Climate change goes underground: effects of elevated atmospheric CO2 on microbial community structure and activities in the rhizosphere

Abstract

General concern about climate change has led to growing interest in the responses of terrestrial ecosystems to elevated concentrations of CO 2 in the atmosphere. Experimentation during the last two to three decades using a large variety of approaches has provided sufficient information to conclude that enrichment of atmospheric CO 2 may have severe impact on terrestrial ecosystems. This impact is mainly due to the changes in the organic C dynamics as a result of the effects of elevated CO 2 on the primary source of organic C in soil, i.e., plant photosynthesis. As the majority of life in soil is heterotrophic and dependent on the input of plant-derived organic C, the activity and functioning of soil organisms will greatly be influenced by changes in the atmospheric CO 2 concentration. In this review, we examine the current state of the art with respect to effects of elevated atmospheric CO 2 on soil microbial communities, with a focus on microbial community structure. On the basis of the existing information, we conclude that the main effects of elevated atmospheric CO 2 on soil microbiota occur via plant metabolism and root secretion, especially in C3 plants, thereby directly affecting the mycorrhizal, bacterial, and fungal communities in the close vicinity of the root. There is little or no direct effect on the microbial community of the bulk soil. In particular, we have explored the impact of these changes on rhizosphere interactions and ecosystem processes, including food web interactions.

Fungal Communities Respond to Long-Term CO 2 Elevation by Community Reassembly

“…In contrast, fungal biomass and relative abundance of total microbial biomass did not change significantly under eCO 2 in this BioCON (biodiversity, CO 2 , and N deposition) experimental site (6,21). Previous studies of fungal responses to eCO 2 were mainly carried out using approaches such as phospholipid fatty-acid analysis, denaturing gradient gel electrophoresis, extracellular enzyme assays, and clone library analysis (6,12,16,(21)(22)(23) and mostly focused on mycorrhizal fungi (15,(24)(25)(26), which have major influences on plant biodiversity and productivity (27). Those previous studies were focused on fungal carbon degradation, nitrogen cycling, and interactions with plants (26,28,29); however, knowledge about fungal community-level responses to eCO 2 is still limited, though some efforts have been made recently (12,30,31).…”

Yield and Yield Attributes Responses of Soybean (Glycine max L. Merrill) to Elevated CO2 and Arbuscular Mycorrhizal Fungi Inoculation in the Humid Transitory Rainforest

“…Their association with crops have been implicated in the improvement in nutrient status of crops especially P and N. Other effects of their symbiotic relation with crops include enhanced water uptake in drought susceptible agroecologies, disease resistance and increased plant productivity (Smith and Read, 2008). Given their widespread importance, AMF may be a major factor in mediating plant and ecosystem responses to climate change ( Drigo et al, 2008;Compant et al, 2010). It had been reported in the literature that elevated CO2 would benefit more the C3 plants than the C4 (Poorter, 1993).…”

Tallgrass prairie soil fungal communities are resilient to climate change

“…These factors are also fundamental drivers of the heterotrophic respiration that is estimated to account for 30-50% of the total soil respiration in most terrestrial systems (Raich & Schlesinger 1992;Bond-Lamberty et al 2004), although estimates may vary widely depending on biome/ecosystem (compare Hanson et al, 2000;Wan & Luo 2003;Chen et al 2009). The significance of the soil respiration and the large contribution of soil-inhabiting microbial communities to CO 2 flux emphasize their importance and underline the need to better understand the compositional and functional attributes of these communities, particularly so in the face of predicted future environmental conditions (Bargett et al 2008;Drigo et al 2008).…”