Maria Victoria Ramos Ballester.

The research objective is to examine, at different scales, the processes that govern the
advection and reaction of carbon in the lowest reach of the Amazon River and along the near-shore coastline of the Western Tropical Atlantic Ocean. The mainstem of the river is a large supplier of carbon dioxide (CO2) to the atmosphere, most of which is sourced as organic carbon from the surrounding landscape and subsequently remineralized in river. The component of the river system that is least well understood is the lower tidal reach, which consists of two main channels across from Macapá down 150 km to the ocean. While tidal forcing does not result in salt intrusion, riverine flow in this reach can be reversed, and complex interactions occur between the river channels and the fringe areas, making the study of this component of the world?s largest river a significant logistical challenge. Through an ambitious field study the project aims to understand the large-scale drivers (e.g. hydrodynamics, areal extent, metabolism) that create the spatial and temporal variability in carbon remineralization and CO2 fluxes in the lower river. This will be addressed using a combination of field work and modeling. In addition, the types of organic matter that are degraded, the microorganisms and consortia that remineralize, and the metabolic pathways (aerobic, anaerobic) that lead to the large production of CO2 will be evaluated using a combination of organic geochemical and molecular biological (proteomic) tools. The proposed work will provide in situ observations in a previously unstudied region of high global importance, experimentation focused on unraveling the influence of physical factors (e.g. tides, current velocity, and mixing) on
biological processes, and modeling tools capable of predicting the sensitivity of Net Ecosystem Exchange (NEE).

LANDMARK is a European Research Project on the sustainable management of land and soil in Europe. The questions that LANDMARK aims to address are: ?How can we make the most of our land? How can we ensure that our soils deliver on the many expectations we have of our land??. These expectations (or ?demands?) include:

Primary productivity (agriculture and forestry)
Water purification and regulation
Carbon sequestration, cycling and regulation
Provision of functional and intrinsic biodiversity
Provision and cycling of nutrients.
LANDMARK is a pan-European multi-actor consortium of 22 partner institutes from 14 EU countries plus Switzerland, China and Brazil. These include universities, applied research institutes, Chambers of Agriculture, an SME and the European Commission that will develop a coherent framework for soil management aimed at sustainable food production across Europe. Landmark is led by Wageningen University and Research (WUR) and is supported by a series of organizations being part of our Stakeholder Steering Committee ( FAO, COPA-COGECA, EFI, EUFRAS, DG-AGRI, DG-ENV, EMBRAPA, EFSA, EEA, EIONET, etc.)

The expansion of agricultural land and the intensification of agricultural production are among the most profound human alterations of the global environment. This expansion, intensification and globalization of agriculture has doubled world production of cereal crops since 1960 and modernized agriculture now provides food for more than 6 billion people?a number once thought impossible. The expansion of more intensive agricultural systems has brought many benefits but it also comes with risks to the water supplies on which both intensive agricultural production and peoples' livelihoods depend. Structuring agricultural production to meet human demands for food while maintaining water security is one of modern humanity?s great challenges.
The earth's tropical regions are now the frontier for this global trend. Most of the expansion and intensification of the world's agricultural production over the next several decades are projected to take place in the tropics. This intensification can involve both changes to cropping systems and the integration of regional animal and crop production. It is taking place in parts of the tropics where rainfall can be both highly seasonal and highly variable from year to year. 
Expansion and intensification of agriculture in these expanding tropical frontiers raises several critical issues for water security:
(1) Expansion of cropland into areas with a shorter rainy season or more variable rainfall makes agriculture more vulnerable to changes in rainfall and climate;
(2) Intensification of agricultural, such as double-cropping, that extends the period of crop growth to the edges of the rainy season when rainfall is less frequent or more sporadic, also make agriculture more vulnerable to changes in rainfall and climate;
(3) Changes to land cover or cropping systems caused by agricultural expansion and intensification alter local patterns of evapotranspiration and runoff in ways that could decrease regional rainfall but increase river flows and potential flooding; 
(4) Expansion and intensification of cropping can degrade water quality by increasing surface runoff and the concentrations of sediment and nutrients in steams and rivers;
(5) Expansion and intensification of agriculture can alter aquatic habitats by reducing riparian forest, increasing stream temperatures, restricting fish movements and degrading the quality of stream channel habitats and lowering fish production;
(6) Integration of animal production facilities with more intensive crop production can degrade water quality, especially if animal waste is not carefully managed.

River systems are significant components of the global carbon cycle because they modulate and adjust the carbon dynamics not only of their watersheds but also of their marine receiving waters. Their primary role is as an immense source of outgassing of CO2 from inland waters to the atmosphere. Globally, inland waters process, transport and bury 2.7 Pg C y-1, a number nearly equal to the size of the terrestrial sink for anthropogenic C (2.8 Pg C y-1). Hence, rivers play an important role in the global C budget by essentially relocating and/or mitigating terrestrial autotrophic processes. If this effect is important, then the global terrestrial CO2 sink may prove to be smaller than current estimations indicate. Unraveling the processes that occur as water travels downstream and into the ocean is critical to understanding the role of freshwater ecosystems in global C cycling, yet a mechanistic understanding of these fluxes remains elusive. While the magnitude of outgassing is becoming well-recognized, understanding the combination of terrestrial sources and in situ processes fueling these globally-relevant CO2 fluxes is fundamentally limited. Understanding the remineralization potential of specific OM types/sources and the underlying mechanisms controlling their fate has significant implications for calculations of the overall carbon balance of a basin and predictions of future change.
Recent advances in technology allow exciting new work that has not been previously possible, and riverine systems can now be effectively examined and understood through the lenses of Net Ecosystem Exchange (NEE) and ?Metabolic Efficiency.? Our overall objective is to examine the processes that govern the advection, reaction, and transitions of carbon through the lower reach of the Amazon River, from Óbidos (the last traditional measuring station on the Amazon), to the ocean. An ambitious field study, combining cutting edge geochemical, metabolomic, and geospatial analyses, will explore the influence of downstream processing on globally-relevant geochemical fluxes. Six unique approaches will be employed: 1) deployment of in situ incubator systems that make continuous measurements of important river components and can collect discrete samples, 2) measurement of CO2 fluxes and 13C isotopic compositions using our incubation systems coupled to a field-portable isotopic gas analyzer, 3) examination of the organic matter fueling respiration using a metabolomics approach based on high resolution mass spectrometry and compound specific radiocarbon dating, 4) determination of the proportion of respired organic matter that is fixed as biomass or lost as CO2 to determine the Metabolic Efficiency of various OM types, 5) deployment of an ADCP-based (Acoustic Doppler Current Profiler) approach to accurately quantify water fluxes along different reaches of a river, and 6) development of a coupled Lagrangian transport/basin hydrology model to provide the quantitative context to integrate terms into the evaluation of Net Ecosystem Exchange.

This project aims to develop the tools to describe comprehensively the biogeochemistry of fluvial systems in the Amazon and the Pantanal and their role in regional and global carbon cycles, in order to predict their influence and responses to a changing climate. We hypothesize that H1. Hydrology is the main driver of the biogeochemistry of carbon (and other nutrients) in rivers of the Amazon and Pantanal. Hence, different amounts of rain (and runoff) will set new functional levels in these systems; H2. There are common set of drivers controlling carbon (and nutrients) biogeochemistry in tropical rivers of the Amazon and Pantanal. Our current inability to model adequately these systems across all scales results from the lack of intercomparable long-time records, instead of the inadequacy of the models; H3. Rivers are active players in the overall carbon balance of these basins. Climatic changes affecting these systems will also change their role in feedbacks with the atmosphere and the regional carbon cycle. The outcome of this project will be fundamental to the development of the Brazilian climatic model, helping to create a unique design in which not only biosphere but also fluvial feedbacks are considered in the regional carbon cycle. 
3) General Goals
	Our main objective is to produce enough scientific information about the functioning of fluvial systems in the Amazon and the Pantanal to be able to develop basin-scale heuristic models linked to regional carbon cycle and allowing to predict their responses to global climate change.
4) Specific goals
	Goal 1. Obtain detailed information on carbon and associated nutrients distribution and processing along the different spatial and temporal scales necessary to define common sets of drivers in the functioning of rivers in the Amazon and Pantanal under pristine and impacted environmental conditions. 
	Goal 2. Reduce the uncertainties in CO2 evasive fluxes (hence on the role of rivers in the regional C cycle) by

Availability of landuse and land cover data is uneven over the LPB. While there is considerable information in Brazil, it is limited and of varying quality and resolution for the other LPB countries. Therefore, the main goal of this activity is to identify data sources, locate, compile and consolidate these data sets on common protocols. The project will take advantage of its multi-national network of researchers to help identify priority data sets on land use, and base the analysis on unified protocols and a standardized database design. Critical data sets will be assembled into a geo-referenced database using consensus formats and protocols. A Web-based system will disseminate results from this activity, providing a collaborative framework to assemble and share expert knowledge about land ecosystem changes from researchers across the basin.

In addition to classifying current landuse, Group1 will build a 10-year time series of detailed changes in land cover/use on local, regional and basin scales, identify gaps in data, and define future fieldwork required. This will be done based on algorithms developed and provided by Group4 (EMBRAPA, Rio de Janeiro) and is further described in that section.

Once regions with significant change have been identified, ground truthing and interviews will provide more detail. In this way, the relevant drivers of land use change in selected parts of the basin will be identified in cooperation between the remote sensing and sociology teams, and an analysis of current competing claims will become possible based on the stakeholder problem identification. This project component will develop close links with relevant stakeholders, such as the AAPRESID and AACREA (farmer associations in the Pampas and Chaco) and governmental agencies such as the Instituto Nacional del Agua in Argentina and Paraguay.

The land use/cover change team has the following specific research objectives:

- describe and categorize the main land cover/use ch

O paradigma desse projeto é que a biodiversidade em bacias hidrográficas é gerada e preservada pelas interações entre o ambiente físico, processos biogeoquímicos e ações antrópicas. Portanto, baseando-se nesse paradigma, a biodiversidade não pode ser apropriadamente investigada sem uma caracterização da estrutura e funcionamento de bacias hidrográficas. O programa Biota-Fapesp abre uma oportunidade única de investigar os efeitos dos atributos da paisagem e biogeoquímica sobre a biodiversidade, uma vez que haverá, de uma maneira interativa, vários projetos lidando com esses tópicos. Nesse projeto pretendemos investigar a biogeoquímica de bacias de meso (103 to 104 km2) e micro-escala (101 to 102 km2) como subsídio para interpretar resultados advindos de projetos relacionados à biodiversidade aquática dentro do programa Biota-Fapesp. A ligação entre fatores ambientais e biodiversidade será feita: (1) trabalhando nas mesmas áreas dos projetos voltados a investigar a biodiversidade aquática e (2) através de parâmetros específicos e análises que ligam atributos da paisagem e biogeoquímica de ecossistemas com aqueles relacionados à biodiversidade. Na meso-escala nosso objetivo específico será determinar se atributos químicos e físicos de rios e da atmosfera respondem diferentemente entre bacias hidrográficas com diferentes impactos

Para completar a análise das vias de transporte do C das fontes terrestres até sua evasão para a atmosfera nos sistemas fluviais, é necessário conhecer as vias dos fluxos que a geram, bem como, os padrões sazonais de inundação para cada segmento da rede de drenagem. Para tal será utilizado o modelo de Capacidade de Infiltração Variável, um modelo físico com parametrização para representar as trocas verticais de umidade e energia entre o dossel e a atmosfera. Neste modelo são representados os efeitos da variabilidade espacial das propriedades do solo, topografia e vegetação, bem como os efeitos destes parâmetros na geração do escoamento superficial. Para produzir não apenas de forma precisa a descarga, mas também representar corretamente as vias que podem alterar as trocas de C, será utilizado um modelo hidrológico de alta resolução, Distributed Hydrology Soil Vegetation. Para calibrar e comparar os resultados dos dois modelos acima sitados foi escolhida a bacia do rio Ji-Paraná, por possuímos um conjunto de bibliotecas digitais georrefenciadas, em várias escalas espaciais, sobre os atributos da superfície. Para reconstruir os padrões regionais de inundação para o canal principal será utilizado o modelo matemático derivado das correlações obtidas entre as cotas dos rios e os mapas mensais das áreas inundadas. Para os rios com largura inferior a 100 metros, partir de dados observacionais de descarga e parâmetros do rio (como largura e profundidade do canal), serão desenvolvidas, empíricamente, equações para caracterizar as relações das Leis de Potência dos rios. Utilizando um SIG e o Modelo Digital de Elevação do Terreno, será derivada a relação área de drenagem-descarga . A partir dos valores de descarga conhecidos, da área das bacias de drenagem e do comprimento ou da largura do canal, será possível estabelecer uma relação entre descarga e área de drenagem.

Recent work by the CD-06 project on the overall patterns and dynamics of pCO2 in Amazonian waters has confirmed and expended upon our perspectives of the overall importance of fluvial outgassing in the Amazon carbon budget. While provocative, these early results represent a work in progress; much remains to be done. It is important to be able to track processes from a local source to downstream aggregation.. Models are needed to be able to express river chemistry in explicit, process-based terms of the attributes of the landscape, and the movement of water through the landscape. The overall objective of the work proposed here is to determine the sequence of processes, from small to large scales, which defines the role of fluvial systems in the C cycle of the Amazon. To conduct the data synthesis and modeling activities, we propose a set of 4 tasks. Task 1 is to conduct 2 integration workshops, as "bookends" on the project. The workshops will include short courses, data integration, and formulation of model algorithms, with the outcomes of papers and a book. Task 2 is to complete and integrate cross-system field data into the modeling environment. Task 3 is to establish a "Virtual Scaleable Basin" modeling and cyber-informatics infrastructure, and to incorporate a fine-scale solute export model, a scaling hydrology model, and a net ecosystem production module (NPP), all driven by surface forcing. With Task 4, we will be able to evaluate coupled the carbon and hydrologic dynamics of the Amazon Basin, under current and changing conditions

This project will advance our understanding of how changes in land cover influence the ecological and biogeochemical functioning of Amazon rivers and how these changes are altering the fluxes of carbon and nutrient fluxes at the regional scale in the Amazon basin. It will improve understanding of carbon and nutrient dynamics of the Amazon and specifically the question of the transport of carbon and nutrients from terrestrial ecosystems to stream and rivers. Our estimates of the extent of stream channel altered by deforestation, linked with our field measurements that have documented major changes to stream function caused by deforestation, will contribute to understanding the magnitude of the effects of deforestation on the aquatic life, fisheries and biological diversity of the Amazon and the sustainability of the goods and services that streams and rivers provide to Amazon residents

Os trópicos úmidos têm um importante, mas ambíguo, papel no ciclo global do carbono. Enquanto estima-se que o desmatamento libere 1,6 Gt (109 T) de C por ano para a atmosfera (Houghton, 2000), as florestas da Amazônia parecem sequestrar (atuar com sorvedouros) carbono, mas em magnitudes incertas. As estimativas atuais de sequestro apresentam grandes variações entre os direrentes tipos de medidas, desde ~1,3 Mg C.ha-1.ano-1, baseadas na acumulação na biomassa e nos solos (Phillips et al., 1998; Trumbore, 2000; Chambers et al., 2001), até 1,0 a 5,9 Mg C.ha-1. ano-1, obtidas por cálculos de fluxos de vórtices turbulentos (eddy covariance) (Fan et al., 1990; Grace et al., 1995; Malhi et al., 1998). Por outro lado, cálculos baseados em modelagem atmosférica global inversa resultam em uma troca líquida de carbono dos trópicos com a atmosfera próxima de zero (Schimel et al., 2001). Estas discrepâncias nas estimativas das taxas de sequestro de carbono podem ser atribuídas, em parte, a diferenças metodológicas e de tempos de integração. Entretanto, é possível, também, que parte do carbono fixado seja "exportado" através de fluxos ainda não quantificados precisamente. De fato, resultados preliminares (Richey et al., 2002) demonstraram que os fluxos evasivos de CO2, a partir de sistemas aquáticos da região central da Amazônia podem ser de magnitude similar à menor estimativa apresentada para o sequestro de carbono pelas florestas em terra firme.
	Neste projeto, pretendemos testar a hipótese que A evasão de CO2 retorna à atmosfera tanto carbono quanto é fixado nas florestas de terra firme em bases interanuais e a exportação de material orgânico das florestas de terra firme para os ambientes fluviais é a fonte primária do carbono que é eventualmente respirado nos rios e evadido como CO2. Para testá-la, pretendemos (1) obter suficientes medidas de pCO2 de sub-bacias características dos distintos ambientes fluviais da Amazônia, abrangendo todo o regime hidrológico, para com

Our proposed research addresses the overall role rivers and periodically inundated environments play in the biogeochemical cycles of the Amazon Basin. Recent evidence suggests that outgassing of CO2 is of comparable magnitude to the lower estimates of carbon sequestration by forests. We have two primary objectives: Objective 1. Complete research on the question of landuse change and its consequences for water chemistry in the Ji-Paraná River Basin
 Objective 2. Expand research on the fluxes of gases between wetlands and the atmosphere, by testing the working hypothesis that ¿CO2 evasion returns as much carbon to the atmosphere as is sequestered in upland forests on an interannual basis. Export of organic material from upland and riparian forests to fluvial environments is the primary source of carbon that is eventually respired in rivers and evaded as CO2.¿ We propose to address our objectives by (1) Conducting fieldwork in characteristic sub-basins to complete water chemistry and to obtain an extensive suite of pCO2 distribution measurements over the hydrologic regime, and to use proven geochemical techniques (gas flux measurements, isotopic tracers, remineralization rates) to quantify the rates of the lateral transfer and cycling of water and bioactive organic matter from the land, through riparian environments and to the river system. (2) Using a terrestrial source/river transport and reaction model to synthesize and extrapolate the site-specific CO2 evasion rate measurements to a basin-wide estimate of CO2 evasion rate. The overall research here is relevant to a series of the LBA-ECO Science questions. The work considers explicitly the effects of changing land use, the relation of surface water chemistry to regional flow patterns, and the role of the extensive wetlands and temporarily inundated or saturated areas in Amazônia.

Deforestation in the Amazon has the potential to alter the biogeochemistry of carbon and major nutrients over large regions and to alter the movements of these materials among adjoining ecosystems. Small streams dominate the total length of stream channels in the landscape. They receive material from adjacent uplands and contribute material to larger rivers. Because of their position, small streams and their riparian zones thus play a key role in the landscape as regulators of material fluxes between terrestrial ecosystems and larger rivers of the Amazon Basin. 
Our goal is to develop an understanding of how carbon (C) and nutrients are transformed as water moves from uplands through small streams to larger rivers in forested and deforested landscapes. We will do this by: 1) focusing on carbon and nutrient transformations in riparian zones and small stream channels¿key connection points in the landscape where these transformations are potentially of major importance but very poorly known in tropical landscapes; 2) comparing these transformations in drainage basins with forest and pasture land use and in streams of different sizes, and; 3) coupling our process level work with information on land use and riparian zone structure derived from remote sensing and models of stream channel processing to predict regional changes in biogeochemical budgets.

The overall question we are addressing in this proposal is, ¿What role does the evasion (outgassing) of CO2 from the river system to the atmosphere play in the carbon cycle of moist tropical forests?¿ Recent evidence suggests that the Amazon may be a net sink of atmospheric CO2 of 1-9 Mg C ha-1 y-1 . We have made recent calculations that suggest that the evasion of CO2 from the river system of the central Amazon basin is on the order of 1.2 ± 0.3 Mg C ha-1 y-1. A flux of this magnitude suggests that the ecosystem processes involved in river corridors represent a significant pathway for the export of carbon fixed on land in the humid tropics at a globally-significant level. Our working hypothesis is that: CO2 evasion returns as much carbon to the atmosphere as is sequestered in upland forests on an interannual basis. Export of organic material from upland forests to fluvial environments is the primary source of carbon that is eventually respired in rivers and evaded as CO2. We propose to test our hypothesis by conducting fieldwork in characteristic sub-basins of the Amazon (to determine the spatial and temporal distributions of pCO2 and to use geochemical techniques to quantify the rates of transfer of water and bioactive organic matter) and to use a terrestrial source/river transport and reaction model to synthesize and extrapolate the site-specific CO2 evasion rate measurements to a basin-wide estimate of CO2 evasion rate. We propose eight specific tasks to do this work: find and characterize representative sampling environments, determine distributions of pCO2, assess gas exchange rates, evaluate the source strength of terrestrial and river margin organic matter and CO2, determine in situ respiration rates and substrates, characterize the isotopic and organic composition of dissolved organic and inorganic carbon, determine the seasonality of inundation and terrestrial runoff, and synthesize observations and modeling in computing downstream fluxes.

O principal objetivo dessa proposta é conhecer como a conversno das florestas em pastagens altera a distribuiçno do carbono e nutrientes (nitrogLnio e fósforo), a produçno primária e seus fatores limitantes, e a biodiversidade em rios tropicais de pequeno e médio porte. Para tal propomos a comparaçno de bacias onde predominam as florestas originais com bacias ou áreas que foram desmatadas e hoje sno cobertas predominantemente por pastagens. Propomos esse tipo de comparaçno em duas escalas: trabalhando em pequenas bacias (~10km2) situadas na Fazenda Nova Vida e ao longo da bacia do rio Ji-Paraná (~104 km2), que é considerada uma bacia de meso-escala para os padrtes da regino Amazônica. A Lnfase deste projeto será dada B distribuiçno espacial e temporal do carbono, nitrogLnio e fósforo. Quanto aos processos limnológicos, serno abordadas mudanças na produçno primária devido B substituiçno de florestas por pastagens e também a fatores limitantes deste processo, tanto abióticos (luz) como nutricionais (nitrogLnio e fósforo). Quanto B biodiversidade, serno analisadas as alteraçtes nas populaçtes de macroinvertebrados ao longo de gradientes de uso do solo. Finalmente, os padrtes ou ¿sinais biogeoquímicos¿ serno acompanhados ao longo destas escalas (micro e meso-escalas), para avaliar suas alteraçtes espaço-temporais. Tendo em vista que o ciclo da água constitui um dos vetores mais importantes da biogeoquímica de bacias de drenagem, paralelamente aos processos acima, serno geradas informaçtes detalhadas sobre a hidrologia das áreas de estudo.

Este projeto teve como objetivo adquirir e tornar operacional uma base de Sistema de Posicionamento Global no Campus de Piracicaba da Universidade de São Paulo

Using a time series of remotely sensed data and site-specific (spatially sampled) sub-pixel measurements of surface elevation, we will filter the spectral reflectance measures to infer the pixel response for surface water, photosynthetic activity, and exposure of non-photosynthetic material. By matching these patterns with measurements which characterize stream density at various scales, we will integrate a spatial/temporal explicit model linked to the observed patterns in the biogeochemistry we measured at our various sampling points. We will develop (presumably jointly with other LBA groups) spatial data layers (topography, soils, land use) sufficient to evaluate 4 km, 1 km, and ultimately 30 m resolution. The model should also be responsive to the hydrological response unit (HRU) being developed elsewhere. The metrics we will determine include: stream density (km of stream length/km2), stream frequency (# of stream segments/km2), confluence density (# of stream confluences/km2), 2-D fractals of streams, interspersion and juxtaposition (IAJ) between riparian zones and land cover types, and basin configuration diversity

Periodically or permanently flooded areas play important roles in the hydrology and biogeochemistry of the Amazon basin, and are particularly subject to changes in land cover and land use. As land cover changes, with concomitant alterations in hydrology and vegetation, significant changes in the partitioning between aqueous and gaseous species are be expected in river corridors. These pathways and fluxes might be seen as a function of the changes in the scale of the spatial and temporal structure (composition and configuration) of land cover. We will address these issues in a project which will include field studies and remote sensing integrated within an overall model/synthesis environment. Field work will be conducted on an ¿intensive¿ study region, the Ji-parana basin in Rondônia, with a focus on tracking the chemical ¿signals¿ of rivers at larger scales back to their points of origin. Work will be targeted to develop process models which specify how flow paths and volumes are required together with soil water chemistry and soil process information to estimate solute delivery to riparian zones and stream channels. Sampling profiles of soil solution and trace gas fluxes from uplands through riparian zones into and through river networks will be conducted.

Para entender e monitorar as mudanças na cobertura e no uso da terra, é necessário caracterizar a paisagem em termos dos componentes físicos, bióticos e antrópicos, através da coleta de dados para testar hipóteses e modelar o ambiente. Modelos matemáticos baseados em computadores e, capazes de simular realisticamente processos ambientais espacial e temporalmente distribuídos, vem sendo reconhecidos como requisito fundamental para avaliar quantitativamente mudanças ambientais locais, regionais e globais. Neste sentido, Sistemas de Informaçtes Geográficas vLm sendo utilizados com bastante sucesso em estudos que lidam com informaçtes espacialmente distribuídas e com manipulaçno de bancos de dados, com as principais aplicaçtes relacionadas com a obtençno de dados derivados para alimentar modelos ou com a representaçno espacial (mapas) dos resultados obtidos nos mesmos . Esta proposta de trabalho foi formulada como parte integrante de um projeto mais amplo de estudos interdisciplinares da bacia de drenagem do Rio Piracicaba (12400 km2), o qual tLm como um dos seus principais objetivos o de desenvolver uma metodologia adequada para o estudo de rios de porte médio. Para tal, é necessário entender a estrutura e o funcionamento do ecossistema bacia do rio Piracicaba, tendo como axioma básico de trabalho o conceito de rio como integrador dos processos que ocorrem em sua bacia de drenagem. O objetivo específico deste estudo é o de gerar informaçtes complementares que auxiliem no desenvolvimento de um modelo quantitativo que permita acoplar dados referentes ao fluxo de água (hidrologia), transporte de elementos (biogeoquímica) e intervençno humana (cobertura e uso do solo) em um rio de médio porte, submetido a uma elevada intervesno humana. Para tal, será elaborado um banco de dados digital georeferenciado, de modo a obter informaçtes que auxiliem no entendimento da estrutura e do funcionamento do ecossistema, permitindo que sejam definidas e estratégias de manejo

O PiraCena é um projeto multidisciplinar e multinstitucional que visa conhecer
os processos hidrológicos e biogeoquímicos que regem o funcionamento
da bacia hidrográfica do rio Piracicaba.

The overall question we are addressing in this proposal is, ¿What role does the evasion (outgassing) of CO2 from the river system to the atmosphere play in the carbon cycle of moist tropical forests?¿ Recent evidence suggests that the Amazon may be a net sink of atmospheric CO2 of 1-9 Mg C ha-1 y-1 . We have made recent calculations that suggest that the evasion of CO2 from the river system of the central Amazon basin is on the order of 1.2 ± 0.3 Mg C ha-1 y-1. A flux of this magnitude suggests that the ecosystem processes involved in river corridors represent a significant pathway for the export of carbon fixed on land in the humid tropics at a globally-significant level. Our working hypothesis is that: CO2 evasion returns as much carbon to the atmosphere as is sequestered in upland forests on an interannual basis. Export of organic material from upland forests to fluvial environments is the primary source of carbon that is eventually respired in rivers and evaded as CO2. We propose to test our hypothesis by conducting fieldwork in characteristic sub-basins of the Amazon (to determine the spatial and temporal distributions of pCO2 and to use geochemical techniques to quantify the rates of transfer of water and bioactive organic matter) and to use a terrestrial source/river transport and reaction model to synthesize and extrapolate the site-specific CO2 evasion rate measurements to a basin-wide estimate of CO2 evasion rate. We propose eight specific tasks to do this work: find and characterize representative sampling environments, determine distributions of pCO2, assess gas exchange rates, evaluate the source strength of terrestrial and river margin organic matter and CO2, determine in situ respiration rates and substrates, characterize the isotopic and organic composition of dissolved organic and inorganic carbon, determine the seasonality of inundation and terrestrial runoff, and synthesize observations and modeling in computing downstream fluxes.