scholarly journals Structural diversity across arbuscular mycorrhizal, ectomycorrhizal, and endophytic plant—fungus networks

2018 ◽  
Author(s):  
Hirokazu Toju ◽  
Hirotoshi Sato ◽  
Satoshi Yamamoto ◽  
Akifumi S. Tanabe
Keyword(s):  
Network Architecture ◽  
High Throughput Sequencing ◽  
Latitudinal Gradient ◽  
Terrestrial Ecosystem ◽  
Arbuscular Mycorrhizal ◽  
Structural Diversity ◽  
Terrestrial Ecosystems ◽  
Ecosystem Dynamics ◽  
Plant Seed ◽  
Scale Properties

AbstractBackgroundBelow-ground linkage between plant and fungal communities is one of the major drivers of terrestrial ecosystem dynamics. However, we still have limited knowledge of how such plant–fungus associations vary in their community-scale properties depending on fungal functional groups and geographic locations.MethodsBased on high-throughput sequencing of root-associated fungi in eight forests along the Japanese Archipelago, we performed a comparative analysis of arbuscular mycorrhizal, ectomycorrhizal, and saprotrophic/endophytic associations across a latitudinal gradient from cool-temperate to subtropical regions.ResultsIn most of the plant–fungus networks analyzed, host–symbiont associations were significantly specialized but lacked “nested” architecture, which has been commonly reported in plant–pollinator and plant–seed disperser networks. Meanwhile, the structure of arbuscular mycorrhizal networks was differentiated from that of ectomycorrhizal and saprotrophic/endophytic networks, characterized by high connectance. Our data also suggested that geographic factors affected the organization of plant–fungus network structure. For example, the southernmost subtropical site analyzed in this study displayed lower network-level specificity of host–symbiont associations and higher (but still low) nestedness than northern localities.ConclusionsOur comparative analyses suggest that arbuscular mycorrhizal, ectomycorrhizal, and saprotrophic/endophytic plant–fungus associations often lack nested network architecture, while those associations can vary, to some extent, in their community-scale properties along a latitudinal gradient. Overall, this study provides a basis for future studies that will examine how different types of plant–fungus associations collectively structure terrestrial ecosystems.

scholarly journals A new terrestrial biosphere model with coupled carbon, nitrogen, and phosphorus cycles (QUINCY v1.0; revision 1772)

2019 ◽  
Author(s):  
Tea Thum ◽  
Silvia Caldararu ◽  
Jan Engel ◽  
Melanie Kern ◽  
Marleen Pallandt ◽  
...  
Keyword(s):  
Terrestrial Ecosystem ◽  
Terrestrial Ecosystems ◽  
Ecosystem Dynamics ◽  
Soil Conditions ◽  
Monitoring Networks ◽  
Nitrogen And Phosphorus ◽  
Element Cycling ◽  
Terrestrial Biosphere ◽  
Ecosystem Monitoring ◽  
Terrestrial Ecosystem Model

Abstract. The dynamics of terrestrial ecosystems are shaped by the coupled cycles of carbon, nitrogen and phosphorus, and strongly depend on the availability of water and energy. These interactions shape future terrestrial biosphere responses to global change. Many process-based models of the terrestrial biosphere have been gradually extended from considering carbon-water interactions to also including nitrogen, and later, phosphorus dynamics. This evolutionary model development has hindered full integration of these biogeochemical cycles and the feedbacks amongst them. Here we present a new terrestrial ecosystem model QUINCY (QUantifying Interactions between terrestrial Nutrient CYcles and the climate system), which is formulated around a consistent representation of element cycling in terrestrial ecosystems. This new model includes i) a representation of plant growth which separates source (e.g. photosynthesis) and sink (growth rate of individual tissues, constrained by nutrients, temperature, and water availability) processes; ii) the acclimation of many ecophysiological processes to meteorological conditions and/or nutrient availabilities; iii) an explicit representation of vertical soil processes to separate litter and soil organic matter dynamics; iv) a range of new diagnostics (leaf chlorophyll content; 13C, 14C, and 15N isotope tracers) to allow for a more in-depth model evaluation. We present the model structure and provide an assessment of its performance against a range of observations from global-scale ecosystem monitoring networks. We demonstrate that the framework is capable of consistently simulating ecosystem dynamics across a large gradient in climate and soil conditions, as well as across different plant functional types. To aid this understanding we provide an assessment of the model's sensitivity to its parameterisation and the associated uncertainty.

scholarly journals Metagenomic Analysis Reveals Correlation Between Microbiome Structure and Leonardite Characteristics from Kazakhstan Coal Deposits

2019 ◽  
Vol 21 (2) ◽  
pp. 135
Author(s):  
A.A. Zhubanova ◽  
Q. Xiaohui ◽  
P.S. Ualieva ◽  
G.Zh. Abdieva ◽  
K.T. Tastambek ◽  
...  
Keyword(s):  
High Throughput Sequencing ◽  
Terrestrial Ecosystem ◽  
Morphological Diversity ◽  
Terrestrial Ecosystems ◽  
Phylogenetic Structure ◽  
Biochemical Processes ◽  
Coal Deposits ◽  
Wide Range ◽  
Composition Structure ◽  
First Time

Coal microbial communities have not been well examined, despite their importance in the formation and maintenance of terrestrial ecosystems. Microorganisms are geographically versatile, exhibit wide morphological diversity and provide a rich platform for studying energy and carbon flows through different ecosystems. The coal characteristics, in turn, are important environmental factors that control the composition, structure and activity of terrestrial bio-communities through various endogenous physiological and biochemical processes. The total phylogenetic structure of prokaryotes is closely related to their functional diversity and, ultimately, to the variety of environmental conditions in oxidized coal (leonardite). Metagenomic studies in this area attempt to assess the relationship between the coal properties and its microbiome. The microbial community of the coal profiles, collected from various Kazakhstan coal deposits, have been studied in detail for the first time using high-throughput sequencing. As part of this study, a wide range of leonardites generated in various bioclimatic and geomorphological conditions are considered. A comprehensive characterization of the phylogenetic structure and diversity of coal was given on the basis of the 16S rDNA gene analysis. The revealed features of the prokaryotic composition can be used as bioindicators of the leonardite condition. In addition, metagenomic characteristics of coals of different origin can serve as valuable platform to assess the terrestrial ecosystem health.

Tree death as a crucial geomorphic agent in temperate forests: effects of weak and severe disturbances from local to continental scale

2020 ◽  
Author(s):  
Pavel Šamonil ◽  
Pavel Daněk ◽  
James A. Lutz ◽  
Jakub Jaroš ◽  
Anna Rousová ◽  
...  
Keyword(s):  
Terrestrial Ecosystem ◽  
Terrestrial Ecosystems ◽  
Ecosystem Dynamics ◽  
Retention Capacity ◽  
Tree Species Composition ◽  
Continental Scale ◽  
Standing Trees ◽  
Forested Landscapes ◽  
Tree Uprooting ◽  
Hillslope Processes

<p>Hillslope processes in terrestrial ecosystems are significantly modified by changes in climate and land use. At the same time they strongly influence ecosystem retention capacity, pedocomplexity and biodiversity. This undoubtedly makes hillslope processes one of the crucial components of terrestrial ecosystem dynamics. In this study we focus on the long overlooked biogeomorphological impact of tree death in forested landscapes. Tree uprooting caused by strong storms affects soil and regolith formation and movement quite differently from the decomposition of intact root systems of standing trees that died due to e.g. fire or bark beetle infestation. We quantify the biogeomorphic processes associated with tree death in various terrestrial forest ecosystems and specifically assess (i) the significance of these processes in hillslope dynamics (e.g. slope denudation) of forested landscapes and (ii) the extent to which infrequent severe disturbances can shape these dynamics.</p><p>We used data from repeated tree censuses carried out in ten permanent forest plots (13–74 ha in area) located in Central Europe and North America, differing in a range of characteristics such as tree species composition, climate and disturbance regime. In total, life history of more than 134,000 trees was recorded over periods of up to 47 years, during which about one third of these trees died. Using this information together with empirical models and allometric equations we were able to quantify the average areas and volumes of soil annually affected by dying trees. These quantities differed markedly between sites with different disturbance regimes. Tree uprooting-related volumes accounted annually for 0.01–13.5 m<sup>3</sup>ha<sup>−1</sup> reaching maximum values on sites with occurrence of infrequent strong windstorms (Zofin and Boubin primeval forests, Czech Republic). Volumes related to trees that died standing ranged anually between 0.17 and 20.7 m<sup>3</sup>ha<sup>−1</sup> and were highest in the presence of stand-replacing fires (Yosemite National Park, U.S.). Comparison of these quantities with long-term erosion rates derived using cosmogenic nuclides (<sup>10</sup>Be) suggests that on certain sites, over the last few millennia, tree uprooting can be the main driver of soil erosion.</p>

scholarly journals Potassium Control of Plant Functions: Ecological and Agricultural Implications

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 419
Author(s):  
Jordi Sardans ◽  
Josep Peñuelas
Keyword(s):  
Food Security ◽  
Stress Responses ◽  
Crop Production ◽  
Terrestrial Ecosystem ◽  
Terrestrial Ecosystems ◽  
Wood Formation ◽  
Cellular Growth ◽  
Ecosystem Functions ◽  
Metabolite Transport ◽  
Physiological Functions

Potassium, mostly as a cation (K+), together with calcium (Ca2+) are the most abundant inorganic chemicals in plant cellular media, but they are rarely discussed. K+ is not a component of molecular or macromolecular plant structures, thus it is more difficult to link it to concrete metabolic pathways than nitrogen or phosphorus. Over the last two decades, many studies have reported on the role of K+ in several physiological functions, including controlling cellular growth and wood formation, xylem–phloem water content and movement, nutrient and metabolite transport, and stress responses. In this paper, we present an overview of contemporary findings associating K+ with various plant functions, emphasizing plant-mediated responses to environmental abiotic and biotic shifts and stresses by controlling transmembrane potentials and water, nutrient, and metabolite transport. These essential roles of K+ account for its high concentrations in the most active plant organs, such as leaves, and are consistent with the increasing number of ecological and agricultural studies that report K+ as a key element in the function and structure of terrestrial ecosystems, crop production, and global food security. We synthesized these roles from an integrated perspective, considering the metabolic and physiological functions of individual plants and their complex roles in terrestrial ecosystem functions and food security within the current context of ongoing global change. Thus, we provide a bridge between studies of K+ at the plant and ecological levels to ultimately claim that K+ should be considered at least at a level similar to N and P in terrestrial ecological studies.

scholarly journals Reduced resilience of terrestrial ecosystems locally is not reflected on a global scale

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Yuhao Feng ◽  
Haojie Su ◽  
Zhiyao Tang ◽  
Shaopeng Wang ◽  
Xia Zhao ◽  
...  
Keyword(s):  
Climate Change ◽  
Global Climate Change ◽  
Vegetation Index ◽  
Global Climate ◽  
Terrestrial Ecosystem ◽  
Terrestrial Ecosystems ◽  
Global Scale ◽  
Ecological Resilience ◽  
Terrestrial Vegetation ◽  
Ecosystem Resilience

AbstractGlobal climate change likely alters the structure and function of vegetation and the stability of terrestrial ecosystems. It is therefore important to assess the factors controlling ecosystem resilience from local to global scales. Here we assess terrestrial vegetation resilience over the past 35 years using early warning indicators calculated from normalized difference vegetation index data. On a local scale we find that climate change reduced the resilience of ecosystems in 64.5% of the global terrestrial vegetated area. Temperature had a greater influence on vegetation resilience than precipitation, while climate mean state had a greater influence than climate variability. However, there is no evidence for decreased ecological resilience on larger scales. Instead, climate warming increased spatial asynchrony of vegetation which buffered the global-scale impacts on resilience. We suggest that the response of terrestrial ecosystem resilience to global climate change is scale-dependent and influenced by spatial asynchrony on the global scale.

A coupled multi-proxy and process modelling approach for extraction of quantitative terrestrial ecosystem information from speleothems

2021 ◽  
Author(s):  
Franziska Lechleitner ◽  
Christopher C. Day ◽  
Oliver Kost ◽  
Micah Wilhelm ◽  
Negar Haghipour ◽  
...  
Keyword(s):  
Climate Change ◽  
Soil Respiration ◽  
Western Europe ◽  
Global Climate ◽  
Terrestrial Ecosystem ◽  
Terrestrial Ecosystems ◽  
Clear Correlation ◽  
Northern Spain ◽  
Regional Temperature ◽  
Global Carbon

<p>Terrestrial ecosystems are intimately linked with the global climate system, but their response to ongoing and future anthropogenic climate change remains poorly understood. Reconstructing the response of terrestrial ecosystem processes over past periods of rapid and substantial climate change can serve as a tool to better constrain the sensitivity in the ecosystem-climate response.</p><p>In this talk, we will present a new reconstruction of soil respiration in the temperate region of Western Europe based on speleothem carbon isotopes (δ<sup>13</sup>C). Soil respiration remains poorly constrained over past climatic transitions, but is critical for understanding the global carbon cycle and its response to ongoing anthropogenic warming. Our study builds upon two decades of speleothem research in Western Europe, which has shown clear correlation between δ<sup>13</sup>C and regional temperature reconstructions during the last glacial and the deglaciation, with exceptional regional coherency in timing, amplitude, and absolute δ<sup>13</sup>C variation. By combining innovative multi-proxy geochemical analysis (δ<sup>13</sup>C, Ca isotopes, and radiocarbon) on three speleothems from Northern Spain, and quantitative forward modelling of processes in soil, karst, and cave, we show how deglacial variability in speleothem δ<sup>13</sup>C is best explained by increasing soil respiration. Our study is the first to quantify and remove the effects of prior calcite precipitation (PCP, using Ca isotopes) and bedrock dissolution (open vs closed system, using the radiocarbon reservoir effect) from the speleothem δ<sup>13</sup>C signal to derive changes in respired δ<sup>13</sup>C over time. Our approach allows us to estimate the temperature sensitivity of soil respiration (Q<sub>10</sub>), which is higher than current measurements, suggesting that part of the speleothem signal may be related to a change in the composition of the soil respired δ<sup>13</sup>C. This is likely related to changing substrate through increasing contribution from vegetation biomass with the onset of the Holocene.</p><p>These results highlight the exciting possibilities speleothems offer as a coupled archive for quantitative proxy-based reconstructions of climate and ecosystem conditions.</p>

scholarly journals Methyl phenlactonoates are efficient strigolactone analogs with simple structure

2017 ◽  
Vol 69 (9) ◽  
pp. 2319-2331 ◽  
Author(s):  
Muhammad Jamil ◽  
Boubacar A Kountche ◽  
Imran Haider ◽  
Xiujie Guo ◽  
Valentine O Ntui ◽  
...  
Keyword(s):  
Mycorrhizal Fungi ◽  
Simple Structure ◽  
Complex Structure ◽  
Arbuscular Mycorrhizal ◽  
Structural Diversity ◽  
Striga Hermonthica ◽  
Biological Processes ◽  
Structural Modifications ◽  
New Class ◽  
Agricultural Applications

abstract Strigolactones (SLs) are a new class of phytohormones that also act as germination stimulants for root parasitic plants, such as Striga spp., and as branching factors for symbiotic arbuscular mycorrhizal fungi. Sources for natural SLs are very limited. Hence, efficient and simple SL analogs are needed for elucidating SL-related biological processes as well as for agricultural applications. Based on the structure of the non-canonical SL methyl carlactonoate, we developed a new, easy to synthesize series of analogs, termed methyl phenlactonoates (MPs), evaluated their efficacy in exerting different SL functions, and determined their affinity for SL receptors from rice and Striga hermonthica. Most of the MPs showed considerable activity in regulating plant architecture, triggering leaf senescence, and inducing parasitic seed germination. Moreover, some MPs outperformed GR24, a widely used SL analog with a complex structure, in exerting particular SL functions, such as modulating Arabidopsis roots architecture and inhibiting rice tillering. Thus, MPs will help in elucidating the functions of SLs and are promising candidates for agricultural applications. Moreover, MPs demonstrate that slight structural modifications clearly impact the efficiency in exerting particular SL functions, indicating that structural diversity of natural SLs may mirror a functional specificity.

scholarly journals A temperature threshold to identify the driving climate forces of the respiratory process in terrestrial ecosystems

2017 ◽  
Author(s):  
Zhiyuan Zhang ◽  
Renduo Zhang ◽  
Yang Zhou ◽  
Alessandro Cescatti ◽  
Georg Wohlfahrt ◽  
...  
Keyword(s):  
Air Temperature ◽  
Driving Forces ◽  
Ecosystem Respiration ◽  
Large Fraction ◽  
Terrestrial Ecosystem ◽  
Terrestrial Ecosystems ◽  
Co2 Concentration ◽  
Temperature Threshold ◽  
Current Scenario ◽  
Ecosystem Flux

Abstract. Terrestrial ecosystem respiration (Re) is the major source of CO2 release and constitutes the second largest carbon flux between the biosphere and atmosphere. Therefore, climate-driven changes of Re may greatly impact on future atmospheric CO2 concentration. The aim of this study was to derive an air temperature threshold for identifying the driving climate forces of the respiratory process in terrestrial ecosystems within different temperature zones. For this purpose, a global dataset of 647 site-years of ecosystem flux data collected at 152 sites has been examined. Our analysis revealed an ecosystem threshold of mean annual air temperature (MAT) of 11 ± 2.3 °C. In ecosystems with the MAT below this threshold, the maximum Re rates were primarily dependent on temperature and respiration was mainly a temperature-driven process. On the contrary, in ecosystems with the MAT greater than 11 ± 2.3 °C, in addition to temperature, other driving forces, such as water availability and surface heat flux, became significant drivers of the maximum Re rates and respiration was a multi-factor-driven process. The information derived from this study highlight the key role of temperature as main controlling factor of the maximum Re rates on a large fraction of the terrestrial biosphere, while other driving forces reduce the maximum Re rates and temperature sensitivity of the respiratory process. These findings are particularly relevant under the current scenario of rapid global warming, given that the potential climate-induced changes in ecosystem respiration may lead to substantial anomalies in the seasonality and magnitude of the terrestrial carbon budget.

scholarly journals Novel Approach to Study the Diversity of Soil Microbial Communities in Qatar

2020 ◽  
Author(s):  
Jane Oja ◽  
Sakeenah Adenan ◽  
Abdel-Fattah Talaat ◽  
Juha Alatalo
Keyword(s):  
Microbial Communities ◽  
High Throughput ◽  
Mycorrhizal Fungi ◽  
High Throughput Sequencing ◽  
Soil Microbial Communities ◽  
Arbuscular Mycorrhizal ◽  
Soil Microbial ◽  
Fungal Abundance ◽  
Novel Approach ◽  
Soil Climate

A broad diversity of microorganisms can be found in soil, where they are essential for nutrient cycling and energy transfer. Recent high-throughput sequencing methods have greatly advanced our knowledge about how soil, climate and vegetation variables structure the composition of microbial communities in many world regions. However, we are lacking information from several regions in the world, e.g. Middle-East. We have collected soil from 19 different habitat types for studying the diversity and composition of soil microbial communities (both fungi and bacteria) in Qatar and determining which edaphic parameters exert the strongest influences on these communities. Preliminary results indicate that in overall bacteria are more abundant in soil than fungi and few sites have notably higher abundance of these microbes. In addition, we have detected some soil patameters, which tend to have reduced the overall fungal abundance and enhanced the presence of arbuscular mycorrhizal fungi and N-fixing bacteria. More detailed information on the diversity and composition of soil microbial communities is expected from the high-throughput sequenced data.

scholarly journals Grammar Guided Genetic Programming for Network Architecture Search and Road Detection on Aerial Orthophotography

2020 ◽  
Author(s):  
Víctor de la Fuente Castillo ◽  
Alberto Díaz-Álvarez ◽  
Miguel-Ángel Manso-Callejo ◽  
Francisco Serradilla García
Keyword(s):  
Genetic Programming ◽  
Network Architecture ◽  
Structural Diversity ◽  
Network Architectures ◽  
Complex Structures ◽  
Road Detection ◽  
Learning Techniques ◽  
Candidate Network ◽  
Optimal Network ◽  
Hidden Layer

Photogrammetry involves aerial photography of the earth’s surface and subsequently processing the images to provide a more accurate depiction of the area (Orthophotography). It’s used by the Spanish Instituto Geográfico Nacional to update road cartography but requires a significant amount of manual labor due to the need to perform visual inspection of all tiled images. Deep Learning techniques (artificial neural networks with more than one hidden layer) can perform road detection but it is still unclear how to find the optimal network architecture. Our system applies grammar guided genetic programming to the search of deep neural network architectures. In this kind of evolutive algorithm all the population individuals (here candidate network architectures) are constrained to rules specified by a grammar that defines valid and useful structural patterns to guide the search process. Grammar used includes well-known complex structures (e.g. Inception-like modules) combined with a custom designed mutation operator (dynamically links the mutation probability to structural diversity). Pilot results show that the system is able to design models for road detection that obtain test accuracies similar to that reached by state of the art models when evaluated over a dataset from the Spanish National Aerial Orthophotography Plan.

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