scholarly journals Atmospheric transport and mixing of biological soil crust microorganisms

2021 ◽  
Vol 8 (5) ◽  
pp. 498-516
Author(s):  
Steven D. Warren ◽  
◽  
Larry L. St. Clair ◽  
Keyword(s):  
Atmospheric Transport ◽  
Biological Soil Crust ◽  
Soil Surface ◽  
Terrestrial Ecosystems ◽  
Arid Ecosystems ◽  
Main Body ◽  
Airborne Dust ◽  
Consolidated Crust ◽  
Transport And Mixing ◽  
Precipitation Events

<abstract> <p>Biological soil crusts (BSCs) are created where a diverse array of microorganisms colonize the surface and upper few millimeters of the soil and create a consolidated crust. They were originally described from arid ecosystems where vascular vegetation is naturally sparse or absent. They have since been discovered in all terrestrial ecosystems. Where present, they perform a variety of important ecological functions, including the capture and accumulation of water and essential plant nutrients, and their release in forms useful to vascular plants. They also stabilize the soil surface against wind and water erosion. BSC organisms include fungi (free-living, lichenized, and mycorrhizal), archaea, bacteria (cyanobacteria and chemotrophic and diazotrophic bacteria), terrestrial algae (including diatoms), and bryophytes (mosses and worts). BSC organisms reproduce primarily asexually via thallus or main body fragmentation or production of asexual spores that are readily dispersed by water and wind. Asexual and sexual propagules of BSC organisms are commonly lifted into the air with vast quantities of dust from the world's arid areas. BSC organisms and/or their propagules have been detected as high as the stratosphere. Some have also been detected in the mesosphere. Airborne dust, microorganisms, and their propagules contribute to the formation of essential raindrop and snowflake nuclei that, in turn, facilitate precipitation events. While airborne in the atmosphere, they also reflect the sun's rays passing laterally through the troposphere and stratosphere at dawn and dusk, often causing brilliant colors at sunrise and sunset.</p> </abstract>

scholarly journals SURFATM-NH3: a model combining the surface energy balance and bi-directional exchanges of ammonia applied at the field scale

2009 ◽  
Vol 6 (8) ◽  
pp. 1371-1388 ◽  
Author(s):  
E. Personne ◽  
B. Loubet ◽  
B. Herrmann ◽  
M. Mattsson ◽  
J. K. Schjoerring ◽  
...  
Keyword(s):  
Energy Budget ◽  
Atmospheric Transport ◽  
Mineral Fertilizer ◽  
Soil Surface ◽  
Terrestrial Ecosystems ◽  
Biophysical Model ◽  
Coupled Models ◽  
Model Combining ◽  
Exchange Processes ◽  
Flux Measurements

Abstract. A new biophysical model SURFATM-NH3, simulating the ammonia (NH3) exchange between terrestrial ecosystems and the atmosphere is presented. SURFATM-NH3 consists of two coupled models: (i) an energy budget model and (ii) a pollutant exchange model, which distinguish the soil and plant exchange processes. The model describes the exchanges in terms of adsorption to leaf cuticles and bi-directional transport through leaf stomata and soil. The results of the model are compared with the flux measurements over grassland during the GRAMINAE Integrated Experiment at Braunschweig, Germany. The dataset of GRAMINAE allows the model to be tested in various meteorological and agronomic conditions: prior to cutting, after cutting and then after the application of mineral fertilizer. The whole comparison shows close agreement between model and measurements for energy budget and ammonia fluxes. The major controls on the ground and plant emission potential are the physicochemical parameters for liquid-gas exchanges which are integrated in the compensation points for live leaves, litter and the soil surface. Modelled fluxes are highly sensitive to soil and plant surface temperatures, highlighting the importance of accurate estimates of these terms. The model suggests that the net flux depends not only on the foliar (stomatal) compensation point but also that of leaf litter. SURFATM-NH3 represents a comprehensive approach to studying pollutant exchanges and its link with plant and soil functioning. It also provides a simplified generalised approach (SVAT model) applicable for atmospheric transport models.

scholarly journals SURFATM-NH<sub>3</sub>: a model combining the surface energy balance and bi-directional exchanges of ammonia applied at the field scale

2009 ◽  
Vol 6 (1) ◽  
pp. 71-114 ◽  
Author(s):  
E. Personne ◽  
B. Loubet ◽  
B. Herrmann ◽  
M. Mattsson ◽  
J. K. Schjoerring ◽  
...  
Keyword(s):  
Energy Budget ◽  
Atmospheric Transport ◽  
Mineral Fertilizer ◽  
Soil Surface ◽  
Terrestrial Ecosystems ◽  
Biophysical Model ◽  
Coupled Models ◽  
Model Combining ◽  
Exchange Processes ◽  
Flux Measurements

Abstract. A new biophysical model SURFATM-NH3, simulating the ammonia (NH3) exchange between terrestrial ecosystems and the atmosphere is presented. SURFATM-NH3 consists of two coupled models: (i) an energy budget model and (ii) a pollutant exchange model, which distinguish the soil and plant exchange processes. The model describes the exchanges in terms of adsorption to leaf cuticles and bi-directional transport through leaf stomata and soil. The results of the model are compared with the flux measurements over grassland during the GRAMINAE Integrated Experiment at Braunschweig, Germany. The dataset of GRAMINAE allows the model to be tested in various climatic and agronomic conditions: prior to cutting, after cutting and then after the application of mineral fertilizer. The whole comparison shows close agreement between model and measurements for energy budget and ammonia fluxes. The major controls on the soil and plant emission potential are the physicochemical parameters for liquid-gas exchanges which are integrated in the compensation points for live leaves, litter and the soil surface. Modelled fluxes are highly sensitive to soil and plant surface temperatures, highlighting the importance of accurate estimates of these terms. The model suggests that the net flux depends not only on the foliar (stomatal) compensation point but also that of leaf litter. SURFATM-NH3 represents a comprehensive approach to studying pollutant exchanges and its link with plant and soil functioning. It also provides a simplified generalised approach (SVAT model) applicable for atmospheric transport models.

scholarly journals Changes in Soil Carbon Sequestration during Woody Plant Encroachment in Arid Ecosystems

2021 ◽  
Vol 4 (4-5) ◽  
pp. 266-276
Author(s):  
Pratap Naikwade
Keyword(s):  
Climate Change ◽  
Carbon Sequestration ◽  
Soil Carbon ◽  
Atmospheric Carbon Dioxide ◽  
Global Climate ◽  
Terrestrial Ecosystems ◽  
Greenhouse Gas Mitigation ◽  
Arid Ecosystems ◽  
Woody Encroachment ◽  
Organic C

Carbon sequestration is one of the most important and highly recommended measures for mitigating climate change. Soil organic carbon (SOC) has potential to sequester the largest amount of carbon (C) for the longest time period in the midst of the organic C sinks in terrestrial ecosystems of the earth. In recent years, apprehension of the role of soils as sink for carbon on a wide-ranging scale has become dynamic. From last 150 years, encroachment of trees and shrubs into grasslands and the ‘thicketization’ of savannas have been reported and is a global phenomenon. One possibly beneficial effect could be that the shrub and tree-dominated ecosystems will sequester more carbon and will be a buffer for elevated atmospheric carbon dioxide (CO2) levels. The question of what is impact of woody encroachment on soil carbon balance of an ecosystem has proved difficult to answer, and the results remain debatable. The magnitude and pattern of changes in the SOC with woody encroachment are exceedingly abstruse and varies from significant increases, to significant decreases to no net change in SOC. Impact of wood plant encroachment on carbon sequestration is discussed in this paper considering various studies with different results so it will lead to better understanding of the complex phenomenon. SOC sequestration is effective greenhouse gas mitigation strategy and a vital ecosystem service. Increasing SOC may helpful to mitigate negative effects of growing concentration of CO2 in atmosphere and may be advantageous in decelerating or reversal in global climate change rate.

Soil erosion controlled by biota along a climate gradient in Chile

2020 ◽  
Author(s):  
Nicolás Riveras ◽  
Kristina Witzgall ◽  
Victoria Rodríguez ◽  
Peter Kühn ◽  
Carsten W. Mueller ◽  
...  
Keyword(s):  
Soil Erosion ◽  
Biological Soil Crust ◽  
Environmental Filtering ◽  
Soil Surface ◽  
Climatic Conditions ◽  
Rainfall Simulation ◽  
Soil Erodibility ◽  
Rainfall Gradient ◽  
The Impact ◽  
Semi Arid

&lt;p&gt;Soil erosion is one of the main problems in soil degradation nowadays and is widely distributed in many landscapes worldwide. Particularly water erosion is widespread and determined by rain erosivity, soil erodibility, topographic factors and the management carried out to mitigate this phenomenon. Although this process is mostly known as a consequence of human management such as agriculture or forestry, it is a process that also occurs naturally, being one of the factors that regulate the shape of the landscape.&lt;/p&gt;&lt;p&gt;One of the main agents that stabilize the soil surface is biota and its activity, either in the form of plants, microorganisms or as an assemblage in the form of a biological soil crust (biocrusts). However, there are limited studies about how and what extent biota drives soil-stabilizing processes. With particular view on the impact of biocrusts on soil erosion, most studies have been carried out in arid and semi-arid regions, so its influence under other climates is largely unknown.&lt;/p&gt;&lt;p&gt;This study focuses on the influence of biota on soil erosion in a temperature and rainfall gradient, covering four climate zones (arid, semi-arid, mediterranean and humid) with very limited human intervention. Other variables such as the origin of the geological formation, geographical longitude and glacial influence were kept constant for all study sites. The effect of vegetation (biocrusts) and its abundance, microbiology and terrain parameters are investigated using rainfall simulation experiments under controlled conditions and by a physico-chemical evaluation of the soil, surface runoff, percolation and sediment discharge, in order to determine the different environmental filtering effects that the soil develops under different climatic conditions.&lt;/p&gt;&lt;p&gt;It is expected that as vegetation vigor and cover increase, soil erodibility will decrease. The biocrust is the protagonist of this stabilization in conditions of low pedological development and will become secondary as edaphoclimatic conditions favor the colonization of plants.&lt;/p&gt;&lt;p&gt;The results of this study will help to achieve a better understanding of the role of biota in soil erosion control and will clarify its influence on soil losses under different climate and slope conditions. Analyses are currently ongoing and first results of our work will be presented at the EGU 2020.&lt;/p&gt;

scholarly journals Broader Impacts for Ecologists: Biological Soil Crust as a Model System for Education

2021 ◽  
Vol 11 ◽  
Author(s):  
Akasha M. Faist ◽  
Anita J. Antoninka ◽  
Nichole N. Barger ◽  
Matthew A. Bowker ◽  
V. Bala Chaudhary ◽  
...  
Keyword(s):  
Spatial Scales ◽  
Biological Soil Crust ◽  
Biotic Interactions ◽  
Soil Surface ◽  
Ecosystem Processes ◽  
Model System ◽  
Teaching Tool ◽  
Biological Interactions ◽  
Excellent Teaching ◽  
Patterns And Processes

Biological soil crusts (biocrusts) are a complex community of algae, cyanobacteria, lichens, bryophytes, and assorted bacteria, fungi, archaea, and bacteriophages that colonize the soil surface. Biocrusts are particularly common in drylands and are found in arid and semiarid ecosystems worldwide. While diminutive in size, biocrusts often cover large terrestrial areas, provide numerous ecosystem benefits, enhance biodiversity, and are found in multiple configurations and assemblages across different climate and disturbance regimes. Biocrusts have been a focus of many ecologists, especially those working in semiarid and arid lands, as biocrusts are foundational community members, play fundamental roles in ecosystem processes, and offer rare opportunities to study biological interactions at small and large spatial scales. Due to these same characteristics, biocrusts have the potential to serve as an excellent teaching tool. The purpose of this paper is to demonstrate the utility of biocrust communities as a model system in science education. Functioning as portable, dynamic mini ecosystems, biocrusts can be used to teach about organisms, biodiversity, biotic interactions, abiotic controls, ecosystem processes, and even global change, and can be easy to use in nearly every classroom setup. For example, education principles, such as evolution and adaptation to stress, or structure and function (patterns and processes) can be applied by bringing biocrusts into the classroom as a teaching tool. In addition, discussing the utility of biocrusts in the classroom – including theory, hypothesis testing, experimentation, and hands-on learning – this document also provides tips and resources for developing education tools and activities geared toward impactful learning.

scholarly journals Cyanobacterial and green algal assemblages in various tundra habitats in the high Arctic (West Spitsbergen, Norway)

2018 ◽  
Vol 87 (4) ◽  
Author(s):  
Dorota Lidia Richter ◽  
Jan Matuła ◽  
Mirosława Pietryka ◽  
Bronisław Wojtuń ◽  
Adrian Zwolicki ◽  
...  
Keyword(s):  
Soil Surface ◽  
Terrestrial Ecosystems ◽  
Moisture Index ◽  
Nitrogen And Phosphorus ◽  
Large Variability ◽  
Green Algal ◽  
Algal Assemblages ◽  
Cyanobacteria And Algae ◽  
Water Saturated ◽  
Seabird Colonies

The diversity of cyanobacteria and algae from various microhabitats in Spitsbergen is comparatively well known. However, the relationships between environmental factors and the structure of microflora communities remain largely unclear. This study was conducted in Hornsund Bay, which exhibits large variability in the physicochemical characteristics of habitats, particularly with regard to the availability of nitrogen and phosphorus. This variability, to a large degree, is caused by seabird colonies, which fertilize nutrient-poor terrestrial ecosystems near their nesting areas. The large variations in ecological conditions and vegetation types in the study area aid assessment of habitats representing different combinations of factors potentially influencing the formation of cyanobacterial and algal assemblages. The aim of this study was to examine the influence of physicochemical parameters on the taxonomic composition and diversity of green algae and cyanobacteria (particularly the coccoid, oscillatorialean, and heterocystous taxa). The study encompassed two groups of habitats – soil surface habitats and water-saturated habitats, both characterized by diverse influences of seabird colonies, vegetation cover, and moisture. Our results showed that taxonomic diversity and composition of cyanobacteria and algae were mainly influenced by P–PO<sub>4</sub><sup>3−</sup>, N–NH<sub>4</sub><sup>+</sup> and Ca<sup>2+</sup> (soil surface habitats), and NO<sub>3</sub><sup>−</sup>, as well as moisture (index of wetness) and pH (water-saturated habitats). The variability of these physicochemical properties was largely due to the variability of the seabird colony influence. Taken together, our findings aid in understanding the processes of formation of phycoflora assemblages in Arctic tundra.

scholarly journals Biological soil crust communities 12–16 years after wildfires in Idaho, USA

2017 ◽  
Author(s):  
Heather T. Root ◽  
John C. Brinda ◽  
E. Kyle Dodson
Keyword(s):  
Species Richness ◽  
Functional Groups ◽  
Fire Severity ◽  
Biological Soil Crust ◽  
Vascular Plant ◽  
Fire Regimes ◽  
Arid Ecosystems ◽  
Plant Functional Groups ◽  
Ecosystem Functions ◽  
Soil Crust

Abstract. Changing fire regimes in western North America may impact biological soil crust (BSC) communities that influence many ecosystem functions, such as soil stability and C and N cycling. However, longer-term effects of wildfire on BSC abundance, species richness, functional groups, and ecosystem functions after wildfire (i.e. BSC resilience) is still poorly understood. We sampled BSC lichen and bryophyte communities at four sites in Idaho, USA, within foothill steppe communities that included wildfires from 12 to 16 years old. We established six plots outside each burn perimeter and compared them with six plots of varying severity within each fire perimeter at each site. BSC cover was most strongly negatively impacted by wildfire at sites that had well-developed BSC communities in adjacent unburned plots. BSC species richness was estimated to be 65 % greater in unburned plots compared with burned plots. In contrast, there was no evidence that vascular plant functional groups or fire severity (as measured by satellite metrics dNBR or RdNBR) significantly affected longer-term BSC responses. Three BSC functional groups (squamulose lichens, vagrant lichens, and tall turf mosses) exhibited a significant decrease in abundance in burned areas relative to adjacent unburned areas. The decreases in BSC cover and richness along with decreased abundance of several functional groups suggest that wildfire can negatively impact ecosystem function in these semi-arid ecosystems for at least one to two decades. This is a concern given that increased fire frequency is predicted for the region due to exotic grass invasion and climate change.

scholarly journals Technical Note: Minerals in dust productive soils – impacts and global distribution

2011 ◽  
Vol 11 (9) ◽  
pp. 26009-26034 ◽  
Author(s):  
S. Nickovic ◽  
A. Vukovic ◽  
M. Vujadinovic ◽  
V. Djurdjevic ◽  
G. Pejanovic
Keyword(s):  
High Resolution ◽  
Mineral Composition ◽  
Atmospheric Transport ◽  
Dust Emission ◽  
Technical Note ◽  
Dust Storms ◽  
Dust Particles ◽  
Atmospheric Conditions ◽  
Airborne Dust ◽  
Aerosol Process

Abstract. Dust storms and associated mineral aerosol transport are mainly driven by meso and synoptic scale atmospheric processes. It is therefore essential that the dust aerosol process and background atmospheric conditions that drive the dust emission and atmospheric transport be represented with sufficiently well resolved spatial and temporal features. Effects of airborne dust interactions with the environment are determent by the mineral composition of dust particles. Fractions of various minerals in the aerosol are determined by the mineral composition of arid soils, therefore high-resolution specification of mineral and physical properties of dust sources is needed as well. Most current dust atmospheric models simulate/predict the evolution of dust concentration but in most cases they do not consider fractions of minerals in dust. Accumulated knowledge on impacts of mineral composition in dust on weather and climate processes emphasizes the importance of considering minerals in modelling systems. Following such needs, in this study we developed a global dataset on mineral composition of potentially dust productive soils. In our study (a) we mapped mineral data into a high-resolution 30-s grid, (b) we included mineral carrying soil types in dust productive regions that were not considered in previous studies, and (c) included phosphorus having in mind their importance for terrestrial and marine nutrition processes.

scholarly journals The regional European atmospheric transport inversion comparison, EUROCOM: first results on European-wide terrestrial carbon fluxes for the period 2006–2015

2020 ◽  
Vol 20 (20) ◽  
pp. 12063-12091
Author(s):  
Guillaume Monteil ◽  
Grégoire Broquet ◽  
Marko Scholze ◽  
Matthew Lang ◽  
Ute Karstens ◽  
...  
Keyword(s):  
Carbon Flux ◽  
Large Scale ◽  
Transport Model ◽  
Atmospheric Transport ◽  
Scale Up ◽  
Terrestrial Ecosystems ◽  
Terrestrial Carbon ◽  
Continental Scale ◽  
First Results

Abstract. Atmospheric inversions have been used for the past two decades to derive large-scale constraints on the sources and sinks of CO2 into the atmosphere. The development of dense in situ surface observation networks, such as ICOS in Europe, enables in theory inversions at a resolution close to the country scale in Europe. This has led to the development of many regional inversion systems capable of assimilating these high-resolution data, in Europe and elsewhere. The EUROCOM (European atmospheric transport inversion comparison) project is a collaboration between seven European research institutes, which aims at producing a collective assessment of the net carbon flux between the terrestrial ecosystems and the atmosphere in Europe for the period 2006–2015. It aims in particular at investigating the capacity of the inversions to deliver consistent flux estimates from the country scale up to the continental scale. The project participants were provided with a common database of in situ-observed CO2 concentrations (including the observation sites that are now part of the ICOS network) and were tasked with providing their best estimate of the net terrestrial carbon flux for that period, and for a large domain covering the entire European Union. The inversion systems differ by the transport model, the inversion approach, and the choice of observation and prior constraints, enabling us to widely explore the space of uncertainties. This paper describes the intercomparison protocol and the participating systems, and it presents the first results from a reference set of inversions, at the continental scale and in four large regions. At the continental scale, the regional inversions support the assumption that European ecosystems are a relatively small sink (-0.21±0.2 Pg C yr−1). We find that the convergence of the regional inversions at this scale is not better than that obtained in state-of-the-art global inversions. However, more robust results are obtained for sub-regions within Europe, and in these areas with dense observational coverage, the objective of delivering robust country-scale flux estimates appears achievable in the near future.

High Andean Soil Landscapes Shaped by Interactions between Geomorphology, Vegetation, and Hydrology

2020 ◽  
Author(s):  
Veerle Vanacker ◽  
Armando Molina ◽  
Santiago Zhiminaicela ◽  
Marife Corre ◽  
Edzo Veldkamp
Keyword(s):  
Chemical Weathering ◽  
Soil Surface ◽  
Terrestrial Ecosystems ◽  
Base Cation ◽  
Parent Material ◽  
Subsurface Water ◽  
Native Forest ◽  
Good Opportunity ◽  
Vegetation Communities ◽  
Environmental Controls

&lt;p&gt;Physical and chemical weathering processes fulfil a crucial function in the biogeochemistry of terrestrial ecosystems. Rock&amp;#8208;derived weathering products provide essential plant nutrients, and regulate the chemical composition of soil, surface, and groundwater. The rate and extent of chemical weathering are influenced by the combined effects of climate, parent material, topography, and vegetation, and ultimately determine the mineral composition and element ratios of soil material. Understanding the spatial variation of rock&amp;#8208;derived weathering products across heterogeneous landscapes not only relies on knowledge of the environmental controls but also of their interactions.&lt;/p&gt;&lt;p&gt;High Andean tropical ecosystems provide a good opportunity to study the association between chemical weathering, local topography and vegetation patterns: the climate, parent material and soil age can be held constant at the landscape scale, while the vegetation and slope morphology can vary greatly from the hilltops to the valley bottoms. In this study, we selected 10 soil toposequences on andesitic flows: 5 under tussock grasses, 3 under cushion forming plants and 2 under native forest. A marginally significant increase in base cation depletion is observed along topographic gradients that can be associated with physical transport of weathered soil particles downslope or subsurface water fluxes. Beyond the hillslope-scale topographic control on chemical weathering extent, we observed highly significant differences in chemical weathering extent between vegetation communities with total mass losses in forest soils being respectively 19% and 22% higher than in grasslands and cushion forming plants. Although biotic factors can play a role in creating the observed patterns in soil development, the vegetation communities can also hint to the existence of hillslope micro-topography and subsurface hydrological patterns that are challenging to map in the field.&lt;/p&gt;

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