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In this paper, we review some critical issues regarding carbon cycling in Amazonia, as revealed by several studies conducted in the Large Scale Biosphere Atmosphere Experiment in Amazonia (LBA). We evaluate both the contribution of this magnificent biome for the global net primary productivity/net ecosystem exchange (NPP/NEE) and the feedbacks of climate(More)
Although only a small amount of the Earth's water exists as continental surface water bodies, this compartment plays an important role in the biogeochemical cycles connecting the land to the atmosphere. The territory of Brazil encompasses a dense river net and enormous number of shallow lakes. Human actions have been heavily influenced by the inland waters(More)
Even though the suitability of macrophytes to act as a carbon source to food webs has been questioned by some studies, some others indicate that macrophyte-derived carbon may play an important role in the trophic transfer of organic matter in the food web of shallow lakes. To evaluate the importance of macrophytes to food webs, we collected primary(More)
Our review focuses on the projections of climate change in the Brazilian semiarid region, the Caatinga, based on recent publications about global climate change and biology. We found several vulnerable points in the initial estimates, the main one being that the data were collected and analyzed without a multidisciplinary knowledge. This review discusses(More)
Phosphorus (P) is generally considered the most common limiting nutrient for productivity of mature tropical lowland forests growing on highly weathered soils. It is often assumed that P limitation also applies to young tropical forests, but nitrogen (N) losses during land-use change may alter the stoichiometric balance of nutrient cycling processes. In the(More)
[1] Large Amazonian rivers are known to emit substantial amounts of CO 2 to the atmosphere, while the magnitude of CO 2 degassing from small streams remains a major unknown in regional carbon budgets. We found that 77% of carbon transported by water from the landscape was as terrestrially-respired CO 2 dissolved within soils, over 90% of which evaded to the(More)
the spatial and temporal heterogeneity of deforestation-driven carbon emissions: the INPE-EM framework applied to the Brazilian Amazon" (2012). NASA Publications. Paper 109. Abstract We present a generic spatially explicit modeling framework to estimate carbon emissions from deforestation (INPE-EM). The framework incorporates the temporal dynamics related(More)
The carbon isotope of a leaf (δ 13 C leaf) is generally more negative in riparian zones than in areas with low soil moisture content or rainfall input. In Central Amazo-nia, the small-scale topography is composed of plateaus and valleys, with plateaus generally having a lower soil moisture status than the valley edges in the dry season. Yet in the dry(More)