scholarly journals The global soil community and its influence on biogeochemistry

Science ◽  
2019 ◽  
Vol 365 (6455) ◽  
pp. eaav0550 ◽  
Author(s):  
T. W. Crowther ◽  
J. van den Hoogen ◽  
J. Wan ◽  
M. A. Mayes ◽  
A. D. Keiser ◽  
...  
Keyword(s):  
Organic Matter ◽  
Complex Nature ◽  
Soil Biodiversity ◽  
Soil Community ◽  
The Past ◽  
Biogeochemical Models ◽  
Global Soil ◽  
Organic Matter Pool ◽  
Diverse Community ◽  
Soil Groups

Soil organisms represent the most biologically diverse community on land and govern the turnover of the largest organic matter pool in the terrestrial biosphere. The highly complex nature of these communities at local scales has traditionally obscured efforts to identify unifying patterns in global soil biodiversity and biogeochemistry. As a result, environmental covariates have generally been used as a proxy to represent the variation in soil community activity in global biogeochemical models. Yet over the past decade, broad-scale studies have begun to see past this local heterogeneity to identify unifying patterns in the biomass, diversity, and composition of certain soil groups across the globe. These unifying patterns provide new insights into the fundamental distribution and dynamics of organic matter on land.

scholarly journals Brief communication: Analysis of organic matter in surface snow by PTR-MS – implications for dry deposition dynamics in the Alps

2019 ◽  
Vol 13 (1) ◽  
pp. 297-307 ◽  
Author(s):  
Dušan Materić ◽  
Elke Ludewig ◽  
Kangming Xu ◽  
Thomas Röckmann ◽  
Rupert Holzinger
Keyword(s):  
Organic Matter ◽  
Dry Deposition ◽  
Historical Record ◽  
Dynamic Processes ◽  
Complex Nature ◽  
Atmospheric Conditions ◽  
Communication Analysis ◽  
The Past ◽  
Surface Snow ◽  
The Alps

Abstract. The exchange of organic matter (OM) between the atmosphere and snow is poorly understood due to the complex nature of OM and the convoluted processes of deposition, re-volatilisation, and chemical and biological processing. OM that is finally retained in glaciers potentially holds a valuable historical record of past atmospheric conditions; however, our understanding of the processes involved is insufficient to translate the measurements into an interpretation of the past atmosphere. This study examines the dynamic processes of post-precipitation OM change at the alpine snow surface with the goal of interpreting the processes involved in surface snow OM.

scholarly journals Brief communication: Analysis of organic matter in surface snow by PTR-MS – implications for dry deposition dynamics in the Alps

2018 ◽  
Author(s):  
Dušan Materić ◽  
Elke Ludewig ◽  
Kangming Xu ◽  
Thomas Röckmann ◽  
Rupert Holzinger
Keyword(s):  
Organic Matter ◽  
Dry Deposition ◽  
Historical Record ◽  
Dynamic Processes ◽  
Complex Nature ◽  
Atmospheric Conditions ◽  
Communication Analysis ◽  
The Past ◽  
Surface Snow ◽  
The Alps

Abstract. The exchange of organic matter (OM) between the atmosphere and snow is poorly understood due to the complex nature of OM and the convoluted processes of deposition, re-volatilisation, chemical, and biological processing. OM that is finally retained in glaciers potentially holds a valuable historical record of past atmospheric conditions; however, our understanding of the processes involved is insufficient to translate the measurements into an interpretation of the past atmosphere. This study examines the dynamic processes of post-precipitation OM change at the alpine snow surface with the goal to interpret the processes involved in surface snow OM.

scholarly journals The Science of Ageism: Two Steps Forward, One Step Back

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 646-646
Author(s):  
Jerin Lee ◽  
Natalie Shook
Keyword(s):  
Psychological Health ◽  
Well Being ◽  
Census Bureau ◽  
Complex Nature ◽  
The Past ◽  
Growing Pains ◽  
Research Findings ◽  
One Step ◽  
Prejudicial Attitudes ◽  
The Impact

Abstract The past two decades have been marked by a rapidly aging population in the U.S. (U.S. Census Bureau, 2018), making prejudicial attitudes toward older adults (i.e., ageism) and the impact of such attitudes more relevant. As such, ageism researchers have worked tirelessly to not only understand this normalized and insidious form of bias, but also develop efforts to combat it. This symposium will feature four ageism researchers who will showcase both the growing pains and novel contributions of ageism research, ranging from the impact of ageism on psychological health to ageism interventions to issues related to the measurement of ageism. Specifically, Dr. Ayalon will present findings regarding difficulties with the assessment of exposure to ageism and the consequences of ageism for psychological well-being. Dr. Horhota will share research demonstrating challenges associated with confronting ageism. Dr. Levy will present a model showcasing factors associated with the reduction of ageism. Ms. Lee will discuss research findings examining the construct validity of several ageism measures. These talks highlight theoretical and real-world implications associated with the complex nature of ageism, providing important directions for enriching ageism research going forward.

scholarly journals A FIELD GUIDE TO SONIC BOTANY: THOUGHTS ABOUT ECO-COMPOSITION

Tempo ◽  
2020 ◽  
Vol 75 (295) ◽  
pp. 31-44
Author(s):  
Maayan Tsadka
Keyword(s):  
Organic Matter ◽  
Performance Practice ◽  
Musical Instruments ◽  
Musical Composition ◽  
Notation System ◽  
Field Guide ◽  
The Past ◽  
Tuning Forks ◽  
Texture Size ◽  
Ongoing Project

AbstractSonic botany is an ongoing project that I have been developing over the past few years. It incorporates natural artefacts: dry leaves, pods, flowers, branches, rocks, bones and other organic findings. These are used as musical instruments that are played on with a scientific/musical tool: tuning forks in various frequencies. The vibration from the tuning forks resonates through the natural artefacts which amplify the vibration and – via sound – reveal the texture, size, material and condition of the organic matter. This process generates new sonic material, new context and new forms of musical composition. The practice developed into several compositions and projects, a performance practice, a notation system and a way of listening. Here I share some of the insights I gained through this process, the tools and the compositional framework.

scholarly journals Impact of soil use on aggregate stability and its relationship with soil organic carbon at two different altitudes in the Colombian Andes

2019 ◽  
Vol 37 (3) ◽  
pp. 263-273
Author(s):  
Efraín Francisco Visconti-Moreno ◽  
Ibonne Geaneth Valenzuela-Balcázar
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Aggregate Stability ◽  
Tropical Climate ◽  
Mineral Particle ◽  
Organic Carbon Content ◽  
Rice Soils ◽  
Organic Matter Pool ◽  
Different Altitudes

The stability of soil aggregates depends on the organic matter, and the soil use and management can affect the soil organicmatter (SOM) content. Therefore, it is necessary to know therelationship between aggregate stability and the content of SOMin different types of soil use at two different altitudes of theColombian Andes. This study examined the conditions of soilaggregate stability expressed as a distribution of the size classes of stable aggregates (SA) and of the mean weighted diameter of the stable aggregates (MWD). To correlate these characteristics with the soil organic carbon (OC), we measured the particulate organic matter pool (POC), the OC associated with the mineral organic matter pool (HOC), the total organic carbon content (TOC), and the humification rate (HR). Soils were sampled at two altitudes: 1) Humic Dystrudepts in a cold tropical climate (CC) with three plots: tropical mountain rainforest, pastures, and crops; 2) Fluvaquentic Dystrudepts in a warm tropical climate (WC) with three plots: tropical rainforest, an association of oil palm and pastures, and irrigated rice. Soils were sampled at three depths: 0-5, 5-10 and 10-20 cm. The physical properties, mineral particle size distribution, and bulk density were measured. The content of SA with size>2.36 mm was higher in the CC soil (51.48%) than in the WC soil (9.23%). The SA with size 1.18-2.36 mm was also higher in the CC soil (7.78%) than in the WC soil (0.62%). The SA with size 0.60-1.18 mm resulted indifferent. The SA with size between 0.30 and 0.60 mm were higher in the WC soil (13.95%) than in the CC soil (4.67%). The SA<0.30 mm was higher in the WC soil (72.56%) than in the CC soil (32.15%). It was observed that MWD and the SA>2.36 mm increased linearly with a higher POC, but decreased linearly with a higher HR. For the SA<0.30 mm, a linear decrease was observed at a higher POC, while it increased at a higher HR.

scholarly journals Surfactant control of gas transfer velocity along an offshore coastal transect: results from a laboratory gas exchange tank

2016 ◽  
Vol 13 (13) ◽  
pp. 3981-3989 ◽  
Author(s):  
R. Pereira ◽  
K. Schneider-Zapp ◽  
R. C. Upstill-Goddard
Keyword(s):  
Organic Matter ◽  
Gas Exchange ◽  
Trace Gas ◽  
Gas Transfer ◽  
Transfer Velocity ◽  
Chl A ◽  
Gas Transfer Velocity ◽  
Biogeochemical Models ◽  
Sea Surface Microlayer ◽  
Laboratory Water

Abstract. Understanding the physical and biogeochemical controls of air–sea gas exchange is necessary for establishing biogeochemical models for predicting regional- and global-scale trace gas fluxes and feedbacks. To this end we report the results of experiments designed to constrain the effect of surfactants in the sea surface microlayer (SML) on the gas transfer velocity (kw; cm h−1), seasonally (2012–2013) along a 20 km coastal transect (North East UK). We measured total surfactant activity (SA), chromophoric dissolved organic matter (CDOM) and chlorophyll a (Chl a) in the SML and in sub-surface water (SSW) and we evaluated corresponding kw values using a custom-designed air–sea gas exchange tank. Temporal SA variability exceeded its spatial variability. Overall, SA varied 5-fold between all samples (0.08 to 0.38 mg L−1 T-X-100), being highest in the SML during summer. SML SA enrichment factors (EFs) relative to SSW were  ∼  1.0 to 1.9, except for two values (0.75; 0.89: February 2013). The range in corresponding k660 (kw for CO2 in seawater at 20 °C) was 6.8 to 22.0 cm h−1. The film factor R660 (the ratio of k660 for seawater to k660 for “clean”, i.e. surfactant-free, laboratory water) was strongly correlated with SML SA (r ≥ 0.70, p ≤ 0.002, each n = 16). High SML SA typically corresponded to k660 suppressions  ∼  14 to 51 % relative to clean laboratory water, highlighting strong spatiotemporal gradients in gas exchange due to varying surfactant in these coastal waters. Such variability should be taken account of when evaluating marine trace gas sources and sinks. Total CDOM absorbance (250 to 450 nm), the CDOM spectral slope ratio (SR = S275 − 295∕S350 − 400), the 250 : 365 nm CDOM absorption ratio (E2 : E3), and Chl a all indicated spatial and temporal signals in the quantity and composition of organic matter in the SML and SSW. This prompts us to hypothesise that spatiotemporal variation in R660 and its relationship with SA is a consequence of compositional differences in the surfactant fraction of the SML DOM pool that warrants further investigation.

scholarly journals The Biodegradation of Soil Organic Matter in Soil-Dwelling Humivorous Fauna

2022 ◽  
Vol 9 ◽  
Author(s):  
Xuliang Lou ◽  
Jianming Zhao ◽  
Xiangyang Lou ◽  
Xiejiang Xia ◽  
Yilu Feng ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Substrates ◽  
Terrestrial Organic Matter ◽  
Symbiotic Associations ◽  
Tropical Areas ◽  
Gut Symbionts ◽  
Diverse Community ◽  
Ecological Success ◽  
Global Vegetation

Soil organic matter contains more carbon than global vegetation and the atmosphere combined. Gaining access to this source of organic carbon is challenging and requires at least partial removal of polyphenolic and/or soil mineral protections, followed by subsequent enzymatic or chemical cleavage of diverse plant polysaccharides. Soil-feeding animals make significant contributions to the recycling of terrestrial organic matter. Some humivorous earthworms, beetles, and termites, among others, have evolved the ability to mineralize recalcitrant soil organic matter, thereby leading to their tremendous ecological success in the (sub)tropical areas. This ability largely relies on their symbiotic associations with a diverse community of gut microbes. Recent integrative omics studies, including genomics, metagenomics, and proteomics, provide deeper insights into the functions of gut symbionts. In reviewing this literature, we emphasized that understanding how these soil-feeding fauna catabolize soil organic substrates not only reveals the key microbes in the intestinal processes but also uncovers the potential novel enzymes with considerable biotechnological interests.

scholarly journals Simulating measurable ecosystem carbon and nitrogen dynamics with the mechanistically-defined MEMS 2.0 model

2021 ◽  
Author(s):  
Yao Zhang ◽  
Jocelyn M. Lavallee ◽  
Andy D. Robertson ◽  
Rebecca Even ◽  
Stephen M. Ogle ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Water ◽  
Root Zone ◽  
Ecosystem Respiration ◽  
Gross Primary Production ◽  
Total N ◽  
Calibration And Validation ◽  
Biogeochemical Models ◽  
Lower Accuracy ◽  
C Stocks

Abstract. For decades, predominant soil biogeochemical models have used conceptual soil organic matter (SOM) pools and only simulated them to a shallow depth in soil. Efforts to overcome these limitations have prompted the development of new generation SOM models, including MEMS 1.0, which represents measurable biophysical SOM fractions, over the entire root zone, and embodies recent understanding of the processes that govern SOM dynamics. Here we present the result of continued development of the MEMS model, version 2.0. MEMS 2.0 is a full ecosystem model with modules simulating plant growth with above and below-ground inputs, soil water, and temperature by layer, decomposition of plant inputs and SOM, and mineralization and immobilization of nitrogen (N). The model simulates two commonly measured SOM pools – particulate and mineral-associated organic matter (POM and MAOM), respectively. We present results of calibration and validation of the model with several grassland sites in the U.S. MEMS 2.0 generally captured the soil carbon (C) stocks (R2 of 0.89 and 0.6 for calibration and validation, respectively) and their distributions between POM and MAOM throughout the entire soil profile. The simulated soil N matches measurements but with lower accuracy (R2 of 0.73 and 0.31 for calibration and validation of total N in SOM, respectively) than for soil C. Simulated soil water and temperature were compared with measurements and the accuracy is comparable to the other commonly used models. The seasonal variation in gross primary production (GPP; R2 = 0.83), ecosystem respiration (ER; R2 = 0.89), net ecosystem exchange (NEE; R2 = 0.67), and evapotranspiration (ET; R2 = 0.71) were well captured by the model. We will further develop the model to represent forest and agricultural systems and improve it to incorporate new understanding of SOM decomposition.

scholarly journals Transport and fate of different components of terrestrial organic matter across the Siberian-Arctic shelves

2020 ◽  
Author(s):  
Örjan Gustafsson ◽  
Igor Semiletov ◽  
Natalia Shakhova ◽  
Oleg Dudarev ◽  
Jorien Vonk ◽  
...  
Keyword(s):  
Organic Matter ◽  
Landscape Heterogeneity ◽  
Oxidation Products ◽  
Terrestrial Organic Matter ◽  
Inverse Approach ◽  
Degradation Rates ◽  
Siberian Arctic ◽  
Global Soil ◽  
Shelf Sea ◽  
Dependent Transport

&lt;p&gt;About one-third to half of the global soil carbon is held in the top 1-3 m of tundra+taiga permafrost PF (~1000 Pg-C) with deeper layers below as Deep-PF (~400 Pg-C) and in Pleistocene Ice Complex Deposit permafrost (ICD-PF, ~400 Pg-C), lining 4000 km of the East Siberian Arctic coast. &amp;#160;In order to overcome the landscape heterogeneity and the stochastic nature of e.g. erosional release processes, we use the East Siberian Arctic Shelf (ESAS) in an inverse approach &amp;#8211; as a natural integrator of the TerrOM releases from both the river drainage basins and from the erosion of ICD-containing bluffs. We are exploring how source-dependent transport and translocated degradation affect the released TerrOM.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;The sources of released terrOM have been increasingly constrained using great rivers and the ESAS as natural integrators through a combination of biomarkers and &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C/&amp;#916;&lt;sup&gt;14&lt;/sup&gt;C on bulk-C and on compound level. There are significant gradients in sources both E-W and S-N across each shelf sea and between water column DOM, POM and sedimentary OM. The largest source of OC to ESAS sediments is not rivers or marine plankton &amp;#8211; it is coastal erosion of old ICD.&amp;#160; Our initial limited dataset has now been much expanded, as has the end-member database while the statistical source apportionment method has been refined. They combine to show more efficient cross-shelf transport of river-borne &amp;#8220;topsoil-PF&amp;#8221; compared to ICD-PF and a clear distinction in sources of TerrOM between western and eastern ESAS regimes separated roughly along 165E, consistent with the local oceanography.&lt;/p&gt;&lt;p&gt;There have been good strides also in understanding degradation of TerrOM exported to ESAS. Studies are demonstrating continuous offshoreward degradation of all TerrOM, yet with large differences between compound classes. Physical association of TerrOM with different sediment components, and sorting of the sediments exert first-order control on TerrOM distribution and degradation. An expanded dataset on specific surface area (SSA) and CuO oxidation products reveals spatial patterns across ESAS. The combination of compound-specific radiocarbon analysis of terrestrial biomarkers with SSA-normalized TerrOM signals constrains the ambient degradation rates and fluxes during the 3-4000 year timescale of cross-shelf transport. The degradation of TerrOM also causes severe ocean acidification of the ESAS.&lt;/p&gt;&lt;p&gt;Investigations of sources and fate of TerrOM on the ESAS &amp;#8211; the World&amp;#8217;s largest shelf sea&amp;#8211; provides a window to constrain permafrost-C remobilization and to study mechanisms of transport and degradability of different components of released terrestrial organic matter.&lt;/p&gt;

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