one that obtained the highest emissions (4.55 μmol m-2 s-1) in contrast to the PI that showed the smallest ones (2.98 μmol m-2 s-1). The EC and HLIFS presented divergent values among the ma-nagement, for example, the SI reached the highest values of EC (17 t ha-1), whereas, the HLIFS of this management reached the lowest rates, therefore, less humid. Conversely, PI had the lo-west values of EC (11.5 t ha -1) and higher values of HLIFS. The results of the variables EC, HLIFS, carbon decay constant (k), soil nitrogen inventory (EN) and soil CN ratio show... (Complete abstract click electronic access below) / Mestre

Abstract Succession is a compositional change of species and other ecosystem characteristics over time. Mire development, i.e., long-term mire succession is basically driven by an increase in peat layer height, promoting changes in hydrology, vegetation and nutrient status of a particular mire. Due to this, ecosystem processes, such as production and loss of carbon due to decomposition (i.e. carbon gas functions), change with increasing successional mire stage. An adequate method for studying the changes in ecosystem C functions is to measure CO2 and CH4 fluxes between the ecosystem and atmosphere. Succession and carbon dynamics of boreal pristine mires have been much studied. However the link between these phenomena is largely unknown. Further, if and how the C gas functions of mires change during mire succession it is rather poorly understood. The main objective of this thesis was to study how ecosystem functions, measured as CO2 and CH4 exchange, change during mire development. The study also aims to explore the drivers of succession in mire development, i.e., mire succession. Successional mire C dynamics were studied along an eight-kilometer-long successional sequence of primary paludified mires located in the land uplift coast of the Bothnian Bay. Due to the short distance between sites, they all have been under the same climatic control for most of their development. The gradual replacement of plant species with different photosynthetic potential, phenology and assimilating green area resulted in lower-level and temporal variation of CO2 exchange patterns at the later successional stages. Similar to this, CH4 also had the lowest interannual variation in the later stages. In general, CH4 emissions increased with mire age even though this trend did not emerge during the rainy season. Further, this study showed that the wintertime C function pattern was related to the C pattern during the previous summer confirming the important effect of growing season patterns on wintertime C dynamics. In addition to the fundamental effect of vegetation as a driver of succession which was also confirmed in this study, the role of hydrological conditions appeared to be equally important. More constant hydrological conditions at later successional stages resulted in lower temporal variation in CH4 and CO2 fluxes. The present results suggest that the stability of ecosystem C gas functions increases during mire development due to increasing autogenic control. / Tiivistelmä Sukkessio on ekosysteemin lajistossa ja sen muissa ominaisuuksissa ajan kuluessa tapahtuva muutos. Suon kehitystä eli pitkäaikaista suosukkessiota vie eteenpäin turpeen paksuuskasvu, joka saa aikaan muutoksia suoekosysteemin hydrologiassa, kasvillisuudessa ja ravinnetilassa. Tästä johtuen myös suoekosysteemin erilaiset prosessit, kuten tuotanto sekä hajoamisen kautta tapahtuva hiilen vapautuminen eli hiilikaasutoiminta muuttuu suon ikääntyessä. Ekosysteemin hiilikaasutoiminnassa tapahtuvia muutoksia voidaan tutkia muun muassa mittaamalla ekosysteemin ja ilmakehän välisiä hiilidioksidi- ja metaanivirtoja. Boreaalisten luonnontilaisten soiden sukkessiota ja hiilidynamiikkaa on tutkittu runsaasti, mutta niiden välistä yhteyttä ei sen sijaan juuri tunneta. Tämän vuoksi ei tiedetä kuinka soiden hiilikaasutoiminta mahdollisesti muuttuu suon kehityksen aikana eli suosukkession edetessä. Tämän tutkimuksen päätavoitteena oli tutkia kuinka hiilidioksidin ja metaanin vaihdolla mitattu ekosysteemitoiminta muuttuu suon kehityksen aikana. Tutkimus pyrki myös selvittämään suosukkessiota kontrolloivat tekijät. Eri-ikäisten soiden hiilikaasudynamiikkaa tutkittiin mittaamalla hiilikaasuja Perämeren maankohoamisrannikolla kahdeksan kilometrin pituisella sukkessiogradientilla, joka koostuu primaarisoistumisen kautta syntyneistä soista. Soiden lyhyestä keskinäisestä etäisyydestä johtuen ne ovat olleet saman ilmastollisen kontrollin alaisena suurimman osan kehityksestään. Vaiheittainen kasvilajien muutos sukkessiogradientilla yhdessä kasvilajien erilaisen yhteyttämispotentiaalin, fenologian ja yhteyttävän lehtipinta-alan kanssa johti hiilidioksidivaihdon alhaisempaan tasoon sekä pienempään ajalliseen vaihteluun vanhemmilla sukkessiovaiheilla. Myös metaanin vaihdolla oli alhaisimmat vuosien väliset vaihtelut vanhemmilla vaiheilla. Yleisesti ottaen metaanipäästöt kasvoivat suon iän myötä, vaikkakaan tätä trendiä ei havaittu sateisena kasvukautena. Lisäksi tutkimus osoitti, että talviaikaiset hiilivirrat (CO2, CH4) seurasivat kesäaikaisen hiilidynamiikan vaihtelua. Kasvillisuuden keskeinen rooli ekosysteemin sukkessiossa havaittiin myös tässä tutkimuksessa. Kasvillisuuden ohella merkittäväksi suosukkessiota sääteleväksi tekijäksi osoittautui hydrologisten olojen vaikutus. Tasaisemmat hydrologiset olot vanhemmilla sukkessiovaiheilla johtivat vähäisempään ajalliseen vaihteluun metaani- ja hiilidioksidivirroissa. Tutkimuksen tulokset viittaavat siihen, että ekosysteemin hiilidynamiikka stabilisoituu suon kehityksen aikana lisääntyvän autogeenisen kontrollin kautta.

The human influence of global climate is an issue currently assessed in various mitigation strategies. Stockholm County has committed to becoming carbon neutral by 2040 and negative by 2045 according to the Paris agreement. The strategy includes cutting of various sectors emissions as well as compensating for remaining emissions with carbon sequestration methods. Accounting for ecosystems ability to sequester carbon at local level in green urban areas is an important in carbon offset efforts. It has emerged from previous research that the sequestration rate may differ depending on vegetation age and thus time passing, which is not assessed on a regional level, which is important for carbon offset efforts to accurately account for the sequestration potential in long-term mitigation strategies. This study therefore aims to fill the knowledge gap of how the temporal aspect affects the current sequestration potential and future predictions, as well as assessing how it can aid in reaching carbon neutrality by 2040. The study are thus aiming to answer the research questions (1) how the carbon sequestration potential of the existing green areas change over time in Stockholm County, (2) if additional measures need to be taken to preserve or increase carbon sequestration to maintain carbon neutrality until 2040 and (3) how the knowledge of sequestration dynamics aid in reaching a carbon neutral city by 2040. A weighing of which Corine Land Cover categories was performed and concluded in the including; discontinuous structures, green urban areas, forests and wetlands, due to their contribution to sequestration potential, estimated change through time, and relevance for Stockholm County. The spatial analysis was made based on calculations with information obtained from processing of obtained data on land cover and species distribution as well as scientific literature on sequestration rates of each vegetation across all life stages, where Net Ecosystem Production was the main measurement used. The estimated results were computed in a Geographic Information System to simulate and visualize the sequestration rates of current and future predictions of 2040 sequestration potential as well as locating areas of interest. The findings show that by including temporal aspects to the assessment of carbon sequestration potential in Stockholm County, the current and future sequestration potential increased from previous research estimations. The total current sequestration potential was 2,8 MtCO2-eq annually and the predictions were estimated to 3,3 MtCO2-eq per year in 2040. As the current emissions in Stockholm County are currently 6 MtCO2-eq per year, the natural sequestration potential provided by the green areas is compensating for 46% of the current emissions. As the estimated future emissions are 0,95 MtCO2-eq annually, the natural sequestration potential more than compensates for the emissions in the county, if the predicted emission reductions are realized. Although further measurements are not seemingly required to achieve carbon neutrality in 2040, the findings further locate areas and species where management practices or protection is beneficial to further add to the sequestration potential of Stockholm County. / Den mänskliga påverkan på det globala klimatet är ett problem som för närvarande bedöms i olika klimatåtgärder. Stockholms län har förbundit sig till ett mål att bli koldioxidneutralt till 2040 och koldioxidnegativt till 2045 enligt Parisavtalets överenskommelser. Strategin innefattar att minska utsläppen från olika sektorer samt att kompensera de återstående utsläppen med olika metoder för koldioxidlagring. Ekosystemens förmåga att binda kol på lokal nivå i gröna stadsområden är en viktig del av ansträngningarna för att kompensera för utsläppen. Det har varit uppenbart från tidigare forskning att potentialen av koldioxidlagring kan skilja sig åt beroende på vegetationens ålder samt passerande tid, även om aktuell forskning inte omfattar frågan på regional nivå, vilket är viktigt för insatser som omfattar koldioxidkompensation så att lagringspotentialen kan redovisas korrekt i de långsiktiga klimatåtgärderna. Denna studie syftar därför till att fylla kunskapsluckan gällande hur den tidsmässiga aspekten påverkar den befintliga lagringspotentialen och framtida prognoser samt hur det kan bidra till att nå koldioxidneutralitet fram till 2040. Studien avser därmed till att svara på forskningsfrågorna (1) hur kolbindningspotentialen för de befintliga grönområdena förändras över tid i Stockholms län, (2) ifall ytterligare åtgärder behöver vidtas för att bevara eller öka koldioxidbindningen för att uppnå eller bibehålla koldioxidneutralitet fram till 2040 och (3) hur kunskapen om koldioxidlagringsdynamiken underlättar för att nå en koldioxidneutral region år 2040. En avvägning av vilka Corina marktäckeskategorier utfördes och resulterade i inkludering av; diskontinuerliga strukturer, gröna stadsområden, skogar och våtmarker, där koldynamiken och omfattningen av lagringspotentialen var relevant för Stockholmsregionen. Den rumsliga analysen gjordes baserad på beräkningar med information erhållen genom bearbetning av införskaffad data om marktäcke och artfördelning samt vetenskaplig litteratur om kolbindningshastighet för varje vegetation över alla livsstadier, där Net Ecosystem Production var det huvudsakliga måttet. De uppskattade resultaten beräknades i ett Geografiskt Informationssystem för att simulera och visualisera lagringshastigheten för nuvarande och framtida förutsägelser om sekvestreringspotentialen år 2040 samt att lokalisera intressanta. Resultaten visar att genom att inkludera tidsmässiga aspekter i bedömningen av kolbindningspotentialen i Stockholms län ökade den nuvarande och framtida bindningspotentialen från tidigare forsknings uppskattningar. Den totala nuvarande lagringspotentialen var 2,8 MtCO2-ekv årligen och de framtida prognoserna uppskattades till 3,3 MtCO2-ekv årligen år 2040. Eftersom de nuvarande utsläppen i Stockholms län för närvarande är 6 MtCO2-ekv årligen, kunde man se att den naturliga lagringspotentialen som grönområdena avsåg, kompenserar för 46 % av de nuvarande utsläppen. Eftersom de beräknade framtida utsläppen är 0,95 MtCO2-ekv per år, mer än kompenserar de gröna områdena för de utsläpp som sker i länet, om den förutsedda reduceringen av utsläppen sker. Även om ytterligare mätningar inte tycks behövas för att uppnå koldioxidneutralitet till 2040, lokaliseras ytterligare områden samt arter i resultatet där förvaltning eller skydd är fördelaktiga för att ytterligare förbättra lagringspotentialen i Stockholms län.

The work presented in this Doctoral Thesis has studied the temporal and spatial patterns of the most relevant soil parameters with special attention posed to soil biological and biochemical dynamics occurring at the studied soils in a very fragile area at Cap de Creus Peninsula, NE Spain. The main objective was to establish evidence of soil quality through the study of soil carbon dynamics (loss and storage) and their interactions with soil ecosystems. Soil environments were classified in terms of degree of soil quality, relating soil properties with plant cover species, especially along a sequence of agricultural abandonment where perturbations like wildfire and strong downpours often cause regressive dynamics in the natural succession of spontaneous vegetation and start erosion and degradation processes. At this regard, when fire occurrence is frequent, a quick drop down of all soil attributes was recorded leading to loss of biodiversity and, ultimately, desertification. / El treball de tesi doctoral ha estudiat els trets espacials i temporals de paràmetres mes rellevants del sòl, amb especial atenció en la dinàmica biològica i bioquímica que es dona en un àrea molt fràgil situada en la Península del Cap de Creus, NE Espanya. L’objectiu principal ha estat establir la qualitat dels sòls mitjançant l’estudi de la dinàmica del carboni (pèrdues i embornals) i la interacció amb l’ecosistema sòl. Els ambients estudiats s’han classificats en termes de qualitat del sòl, relacionant les seves propietats amb la coberta vegetal, especialment al llarg d’una seqüència d’abandonament agrícola on la presencia de pertorbacions com incendis o pluges causen sovint una dinàmica regressiva en la successió natural de la vegetació espontània i activen processos d’erosió i degradació. Tanmateix, en cas d’incendis freqüents, es registra un ràpid deteriorament de les propietats del sòl que provoca una pèrdua de biodiversitat i, mes tard, una desertificació.