Archaeal Abundance across a pH Gradient in an Arable Soil and Its Relationship to Bacterial and Fungal Growth Rates

Abstract

<jats:title>ABSTRACT</jats:title><jats:p>Soil pH is one of the most influential factors for the composition of bacterial and fungal communities, but the influence of soil pH on the distribution and composition of soil archaeal communities has yet to be systematically addressed. The primary aim of this study was to determine how total archaeal abundance (quantitative PCR [qPCR]-based estimates of 16S rRNA gene copy numbers) is related to soil pH across a pH gradient (pH 4.0 to 8.3). Secondarily, we wanted to assess how archaeal abundance related to bacterial and fungal growth rates across the same pH gradient. We identified two distinct and opposite effects of pH on the archaeal abundance. In the lowest pH range (pH 4.0 to 4.7), the abundance of archaea did not seem to correspond to pH. Above this pH range, there was a sharp, almost 4-fold decrease in archaeal abundance, reaching a minimum at pH 5.1 to 5.2. The low abundance of archaeal 16S rRNA gene copy numbers at this pH range then sharply increased almost 150-fold with pH, resulting in an increase in the ratio between archaeal and bacterial copy numbers from a minimum of 0.002 to more than 0.07 at pH 8. The nonuniform archaeal response to pH could reflect variation in the archaeal community composition along the gradient, with some archaea adapted to acidic conditions and others to neutral to slightly alkaline conditions. This suggestion is reinforced by observations of contrasting outcomes of the (competitive) interactions between archaea, bacteria, and fungi toward the lower and higher ends of the examined pH gradient.</jats:p>

Influence of 34-years of fertilization on bacterial communities in an intensively cultivated black soil in northeast China

“…Li et al, 2014). Crenarchaeota may be the dominant group of microorganisms governing NH 4 þ oxidation (Leininger et al, 2006) and a massive decline at pH 4.7e5.2 was previously observed (Bengtson et al, 2012). We observed that the N 1 treatment had the highest relative abundance of Crenarchaeota, which indicated that the higher soil NH 4 þ concentration and lower pH resulting from other more concentrated fertilizer treatments (N 1 P 1 , N 2 and N 2 P 2 ) may inhibit their growth.…”

Spatial and Temporal Variation of Archaeal, Bacterial and Fungal Communities in Agricultural Soils

“…Previous studies have reported negative effects of pH on group 1.1c Crenarchaeota [50] in acid forest soils and negative relationships between nitrate and archaeal abundance [21]. The positive correlations between archaeal abundance and soil pH observed here suggest that our soils might be dominated by crenarchaeal species that are adapted to conditions of higher soil pH (7.0–7.5) [51], which may be linked to the long agricultural history of the plots studied here.…”

pH dominates variation in tropical soil archaeal diversity and community structure

“…() studied the dominant archaeal populations in 146 soils covering different biomes such as forest, grasslands, deserts, and agricultural soil across North and South America and Antarctica. These global surveys, together with other local‐ and regional‐scale studies, have revealed a number of factors that may affect archaeal communities, including salinity (Auguet et al ., ), pH (Nicol et al ., ; Bengtson et al ., ; Cao et al ., ), elevation (Zhang et al ., ), climate and vegetation cover (Angel et al ., ), and C/N ratio (Bates et al ., ).…”