Soluble iron nutrients in Saharan dust over the central Amazon rainforest

Abstract. The intercontinental transport of aerosols from the Sahara desert plays a significant role in nutrient cycles in the Amazon rainforest, since it carries many types of minerals to these otherwise low-fertility lands. Iron is one of the micronutrients essential for plant growth, and its long-range transport might be an important source for the iron-limited Amazon rainforest. This study assesses the bioavailability of iron Fe(II) and Fe(III) in the particulate matter over the Amazon forest, which was transported from the Sahara desert (for the sake of our discussion, this term also includes the Sahel region). The sampling campaign was carried out above and below the forest canopy at the ATTO site (Amazon Tall Tower Observatory), a near-pristine area in the central Amazon Basin, from March to April 2015. Measurements reached peak concentrations for soluble Fe(III) (48 ng m−3), Fe(II) (16 ng m−3), Na (470 ng m−3), Ca (194 ng m−3), K (65 ng m−3), and Mg (89 ng m−3) during a time period of dust transport from the Sahara, as confirmed by ground-based and satellite remote sensing data and air mass backward trajectories. Dust sampled above the Amazon canopy included primary biological aerosols and other coarse particles up to 12 µm in diameter. Atmospheric transport of weathered Saharan dust, followed by surface deposition, resulted in substantial iron bioavailability across the rainforest canopy. The seasonal deposition of dust, rich in soluble iron, and other minerals is likely to assist both bacteria and fungi within the topsoil and on canopy surfaces, and especially benefit highly bioabsorbent species. In this scenario, Saharan dust can provide essential macronutrients and micronutrients to plant roots, and also directly to plant leaves. The influence of this input on the ecology of the forest canopy and topsoil is discussed, and we argue that this influence would likely be different from that of nutrients from the weathered Amazon bedrock, which otherwise provides the main source of soluble mineral nutrients.

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Mineral nutrients in Saharan dust and their potential impact on Amazon rainforest ecology

10.5194/acp-2016-557 ◽

2016 ◽

Cited By ~ 2

Author(s):

Joana A. Rizzolo ◽

Cybelli G. G. Barbosa ◽

Guilherme C. Borillo ◽

Ana F. L. Godoi ◽

Rodrigo A. F. Souza ◽

...

Keyword(s):

Forest Canopy ◽

Atmospheric Transport ◽

Mineral Nutrients ◽

Iron Bioavailability ◽

Saharan Dust ◽

Low Fertility ◽

Amazon Rainforest ◽

Dust Particles ◽

Sampling Campaign ◽

Potential Impact

Abstract. The intercontinental transport of aerosols from the Sahara is likely to play a significant role in nutrient cycles in the Amazon rainforest, since it carries many types of minerals to these otherwise low-fertility lands. Iron is one of the micronutrients essential for plant growth, and the Amazon rainforest is iron-limited. The main aim of this study was to assess the input and potential impact of iron bioavailability from Saharan dust, namely, the soluble fraction Fe(II)/Fe(III). Seven other soluble elements that are also essential for plants were measured. Dust particles entrained in the air were collected and analyzed, but not dust deposited in rainfall as atmospheric washout. The sampling campaign was carried out at the ATTO site (Amazon Tall Tower Observatory), from March to April 2015, and samplers were placed both above and below the canopy. Mineral dust aerosol at ATTO showed peak concentrations for Fe(III) (47.6 ng m−3), Fe(II) (16.2 ng m−3), Na (470 ng m−3), Ca (194 ng m−3), K (64.7 ng m−3), and Mg (88.8 ng m−3) during the presence of dust transported from the Sahara, as determined by remote ground-based and satellite sensing data and backward trajectories. Atmospheric transport of weathered Saharan dust, followed by surface deposition, results in substantial iron bioavailability across the rainforest canopy. The seasonal deposition of dust rich in soluble iron and other minerals is likely to affect both bacteria and fungi within the topsoil and on canopy surfaces, and especially benefit highly bioabsorbent epiphytes, such as lichens. In this scenario, Saharan dust can provide essential macronutrients and micronutrients to plant roots, and also directly to plant leaves. The influence on the ecology of the forest canopy and topsoil would likely be different from that of nutrients from the weathered Amazon bedrock, which provides the main source of soluble mineral nutrients.

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Contribution to the knowledge of Camillea (Ascomycota, Graphostromataceae) in the Amazon forest in Pará, Brazil

Acta Amazonica ◽

10.1590/1809-4392201903212 ◽

2020 ◽

Vol 50 (3) ◽

pp. 273-277

Author(s):

Marcos Diones Ferreira SANTANA ◽

Douglas de Moraes COUCEIRO ◽

Sheyla Regina Marques COUCEIRO

Keyword(s):

First Record ◽

The State ◽

Identification Key ◽

Amazon Rainforest ◽

Morphological Description ◽

Amazon Forest ◽

The West

ABSTRACT Three species of the Ascomycetes genus Camillea were recorded in a fragment of Amazon rainforest in the region of Santarém, Pará state, Brazil. The occurrence of C. leprieurii, C. cyclops and C. bilabiata expand the range of distribution of these species in the state. Camillea leprieurii has previous records in the regions of Marabá, Oriximiná, Itaituba and Novo Progresso, while C. cyclops had been recorded in the west of the state. This is the first record of C. bilabiata for Pará. We provide a morphological description of the specimens and an identification key for Camillea species found in Pará.

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Evaluation of MEGAN-CLM parameter sensitivity to predictions of isoprene emissions from an Amazonian rainforest

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-14-23995-2014 ◽

2014 ◽

Vol 14 (17) ◽

pp. 23995-24041 ◽

Cited By ~ 6

Author(s):

J. A. Holm ◽

K. Jardine ◽

A. B. Guenther ◽

J. Q. Chambers ◽

E. Tribuzy

Keyword(s):

Land Surface ◽

Field Measurements ◽

Leaf Temperature ◽

Surface Model ◽

Amazon Forest ◽

Biophysical Parameters ◽

Area Index ◽

Central Amazon ◽

Community Land Model ◽

Environmental Controls

Abstract. Tropical trees are known to be large emitters of biogenic volatile organic compounds (BVOC), accounting for up to 75% of the global isoprene budget. Once in the atmosphere, these compounds influence multiple processes associated with air quality and climate. However, uncertainty in biogenic emissions is two-fold, (1) the environmental controls over isoprene emissions from tropical forests remain highly uncertain; and (2) our ability to accurately represent these environmental controls within models is lacking. This study evaluated the biophysical parameters that drive the global Model of Emissions of Gases and Aerosols from Nature (MEGAN) embedded in a biogeochemistry land surface model, the Community Land Model (CLM), with a focus on isoprene emissions from an Amazonian forest. Upon evaluating the sensitivity of 19 parameters in CLM that currently influence isoprene emissions by using a Monte Carlo analysis, up to 61% of the uncertainty in mean isoprene emissions was caused by the uncertainty in the parameters related to leaf temperature. The eight parameters associated with photosynthetic active radiation (PAR) contributed in total to only 15% of the uncertainty in mean isoprene emissions. Leaf temperature was strongly correlated with isoprene emission activity (R2 = 0.89). However, when compared to field measurements in the Central Amazon, CLM failed to capture the upper 10–14 °C of leaf temperatures throughout the year (i.e., failed to represent ~32 to 46 °C), and the spread observed in field measurements was not representative in CLM. This is an important parameter to accurately simulate due to the non-linear response of emissions to temperature. MEGAN-CLM 4.0 overestimated isoprene emissions by 60% for a Central Amazon forest (5.7 mg m−2 h−1 vs. 3.6 mg m−2 h−1), but due to reductions in leaf area index (LAI) by 28% in MEGAN-CLM 4.5 isoprene emissions were within 7% of observed data (3.8 mg m−2 h−1). When a slight adjustment to leaf temperature was made to match observations, isoprene emissions increased 24%, up to 4.8 mg m−2 h−1. Air temperatures are very likely to increase in tropical regions as a result of human induced climate change. Reducing the uncertainty of leaf temperature in BVOC algorithms, as well as improving the accuracy of replicating leaf temperature output in land surface models is warranted in order to improve estimations of tropical BVOC emissions.

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Transport of Saharan dust from the Bodélé Depression to the Amazon Basin: a case study

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-10-4345-2010 ◽

2010 ◽

Vol 10 (2) ◽

pp. 4345-4372 ◽

Cited By ~ 10

Author(s):

Y. Ben-Ami ◽

I. Koren ◽

Y. Rudich ◽

P. Artaxo ◽

S. T. Martin ◽

...

Keyword(s):

Atlantic Ocean ◽

Amazon Basin ◽

Marine Boundary Layer ◽

Average Concentration ◽

Saharan Dust ◽

Aerosol Layer ◽

Amazon Forest ◽

Close Link ◽

Bodele Depression

Abstract. Through long-range transport of dust, the Sahara desert supplies essential minerals to the Amazon rain forest. Since Saharan dust reaches South America mostly during the Northern Hemisphere winter, the dust sources active during winter are the main contributors to the forest. Given that the Bodélé depression area in Southwestern Chad is the main winter dust source, a close link is expected between the Bodélé emission patterns and volumes and the mineral supply flux to the Amazon. Until now, the particular link between the Bodélé and the Amazon forest was based on sparse satellite measurements and modeling studies. In this study, we combine a detailed analysis of space-borne and ground data with reanalysis model data and surface measurements taken in the Central Amazon during the Amazonian Aerosol Characterization Experiment (AMAZE-08) in order to explore the validity and the nature of the proposed link between the Bodélé depression and the Amazon forest. This case study follows the dust events of 11–16 and 18–27 February 2008, from the emission in the Bodélé over West Africa, the crossing of the Atlantic Ocean, to the observed effects above the Amazon canopy about 10 days after the emission. The dust was lifted by surface winds stronger than 14 m s−1, usually starting early in the morning. The lofted dust mixed with biomass burning aerosols over Nigeria, was transported over the Atlantic Ocean, and arrived over the South American continent. The top of the aerosol layer reached above 3 km, and the bottom merged with the marine boundary layer. The arrival of the dusty air parcel over the Amazon forest increased the average concentration of aerosol crustal elements by an order of magnitude.

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Biomass burning emission disturbances of isoprene oxidation in a tropical forest

Atmospheric Chemistry and Physics ◽

10.5194/acp-18-12715-2018 ◽

2018 ◽

Vol 18 (17) ◽

pp. 12715-12734 ◽

Cited By ~ 4

Author(s):

Fernando Santos ◽

Karla Longo ◽

Alex Guenther ◽

Saewung Kim ◽

Dasa Gu ◽

...

Keyword(s):

Chemical Composition ◽

Biomass Burning ◽

Oxidative Capacity ◽

Oxidation Products ◽

Amazon Rainforest ◽

Amazon Forest ◽

Oxidation Reactions ◽

Smoke Plumes ◽

Isoprene Oxidation ◽

The Impact

Abstract. We present a characterization of the chemical composition of the atmosphere of the Brazilian Amazon rainforest based on trace gas measurements carried out during the South AMerican Biomass Burning Analysis (SAMBBA) airborne experiment in September 2012. We analyzed the observations of primary biomass burning emission tracers, i.e., carbon monoxide (CO), nitrogen oxides (NOx), ozone (O3), isoprene, and its main oxidation products, methyl vinyl ketone (MVK), methacrolein (MACR), and isoprene hydroxy hydroperoxide (ISOPOOH). The focus of SAMBBA was primarily on biomass burning emissions, but there were also several flights in areas of the Amazon forest not directly affected by biomass burning, revealing a background with a signature of biomass burning in the chemical composition due to long-range transport of biomass burning tracers from both Africa and the eastern part of Amazonia. We used the [MVK + MACR + ISOPOOH] ∕ [isoprene] ratio and the hydroxyl radical (OH) indirect calculation to assess the oxidative capacity of the Amazon forest atmosphere. We compared the background regions (CO < 150 ppbv), fresh and aged smoke plumes classified according to their photochemical age ([O3] ∕ [CO]), to evaluate the impact of biomass burning emissions on the oxidative capacity of the Amazon forest atmosphere. We observed that biomass burning emissions disturb the isoprene oxidation reactions, especially for fresh plumes ([MVK + MACR + ISOPOOH] ∕ [isoprene] = 7) downwind. The oxidation of isoprene is higher in fresh smoke plumes at lower altitudes (∼ 500 m) than in aged smoke plumes, anticipating near the surface a complex chain of oxidation reactions which may be related to secondary organic aerosol (SOA) formation. We proposed a refinement of the OH calculation based on the sequential reaction model, which considers vertical and horizontal transport for both biomass burning regimes and background environment. Our approach for the [OH] estimation resulted in values on the same order of magnitude of a recent observation in the Amazon rainforest [OH] ≅ 106 (molecules cm−3). During the fresh plume regime, the vertical profile of [OH] and the [MVK + MACR + ISOPOOH] ∕ [isoprene] ratio showed evidence of an increase in the oxidizing power in the transition from planetary boundary layer to cloud layer (1000–1500 m). These high values of [OH] (1.5 × 106 molecules cm−3) and [MVK + MACR + ISOPOOH] ∕ [isoprene] (7.5) indicate a significant change above and inside the cloud decks due to cloud edge effects on photolysis rates, which have a major impact on OH production rates.

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Long-Term Impacts of Selective Logging on Amazon Forest Dynamics from Multi-Temporal Airborne LiDAR

Remote Sensing ◽

10.3390/rs11060709 ◽

2019 ◽

Vol 11 (6) ◽

pp. 709 ◽

Cited By ~ 10

Author(s):

Ekena Rangel Pinagé ◽

Michael Keller ◽

Paul Duffy ◽

Marcos Longo ◽

Maiza dos-Santos ◽

...

Keyword(s):

Laser Scanning ◽

Forest Canopy ◽

Binary Classification ◽

Forest Degradation ◽

Selective Logging ◽

Ecological Impacts ◽

Airborne Lidar ◽

Classification Model ◽

Amazon Forest ◽

Gap Formation

Forest degradation is common in tropical landscapes, but estimates of the extent and duration of degradation impacts are highly uncertain. In particular, selective logging is a form of forest degradation that alters canopy structure and function, with persistent ecological impacts following forest harvest. In this study, we employed airborne laser scanning in 2012 and 2014 to estimate three-dimensional changes in the forest canopy and understory structure and aboveground biomass following reduced-impact selective logging in a site in Eastern Amazon. Also, we developed a binary classification model to distinguish intact versus logged forests. We found that canopy gap frequency was significantly higher in logged versus intact forests even after 8 years (the time span of our study). In contrast, the understory of logged areas could not be distinguished from the understory of intact forests after 6–7 years of logging activities. Measuring new gap formation between LiDAR acquisitions in 2012 and 2014, we showed rates 2 to 7 times higher in logged areas compared to intact forests. New gaps were spatially clumped with 76 to 89% of new gaps within 5 m of prior logging damage. The biomass dynamics in areas logged between the two LiDAR acquisitions was clearly detected with an average estimated loss of −4.14 ± 0.76 MgC ha−1 y−1. In areas recovering from logging prior to the first acquisition, we estimated biomass gains close to zero. Together, our findings unravel the magnitude and duration of delayed impacts of selective logging in forest structural attributes, confirm the high potential of airborne LiDAR multitemporal data to characterize forest degradation in the tropics, and present a novel approach to forest classification using LiDAR data.

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Valuation of Rainforest Preservation in the Amazon

Oxford Research Encyclopedia of Environmental Science ◽

10.1093/acrefore/9780199389414.013.467 ◽

2019 ◽

Author(s):

Jon Strand

Keyword(s):

Forest Fires ◽

Stated Preference ◽

Economic Value ◽

Forest Products ◽

Carbon Price ◽

Amazon Rainforest ◽

Amazon Forest ◽

Marginal Value ◽

Regulating Services ◽

Provisioning Services

Different ecosystem values of the Amazon rainforest are surveyed in economic terms. Spatial rainforest valuation is crucial for good forest management, such as where to put the most effort to stop illegal logging and forest fires, and which areas to designate as new nationally protected areas. Three classes of economic value are identified, according to who does the valuation: values accruing to the local and regional populations (of South America); carbon values (which are global); and other global (noncarbon) values. Only the first two classes are discussed. Three types of value are separated according to ecosystem service delivered from the rainforest: provisioning services; supporting and regulating services; and cultural and other human services. Net values of provisioning services, including reduced impact logging and various non-timber forest products, are well documented for the entire Brazilian Amazon at a spatially detailed scale and amount to at least $20–50/ha/year. Less-detailed information exists about values of fish, game, and bioprospecting from the Amazon, although their total values can be shown to be sizable. Many supporting and regulating services are harder to value economically, in particular climate regulation and watershed and erosion protection. Impacts of changed rainfall when Amazon rainforest is lost have been valued at detailed scale, but with relative model values of $10–20/ha/year. Carbon values are much larger, at a carbon price of $30/ton CO2, around $14,000/ha as capitalized value. The average per-hectare value of tourism and the health benefits from having the Amazon forest are low, and such values cannot easily be pinned down to individual areas of the Amazon. Finally, the biodiversity values of the Amazon, as accruing to the local and regional population, seem to be small based on recent stated-preference work in Brazil. Most of the values related to biodiversity are likely to be global and may. in principle, be very large, but the global components are not valued here. The concept of value is discussed, and a marginal valuation concept (practically useful for policy) is favored as opposed to an average or total valuation. Marginal value can be below average value (as is likely for biodiversity and tourism), but can also in some contexts be higher. This can occur where losing forest at a local scale increases the prevalence of forest fires and where it increases forest dryness, leading to a multiplier process whereby more forest is lost. While strides have recently been made to improve rainforest valuation at both micro- and macroscales, much work still remains.

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Asynchronous Amazon forest canopy phenology indicates adaptation to both water and light availability

Environmental Research Letters ◽

10.1088/1748-9326/9/12/124021 ◽

2014 ◽

Vol 9 (12) ◽

pp. 124021 ◽

Cited By ~ 45

Author(s):

Matthew O Jones ◽

John S Kimball ◽

Ramakrishna R Nemani

Keyword(s):

Forest Canopy ◽

Light Availability ◽

Amazon Forest

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Causes of reduced leaf-level photosynthesis during strong El Niño drought in a Central Amazon forest

Global Change Biology ◽

10.1111/gcb.14293 ◽

2018 ◽

Vol 24 (9) ◽

pp. 4266-4279 ◽

Cited By ~ 23

Author(s):

Victor Alexandre Hardt Ferreira dos Santos ◽

Marciel José Ferreira ◽

João Victor Figueiredo Cardoso Rodrigues ◽

Maquelle Neves Garcia ◽

João Vitor Barbosa Ceron ◽

...

Keyword(s):

El Niño ◽

El Nino ◽

Amazon Forest ◽

Central Amazon ◽

Leaf Level

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Review of the genus Ceratotarsonemus De Leon, 1956 (Acari: Prostigmata: Tarsonemidae), with description of a new species from the Amazon Forest

Zootaxa ◽

10.11646/zootaxa.4483.2.3 ◽

2018 ◽

Vol 4483 (2) ◽

pp. 271

Author(s):

JOSÉ MARCOS REZENDE ◽

ANTONIO CARLOS LOFEGO ◽

CONNOR GULBRONSON ◽

GARY BAUCHAN ◽

RONALD OCHOA

Keyword(s):

Phase Contrast ◽

Brazilian Amazon ◽

Amazon Rainforest ◽

Amazon Forest ◽

Differential Interference Contrast ◽

Ecological Aspects ◽

Temperature Scanning ◽

A New Species ◽

Scanning Electron

The genus Ceratotarsonemus De Leon (Acari: Prostigmata: Tarsonemidae) is reviewed here, with the addition of an updated key for the genus. Ceratotarsonemus amazonicus, sp. nov., found in the Brazilian Amazon rainforest, is described. Phase contrast (PC), differential interference contrast (DIC), low temperature scanning electron microscopy (LT-SEM) and confocal microscopy (CLSM) micrographs are provided. Biological and ecological aspects about the role of this species in its ecosystem are also discussed.

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