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Sensitivity of Amazon Carbon Balance to climate and human-driven changes in Amazon
2019 - GATTI, LUCIANA V.; DOMINGUES, LUCAS G.; BASSO, LUANA S.; MILLER, JOHN B.; CASSOL, HENRIQUE L.G.; MARANI, LUCIANO; CORREIA, CAIO S. de C.; TEJADA, GRACIELA; ARAGAO, LUIZ E.O.C.; ANDERSON, LIANA O.; GLOOR, MANUEL; PETERS, WOUTER; VON RANDOW, CELSO; NEVES, RAIANE A.L.; IPIA, ALBER; CRISPIM, STEPHANE P.; ARAI, EGIDIO
Amazon is the major tropical land region, with critical processes, such as the carbon cycle, not yet fully understood. Only very few long-term greenhouse gas measurements is available in the tropics. The Amazon accounts for 50% of Earth’s tropical rainforests hosting the largest carbon pool in vegetation and soils (~200 PgC). The net carbon exchange between tropical land and the atmosphere is critically important because the stability of carbon in forests and soils can be disrupted in short time-scales. The main processes releasing C to the atmosphere are deforestation, fires and changes in growing conditions due to increased temperatures and droughts. Such changes may thus cause feedbacks on global climate. In the last 40 years, Amazon mean temperature increased by 1.1ºC. The length of the dry season is also increasing. We observed a reduction of 50.5mm in the annual mean precipitation during this same 40 years period. Precipitation reduction occurred mainly in the dry season, exacerbating vegetation water stress with consequences for the carbon balance. To understand the consequences of climate and human-driven changes on the C budget of Amazonia, we put in place the first program with regional representativeness, from 2010 onwards, aiming to quantify greenhouse gases based on extensive collection of vertical profiles of CO2 and CO. Regular vertical profiles from the ground up to 4.5 km height were performed at four sites along the main air-stream over the Amazon. Here we will report what these new data tell us about the greenhouse gas balance and its controls during the 2010-2017. Along this period we performed 513 vertical profiles over four strategic regions that represent fluxes over the entire Amazon region. The observed variability of carbon fluxes during these 8 years is correlated with climate variability (Temperature, precipitation, GRACE) and human-driven changes (Biomass Burning). The correlations were performed inside each influenced area for each studied site. It was observed a persistent C source from the Amazon (natural plus anthropogenic sources) to the atmosphere. Amazon was a consistent source of 0.4 ± 0.2 PgC/year on average considering the Amazon area of 7.2 million km2. Fire emission is the main source of carbon to the atmosphere, which is not compensate by the C removal from old-growth Amazon forest.
Increasing of carbon emission from biomass burning due to the temperature rising and precipitation reduction in the Amazon
2019 - CASSOL, HENRIQUE L.G.; DOMINGUES, LUCAS G.; BASSO, LUANA S.; GATTI, LUCIANA V.; MARANI, LUCIANO; TEJADA, GRACIELA; CRISPIM, STEPHANE P.; NEVES, RAIANE A.L.; CORREIA, CAIO S. de C.; ARAI, EGIDIO; GLOOR, MANUEL; MILLER, JOHN B.; ANDERSON, LIANA O.; ARAGAO, LUIZ E.O.C.
Recent droughts have increased the magnitude and frequency of the forest fires in the Amazon (Aragão et al. 2018). As a consequence, the Amazon has become a Carbon source due to the rising of the Carbon emission from biomass burned in the El Niño events. Faced with climate change and the likely acceleration of temperature in tropical regions, we hypothesize that Amazon will become a Carbon source even in non-droughts years, due to the increase of forest fires. Therefore, we compared 7 years of atmospheric profiles of CO2 obtained from aircraft overfly at four sites of the Amazon, since 2010, with temperature, precipitation, and fire counts (FC). Carbon emission from fires was obtained by the ratio of CO/CO2 and differs by site and year. The FC and climatic variables were extracted from quarterly influence areas by site and weighted by the amount of trajectories within a cell of one degree resolution. The fire emissions released by the Amazon is about 0.38 ± 0.086 Pg.C.yr-1, which represent roughly 17% of the annual global fires emissions (Werf et al. 2017). However, there are markedly divergences in the Fire emissions across Amazon. For instance, the emission from the Eastern is 400% higher and account of an average 60% more FC than observed in the Western. FC were positively and significantly correlated with Carbon from fires at all sites (ρ = 0.55-0.83, α = 0.05, p-value<0.001), being higher in the Southeastern of Amazon (Alta Floresta and Santarém sites), and lower in the Northwest of Amazon (Tefé site and Rio Branco Sites). This discrepancy may occur due to the Southeastern of Amazon be located inside the “Arc of deforestation” where the dynamic of the Land-Use Land-Cover Change is more pronounced. We also found a strong relationship between FC and temperature and precipitation (r² adj = 0.44-0.67, p-value<0.001). Temperature is positively correlated with FC and explains circa of 90% of their variability in the linear model (r² partial = 0.4-0.59, α = 0.05, p-value<0.001). It means that an increase of one degree (1°C) in the Amazon represents an increase of about 13600 fire counts; and the reduction of 100 mm precipitation means an increase of 315 in the fire counts. In the balance of the Fire emissions, it would add 1.27 Pg Pg.C.yr-1 at each degree celsius of increase and 0.2 Pg.C.yr-1 at each 100 mm of precipitation reduction.
Carbon and beyond
2020 - SOPER, FIONA; COVEY, KRISTOFER R.; PANGALA, SUNITHA R.; BERNADINO, ANGELO; BASSO, LUANA S.; CASSOL, HENRIQUE L.G.; FEARNSIDE, PHILIP M.; NOVOA, SIDNEY; SAWAKUCHI, HENRIQUE O.; LOVEJOY, THOMAS; MARENGO, JOSE A.; PERES, CARLOS; BERNASCONI, PAULA; NARDOTO, GABRIELA B.; NOBRE, ISMAEL; MESQUITA, RITA G.; PINTO, FLAVIA; HOFFMAN, BRUCE; FREITAS, CAROLINA; ASSIS, RAFAEL L. de; BAHL, ALEXIS A.; ELMORE, AURORA; BAILLIE, JONATHON
The Amazon is at the center of an intensifying conversation about multiple anthropogenic impacts, both direct (e.g. land use change) and indirect (climate and hydrologic change). Thus far, research has focused primarily on the cycling and storage of carbon (C) and its implications for global climate. Missing is a holistic consideration of the interactions between these anthropogenic impacts and the full suite of climate forcing agents originating in the basin, including other greenhouse gases (methane, nitrous oxide), biogenic volatile organic compounds (BVOCs), black C, transpiration and albedo. Doing so is complicated by the very large variation in biophysical, ecological, cultural and political factors across the large area of the basin. Here, we synthesize the current understanding of 1) the nature, extent, rates and drivers of all major anthropogenic changes, and 2) their expected magnitude and direction of effect on each major climate forcing agent. Studied anthropogenic impacts span a range of scales and include deforestation, agricultural conversion, hydrologic and climatic regime change, reservoir construction, fire, mining/oil extraction, hunting, severe storms and others. We identify key knowledge gaps and identify likely impacts on the net climate forcing effect of the region. We conclude that the current net positive radiative forcing of non-CO2 agents in the Amazon (in particular methane, nitrous oxide and black C) is likely be equal to or greater than the more often considered CO2 climate impact. If unchecked, the majority of anthropogenic change agents are likely to further increase net radiative forcing from the region, both by reducing C uptake and increasing emission of other agents. Most significant rate and response uncertainties are associated with 1) methane production in seasonally inundated areas and effects of temperature/hydrologic change 2) patterns and radiative forcing impacts of BVOCs, 3) impacts of spatially/temporally variable phenomena such as severe storms and 4) biogeochemical and ecological resiliency of freshwater systems. Given the large contribution of these less-recognized forcing agents, a continuing focus on a single metric of climate service is incompatible with understanding and managing the biogeochemistry of climate in a rapidly changing Amazon.
Invited Keynote: Inter-annual variation of Amazon greenhouse balances 2010- 2014
2017 - GATTI, LUCIANA V.; GLOOR, MANUEL; MILLER, JOHN B.; DOMINGUES, LUCAS G.; SILVA, MARCELO G.; ARAGAO, LUIZ E.O.C.; MARANI, LUCIANO; CORREIA, CAIO C.S.; PETERS, WOUTER; BORGES, VIVIANE F.; IPIA, ALBER H.S.; BASSO, LUANA S.; ANDERSON, LIANA O.; ALDEN, CAROLINE B.; VAN DER LAAN-LUIJKX, INGRID; BARICHIVICH, JONATHAN; SANTOS, RICARDO S.; CRISPIM, STEPHANE P.; COSTA, WELLISSON R.; ROSAN, THAIS M.
Net carbon exchange between tropical land and the atmosphere is potentially important because the vast amounts of carbon in forests and soils can be released on short time-scales e.g. via deforestation or changes in temperature and moisture. Such changes may thus cause feedbacks on global climate, as have been predicted in earth system models. In the tropics, the Amazon is most significant in the global carbon cycle, hosting by far the largest carbon vegetation and soil carbon pools (~200 PgC). Because of the very large precipitation amounts, approximately 20-25% of its area is seasonally flooded and thus it is also an important region for methane emissions. From 2010 onwards we have extended an earlier greenhouse gas measurement program to include regular vertical profiles of CO2, CH4, N2O, CO, SF6, from the ground up to 4.5 km height at four sites along the main air-stream over the Amazon Basin. Our measurements demonstrate that surface flux signals are primarily concentrated to the lower 2 km and thus vertical profile measurements are ideally suited to estimate greenhouse gas balances. Clearly a higher measurement density is desirable. We are in the process of expanding the number of surface and airborne sampling sites as well as the number of trace gases measured. Nonetheless, because of the homogeneity of the vegetation (forests) and the coherent east to west trade-winds over the Basin, these data already permit a range of insights about the magnitude, seasonality, inter-annual variation of carbon fluxes and their controls. Most recent years have been anomalously hot with the southern part of the Basin having warmed the most. Precipitation regimes also seem to have shifted with an increase in extreme floods. Approximately 20 percent of Amazon forests have been deforested by now and development pressure on forests continues. For the specific period we will discuss the year 2010 was anomalously dry, followed by 4 years wet (2011, 2012, 2013 and 2014) and another dry year (2015/16 -El Nino year). This period provides an interesting contrast of climatic conditions in a warming world with increasing human pressures. We will analyze the effect of this climate variability on annual and seasonal carbon balances for these five years using our atmospheric data. We will estimate fluxes using a simple, but powerful back-trajectory based atmospheric mass balance approach. Our data permit us not only to estimate net CO2 and CH4 fluxes, but using carbon monoxide we estimate carbon release via fires and thus the net carbon balance of the unburned land vegetation. We will relate fire emissions to controls of land vegetation functioning and independent diagnostics like fire counts. We will also discuss what our results suggest for the role of the tropics of the global carbon balance.
Amazon Basin biomass burning emission and its correlation with climatology and deforestation
2017 - DOMINGUES, LUCAS G.; GATTI, LUCIANA V.; GLOOR, MANUEL; MILLER, JOHN B.; AQUINO, AFONSO R.; ARAGAO, LUIZ E.O. e C.; ANDERSON, LIANA O.; MARANI, LUCIANO; CORREIA, CAIO S. de C.; SILVA, MARCELO G.; BORGES, VIVIANE F.; IPIA, ALBER H.S.; BASSO, LUANA S.; SANTOS, RICARDO S.; CRISPIM, STEPHANI P.; COSTA, WELLISON R.
Tropical rainforests have great potential to affect the global carbon budget considering their large quantities of labile carbon stored in forests and soils. Among the tropical regions, the Amazon forest covers the largest area and also hosts the largest carbon pool (~200 PgC), corresponding for 50% of its biome globally. It has a total area of approximately 6.7 million km2, of which, 4.2 million km2 is in Brazil, which corresponds to approximately 60 % of Amazon territory, and contains one quarter of global biodiversity. Over recent years, the Amazon Basin hydrological cycle has changed considerably which presented severe droughts in 2005, 2010 and 2015. 2015 is likely the largest drought over the past 15 years. Droughts in the Amazon are intrinsically correlated to extensive wildfires. At 2004/2005 the number of fire hot spots reached its maximum, coincident with the peak in deforestation. However, in the recent years, despite the decrease in deforestation rates, increase in fire hot spots have been observed, particularly during the years of extreme drought, 2010 and 2015. 2011 had the fewest number of fire hot spots, but since 2013 a positive trend was identified, reaching the maximum peak in 2015. Although deforestation estimation has decreased strongly over the last decade (71% reduction from 2004 to 2012), estimates of fire related carbon fluxes to the atmosphere estimated using regular atmospheric carbon monoxide concentration measurements indicate that there may be a discrepancy. These data do suggest a much smaller decrease, which lead us to believe that deforestation, as observed from satellite, is not the only process causing release of carbon by fires. Thus, understanding the relation between carbon emissions from biomass burning and climate, fire hot spots based on remote sensing and deforestation is important as it may reveal biases in remote sensing based estimates of deforestation. In turn it may help to evaluate the effectiveness of actions to preserve the forests. To elucidate the actual contribution and the carbon emission from biomass burning in the Amazon Basin, measurements of carbon monoxide are an important tool. We will report the results from a recently established pan Amazon lower troposphere biweekly to monthly atmospheric sampling program for the years 2010 to 2014. Amazon Basin biomass burning carbon emissions have been determined by applying a mass balance technique to carbon monoxide measured from vertical profiles in four sites over the Amazon Basin. We will present these results from biomass burning and compare the carbon monoxide emissions with those from carbon dioxide, resulting in a ratio of carbon biomass burning emission which we will analyze with respect to climate, deforestation and number of fire hot spots.
Amazon Atlantic outflow region carbon cycling constrained by atmospheric greenhouse gas data
2017 - BORGES, VIVIANE F.; GATTI, LUCIANA V.; GLOOR, EMANUEL U.; MILLER, JOHN B.; BOESCH, HARTMUT; DOMINGUES, LUCAS G.; CORREIA, CAIO S. de C.; BASSO, LUANA S.; SANTOS, RICARDO S.
Estuaries and near-coastal regions may process substantial amounts of carbon causing a nonnegligible carbon uptake from the atmosphere. For purpose of characterizing the greenhouse gas levels of air entering the Amazon basin from the Atlantic we have been measuring regularly greenhouse gas concentrations at several sites along the North-East Atlantic coast of Brazil over approximately the past six years (at some of the sites for much longer). At some of the sites sampling is restricted close to the surface while at other sites we have been measuring vertical profiles. At Salinopolis which is located close to the Amazon outflow region to the Atlantic seasonally strong CO2 depletion in both surface records and aircraft vertical profiles compared to background sites like Ascension Island is clearly discernible. The seasonality is synchronous with increases in chlorophyll observed from space e.g. by the SeaWiFS mission. Incidentally during the CO2 depletion period airmass trajectories tend to pass over the shelf region along the Brazilian coast travelling from the South along the coast. This enables us to apply an air column mass balance approach to estimate the magnitude of the CO2 flux into the sea along the coast during the blooms. Using the chlorophyll maps we may furthermore extrapolate the flux estimates spatially to obtain an area integrated flux. We will discuss our findings and put our flux estimates into perspective with estimates for productivity and carbon uptake in coastal regions of major tropical rivers as well as the extra-tropics. Acknowledgment: CNPq, NERC, FAPESP, MCTI, NOAA, IPEN and INPE.
Greenhouse gases
2017 - BORGES, V.F.; GATTI, L.V.; DOMINGUES, L.G.; CORREIA, C.S.C.; BASSO, L.S.; SANTOS, R.S.; COSTA, W.R.; CRISPIM, S.P.; MARANI, L.; PENHA, T.L.B.; PAULA, A.L.S.; GLOOR, E.U.; MILLER, J.B.; KOFLER, J.
In Tropical areas, and specifically in the Atlantic Ocean, there are not enough measures on greenhouse gases (GHG), and Amazon Basin represent around 50% of the world's rainforest [1]. Understand the characteristic GHG concentrations in Tropical Global range on Atlantic Ocean is an important task for many studies to determine GHG balances. The motivation of this study was understanding better the typical background for Amazon Basin from the air masses that arrived on North and Northeast Brazilian coast, come from the Atlantic Ocean in the period 2006 to 2016. We started to collect air samples on the Brazilian coast: Arembepe/BA (ABP: 12º45’46.79”S; 38º10’08.39”W – from 2006 to 2010, 15 meters above sea-level), Salinopolis/PA (SAL: 00º36’15.03”S; 47º22’25.02”W – from 2010 to 2017, 10 m a.s.l.), Natal/RN (NAT: 05º29’22.05”S; 35º15’39.64”W 15 m a.s.l – since 2010 to December 2015, then the site moved to 05º47’42.77”S; 35º11’07.10”W, 87 m a.s.l.), Camocim/CE (CAM: 02º51’47.00”S; 40º51’36.70”W – since 2014, 21.5 m a.s.l.), and in December 2016 it was started a special place at Itarema/CE (ITA: 02º55’57.11”S; 39º50’38.49”W, 96.5 m a.s.l.), where the inlet was installed in the top of a 100 m tower in the beach. In each site, the air samples, with variable height were collected weekly by using a pair of glass flasks (2.5L) and a portable sampler. The air samples were analysed on the Greenhouse Gas Laboratory (LaGEE) at IPEN (until April 2015) and later at INPE/CCST. It was quantified the respective gases: carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), sulphur hexafluoride (SF6) and carbon monoxide (CO). Results showed that each site presents seasonality when compared to Ascension Island (ASC: 07º96'67.00"S; 14º0'00.00"W, South Atlantic Ocean) and Ragged Point Barbados (RPB: 13º16'50.00"N, 59º43'20.00"W, North Atlantic Ocean) global stations. Simulations of backward trajectories by HYSPLIT model (using 240 hours) [2], allowed observing how each study site is influenced by global circulation and process like Intertropical Convergence Zone [3]. Between Jan-May, the ITCZ is below SAL and CAM latitude, influencing the air masses that arrived at sites in this period. At SAL and CAM the air masses came from both North and South Atlantic Ocean, depending on time of the year, and at NAT and ABP the air masses came from only South Atlantic Ocean. The GHG concentrations showed seasonality and sometimes periods with high concentrations. Overall, all Brazilian coast sites, showed the same increase on the GHG concentrations than global mean.
Amazon basin and brazilian coast SF6 study in a 15 years time series
2017 - SANTOS, R.S.; GATTI, L.V.; DOMINGUES, L.G.; CORREIA, C.S.C.; AQUINO, A.R.; BASSO, L.S.; BORGES, V.F.; COSTA, W.R.; CRISPIM, S.P.; MARANI, L.; GLOOR, E.U.; MILLER, J.B.; PETERS, W.
The sulphur hexafluoride (SF6) is known as a potent Long Lived Greenhouse Gases and it is a synthetic gas with a millennia lifetime, about 3200 years, and has a Global Warm Potential 23000 time higher than the Carbon Dioxide (CO2). Levin et al. (2010)1 showed that SF6 emissions decreased after 1995, most likely because of emissions reductions in developed countries, but then increased after 1998. It is produced by the chemical industry, mainly as an electrical insulator in power distribution equipment2. Due its very long lifetime, SF6 emissions are accumulating in the atmosphere. Its global mole fraction increased nearly linearly in recent decades and in 2014 is about twice the level observed in the mid-1990s3. Its concentration was 4.2 parts per trillion (ppt) in 1998 (TAR) and has continued to increase linearly over the past decade, implying that emissions are approximately constant. Because of these characteristics, the SF6 has been as an essentially inert tracer to study atmospheric and oceanic transport processes3. The Amazon Basin is an ecosystem that has a growing interest by researchers around the world because of its role at the Climate Change. The emissions of SF6 in the Amazon Basin are considered non existents and, a time series of 15 years has the potential to show the behaviour of this gas in a large area. Until now, our mainly interest in SF6 concentrations is to use this gas as a transport tracer to calculate the BKG to Amazon and determinate the CO2, CH4 and N2O fluxes over the Amazon Basin. SF6 atmospheric measurements were started with vertical profiles using small aircrafts, since 2000 in Santarém (SAN; 2.86ºS; 54.95ºW), 2009 in Rio Branco (RBA; 9.38ºS, 67.62ºW), 2010 in Alta Floresta (ALF; 8.80ºS, 56.75ºW)and Tabatinga (TAB; 5.96ºS, 70.06ºW), all these sites located in Brazilian Amazon Basin. Since 2010, we started flasks measurements at two sites located at the Brazilian Atlantic coast: in Salinópolis (SAL; 0.60°S, 47.37°W) and in Natal (NAT; 5.48°S, 35.26°W) and later in 2014 at Camocim (CAM; 2.86°S, 40.08°W) and in 2016 at Itarema in a 100m tower (ITA; 2.93°S, 39.84°W). This work will present analyse of 15 years SF6 measurements at the Amazon Basin and Brazilian coast show the trends, comparing the years and the behaviour among the sites regions which is expect to change mainly by the differences of the air masses origin.
Large emissions from floodplain trees close the Amazon methane budget
2017 - PANGALA, SUNITHA R.; ENRICH-PRAST, ALEX; BASSO, LUANA S.; PEIXOTO, ROBERTA B.; BASTVIKEN, DAVID; HORNIBROOK, EDWARD R.C.; GATTI, LUCIANA V.; MAROTTA, HUMBERTO; CALAZANS, LUANA S.B.; SAKURAGUI, CASSIA M.; BASTOS, WANDERLEY R.; MALM, OLAF; GLOOR, EMANUEL; MILLER, JOHN B.; GAUCI, VINCENT
Wetlands are the largest global source of atmospheric methane (CH4)1, a potent greenhouse gas. However, methane emission inventories from the Amazon floodplain2,3, the largest natural geographic source of CH4 in the tropics, consistently underestimate the atmospheric burden of CH4 determined via remote sensing and inversion modelling4,5, pointing to a major gap in our understanding of the contribution of these ecosystems to CH4 emissions. Here we report CH4 fluxes from the stems of 2,357 individual Amazonian floodplain trees from 13 locations across the central Amazon basin. We find that escape of soil gas through wetland trees is the dominant source of regional CH4 emissions. Methane fluxes from Amazon tree stems were up to 200 times larger than emissions reported for temperate wet forests6 and tropical peat swamp forests7, representing the largest non-ebullitive wetland fluxes observed. Emissions from trees had an average stable carbon isotope value (δ13C) of −66.2 ± 6.4 per mil, consistent with a soil biogenic origin. We estimate that floodplain trees emit 15.1 ± 1.8 to 21.2 ± 2.5 teragrams of CH4 a year, in addition to the 20.5 ± 5.3 teragrams a year emitted regionally from other sources. Furthermore, we provide a ‘top-down’ regional estimate of CH4 emissions of 42.7 ± 5.6 teragrams of CH4 a year for the Amazon basin, based on regular vertical lower-troposphere CH4 profiles covering the period 2010–2013. We find close agreement between our ‘top-down’ and combined ‘bottom-up’ estimates, indicating that large CH4 emissions from trees adapted to permanent or seasonal inundation can account for the emission source that is required to close the Amazon CH4 budget. Our findings demonstrate the importance of tree stem surfaces in mediating approximately half of all wetland CH4 emissions in the Amazon floodplain, a region that represents up to one-third of the global wetland CH4 source when trees are combined with other emission sources.
Analysis of the influence of co2 concentration and others external factors on the N2O quantification
2013 - PRETTO, A.; IZIDORO, J.C.; GATTI, L.V.; CORREIA, C.S.C.; MARTINEWSKI, A.; BASSO, L.S.; BORGES, V.F.; ROSSATI, C.; MILLER, J.B.; CROTWELL, A.; TANS, P.