scholarly journals Multifunctionality of belowground food webs: resource, size and spatial energy channels

2021 ◽  
Author(s):  
Anton M. Potapov
Keyword(s):  
Organic Matter ◽  
Food Web ◽  
Food Webs ◽  
Terrestrial Ecosystems ◽  
Feeding Preference ◽  
Size Spectrum ◽  
Soil Food Web ◽  
Energy Fluxes ◽  
Biogeochemical Models ◽  
Web Reconstruction

The belowground compartment of terrestrial ecosystems drives nutrient cycling, the decomposition and stabilisation of organic matter, and supports aboveground life. Belowground consumers create complex food webs that regulate functioning, ensure stability and support biodiversity both below and above ground. However, existing soil food-web reconstructions do not match recently accumulated empirical evidence and there is no comprehensive reproducible approach that accounts for the complex resource, size and spatial structure of food webs in soil. Here I build on generic food-web organization principles and use multifunctional classification of soil protists, invertebrates and vertebrates, to reconstruct "multichannel" food-web across size classes of soil-associated consumers. This reconstruction is based on overlying feeding preference, prey protection, size spectrum and spatial distribution matrices combined with biomasses of trophic guilds to infer weighted trophic interactions. I then use food-web reconstruction, together with assimilation efficiencies, to calculate energy fluxes assuming a steady-state energetic system. Based on energy fluxes, I describe a number of indicators, related to stability, biodiversity and multiple ecosystem-level functions such as herbivory, top-down control, translocation and transformation of organic matter. I illustrate the approach with an empirical example, comparing it with traditional resource-focused soil food-web reconstruction. The multichannel reconstruction can be used to assess trophic multifunctionality (analogous to ecosystem multifunctionality), i.e. simultaneous support of multiple trophic functions by the food-web, and compare it across communities and ecosystems spanning beyond the soil. With further validation and parametrization, my multichannel reconstruction approach provides an effective tool for understanding and analysing soil food webs. I believe that having this tool will inspire more people to comprehensively describe soil communities and belowground-aboveground interactions. Such studies will provide informative indicators for including consumers as active agents in biogeochemical models, not only locally but also on regional and global scales.

scholarly journals Stream Macroinvertebrates and Carbon Cycling in Tangled Food Webs

Ecosystems ◽  
2021 ◽  
Author(s):  
Benoît O. L. Demars ◽  
Joanna L. Kemp ◽  
Baptiste Marteau ◽  
Nikolai Friberg ◽  
Barry Thornton
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Food Web ◽  
Food Webs ◽  
Carbon Sources ◽  
Terrestrial Ecosystems ◽  
Terrestrial Organic Matter ◽  
Before And After ◽  
Reference Stream ◽  
Induced Changes

AbstractThe annual global loss of organic carbon from terrestrial ecosystems into rivers is similar to the organic carbon stored in soils each year. Dissolved organic matter (DOM) flows through the food web to macroinvertebrates, but little is known about the effect of DOM increase on stream food webs and how much macroinvertebrates may contribute to the regulation of carbon fluxes in rivers. Using a before and after control impact (BACI) experimental design, we increased by 12% (+ 0.52 mg C L−1) the concentration of DOM in a stream for three weeks by adding sucrose, with a distinctive δ13C signature, to simulate a pulse of natural DOM supply from soils. We partitioned the diet of macroinvertebrates from carbon sources according to the green pathway (autotrophs) and detrital pathways (bacteria and terrestrial organic matter). Our flow food web approach based on C fluxes, with bacteria as a key node, showed the dominant contribution of the detrital pathways for macroinvertebrates in the reference stream. DOM addition induced changes in the diets of individual taxa, but did not have any strong effects on the relative overall contribution of the detrital pathways versus the green pathway. Autotrophic uptake of CO2 respired by bacteria was much larger than bacterial C flux to invertebrates (that is, the classic microbial loop) and allowed a significant fraction of natural allochthonous organic carbon to make its way to macroinvertebrates via autotrophs fixing CO2 respired by bacteria. Overall macroinvertebrates did not regulate directly to any great extent the flux of stream DOM towards downstream ecosystems.

scholarly journals Oribatid mites show that soil food web complexity and close aboveground-belowground linkages emerged in the early Paleozoic

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Ina Schaefer ◽  
Tancredi Caruso
Keyword(s):  
Food Web ◽  
Food Webs ◽  
Higher Plants ◽  
Early Paleozoic ◽  
Soil Food Web ◽  
Deep Time ◽  
Animal Group ◽  
Soil Microarthropods ◽  
Early Devonian ◽  
Food Web Complexity

Abstract The early evolution of ecosystems in Palaeozoic soils remains poorly understood because the fossil record is sparse, despite the preservation of soil microarthropods already from the Early Devonian (~410 Mya). The soil food web plays a key role in the functioning of ecosystems and its organisms currently express traits that have evolved over 400 my. Here, we conducted a phylogenetic trait analysis of a major soil animal group (Oribatida) to reveal the deep time story of the soil food web. We conclude that this group, central to the trophic structure of the soil food web, diversified in the early Paleozoic and resulted in functionally complex food webs by the late Devonian. The evolution of body size, form, and an astonishing trophic diversity demonstrates that the soil food web was as structured as current food webs already in the Devonian, facilitating the establishment of higher plants in the late Paleozoic.

scholarly journals fluxweb: a R package to easily estimate energy fluxes in food webs

2017 ◽  
Author(s):  
Benoit Gauzens ◽  
Andrew Barnes ◽  
Darren Giling ◽  
Jes Hines ◽  
Malte Jochum ◽  
...  
Keyword(s):  
Steady State ◽  
Food Web ◽  
Food Webs ◽  
Ecosystem Functioning ◽  
R Package ◽  
Estimation Methods ◽  
List Type ◽  
Energy Fluxes ◽  
Flux System ◽  
Primary Output

AbstractUnderstanding how changes in biodiversity will impact the stability and functioning of ecosystems is a central challenge in ecology. Food-web approaches have been advocated to link community composition with ecosystem functioning by describing the fluxes of energy among species or trophic groups. However, estimating such fluxes remains problematic because current methods become unmanageable as network complexity increases.We developed a generalisation of previous indirect estimation methods assuming a steady state system [1, 2, 3]: the model estimates energy fluxes in a top-down manner assuming system equilibrium; each node’s losses (consumption and physiological) balances its consumptive gains. Jointly, we provide theoretical and practical guidelines to use the fluxweb R package (available on CRAN at https://bit.ly/2OC0uKF).We also present how the framework can merge with the allometric theory of ecology [4] to calculate fluxes based on easily obtainable organism-level data (i.e. body masses and species groups -eg, plants animals), opening its use to food webs of all complexities. Physiological losses (metabolic losses or losses due to death other than from predation within the food web) may be directly measured or estimated using allometric relationships based on the metabolic theory of ecology, and losses and gains due to predation are a function of ecological efficiencies that describe the proportion of energy that is used for biomass production.The primary output is a matrix of fluxes among the nodes of the food web. These fluxes can be used to describe the role of a species, a function of interest (e.g. predation; total fluxes to predators), multiple functions, or total energy flux (system throughflow or multitrophic functioning). Additionally, the package includes functions to calculate network stability based on the Jacobian matrix, providing insight into how resilient the network is to small perturbations at steady state.Overall, fluxweb provides a flexible set of functions that greatly increase the feasibility of implementing food-web energetic approaches to more complex systems. As such, the package facilitates novel opportunities for mechanistically linking quantitative food webs and ecosystem functioning in real and dynamic natural landscapes.

scholarly journals Organic manure induced soil food web of microbes and nematodes drive soil organic matter under jackfruit planting

2021 ◽  
Vol 166 ◽  
pp. 103994
Author(s):  
Lanxi Su ◽  
Tingyu Bai ◽  
Xiaowei Qin ◽  
Huan Yu ◽  
Gang Wu ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Food Web ◽  
Organic Manure ◽  
Soil Food Web

Romul_Hum—A model of soil organic matter formation coupling with soil biota activity. II. Parameterisation of the soil food web biota activity

2017 ◽  
Vol 345 ◽  
pp. 125-139 ◽  
Author(s):  
Oleg Chertov ◽  
Alexander Komarov ◽  
Cindy Shaw ◽  
Sergey Bykhovets ◽  
Pavel Frolov ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Food Web ◽  
Soil Biota ◽  
Soil Food Web ◽  
Soil Organic Matter Formation

Effects of organic matter removal on the soil food web: Forestry practices meet ecological theory

1998 ◽  
Vol 9 (1-3) ◽  
pp. 137-143 ◽  
Author(s):  
Jan Bengtsson ◽  
Heléne Lundkvist ◽  
Peter Saetre ◽  
Björn Sohlenius ◽  
Berit Solbreck
Keyword(s):  
Organic Matter ◽  
Food Web ◽  
Ecological Theory ◽  
Soil Food Web ◽  
Organic Matter Removal ◽  
Forestry Practices

scholarly journals Evaluation of Daphnid Grazing on Microscopic Zoosporic Fungi by Using Comparative Threshold Cycle Quantitative PCR

2016 ◽  
Vol 82 (13) ◽  
pp. 3868-3874 ◽  
Author(s):  
Michelle A. Maier ◽  
Kimiko Uchii ◽  
Tawnya D. Peterson ◽  
Maiko Kagami
Keyword(s):  
Organic Matter ◽  
Food Web ◽  
Food Webs ◽  
Quantitative Pcr ◽  
Morphological Characteristics ◽  
Life Cycles ◽  
Molecular Techniques ◽  
Aquatic Environments ◽  
Content Type ◽  
Zoosporic Fungi

ABSTRACTLethal parasitism of large phytoplankton by chytrids (microscopic zoosporic fungi) may play an important role in organic matter and nutrient cycling in aquatic environments by shunting carbon away from hosts and into much smaller zoospores, which are more readily consumed by zooplankton. This pathway provides a mechanism to more efficiently retain carbon within food webs and reduce export losses. However, challenges in accurate identification and quantification of chytrids have prevented a robust assessment of the relative importance of parasitism for carbon and energy flows within aquatic systems. The use of molecular techniques has greatly advanced our ability to detect small, nondescript microorganisms in aquatic environments in recent years, including chytrids. We used quantitative PCR (qPCR) to quantify the consumption of zoospores byDaphniain laboratory experiments using a culture-based comparative threshold cycle (CT) method. We successfully quantified the reduction of zoospores in water samples duringDaphniagrazing and confirmed the presence of chytrid DNA inside the daphnid gut. We demonstrate that comparativeCTqPCR is a robust and effective method to quantify zoospores and evaluate zoospore grazing by zooplankton and will aid in better understanding how chytrids contribute to organic matter cycling and trophic energy transfer within food webs.IMPORTANCEThe study of aquatic fungi is often complicated by the fact that they possess complex life cycles that include a variety of morphological forms. Studies that rely on morphological characteristics to quantify the abundances of all stages of the fungal life cycle face the challenge of correctly identifying and enumerating the nondescript zoospores. These zoospores, however, provide an important trophic link between large colonial phytoplankton and zooplankton: that is, once the carbon is liberated from phytoplankton into the parasitic zoospores, the latter are consumed by zooplankton and carbon is retained in the aquatic food web rather than exported from the system. This study provides a tool to quantify zoospores and evaluate the consumption of zoospores by zooplankton in order to further our understanding of their role in food web dynamics.

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