The effect of varying gamma irradiation doses and soil moisture content on nematodes, the microbial communities and mineral nitrogen

Gebremikael, Mesfin Tsegaye; Waele, Jeroen De; Buchan, David; Soboksa, Gizachew Ebisa

doi:10.1016/j.apsoil.2015.03.003

Cited by 26 publications

(17 citation statements)

References 30 publications

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“…In contrast to the previous experimental studies that comprised only a few selected species of bacterial feeding nematodes and bacteria (2, 18, 36), the current study includes all feeding groups of nematodes (S1) and indigenous microbial communities ( Table 3 ). The indigenous microbial communities were left largely unaffected by applying low doses of gamma irradiation as reported in previous studies [ 19 , 20 , 28 , 36 ]. High doses of gamma irradiation (e.g.…”

Section: Discussionsupporting

confidence: 52%

“…Two of the PVC columns (one amended and one unamended) were prepared for gamma irradiation, a technique that removes all nematodes and other soil fauna without significantly altering the microbial community (bacteria and fungi) as described in detail in [ 19 ] and [ 20 ] ( Fig 1 ). Briefly, the moisture content of the soil in each PVC column was adjusted to 80% water-filled pore space (WFPS) by adding demineralized water and left overnight to let the water uniformly distribute throughout the column.…”

Section: Methodsmentioning

confidence: 99%

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Quantifying the Contribution of Entire Free-Living Nematode Communities to Carbon Mineralization under Contrasting C and N Availability

Gebremikael¹,

Steel

Bert

et al. 2015

PLoS ONE

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To understand the roles of nematodes in organic matter (OM) decomposition, experimental setups should include the entire nematode community, the native soil microflora, and their food sources. Yet, published studies are often based on either simplified experimental setups, using only a few selected species of nematode and their respective prey, despite the multitude of species present in natural soil, or on indirect estimation of the mineralization process using O2 consumption and the fresh weight of nematodes. We set up a six-month incubation experiment to quantify the contribution of the entire free living nematode community to carbon (C) mineralization under realistic conditions. The following treatments were compared with and without grass-clover amendment: defaunated soil reinoculated with the entire free living nematode communities (+Nem) and defaunated soil that was not reinoculated (-Nem). We also included untreated fresh soil as a control (CTR). Nematode abundances and diversity in +Nem was comparable to the CTR showing the success of the reinoculation. No significant differences in C mineralization were found between +Nem and -Nem treatments of the amended and unamended samples at the end of incubation. Other related parameters such as microbial biomass C and enzymatic activities did not show significant differences between +Nem and -Nem treatments in both amended and unamended samples. These findings show that the collective contribution of the entire nematode community to C mineralization is small. Previous reports in literature based on simplified experimental setups and indirect estimations are contrasting with the findings of the current study and further investigations are needed to elucidate the extent and the mechanisms of nematode involvement in C mineralization.

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Section: Discussionsupporting

confidence: 52%

Section: Methodsmentioning

confidence: 99%

Quantifying the Contribution of Entire Free-Living Nematode Communities to Carbon Mineralization under Contrasting C and N Availability

Gebremikael¹,

Steel

Bert

et al. 2015

PLoS ONE

Self Cite

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“…Plant community productivity was initially greater in inoculated soils, which was 284 reflected in an overall main effect of soil treatment and a significant interaction with year 285 (Table 1). This was probably caused by the nutrient flush associated with gamma-sterilization 286 of the soil (Gebremikael et al 2015). But we found no evidence that our soil treatments 287 modified the differences in biodiversity effects between communities of co-selected plants 288 and naïve communities (P > 0.2 for the three-way interactions of contrasts of the logarithm of 289 species richness or the 4-level factor of species richness with soil and community-evolution 290 treatments).…”

Section: Influence Of Soil Environment 283mentioning

confidence: 72%

Community evolution increases plant productivity at low diversity

Moorsel

Hahl

Wagg

et al. 2017

Preprint

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28Species extinctions from local communities negatively affect ecosystem functioning. 29Ecological mechanisms underlying these impacts are well studied but the role of evolutionary 30 processes is rarely assessed. Using a long-term field experiment, we tested whether natural 31 selection in plant communities increased biodiversity effects on productivity. We re-32 assembled communities with 8-year co-selection history adjacent to communities with 33 identical species composition but no history of co-selection ("naïve communities"). 34Monocultures and in particular mixtures of two to four co-selected species were more 35 productive than their corresponding naïve communities over four years in soils with or 36 without co-selected microbial communities. At the highest diversity level of eight plant 37 species, no such differences were observed. Our findings suggest that plant community 38 evolution can lead to rapid increases in ecosystem functioning at low diversity but may take 39 longer at high diversity. This effect was not modified by treatments simulating co-40 evolutionary processes between plants and soil organisms.

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“…This was probably caused by the nutrient flush associated with gamma‐sterilisation of the soil (Gebremikael et al . ). But we found no evidence that our soil treatments modified the differences in biodiversity effects between communities of co‐selected plants and naïve communities ( P > 0.2 for the three‐way interactions of contrasts of the logarithm of species richness or the four‐level factor of species richness with soil and community‐evolution treatments).…”

Section: Resultsmentioning

confidence: 97%

Community evolution increases plant productivity at low diversity

et al. 2017

View full text Add to dashboard Cite

Species extinctions from local communities negatively affect ecosystem functioning. Ecological mechanisms underlying these impacts are well studied, but the role of evolutionary processes is rarely assessed. Using a long-term field experiment, we tested whether natural selection in plant communities increased biodiversity effects on productivity. We re-assembled communities with 8-year co-selection history adjacent to communities with identical species composition but no history of co-selection ('na€ ıve communities'). Monocultures, and in particular mixtures of two to four co-selected species, were more productive than their corresponding na€ ıve communities over 4 years in soils with or without co-selected microbial communities. At the highest diversity level of eight plant species, no such differences were observed. Our findings suggest that plant community evolution can lead to rapid increases in ecosystem functioning at low diversity but may take longer at high diversity. This effect was not modified by treatments simulating co-evolutionary processes between plants and soil organisms.

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The effect of varying gamma irradiation doses and soil moisture content on nematodes, the microbial communities and mineral nitrogen

Cited by 26 publications

References 30 publications

Quantifying the Contribution of Entire Free-Living Nematode Communities to Carbon Mineralization under Contrasting C and N Availability

Quantifying the Contribution of Entire Free-Living Nematode Communities to Carbon Mineralization under Contrasting C and N Availability

Community evolution increases plant productivity at low diversity

Community evolution increases plant productivity at low diversity

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