Metabarcoding mites: Three years of elevated CO2 has no effect on oribatid assemblages in a Eucalyptus woodland

Ross, Giles M.; Horn, Sebastian; Macdonald, Catriona A.; Powell, Jeff R.; Reynolds, Jason K.; Ryan, Michelle M.; Cook, James M.; Nielsen, Uffe N.

doi:10.1016/j.pedobi.2020.150667

Cited by 11 publications

(10 citation statements)

References 60 publications

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“…(2020) and Ross et al. (2020). The details for analytical processing of

{NH}_{4}^{+}

{NO}_{3}^{‐}

and

{PO}_{4}^{3 ‐}

are available elsewhere (Drake et al., 2016; Hasegawa et al., 2016).…”

Section: Methodsmentioning

confidence: 97%

“…A detailed description of the site, including vegetation and soil characteristics, can be found elsewhere (Crous et al., 2015; Drake et al., 2016; Gimeno et al., 2016). The site sits on variable soil formation (Ross et al., 2020) with red loams of the Pleistocene alluvial terrace Clarendon Formation at the northern portion of the site that recede to expose underlying Tertiary Londonderry Clay as described by Atkinson (1988). The soil profile presents pale sands with small amounts of loam (<20%) overlying a patchwork of mottled yellow/orange clays and ferruginized sands and weak pedological organization.…”

Section: Methodsmentioning

confidence: 99%

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Rainfall frequency and soil water availability regulate soil methane and nitrous oxide fluxes from a native forest exposed to elevated carbon dioxide

et al. 2021

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Free‐air carbon dioxide enrichment (FACE) experiments in terrestrial ecosystems have demonstrated ecological responses of key ecosystem processes to rising atmospheric carbon dioxide (CO2). However, CO2 fertilization responses in field conditions have seldom included methane (CH4) and nitrous oxide (N2O), particularly in natural and mature forests, which are expected to have an important role in climate change mitigation. Herein, we aimed to capture the effect of elevated CO2 (eCO2; ambient vs. +150 ppm) on long‐term temporal dynamics of CH4 and N2O fluxes, followed by identification of climo‐edaphic factors explaining feedback responses. To achieve this, continuous monitoring of greenhouse gas (GHG) fluxes using a manual chamber technique, over a 3‐year period was implemented in a mature dryland Eucalypt forest FACE (EucFACE) facility in Australia. The relationship between CH4 and N2O fluxes with rainfall indices and soil properties was also explored since they directly impact the microbial communities in the soil responsible for CH4 and N2O net emissions. Our results showed that in 3 years of eCO2 treatment, the amount and frequency of rainfall predicted GHG emissions in this native forest. We also found a significant reduction in CH4 sink (15%–25%) for some of the years as well as an overall treatment effect index reduction in N2O emissions under eCO2. Higher frequency of rain events with lower intensity led to highest CH4 sink followed by lowest N2O emissions due to fewer wet–dry cycles. Of all the environmental variables included, soil moisture, rainfall and pH were the main predictors of net CH4 and N2O emissions. Methane flux was also strongly influenced by soil texture. Our findings highlight the need to account for reduced forest CH4 sink under eCO2 in dryland ecosystems, which has implications for GHG budget predictions under future climate conditions. A free Plain Language Summary can be found within the Supporting Information of this article.

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“…(2020) and Ross et al. (2020). The details for analytical processing of

{NH}_{4}^{+}

{NO}_{3}^{‐}

and

{PO}_{4}^{3 ‐}

are available elsewhere (Drake et al., 2016; Hasegawa et al., 2016).…”

Section: Methodsmentioning

confidence: 97%

Section: Methodsmentioning

confidence: 99%

Rainfall frequency and soil water availability regulate soil methane and nitrous oxide fluxes from a native forest exposed to elevated carbon dioxide

et al. 2021

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“…This grassy woodland is dominated by Eucalyptus tereticornis and E. moluccana in the overstorey while Microlaena stipoides, Cynodon dactylon and Paspalidium distans dominate the understorey (Hasegawa et al, 2018;Tozer, 2003). The soil is classified as an aeric podosol, with details provided in Ross et al (2020). The top soil (0-50 cm) is slightly acidic (pH water = 5.29, 0-10 cm) with a loamy sand texture (76% sand) and low organic matter content (18 mg/g C, 0-15 cm; Total nitrogen (N) = 1.1 mg/g and phosphorus p = 0.076 mg/g; Drake et al, 2016).…”

Section: Study Areamentioning

confidence: 99%

“…eCO 2 condition (aCO 2 +150 ppm) is approximately 550 ppm since 2013 after 'ramp' increases starting on September 2012. Refer to Tozer (2003), Crous et al (2015, Nielsen et al (2015), Drake et al (2016) and Ross et al (2020) for additional information of the experimental site.…”

Section: Study Areamentioning

confidence: 99%

The influence of roots on mycorrhizal fungi, saprotrophic microbes and carbon dynamics in a low‐phosphorus Eucalyptus forest under elevated CO₂

et al. 2021

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1. Elevated atmospheric carbon dioxide (eCO 2 ) can impact soil organic matter (SOM) dynamics by changing the rates of carbon (C) losses and gains. In the rhizosphere, these changes are usually assumed to be the result of root-mediated eCO 2 impacts on saprotrophic microbes via altered below-ground C allocation. This C allocation can also impact mycorrhizal fungi and their role in SOM dynamics. However, direct field quantifications of the influence of roots on both mycorrhizal fungi and saprotrophs together with SOM dynamics in forests exposed to eCO 2 are rare. This is especially true in phosphorus (P)-limited systems, even though ecosystem responses to eCO 2 are known to depend on P availability.2. We assessed root mediation of eCO 2 impacts on saprotrophs, mycorrhizal fungi, and C dynamics of root litter and mineral soil C (SOM-C) in a mature, P-limited Eucalyptus woodland exposed to eCO 2 . We used a novel nested-mesh-bag method to manipulate roots access to the substrates in a 1-year field incubation.We used an isotopic approach to trace C dynamics and performed a comprehensive microbial community analysis, along with nutrients and enzymatic activity measurements.3. Roots increased microbial biomass, fungal:bacterial ratio, plant-derived C gains and substrate C losses while decreasing P availability and specific enzymatic activity. eCO 2 increased bacterial relative abundance in root litter and protozoa in SOM-C, but it did not enhance root impacts or mycorrhizal fungi biomass. 4. Our combination of in-situ approaches allowed us to demonstrate that while roots have multiple impacts on soil microbial communities and C dynamics, they are not the main drivers of responses to eCO 2 in this P-limited forest. Other factors beyond enhanced root-derived below-ground C inputs such as seasonality of nutrient and water availability, and shifts in plant communities may be more important in modulating eCO 2 impacts on soil dynamics in P-limited systems. K E Y W O R D Scarbon substrates, elevated CO 2 , forests, free-air CO 2 enrichment, mycorrhizae, rhizosphere, soil organic matter, stable isotopes | 2057Functional Ecology CASTAÑEDA-GÓMEZ ET Al.

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“…Longer, more accurate metabarcoding and genomic readouts will also expand our knowledge beyond the model organisms of C. elegans and Pristionchus pacificus , and overcome the potential under‐estimation of genetic distance that is the potential when based on marker genes. High‐throughput sequencing can illustrate belowground assemblages in greater resolution (Ross et al ., 2020), with correction factors to quantify sequencing read‐outs (Lamb et al ., 2019). These would allow for the rendering of ecological information directly from genetic signatures with local reference libraries that incorporate alternate rates of genetic drift and generation time (Collins et al ., 2019), with small geographic distributions or factors influencing speciation rates and genetic drift (Lim et al ., 2012).…”

Section: Discussionmentioning

confidence: 99%

Phylogenies of traits and functions in soil invertebrate assemblages

et al. 2022

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Soil invertebrates are members of terrestrial ecosystems, contributing to the processing of organic matter, resulting in carbon and nutrient cycling that is essential for continuous productivity. By linking species delineations, morphological traits and measured or inferred functional roles, we demonstrate a method for functional identification of soil faunal assemblages based on molecular information. Here we align the genetic interrelatedness and functional trait expression in nematodes and springtails. Nematodes were assigned feeding guild, plant parasitic feeding type and coloniser-persister (c-p) value, with springtail sequences assigned to soil vertical stratification level, soil moisture preference and a selection of morphological traits. We found that both nematode and springtail feeding preferences show significant phylogenetic clustering. In contrast, greater dispersal was found amongst nematode coloniser-persister (c-p) values and springtail soil vertical stratification level and moisture preferences. Minimum patristic (p) distances between species supported the clustering amongst nematode feeding guilds, with plant feeders being separated from all other guilds by at least p = 0.99. Distances between endoparasitic, ectoparasitic and sedentary plant parasitic nematodes were also distinct with minimal distances of p = 0.35-0.72 between parasitic types. Springtail stratification level and soil moisture preferences showed greater dispersion across phylogenies, with negligible between-group minimum patristic distances. However, nematode c-p values and springtail moisture preference alignments indicate some genetic conservation at the genus level. These results indicate how ecosystems can direct trait conservation beyond that of environmental stimuli. Being able to assign functional traits to novel sequences will allow individual species' likely contribution to ecosystem functioning to be inferred without the need for exact taxonomic identification. More broadly, such information can advance our understanding of the evolution of soil faunal traits and the contribution of diverse soil assemblages to functional soil systems, particularly those with a high proportion of undescribed species.

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Metabarcoding mites: Three years of elevated CO2 has no effect on oribatid assemblages in a Eucalyptus woodland

Cited by 11 publications

References 60 publications

Rainfall frequency and soil water availability regulate soil methane and nitrous oxide fluxes from a native forest exposed to elevated carbon dioxide

Rainfall frequency and soil water availability regulate soil methane and nitrous oxide fluxes from a native forest exposed to elevated carbon dioxide

The influence of roots on mycorrhizal fungi, saprotrophic microbes and carbon dynamics in a low‐phosphorus Eucalyptus forest under elevated CO₂

Phylogenies of traits and functions in soil invertebrate assemblages

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Metabarcoding mites: Three years of elevated CO2 has no effect on oribatid assemblages in a Eucalyptus woodland

Cited by 11 publications

References 60 publications

Rainfall frequency and soil water availability regulate soil methane and nitrous oxide fluxes from a native forest exposed to elevated carbon dioxide

Rainfall frequency and soil water availability regulate soil methane and nitrous oxide fluxes from a native forest exposed to elevated carbon dioxide

The influence of roots on mycorrhizal fungi, saprotrophic microbes and carbon dynamics in a low‐phosphorus Eucalyptus forest under elevated CO2

Phylogenies of traits and functions in soil invertebrate assemblages

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The influence of roots on mycorrhizal fungi, saprotrophic microbes and carbon dynamics in a low‐phosphorus Eucalyptus forest under elevated CO₂