Denitrification and associated nitrous oxide and carbon dioxide emissions from the Amazonian wetlands

In this paper, we quantify the CO2 and N2O emissions from denitrification over the Amazonian wetlands. The study concerns the entire Amazonian wetland ecosystem with a specific focus on three floodplain (FP) locations: the Branco FP, the Madeira FP and the FP alongside the Amazon River. We adapted a simple denitrification model to the case of tropical wetlands and forced it by open water surface extent products from the Soil Moisture and Ocean Salinity (SMOS) satellite. A priori model parameters were provided by in situ observations and gauging stations from the HYBAM Observatory. Our results show that the denitrification and the trace gas emissions present a strong cyclic pattern linked to the inundation processes that can be divided into three distinct phases: activation, stabilization and deactivation. We quantify the average yearly denitrification and associated emissions of CO2 and N2O over the entire watershed at 17.8 kgN ha−1 yr−1, 0.37 gC-CO2 m−2 yr−1 and 0.18 gN-N2O m−2 yr−1 respectively for the period 2011–2015. When compared to local observations, it was found that the CO2 emissions accounted for 0.01 % of the integrated ecosystem, which emphasizes the fact that minor changes to the land cover may induce strong impacts on the Amazonian carbon budget. Our results are consistent with the state of the art of global nitrogen models with a positive bias of 28 %. When compared to other wetlands in different pedoclimatic environments we found that the Amazonian wetlands have similar emissions of N2O with the Congo tropical wetlands and lower emissions than the temperate and tropical anthropogenic wetlands of the Garonne (France), the Rhine (Europe) and south-eastern Asia rice paddies. In summary our paper shows that a data-model-based approach can be successfully applied to quantify N2O and CO2 fluxes associated with denitrification over the Amazon basin. In the future, the use of higher-resolution remote sensing products from sensor fusion or new sensors like the Surface Water and Ocean Topography (SWOT) mission will permit the transposition of the approach to other large-scale watersheds in tropical environments.

Denitrification, carbon and nitrogen emissions over the Amazonian wetlands

In this paper, we quantify CO2 and N2O emissions from denitrification over the Amazonian wetlands. The study concerns the entire Amazonian wetland ecosystem with a specific focus on three focal locations: the Branco Floodplain, the Madeira Floodplain and the floodplains alongside the Amazon River. We adapted a simple denitrification model to the case of tropical wetlands and forced it by open water surface extent products from the Soil Moisture and Ocean Salinity (SMOS) satellite. A priori model parameters were provided by in situ observations and gauging stations from the HyBAm observatory. Our results show that the denitrification and emissions present a strong cyclic pattern linked to the inundation processes that can be divided into three distinct phases: activation – stabilization – deactivation. We quantify the average yearly denitrification and associated emissions of CO2 and N2O over the entire watershed at 17.8 kgN/ha/yr, 0.37 gC/m2/yr and 0.18 gN/m2/yr respectively. When compared to local observations, it was found that the CO2 emissions accounted for 0.01 % of the integrated ecosystem, which emphasis the fact that minor changes to the land cover may induce strong impacts to the Amazonian carbon budget. Our results are quite consistent with the state of the art global nitrogen models with a positive bias of 28 %. When compared to other wetlands in different pedo-climatic environments we found that the Amazonian wetlands have close emissions of N2O to the tropical Congo wetlands and lower emissions than the tropical and temperate anthropogenic wetlands of the Garonne river, the Rhine river, and south-eastern Asia rice paddies. In summary our paper shows that a data driven approach can be successfully applied to quantify N2O and CO2 fluxes associated with denitrification over the Amazon basin. In the future, the use of higher resolution remote sensing product from sensor fusion or new sensors like the SWOT mission will permit the transposition to other large scale watersheds in tropical environment.

HUMEDALES DE LA YUNGA AMAZÓNICA EN LOS DEPARTAMENTOS HUANUCO Y SAN MARTÍN, PERÚ

HUMEDALES DE LA YUNGA AMAZÓNICA EN LOS DEPARTAMENTOS HUANUCO Y SAN MARTÍN, PERÚ WETLANDS OF AMAZONIAN YUNGA IN DEPARTMENTS OF HUANUCO AND SAN MARTIN, PERU Manuel Ñique Alvarez, Luis Vivar Luque y Edilberto Chiquilín Bustamante. DOI: https://doi.org/10.33017/RevECIPeru2009.0010/ RESUMEN El estudio tuvo como objetivos identificar y generar cartografía de humedales de la yunga amazónica, aportar información sobre los humedales amazónicos y contribuir a su gestión. El área de estudio se ubica en el Hotspot Andes Tropicales y comprende los departamentos de San Martín y Huanuco, considerándose únicamente los humedales que están en el rango de elevación de 600 a 3600 msnm. Se utilizo imágenes de satélite y se genero un bancos de datos en medio digital y además se hizo la verificación en campo en base a un muestreo tipo dirigido. Se identificaron 109 humedales en San Martín y 74 en Huanuco, generándose la Base de Datos “Humedales identificados en la Ecorregión Yunga, departamentos Huanuco y San Martín”, que comprende para cada humedal: área, ubicación política, coordenadas UTM. Asimismo se ha hecho una clasificación por áreas determinándose que la mayoría de los humedales tiene un área mayor o igual a 1 ha pero menor de 10 ha. El área total de los humedales identificados comprende 1,620.94 ha. de espejo de agua dulce y el humedal de mayor superficie es la laguna “El Sauce” que posee 473.71 ha. Palabras clave: humedales, yunga, amazonia. ABSTRACT The objectives were identify and generate wetland’s cartography of Amazonian yunga, provide information about Amazonian wetlands and contribute to their management. The study area is located in the Tropical Andes Hotspot, and includes the departments of Huanuco and San Martin, considering only those wetlands that are in the range of elevation of 600 to 3600 meters above sea level. Were used satellite images and creates a database in digital media and also made the field verification based on a directed sampling. 109 wetlands in San Martin and 74 in Huanuco were identified, generating a Database: “Wetlands identified in the Ecoregion Yunga departments Huanuco and San Martín”, which includes for each wetland: area, location policy, UTM coordinates. It also has a classification determined by areas that most of the wetland has an area greater than or equal to 1 but has less than 10 ha. The total area of studied wetlands is 1620.94. ha. and largest wetland is the lagoon "El Sauce" which has 473.71 ha. Keywords: wetlands, yunga, amazon.

Possible impacts of climate change on wetlands and its biota in the Brazilian Amazon

Wetlands cover approximately 6% of the Earth's surface. They are frequently found at the interface between terrestrial and aquatic ecosystems and are strongly dependent on the water cycle. For this reason, wetlands are extremely vulnerable to the effects of climate change. Mangroves and floodplain ecosystems are some of the most important environments for the Amazonian population, as a source of proteins and income, and are thus the types of wetlands chosen for this review. Some of the main consequences that can be predicted from climate change for wetlands are modifications in hydrological regimes, which can cause intense droughts or inundations. A possible reduction in rainfall can cause a decrease of the areas of mangroves and floodplains, with a consequent decline in their species numbers. Conversely, an increase in rainfall would probably cause the substitution of plant species, which would not be able to survive under new conditions for a long period. An elevation in water temperature on the floodplains would cause an increase in frequency and duration of hypoxic or anoxic episodes, which might further lead to a reduction in growth rates or the reproductive success of many species. In mangroves, an increase in water temperature would influence the sea level, causing losses of these environments through coastal erosion processes. Therefore, climate change will likely cause the loss of, or reduction in, Amazonian wetlands and will challenge the adaptability of species, composition and distribution, which will probably have consequences for the human population that depend on them.