Dans la dernière décennie, plusieurs hectares de terre agricole ont été convertis à la culture intensive sur courtes rotations (CICR) de saules dans le sud du Québec (Canada). Peu d’études ont été réalisées afin de déterminer comment se comporte la dynamique du carbone organique (Corg) dans le sol suivant cette conversion. Nous avons donc comparé la quantité du Corg et de deux pools labiles de carbone (carbone extractible à l’eau chaude et les sucres aminés) entre des CICR en phase initiale d’établissement (1-2 ans) et des parcelles appariées représentant le système de culture qui prévalait avant la transformation en culture de saules (culture fourragère) et d’autres cultures d’intérêt. La même chose a été faite pour une CICR en exploitation (depuis 9 ans) à un autre site. La quantité de Corg du sol n’était pas différente entre les CICR et les parcelles sous culture fourragère. Une plus haute concentration de sucres aminés dans le Corg total des CICR en établissement, par rapport aux autres parcelles sur le même site, permet de soupçonner que les perturbations liées à l’établissement ne mènent pas à une minéralisation accrue du Corg à court terme. La proportion de sucres aminés fongiques, qui diminue théoriquement lors de perturbations, était aussi plus élevée sous la plus jeune culture. Sous la CICR de neuf ans, le Corg était redistribué dans le profil vertical et les pools labiles étaient de plus petite taille (à une profondeur de 20-40 cm) comparativement à une parcelle témoin. La conversion d’une culture fourragère en plantation de saules en CICR n’a pas mené à la formation d’un puits de carbone. L’étude laisse entrevoir qu’un tel puits pourrait être créé si la conversion se faisait à partir d’un aménagement impliquant la culture en rotation de plantes annuelles et des labours. / Over the last ten years, many hectares of short-rotation willow coppice (SRWC) have been established on abandoned agricultural lands in southern Quebec (Canada). However, few studies were conducted to determine if these changes from a conventional crop to SRWC of willows would affect the soil carbon dynamic. A preliminary paired-site study was conducted to assess the impact of this land-use conversion on soil carbon stocks and dynamics shortly after they were established (1-year and 2-year) at one site and after multiple rotations (9-year) at another site. Apart from the total soil organic carbon pool, two labile carbon pools were investigated: the hot-water extractable carbon (HWC) pool and the amino sugars (AS) pool. Willow establishment and exploitation for nine years did not bring any changes in total organic carbon compared to an abandoned hay culture. The mature SRWC displayed a redistribution of TSOC in the vertical soil profile. We also measured a higher proportion of AS, compared to other plots on the same site, in total organic carbon under the 1-year-old SRWC; especially the proportion in AS of fungi origin that theorically decrease with perturbation intensity. Proportion of AS was also elevated under 2-year-old SRWC. A possible interpretation is that establishment-linked perturbations did not shift carbon dynamic toward an increased mineralization. The mature willow plantation exhibited depletion of HWC and the more labile amino sugar (muramic acid) in the deeper soil layer (20-40cm). This case study shows that conversion from an abandoned hay culture to a SRWC did not create a carbon sink. It was also found that the 9- year old willow plantation contained higher TSOC and had better soil quality than an adjacent short-term no-till crop rotation culture.

Orientador: Osmar de Carvalho Bueno / Banca: Maria Aparecida Mourão Brasil / Banca: Thelma Krug / Resumo: O alerta de cientistas sobre o aquecimento do planeta vem desde a década de 60. Entretanto, a comunidade internacional passou a discutir mais profundamente o tema a partir dos anos 80, mas foi na década de 90 que se conseguiram os maiores avanços diplomáticos, com o advento da Convenção-Quadro das Nações Unidas sobre Mudança do Clima e suas Conferências das Partes, onde em 1997 negociou-se o Protocolo de Quioto. Este trabalho discorre sobre a regulamentação internacional relacionada ao aquecimento global, enfocando em particular o papel da agroenergia brasileira dentro do Mecanismo de Desenvolvimento Limpo (MDL) e seu potencial de mitigação para a mudança climática. . Utiliza-se do método dedutivo para o desenvolvimento da dissertação. A atuação do Brasil apresenta-se controversa, pois é grande emissor de gases de efeito estufa (GEE) decorrente do desmatamento. Entretanto, a agroenergia brasileira destaca-se no cenário mundial com o grande potencial de substituição de matrizes energéticas não-renováveis por renováveis. Conclui-se que a agroenergia brasileira poderá contribuir para a mitigação do efeito estufa A discussão enfocou a demonstração da adicionalidade nos projetos de MDL, o potencial dos projetos de co-geração de energia e a necessidade de incluir no segundo período de compromisso do Protocolo de Quioto atividades relacionadas a uso da terra e mudança do uso da terra como ferramentas que contribuem para o controle do aquecimento global. As conclusões indicam a diferenciação entre projetos de redução de emissão e projetos de MDL; a potencialidade da agroenergia e o trabalho do Brasil para se destacar no mercado de carbono. / Abstract: Scientists have been warning about the planet warming since the 1960s. However, the international community started discussing it more deeply in the 1980s, but it was in the 1990s that the greatest diplomatic advances were reached, with the United Nations Framework Convention on Climate Change and its Conference of Parties when, in 1997, the Kyoto Protocol was negotiated. This study concerns the international regulation related to global warming, focusing on the particular Brazilian agroenergy role within the Clean Development Mechanism (CDM) and its mitigation potential to the climate change. The deductive approach was used in this paper. The Brazilian performance is antagonistic, once it is a great greenhouse gas emissary due to deforestation. Nevertheless, the Brazilian Agroenergy stands out in the world scenario with the huge replacement potential from nonrenewable energetic matrix to renewable ones. In this way, it is possible to conclude that the Brazilian Agroenergy can contribute to the greenhouse effect reduction. The discussion focused on the addition demonstration on CDM projects, the energy cogeneration potential of the projects, and the need to include activities concerning the land use and land use changes as a tool that comes through the global warming control in the second commitment period of Kyoto Protocol. The conclusion shows the difference between the reduction emission projects and the CDM projects; the agroenergy potencial as well as the Brazilian effort to stand out in the carbon market. / Mestre

A atividade humana tem contribuído com as emissões de gases de efeito estufa (GEE) associadas, principalmente, com queima de combustíveis fósseis e mudanças no uso da terra. Assim, se faz necessário que sejam adotadas medidas visando o retardamento dos efeitos das mudanças climáticas. As florestas exercem papel essencial no balanço de carbono principalmente por funcionarem como sumidouros de CO2. Por outro lado, se desmatadas, promovem emissões e liberam parte do carbono estocado. A quantidade de biomassa florestal e o teor de carbono podem variar em função do tipo florestal, bem como de sua localização. Entretanto, fator importante diz respeito à confiabilidade dos dados mensurados neste tipo de pesquisa. A biomassa e o carbono da parte aérea podem ser determinados via método destrutivo, ou estimados via método não destrutivo. A construção do Rodoanel Mário Covas trecho norte e a supressão de uma área de Mata Atlântica possibilitou a realização de estudo de biomassa da parte aérea via método destrutivo. O objetivo deste trabalho foi estudar o tamanho e forma de parcelas, a intensidade amostral, quantificar a biomassa e o carbono na parte aérea, comparar métodos destrutivos e não destrutivos para a quantificação de biomassa e carbono na parte aérea, estudar a variação da densidade básica da madeira das espécies nas diferentes classes de DAP e grupos sucessionais e comparar as medidas de altura total e DAP obtidas a campo no inventário com as medidas coletadas após o corte. O tamanho mais conveniente de parcela foi 400 m 2, com forma retangular e dimensão de 10 x 40 m. A intensidade amostral variou entre 39 e 75 unidades amostrais. A biomassa da parte aérea obtida, via método destrutivo, foi de 188,3 Mg ha-1 e o carbono, 85,1 Mg ha-1. A biomassa estimada por equações alométricas da literatura foi subestimada, quando comparada ao valor real, obtido via método destrutivo. As menores classes de DAP apresentaram as maiores densidades básicas da madeira. A densidade básica foi 0,488 g cm-3 na média das espécies. A porcentagem de carbono contida nos troncos e galhos não diferiu entre as classes de DAP. O teor de carbono foi 45,41%, na média dos troncos e galhos. Espécies pioneiras acumularam maior quantidade de biomassa e carbono nos galhos e apresentaram maior densidade básica que as não pioneiras. A utilização dos dados coletados na fase de inventário e após o corte não afetaram os valores de biomassa estimados. / Human activity has contributed to the emission of greenhouse gases associated mainly with burning fossil fuels and changes in land use. Thus, it is necessary that measures be adopted to delay the effects of climate change. Forests play an essential role in the carbon balance mainly acting as CO2 sinks. On the other hand, if they are deforested, they will promote emissions and release some of the stocked carbon. The amount of forest biomass and the carbon content may vary depending on the forest type and its location. However, an important factor is about the reliability of the data measured in this type of research. Aboveground biomass and carbon can be determined via destructive method or estimated by non-destructive method. The construction of the north extension of Mário Covas Road and the suppression of an Atlantic forest area made it possible to carry out study of the aboveground biomass via destructive method. The goal of this work was to study the size and shape of plots, the sampling intensity, their aboveground biomass and carbon, compare destructive and non-destructive methods for the quantification of biomass and carbon, study the variation of wood basic density in the species in different classes of diameter of trunk at breast height (DBH) and successional groups and compare the total height and DBH measures obtained on field in the inventory with the measures taken after the cut. The most convenient plot size is 400 m2, with rectangular shape and size of 10 x 40 m. The sampling intensity varied between 39 and 75 sample units. The aboveground biomass obtained, via destructive method, was 188.3 Mg ha-1 and carbon, 85.1 Mg ha-1. The biomass estimated by allometric equations of the literature was underestimated compared to the real value obtained via destructive method. Smaller DBH classes had the highest wood basic density. The basic density was 0.488 g cm-3 in average of the species. The percentage of carbon contained in the trunks and branches did not differ between the DBH classes. The carbon content was 45.41%, in the average of the trunks and branches. Pioneer species accumulated higher amount of biomass and carbon in the branches and had a higher wood basic density than non pioneers species. The utilization of data collected in the inventory phase and after the cut did not affect the estimated biomass values.

As árvores de Tectona grandis (Verbenaceae) e de Pinus caribaea var. hondurensis (Pinaceae) são utilizadas em estudos dendroecológicos e dendroclimatológicos pela formação de anéis de crescimento anuais duas espécies plantadas na Mata da Pedreira do Campus da ESALQ/USP para estudos ecológicos e climáticos. Foram selecionadas 8 árvores de Tectona grandis (4 com e 4 sem lianas ocupando a copa das árvores) e 10 árvores de Pinus caribaea var. hondurensis (8 vivas - 4 com e 4 sem lianas ocupando a copa das árvores - e 2 mortas). Com a utilização de sondas de Pressler foram extraídas 2-6 amostras do lenho/árvore das 2 espécies para analisar seus anéis de crecimiento. Foi realizada (i) a caracterização anatômica macro e microscópica dos anéis de crescimento; (ii) estudos de dendrocronologia, pela datação e avaliação do crescimento radial do tronco das árvores; (iii) avaliação da densidade do lenho por densitometria de raios X para a determinação da densidade dos anéis de crescimento, incremento de biomassa e de carbono; (iv) avaliação da influência do clima local e em grande escala no crescimento do tronco das árvores; (v) análise dos vasos das árvores de T. grandis e dos anéis de crescimento falsos nas árvores de P. caribaea. Os resultados principais mostraram que as características anatômicas dos anéis de crescimento das árvores as 2 espécies coincidem com os descritos na literatura; a série de anéis de crescimento mostrou correlação significativa em relação à sincronização dos anéis de crescimento das árvores das 2 espécies. O efeito prejudicial das lianas na copa das árvores de T. grandis e de P. caribaea foi comprovado pela redução da largura dos anéis de crescimento no período de 2000-11 e de 1971-2011, respectivamente. A densidade aparente média dos anéis de crescimento (T. grandis: 0,64 g/cm3 e de P. caribaea: 0,60 g/cm3) permitiu calcular o incremento de massa de carbono, resultando que as árvores sem lianas apresentam maior estoque de carbono do que as com lianas. A análise dendroclimatológica mostrou que as árvores de P. caribaea apresentaram correlações positivas com a disponibilidade de água no solo no período de seca; as árvores de T. grandis mostram correlação positiva com o período de maior chuva, temperatura de primavera e a oscilação antártica (AAO) de outono no ano corrente de crescimento, e correlação negativa com o evento de El Niño (TNI) em outono anterior. A ocupação das lianas na copa das árvores de T. grandis provocou o aumento da área dos vasos; os vasos do lenho inicial (e sua frequência) mostraram correlação significativa com a largura dos anéis de crescimento, possibilitando a construção de cronologias desses parâmetros e a avaliação da influência climática nas árvores. A ocupação das lianas na copa das árvores de P. caribaea induziu diminuição da frequência dos anéis de crescimento falsos, formados, principalmente, pelo aumento das pricipatações de Julio anterior y verão (DJF) e corrente. Os resultados deste estudo permitiram concluir que a análise dos anéis de crescimento das árvores das 2 espécies tem grande potencial para estudos ecológicos e ambientais no Brasil. / The trees of Tectona grandis (Verbenaceae) and Pinus caribaea var. hondurensis (Pinaceae) are used in dendroecological and dendroclimatologal studies by formation the annual growth rings. For these reasons, the study aimed to examine the tree-rings of the two species planted in Mata da Pedreira in Campus ESALQ/USP to climatic and ecological studies. We selected eight T. grandis trees (4 with and 4 without lianas occupying the trees canopy) and 10 P. caribaea trees (8 live - 4 with and 4 without lianas- and 2 dead). With the use Pressler increment borer was extracted 2-6 wood samples/tree of two species to analyze their trees-rings growth. Were applied: i) anatomical characterization macro and microscopic of trees-rings; ii) dendrochronology studies, by dating and evaluation of the trees radial growth; iii) evaluating the density of the wood by X-ray densitometry for determination of tree-rings density, biomass and carbon increment; iv) evaluating of influence of local climate and large-scale on tree-rings; v) Analysis of the vessel in T. grandis trees and false rings in P.caribaea trees. The main results showed that the anatomical characteristics of trees-rings of the both species coincide with those described in the literature; the series of trees-rings showed significant correlation with respect to the synchronization of trees-rings in the two species. The unfavorable effect of lianas in the canopy of trees T. grandis and P. caribaea was confirmed by the reduction of the tree-rings width in period 2000-2011 and 1976-2011, respectively. . The apparent density average of tree-rings (T. grandis: 0,64 g/cm3 e de P. caribaea: 0,60 g/cm3) allowed us to calculate the increase of carbon mass, resulting that trees without lianas had higher carbon stocks than those with lianas. The climatological analysis showed that P. caribaea showed positive correlations with water availability in the soil in the dry season; T. grandis trees showed positive correlations with period of highest rainfall, temperature of spring and AAO of fall in the current growing season, and negative correlation with El Niño event (TNI) in the fall. The ocupation of lianas on T. grandis trees caused the increase of the vessels area; the earlywood vessels (and frequency) had a significant correlation with the tree-rings, allowing build of chronologies of these parameters and evaluate the influences climate in the trees. The ocupation of lianas on P. caribaea trees induced a decrease in false rings, which are formed primarily by the increase of the previous July and current summer (DJF). The results of this study showed that the tree-rings analysis of the two species has great potential to ecological and climatical studies in Brazil.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In the state of Rio Grande do Sul the expansion of forestry has been one of the major agents of landscape change, occupying land previously intended for livestock farming and agriculture with low technical level, in areas under the influence of the Pampa biome and the transition of this biome for the Atlantic Forest. There is a widespread belief about the negative impacts caused by forest plantations on natural resources. Thus, it is necessary to evaluate the impacts caused by the introduction of forest plantations on the landscape components, especially on the soil and organic matter. This study was performed to characterize the components of the landscape topography, vegetation cover and their relations with soil, as well as temporal variation in soillandscape Forestry Experiment Station, located in the central region of Rio Grande do Sul were also found, changes in inventory levels and nitrogen (N and SN) and organic carbon (CO and SCO) in profiles Typic Umbrian and the labile and stable organic matter in surface horizon of the soil under native forest at the intermediate stage regeneration and field man-made with over 35 years, mixed forest of Eucalyptus and Eucalyptus robusta 35, forest of Eucalyptus grandis with 4 and 21 years, forest of Acacia mearnsii at age 7, forest of Eucalyptus saligna and 6 years mixed forest with Pinus 10 years. The results indicated that there is a transitory components of the landscape between the edge of the Southern Rio Grande Plateau and the Central Depression of Rio Grande do Sul, as well, there is a characterization of the natural vegetation types and conflicts of land use. It was also found that the relief and the genesis of the soils were vegetational conditions for development and that in 22 years there have been expanding cultivation of Eucalyptus and Pinus and the native forest on the anthropic field, especially in lands with Argissolos Bruno-Acinzentados and Argissolos Vermelhos. The organic matter of Argissolo Vermelho distrófico úmbrico, the results suggest that the levels and stocks of nitrogen and organic carbon of their surface horizon, altered by the introduction of man-made forest and field areas of deciduous forest, with a decrease especially in land occupied by forest of Acacia mearnsii and field of human activity. In relation to the stocks of organic carbon and nitrogen in the soil profile had a greater influence of other factors and processes of soil formation than the occupation of land in the last four decades. We also observed changes in the distribution of particulate organic carbon (POC g.kg-1) in the surface horizon of the soil, and this organic matter fraction of a sensitive indicator of changes in land use and soil. / No estado do Rio Grande do Sul a expansão da silvicultura tem atuado como um dos principais agentes de alteração da paisagem, ocupando terras anteriormente destinadas à pecuária extensiva e à agricultura com baixa tecnificação, em áreas sob a influência do bioma Pampa e na transição desse bioma para o de Mata Atlântica. Existe uma crença generalizada acerca dos impactos negativos ocasionados pelas plantações florestais sobre os recursos naturais. Assim, faz-se necessária a avaliação dos impactos causados pela introdução dos plantios florestais sobre os componentes da paisagem, principalmente sobre o solo e sua matéria orgânica. Neste estudo foi realizada a caracterização dos componentes da paisagem relevo, cobertura vegetal e suas relações com os solos, além da variação temporal da relação solo-paisagem numa Estação Experimental de Silvicultura, localizada na região central do Rio Grande do Sul. Foram verificadas também, as alterações nos teores e estoques de nitrogênio (N e SN) e de carbono orgânico (CO e SCO) em perfis de Argissolo Vermelho distrófico úmbrico e as frações lábeis e estáveis da matéria orgânica do horizonte superficial desse solo sob a Floresta nativa em estágio médio de regeneração e campo antrópico com mais de 35 anos, floresta mista do gênero Eucalyptus e de Eucalyptus robusta com 35 anos, floresta de Eucalyptus grandis com 4 e 21 anos , floresta de Acacia Mearnsii com 7 anos, floresta de Eucalyptus saligna com 6 anos e floresta mista do gênero Pinus com 10 anos. Os resultados indicaram que há um caráter transitório nos componentes da paisagem, entre o Rebordo do Planalto Sul-Riograndense e a Depressão Central do Rio Grande do Sul, como também, existe uma descaracterização das fitofisionomias naturais e a existência de conflitos de uso do solo. Constatou-se também, que o relevo e a gênese dos solos foram condicionantes para o desenvolvimento fitofisionômico e que em 22 anos houve expansão dos cultivos de Eucalyptus e Pinus, e da floresta nativa sobre o campo antrópico, principalmente nas terras com Argissolos Bruno-Acinzentados e Argissolos Vermelhos. Quanto à matéria orgânica do Argissolo Vermelho distrófico úmbrico, os resultados sugerem que os teores e estoques de nitrogênio e carbono orgânico do seu horizonte superficial, apresentam alterações frente à introdução de florestamentos e do campo antrópico sobre áreas de Floresta Estacional Decidual, havendo decréscimo principalmente em terras ocupadas pela floresta de Acacia Mearnsii e campo antrópico. Já em relação aos estoques de nitrogênio e carbono orgânico no perfil do solo, houve maior influência dos demais fatores e processos de formação do solo do que a ocupação das terras nas últimas quatro décadas. Foram constatadas também alterações na distribuição do carbono orgânico particulado (POC g.kg-1) no horizonte superficial do solo, sendo esta fração da matéria orgânica um indicador sensível às alterações no uso e ocupação do solo.

Though heavily criticized, the Kyoto Protocol has stood out as the key political tool in addressing climate change. However the only of its instruments (IET, JI, CDM) that allows industrialized and developing countries to cooperate towards mitigation of GHGs is CDM. The underlying assumption of forestry CDM is that forest plantations (afforestation/ reforestation) might help to remove carbon dioxide (the most representative GHG) emissions. This assumption takes for granted that forest plantations might compensate for the loss of natural forests. Therefore this alleged trade-off constitutes the very focus of this study. Due to high monetary price instability in brand new markets, like the carbon offset one, the analysis abstracts out money variables. Additionally, this engine helps overcome the trap set up by monetary prices as scarcity indicators. Thus, to go along with the bioeconomic analysis, a Gordon-Schaefer fishery-like model is applied to carbon forest sequestration in Rio Grande do Sul. This state is thought of bringing an interesting picture to the analysis of the claimed trade-off between natural and planted forests. This owes both to Rio Grande do Sul s unworthy deforestation rates and to its high natural-to-planted forest ratio. This land use assortment is thought of as if there were two countries or regions: a forest-rich one, where natural forests still remain, and a forest-poor one, where afforestation and/or reforestation takes place. Only physical units (MtC) are used to calculate exchange and interest rates as well as non-monetary prices. Next, a function that assigns the land use to natural and planted forests is arrived at. As such, it works as the emission removal demand. On the other hand, the emission supply function depends on the economic growth rates. The results show that, eventually, the sustainability of economic growth hinges on a region s or country s ecological situation namely, equilibrium, credit or debt. The economic and environmental advantages of each mitigation strategy CDM and natural forest conservation are crosschecked. A nearly 40-year long overshoot rate is, after all, estimated for the forest sector in Rio Grande do Sul. The estimates suggest that CDM might help relieve environmental stress only where ecological credit is reported. Where ecological debt is already on, CDM was found unable to compensate for conservation disregard. / Apesar das críticas que tem sofrido, o Protocolo de Kyoto tem-se constituído na principal ferramenta política para enfrentar a mudança climática. No entanto o único de seus instrumentos (comércio internacional de emissões, implementação conjunta e MDL) que prevê a cooperação entre países industrializados e em desenvolvimento para mitigar as emissões de GEE é o MDL. A modalidade florestal do MDL pressupõe que as plantações florestais (florestamento/reflorestamento) podem ajudar na remoção das emissões de dióxido de carbono (o GEE mais representativo). Esse pressuposto aceita que as plantações florestais podem compensar a perda de florestas naturais. Por isso esse proclamado trade-off constitui o foco principal deste estudo. Devido à grande instabilidade dos preços monetários em mercados incipientes como o do carbono, a análise abstém-se de utilizar variáveis monetárias. De resto, esse artifício ajuda a contornar certas dificuldades decorrentes da utilização dos preços monetários como indicadores de escassez. Assim, a análise bioeconômica prossegue com a aplicação, ao seqüestro florestal de carbono no Rio Grande do Sul, de um modelo similar ao de Gordon-Schaefer, tradicionalmente empregado na gestão da pesca. Por duas razões principais, o caso do Rio Grande do Sul contribui para a análise do suposto trade-off entre florestas naturais e plantadas. Em primeiro lugar, por não se registrarem taxas de desmatamento pronunciadas no estado. Em segundo lugar, pela elevada proporção de florestas naturais em relação às florestas plantadas em seu território. A repartição do uso do solo entre as florestas é utilizada para estudá-las como se representassem nações ou regiões diferentes: uma, rica em florestas, onde as formações florestais nativas permanecem em pé; outra, pobre em florestas, onde as plantações florestais se estabelecem através de florestamento e/ou reflorestamento. Apenas unidades físicas (MtC) são utilizadas para calcular taxas de câmbio, taxas de juro e preços não-monetários. A seguir, deduz-se uma função que reparte o uso da terra entre florestas naturais e plantadas. Essa função equivale à demanda por remoção de emissões. Sua contraparte é a função oferta de emissões, que depende das taxas de crescimento econômico. Os resultados mostram como, em última análise, a sustentação do crescimento econômico está condicionada à situação ecológica (dívida, crédito ou equilíbrio) de um país ou região. Em cada cenário, confrontam-se as vantagens econômicas e ambientais das estratégias do MDL e da conservação de florestas naturais. Além disso, estima-se uma taxa de overshoot para a atividade florestal no Rio Grande do Sul ao longo dos últimos 40 anos aproximadamente. As estimativas sugerem que o MDL pode aliviar pressões ambientais somente onde se registre crédito ecológico. Onde o endividamento ecológico já esteja em curso, o MDL não substitui a conservação.

Communicating science in three-dimensional (3D) multimedia is an immersive and interactive way to explore scientific processes (Signals and Communication Technology, 2019). Geovisualization is an emerging 3D multimedia method for visual analysis, synthesis, and presentation of geospatial, geologic, and geophysical data (MacEachren & Kraak, 2001). There is an identified need to develop scientific communication tools to further understand boreal peatland evolution, hydrogeology, ecology, and geochemistry (Bubier et al., 2003) since the International Union of Conservation of Nature asserts that peatlands are among the most valuable ecosystems on Earth, critical for preserving global biodiversity, providing drinking water, minimising flood risk, preventing wildfire, and mitigating climate change (Hama et al., 2000). The intention of this thesis is to communicate a novel approach to geovisualize boreal peatland architecture using Light Detection and Ranging (LiDAR) and Ground Penetrating Radar (GPR). GPR and LiDAR have been used to create 3D subsurface geovisualizations for archaeology (Kenady et al., 2018; Schultz & Martin, 2011) and resource geology (Corradini et al., 2020; Koyan & Tronicke, 2020) although application to peatland hydrogeology is uncommon. Point-source hydrogeological and geochemical data were integrated with 3D geological models to estimate carbon and nitrogen storage in an archetypal boreal peatland near Mariana Lakes, Alberta. Peatland geometry resembled a shallow lake basin with depths greatest in fens (>10 m) and thinnest in bogs (<2 m). Hydraulic conductivity was only a few meters per year and vertical groundwater movement was limited. Sequestered carbon and nutrients increased with depth. The average concentration of dissolved ammonium was 3 grams per cubic metre of peat (g/m3), 5g/m3of Total Kjeldahl Nitrogen, 60g/m3 of dissolved organic carbon and 200g/m3 of dissolved inorganic carbon. Tritium detection from atmospheric atomic weapons radionuclide fallout revealed that in deeper anaerobic peat (catotelm), tritium was absent, signifying groundwater was older than 50 years and not mixed with meteoric waters. Fen catotelm channels are likely acting as gravity-driven hydraulic traps (Tóth, 1999). / Graduate

<p>Methane (CH₄) is the second most powerful greenhouse gas (GHG) behind carbon dioxide (CO₂), and is able to trap a large amount of long-wave radiation, leading to surface warming. Carbon monoxide (CO) plays an important role in controlling the oxidizing capacity of the atmosphere by reacting with OH radicals that affect atmospheric CH₄ dynamics. Terrestrial ecosystems play an important role in determining the amount of these gases into the atmosphere. However, global quantifications of CH₄ emissions from wetlands and its sinks from uplands, and CO exchanges between land and the atmosphere are still fraught with large uncertainties, presenting a big challenge to interpret complex atmospheric CH₄ dynamics in recent decades. In this dissertation, I apply modeling approaches to estimate the global CH₄ and CO exchanges between land ecosystems and the atmosphere and analyze how they respond to contemporary and future climate change.</p> <p>Firstly, I develop a process-based biogeochemistry model embedded in Terrestrial Ecosystem Model (TEM) to quantify the CO exchange between soils and the atmosphere at the global scale (Chapter 2). Parameterizations were conducted by using the CO <i>in situ</i> data for eleven representative ecosystem types. The model is then extrapolated to global terrestrial ecosystems. Globally soils act as a sink of atmospheric CO. Areas near the equator, Eastern US, Europe and eastern Asia will be the largest sink regions due to their optimum soil moisture and high temperature. The annual global soil net flux of atmospheric CO is primarily controlled by air temperature, soil temperature, SOC and atmospheric CO concentrations, while its monthly variation is mainly determined by air temperature, precipitation, soil temperature and soil moisture. </p> <p>Secondly, to better quantify the global CH₄ emissions from wetlands and their uncertainties, I revise, parameterize and verify a process-based biogeochemical model for methane for various wetland ecosystems (Chapter 3). The model is then extrapolated to the global scale to quantify the uncertainty induced from four different types of uncertainty sources including parameterization, wetland type distribution, wetland area distribution and meteorological input. Spatially, the northeast US and Amazon are two hotspots of CH₄ emissions, while consumption hotspots are in the eastern US and eastern China. The relationships between both wetland emissions and upland consumption and El Niño and La Niña events are analyzed. This study highlights the need for more in situ methane flux data, more accurate wetland type and area distribution information to better constrain the model uncertainty.</p> <p>Thirdly, to further constrain the global wetland CH₄ emissions, I develop a predictive model of CH₄ emissions using an artificial neural network (ANN) approach and available field observations of CH₄ fluxes (Chapter 4). Eleven explanatory variables including three transient climate variables (precipitation, air temperature and solar radiation) and eight static soil property variables are considered in developing the ANN models. The models are then extrapolated to the global scale to estimate monthly CH₄ emissions from 1979 to 2099. Significant interannual and seasonal variations of wetland CH₄ emissions exist in the past four decades, and the emissions in this period are most sensitive to variations in solar radiation and air temperature. This study reduced the uncertainty in global CH₄ emissions from wetlands and called for better characterizing variations of wetland areas and water table position and more long-term observations of CH₄ fluxes in tropical regions.</p> <p>Finally, in order to study a new pathway of CH₄ emissions from palm tree stem, I develop a two-dimensional diffusion model. The model is optimized using field data of methane emissions from palm tree stems (Chapter 5). The model is then extrapolated to Pastaza-Marañón foreland basin (PMFB) in Peru by using a process-based biogeochemical model. To our knowledge, this is among the first efforts to quantify regional CH₄ emissions through this pathway. The estimates can be improved by considering the effects of changes in temperature, precipitation and radiation and using long-period continuous flux observations. Regional and global estimates of CH₄ emissions through this pathway can be further constrained using more accurate palm swamp classification and spatial distribution data of palm trees at the global scale.</p>

<p>This thesis is a collection of three research articles to quantify carbon fluxes and isotopic signature changes across global terrestrial ecosystems. Chapter 2, the first article of this thesis, focuses on the importance of an under-estimated methane soil sink for contemporary and future methane budgets in the pan-Arctic region. Methane emissions from organic-rich soils in the Arctic have been extensively studied due to their potential to increase the atmospheric methane burden as permafrost thaws. However, this methane source might have been overestimated without considering high affinity methanotrophs (HAM, methane oxidizing bacteria) recently identified in Arctic mineral soils. From this study, we find that HAM dynamics double the upland methane sink (~5.5 TgCH₄yr^-1) north of 50°N in simulations from 2000 to 2016 by integrating the dynamics of HAM and methanogens into a biogeochemistry model that includes permafrost soil organic carbon (SOC) dynamics. The increase is equivalent to at least half of the difference in net methane emissions estimated between process-based models and observation-based inversions, and the revised estimates better match site-level and regional observations. The new model projects double wetland methane emissions between 2017-2100 due to more accessible permafrost carbon. However, most of the increase in wetland emissions is offset by a concordant increase in the upland sink, leading to only an 18% increase in net methane emission (from 29 to 35 TgCH₄yr^-1). The projected net methane emissions may decrease further due to different physiological responses between HAM and methanogens in response to increasing temperature. This article was published in <i>Nature Climate Change</i> in March 2020.</p> <p>In Chapter 3, the second article of this thesis, I develop and validate the first biogeochemistry model to simulate carbon isotopic signatures (δ¹³C) of methane emitted from global wetlands, and examined the importance of the wetland carbon isotope map for studying the global methane cycle. I incorporated a carbon isotope-enabled module into an extant biogeochemistry model to mechanistically simulate the spatial and temporal variability of global wetland δ¹³C-CH₄. The new model explicitly considers isotopic fractionation during methane production, oxidation, and transport processes. I estimate a mean global wetland δ¹³C-CH₄ of -60.78‰ with its seasonal and inter-annual variability. I find that the new model matches field chamber observations 35% better in terms of root mean square estimates compared to an empirical static wetland δ¹³C-CH₄ map. The model also reasonably reproduces the regional heterogeneity of wetland δ¹³C-CH₄ in Alaska, consistent with vertical profiles of δ¹³C-CH₄ from NOAA aircraft measurements. Furthermore, I show that the latitudinal gradient of atmospheric δ¹³C-CH₄ simulated by a chemical transport model using the new wetland δ¹³C-CH₄ map reproduces the observed latitudinal gradient based on NOAA/INSTAAR global flask-air measurements. I believe this study is the first process-based biogeochemistry model to map the global distribution of wetland δ¹³C-CH₄, which will significantly help atmospheric chemistry transport models partition global methane emissions. This article is in preparation for submission to <i>Nature Geoscience</i>.</p> <p>Chapter 4 of this thesis, the third article, investigates the importance of leaf carbon allocation for seasonal leaf carbon isotopic signature changes and water use efficiency in temperate forests. Temperate deciduous trees remobilize stored carbon early in the growing season to produce new leaves and xylem vessels. The use of remobilized carbon for building leaf tissue dampens the link between environmental stomatal response and inferred intrinsic water use efficiency (iWUE) using leaf carbon isotopic signatures (δ¹³C). So far, few studies consider carbon allocation processes in interpreting leaf δ¹³C signals. To understand effects of carbon allocation on δ¹³C and iWUE estimates, we analyzed and modeled the seasonal leaf δ¹³C of four temperate deciduous species (<i>Acer saccharum, Liriodendron tulipifera, Sassafras albidum, </i>and <i>Quercus alba</i>) and compared the iWUE estimates from different methods, species, and drought conditions. At the start of the growing season, leaf δ¹³C values were more enriched, due to remobilized carbon during leaf-out. The bias towards enriched leaf δ¹³C values explains the higher iWUE from leaf isotopic methods compared with iWUE from leaf gas exchange measurements. I further showed that the discrepancy of iWUE estimates between methods may be species-specific and drought sensitive. The use of δ¹³C of plant tissues as a proxy for stomatal response to environmental processes, through iWUE, is complicated due to carbon allocation and care must be taken when interpreting estimates to avoid proxy bias. This article is in review for publication in <i>New Phytologist</i>.</p> <p> </p>

Indiana University-Purdue University Indianapolis (IUPUI) / Deep injection of waste CO2 and fluids from regional energy plants into the St. Peter Formation of the Illinois Basin, could effectively provide long term deep geologic storage. This research aims to explore the viability of this proposed injection. There are some basic criteria that must be met to effectively store waste in a geologic reservoir. First, the reservoir must have sufficient porosity and permeability for both injectivity and for migration of the injected fluid through the reservoir. Second, the reservoir must be overlain by some form of impermeable seal or cap layer(s). Third, the reservoir should be sufficiently isolated from interaction with surface and near surface water. Finally, the formation must contain enough storage volume to handle significant amounts of injected material. Massive sandstone formations that host large saline aquifers have the potential to serve as high capacity storage sites. Much of the research targeting the potential suitability and storage capacity attributes of these formations has been promising, but reproducibility of the results has been less than ideal. Some of this variability has been attributed to petrological differences in the sandstone reservoirs that are not readily evident when studying the target formation over a geographically significant area. Based on the criteria, a promising candidate for injection and storage is the St. Peter Sandstone of the Illinois Basin. This study investigates the viability of liquefied CO2 storage within the St. Peter Sandstone on a micro scale. Initial porosity and permeability of the formation plug samples ranged from 16% to 19% and 26 to 981 millidarcies (mD), respectively. The wide difference in permeability is attributed to variations in strength of the cement, in this case quartz overgrowth in the sandstone. This preliminary evidence indicates that the storage capacity of the formation will remain constant or increase depending on injection location, suggesting that the St. Peter Formation will lend itself well to future storage.