Fire affects root decomposition, soil food web structure, and carbon flow in tallgrass prairie

Abstract. Root litter decomposition is a major component of carbon (C) cycling in grasslands, where it provides energy and nutrients for soil microbes and fauna. This is especially important in grasslands where fire is common and removes aboveground litter accumulation. In this study, we investigated whether fire affects root decomposition and C flow through the belowground food web. In a greenhouse experiment, we applied 13C-enriched big bluestem (Andropogon gerardii) root litter to intact tallgrass prairie soil cores collected from annually burned (AB) and infrequently burned (IB) treatments at the Konza Prairie Long Term Ecological Research (LTER) site. Incorporation of 13C into microbial phospholipid fatty acids and nematode trophic groups was measured on six occasions during a 180-day decomposition study to determine how C was translocated through the soil food web. Results showed significantly different soil communities between treatments and higher microbial abundance for IB. Root decomposition occurred rapidly and was significantly greater for AB. Microbes and their nematode consumers immediately assimilated root litter C in both treatments. Root litter C was preferentially incorporated in a few groups of microbes and nematodes, but depended on burn treatment: fungi, Gram-negative bacteria, Gram-positive bacteria, and fungivore nematodes for AB and only omnivore nematodes for IB. The overall microbial pool of root-litter-derived C significantly increased over time but was not significantly different between burn treatments. The nematode pool of root-litter-derived C also significantly increased over time, and was significantly higher for the AB treatment at 35 and 90 days after litter addition. In conclusion, the C flow from root litter to microbes to nematodes is not only measurable but also significant, indicating that higher nematode trophic levels are critical components of C flow during root decomposition, which, in turn, is significantly affected by fire. Not only does fire affect the soil community and root decomposition, but the lower microbial abundance, greater root turnover, and the increased incorporation of root litter C by microbes and nematodes for AB suggests that annual burning increases root-litter-derived C flow through the soil food web of the tallgrass prairie.

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Burning management in the tallgrass prairie affects root decomposition, soil food web structure and carbon flow

SOIL Discussions ◽

10.5194/soild-2-923-2015 ◽

2015 ◽

Vol 2 (2) ◽

pp. 923-953

Author(s):

E. A. Shaw ◽

K. Denef ◽

C. Milano de Tomasel ◽

M. F. Cotrufo ◽

D. H. Wall

Keyword(s):

Food Web ◽

Tallgrass Prairie ◽

Trophic Levels ◽

Root Decomposition ◽

Microbial Abundance ◽

Konza Prairie ◽

Soil Food Web ◽

Root Litter ◽

Flow Through ◽

Over Time

Abstract. Root litter decomposition is a major component of carbon (C) cycling in grasslands, where it provides energy and nutrients for soil microbes and fauna. This is especially important in grasslands where fire is a common management practice and removes aboveground litter accumulation. In this study, we investigated whether fire affects root decomposition and C flow through the belowground food web. In a greenhouse experiment, we applied 13C-enriched big bluestem (Andropogon gerardii) root litter to intact tallgrass prairie soil cores collected from annually burned (AB) and infrequently burned (IB) treatments at the Konza Prairie Long Term Ecological Research (LTER) site. Incorporation of 13C into microbial phospholipid fatty acids and nematode trophic groups was measured on six occasions during a 180-day decomposition study to determine how C was translocated through the soil food web. Results showed significantly different soil communities between treatments and higher microbial abundance for IB. Root decomposition occurred rapidly and was significantly greater for AB. Microbes and their nematode consumers immediately assimilated root litter C in both treatments. Root litter C was preferentially incorporated in a few groups of microbes and nematodes, but depended on burn treatment: fungi, Gram-negative bacteria, Gram-positive bacteria, and fungivore nematodes for AB and only omnivore nematodes for IB. The overall microbial pool of root litter-derived C significantly increased over time but was not significantly different between burn treatments. The nematode pool of root litter-derived C also significantly increased over time, and was significantly higher for the AB treatment at 35 and 90 days after litter addition. In conclusion, the C flow from root litter to microbes to nematodes is not only measurable, but significant, indicating that higher nematode trophic levels are critical components of C flow during root decomposition which, in turn, is significantly affected by fire management practices. Not only does fire affect the soil community and root decomposition for Konza Prairie LTER soils, but the lower microbial abundance, greater root turnover, and the increased incorporation of root litter C by microbes and nematodes for AB suggests that tallgrass prairie management through annual burning increases root litter-derived C flow through the soil food web.

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Exploring carbon flow through the root channel in a temperate forest soil food web

Soil Biology and Biochemistry ◽

10.1016/j.soilbio.2014.05.005 ◽

2014 ◽

Vol 76 ◽

pp. 45-52 ◽

Cited By ~ 40

Author(s):

Kadeem J. Gilbert ◽

Timothy J. Fahey ◽

John C. Maerz ◽

Ruth E. Sherman ◽

Patrick Bohlen ◽

...

Keyword(s):

Food Web ◽

Forest Soil ◽

Temperate Forest ◽

Carbon Flow ◽

Soil Food Web ◽

Flow Through ◽

Root Channel

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Using Nematode Community to Evaluate Banana Soil Food Web in Mekargalih, Cianjur, West Java

Pertanika Journal of Tropical Agricultural Science ◽

10.47836/pjtas.44.2.12 ◽

2021 ◽

Vol 44 (2) ◽

Author(s):

Dale Akbar Yogaswara ◽

Hikmat Kasmara ◽

Wawan Hermawan

Keyword(s):

Food Web ◽

Profile Analysis ◽

Biological Indicator ◽

Nematode Community ◽

Trophic Levels ◽

Maturity Index ◽

Soil Nematode ◽

Soil Food Web ◽

Undisturbed Soil ◽

Decomposition Pathway

Soil biota is very diverse and contributes widely to ecosystem services that are important in the sustainable function of natural and managed ecosystems. Knowing the condition of the soil food web through the communities that inhabit it is necessary to assess the productivity of the soil. Nematode communities in the soil food web can be used as indicators because of their high abundance, and they inhabit various trophic levels, and participate in several important processes in the soil. The soil food web condition from three locations (Agr1, Agr2, Agr3) through the nematode functional index was evaluated using the maturity index (MI), the maturity index 2-5 (MI-25), the plant-parasitic index (PPI), the channel index (CI), the enrichment index (EI), the structure index (SI), and the basal index (BI). Nematode diversity was evaluated using Simpson’s index of diversity, dominance, and evenness. The MI and MI2-5 scores indicated that Agr3 (3.81) had an undisturbed food web, while Agr2 (2.88 and 3.0) and Agr1 (2.5 and 2.51) were in a moderate condition with minor disturbances. Fauna profile analysis using SI and EI shows that Agr3 and Agr1 had an undisturbed soil food web, and Agr2 was in enriched conditions. CI results found that Agr1 and Agr3 had a fungal decomposition pathway while Agr2 had a bacterial decomposition pathway. We concluded from this research, that prospect of the nematode community to serve as a collection of biological indicator data in assessing soil or ecosystem health can be considered in further research.

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Nematodes as Important Source for Omega-3 Long-Chain Fatty Acids in the Soil Food Web and the Impact in Nutrition for Higher Trophic Levels

Frontiers in Ecology and Evolution ◽

10.3389/fevo.2018.00096 ◽

2018 ◽

Vol 6 ◽

Cited By ~ 6

Author(s):

Ralph Menzel ◽

Diana Geweiler ◽

Annika Sass ◽

Dilara Simsek ◽

Liliane Ruess

Keyword(s):

Fatty Acids ◽

Food Web ◽

Trophic Levels ◽

Long Chain Fatty Acids ◽

Omega 3 ◽

Soil Food Web ◽

The Impact ◽

Long Chain ◽

Chain Fatty Acids

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Plant species identity and diversity effects on different trophic levels of nematodes in the soil food web

Oikos ◽

10.1111/j.0030-1299.2004.13265.x ◽

2004 ◽

Vol 106 (3) ◽

pp. 576-586 ◽

Cited By ~ 218

Author(s):

Gerlinde B. De Deyn ◽

Ciska E. Raaijmakers ◽

Jasper van Ruijven ◽

Frank Berendse ◽

Wim H. van der Putten

Keyword(s):

Food Web ◽

Plant Species ◽

Trophic Levels ◽

Soil Food Web ◽

Species Identity ◽

Diversity Effects

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Microplastics and phagotrophic soil protists: evidence of ingestion

10.22541/au.162005469.96001976/v1 ◽

2021 ◽

Author(s):

E P Kanold ◽

M C Rillig ◽

PM Antunes

Keyword(s):

Global Change ◽

Fluorescence Microscopy ◽

Food Web ◽

Ecosystem Functioning ◽

Marine Environments ◽

Soil Food Web ◽

Fluorescent Microspheres ◽

Food Vacuoles ◽

Soil Protists ◽

Over Time

Microplastics (MPs) can now be found in all the Earth’s biomes, thereby representing a global change phenomenon with largely unknown consequences for biodiversity and ecosystem functioning. Soil protists are eukaryotic, primarily single celled organisms that play important roles in the soil food web. Microplastics have been shown to affect protist populations in freshwater and marine environments, yet the interactions between soil protists and MPs remains largely unknown. Here we examined whether phagotrophic soil protists can ingest MPs and experience declines in abundance. We exposed protists to soil treatments with different concentrations of MPs using commercial polymer fluorescent microspheres and used fluorescence microscopy to find evidence of MP ingestion. In addition, we quantified the total number of active phagotrophic protists over time. We show that most soil protists (>75% individuals) can readily ingest and keep MP within their food vacuoles, even at relatively small MP concentrations (0.1% w/w). There was a trend for higher prevalence of ingestion and for declines in protist abundance at the highest concentration of MPs (1% w/w). However, more data are necessary to further ascertain cause-effect relationships. This is the first report indicating that soil protists can play an important role in the transport and uptake of MPs in the soil food web.

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