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LC-04 Abstract

Exploring Interactions Among the Ecological, Hydrological and Climate Systems of Amazonia

Marcos Costa — UFV - Universidade Federal de Viçosa (SA-PI)
Jonathan A. Foley — Institute on the Environment (US-PI)

This

proposal describes a research project that focuses on the large-scale, integrated behavior of environmental systems in the Amazon

basin. We aim to address several broad research

questions:









·        

How do the terrestrial ecosystems

across the Amazon behave?  How do

they interact with the freshwater and climate systems of the region?









·        

How do the terrestrial ecosystems,

freshwater systems and atmosphere of the Amazon operate as a single, integrated

system?









·        

How does this integrated regional

environmental system respond to human activity and global environmental change? 

How do changes in the environmental systems of the Amazon affect the rest

of the Earth system?









In order to address these questions, our research team is actively

building state-of-the-art coupled models of terrestrial ecosystems, hydrological

systems, and the atmosphere. These

integrated modeling tools will be used to explore the complex behavior of

regional environmental systems, and examine how they may respond to human

activity and global environmental change.  By

considering the coupled behavior of the atmosphere, terrestrial ecosystems, and

freshwater systems, we will explore the rich dynamics of this regional

environmental system – including complex responses that could not be

anticipated by considering each system in isolation.









Our

project has three major objectives:









Objective 1.  Understand the Dynamics of Terrestrial Ecosystems – Variability,

Disturbance, and Long-Term Change. We will use a regional-scale terrestrial ecosystem

model (IBIS) to explore the behavior of terrestrial ecosystems across the Amazon

basin.  First, we will continue to

test the components of the model against a hierarchy of measurements being made

in LBA, including tower flux data, in situ

biomass and canopy measurements, isotope samples, stream-flow data, and

satellite measures.  Next, we will

examine how terrestrial ecosystems across the basin respond to climatic

variability, disturbances, and land use / land cover change.  In particular, we will use the IBIS modeling system to examine changes in

ecosystem functioning (including terrestrial carbon cycling, water balance,

nutrient cycling), as well as changes in ecosystem structure (including leaf

area, biomass, and vegetation composition).









Objective 2. Investigate

the Interactions between Terrestrial Ecosystems and Freshwater Systems –

Hydrological and Biogeochemical Linkages. First,

we will examine the hydrological connections between terrestrial ecosystems and

the rivers, streams, floodplains and wetlands of the basin.  We will use our terrestrial ecosystem model (IBIS) to examine how the

surface water balance responds to climate variability and land use / land cover

change. We will also use our large-scale hydrological transport model (HYDRA) to

examine the effects of changing water balance on river discharge, as well as the

extent of wetlands and flooding.  Next

we will consider the biogeochemical linkages between terrestrial ecosystems and

the freshwater systems in Amazonia.  In

particular, we will consider the transport of carbon from terrestrial ecosystems

into freshwater systems, and the biological processing of carbon within aquatic

ecosystems.  The transport of carbon

from terrestrial ecosystems to the rivers and wetlands of Amazonia is

particularly relevant to the goals of LBA-ECO, as it may represent a significant

fraction of the basin’s carbon balance.









Objective 3.  Explore the Interactions between Terrestrial Ecosystems and the

Atmosphere – Physical and Biogeochemical Linkages. We will use a fully

coupled climate – ecosystem model (CCM3-IBIS) to investigate

how the climate and ecosystems of Amazonia will change in response to different

scenarios of land use, rising CO2 (considering both the ecological

and climatic effects of CO2), as well as different patterns of sea

surface temperatures in the tropical Atlantic. We will use the modeling

studies to evaluate the biogeophysical feedbacks of changing land cover

conditions (either directly from land use practices, or indirectly through

climate changes) on the regional climate, as well as the biogeochemical

feedbacks of changing terrestrial carbon balance on atmospheric CO2

concentrations and the global climate.

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