Earthworms increase the ratio of bacteria to fungi in northern hardwood forest soils, primarily by eliminating the organic horizon

Dempsey, Mark; Fisk, Melany C.; Fahey, Timothy J.

doi:10.1016/j.soilbio.2011.06.017

Cited by 60 publications

(45 citation statements)

References 45 publications

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“…Our results showed that earthworms significantly increase the bacterial diversity (Table 3) and change the abundance of bacterial diversity (Fig. 2), which were consistent with previous reports that earthworms increased bacteria abundance by labile C introduced in the earthworm gut and the highly processed organic matter in earthworm castings (Dempsey et al, 2011). In the present study, earthworm activity increased the bacterial diversity and stimulated specific bacteria with two general mechanisms: (1) the OCED soil we used was relatively nutrient poor, and the earthworms improved the nutrient supply in the soil through their metabolic processes, such as increased C and N availability in their mucus and urine that stimulate bacterial growth and activity (Bernard et al, 2011), and (2) soil passage through the earthworm results in increased bacterial activity and growth due to the increased particle surface area and the accompanying substrate accessibility (McLean et al, 2006).…”

Section: Impact Of Earthworms and Amf On Soil Bacterial Diversitysupporting

confidence: 92%

Rhizosphere interactions between earthworms (Eisenia fetida) and arbuscular mycorrhizal fungus (Funneliformis mosseae) promote utilization efficiency of phytate phosphorus in maize

Cao

Huang

Wang

2015

Applied Soil Ecology

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Section: Impact Of Earthworms and Amf On Soil Bacterial Diversitysupporting

confidence: 92%

Rhizosphere interactions between earthworms (Eisenia fetida) and arbuscular mycorrhizal fungus (Funneliformis mosseae) promote utilization efficiency of phytate phosphorus in maize

Cao

Huang

Wang

2015

Applied Soil Ecology

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“…While the effects of earthworms on resource availability and soil microbes have been widely studied (Butenschoen et al, 2007;Jayasinghe and Parkinson, 2009;Eisenhauer et al, 2011;Dempsey et al, 2011Dempsey et al, , 2013Sackett et al, 2013), less is known about how the different processes involved mediate the effects of earthworms on soil respiration and its different components. The earthworminduced short-term increase in soil respiration, followed by gradual decrease back towards the baseline (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…Through feeding, burrowing and casting behaviors, invasive European earthworms negatively affect the understory vegetation, reducing the leaf litter and organic layers and mixing the organic matter into the mineral soil (Hale et al, 2005(Hale et al, , 2006Nuzzo et al, 2009;Dempsey et al, 2011;Dobson and Blossey, 2015). Earthworm activities also lead to major changes in soil properties and biogeochemistry, including altered water retention capacity, pH, and soil C and N distribution and availability, as well as increased bulk density, aggregate formation, incorporation of organic matter, and CO 2 and N 2 O efflux (Bohlen et al, 2004a;Hale et al, 2005Hale et al, , 2008Eisenhauer et al, 2007;Szlavecz et al, 2011;Lubbers et al, 2013;Ma et al, 2013;Dobson and Blossey, 2015;Lyttle et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Species-specific effects of earthworms on microbial communities and the fate of litter-derived carbon

Chang

Szlávecz

Buyer

2016

Soil Biology and Biochemistry

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a b s t r a c tSoil respiration is frequently measured as a surrogate for biological activities and is important in soil carbon cycling. The heterotrophic component of soil respiration is primarily driven by microbial decomposition of leaf litter and soil organic matter, and is partially controlled by resource availability. In North American temperate deciduous forests, invasive European and Asian earthworms are known to variously affect soil properties and resource availability through their feeding, burrowing, and casting behaviors, and may affect different components of soil respiration through modulating the microbial communities. By tracing litter-derived C from 13 C and 15 N double-enriched leaf litter into soil and CO 2 efflux in a mesocosm experiment, we tested the hypothesis that earthworms inhibit litter C-derived soil respiration by reducing resource availability and microbial biomass, and further examined how speciesspecific effects of earthworms on soil respiration are mediated by soil microbial community. We showed that while earthworms generally had no effect on total soil respiration, the interaction between Octolasion lacteum and Lumbricus rubellus had a significant negative non-additive effect, presumably through affecting anaerobic microsites in the soil. Moreover, litter C-derived soil respiration was reduced by the Asian Amynthas hilgendorfi, the European L. rubellus, and the North American native species Eisenoides lonnbergi, but not by the European species O. lacteum. Phospholipid fatty acid (PLFA) analysis and structural equation modeling indicated that while soil bacteria and fungi abundances were affected by earthworm species identities, the observed reduction of litter C-derived soil respiration could not be fully explained by changes in microbial biomass. We attributed these effects to earthworm-induced aggregate formation, reduction of microbial transformation of labile carbon, and antimicrobial peptide activities, and concluded that the mechanisms through which the four earthworm species affect the fate of litterderived C and its mineralization are species-specific.

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“…This action homogenizes soil, bringing bacterial communities into close contact with their food source resulting in increased soil nutrient cycling (Bohlen and Scheu, 2004;Groffman et al, 2004). Microbial communities within the castings of earthworms are greatly altered relative to bulk soil (Brown et al, 2000), favoring populations capable of surviving through the anoxic environment of the earthworm gut (Drake and Horn, 2007) and disrupting mycorrhizal relationships (Dempsey et al, 2011). There is little doubt that through the above processes invading earthworms are increasing the mineralization of C in the short term (Lubbers et al, 2013) however in the long term there is a growing body of evidence suggesting that earthworms may increase C sequestration (Zhang et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Effect of the endogeic earthworm Aporrectodea tuberculata on aggregation and carbon redistribution in uninvaded forest soil columns

Knowles

Ross

Görres

2016

Soil Biology and Biochemistry

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a b s t r a c tThe long-term impact of earthworm presence on soil carbon (C) dynamics of previously uninhabited northeastern forests is still largely unknown. Currently, earthworm presence is understood to both enhance soil respiration and create stable microaggregates, processes assumed to have conflicting effects on long term C storage. To date, studies investigating earthworm-created microaggregates and occluded C have rarely been done in undisturbed forest soils. A paired mesocosm study (n ¼ 5) was conducted investigating the impact of the endogeic earthworm species Aporrectodea tuberculata on the physical proportion of microaggregates and the associated mineral soil C of a minimally disturbed forest soil. Pairs analyzed after 4 weeks of incubation demonstrated no significant aggregate effects. At 4 months, paired cores with earthworms (WW) showed a 67% increase in large macroaggregates (>2000 mm diameter, lgMA), compared to cores without earthworms (NW). While distribution shifted among various microaggregate pools (free and occluded within macroaggregates), the net proportion of microaggregates in the soil (dry weight basis) was unaltered. After 4 months, the mineral soil of WW cores had an average of 60% more C than the NW cores due to the relocation of the forest floor. The C associated with the microaggregate fractions increased an average of 56%. Of this increase in C, 95% was accounted for by the microaggregates occluded within the lgMA fraction, a fraction that was almost 4 times greater in the WW cores. Over 50% of the C relocated into the mineral soil was associated with the physically protected microaggregate fractions, indicating that though this species of earthworm did not alter the proportion of microaggregates in these soils, they occluded a substantial proportion of C within those physical fractions. In this particular forest soil, the actions of Aporrectodea tuberculata increased the physically protected C pool through microaggregate restructuring and C enrichment.

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Earthworms increase the ratio of bacteria to fungi in northern hardwood forest soils, primarily by eliminating the organic horizon

Cited by 60 publications

References 45 publications

Rhizosphere interactions between earthworms (Eisenia fetida) and arbuscular mycorrhizal fungus (Funneliformis mosseae) promote utilization efficiency of phytate phosphorus in maize

Rhizosphere interactions between earthworms (Eisenia fetida) and arbuscular mycorrhizal fungus (Funneliformis mosseae) promote utilization efficiency of phytate phosphorus in maize

Species-specific effects of earthworms on microbial communities and the fate of litter-derived carbon

Effect of the endogeic earthworm Aporrectodea tuberculata on aggregation and carbon redistribution in uninvaded forest soil columns

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