Soil Biology & Biochemistry 57 (2013) 204e211
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Soil pH drives the spatial distribution of bacterial communities along elevation on Changbai Mountain Congcong Shen a, c, Jinbo Xiong a, Huayong Zhang a, Youzhi Feng a, Xiangui Lin a, **, Xinyu Li b, Wenju Liang b, Haiyan Chu a, * a b c
State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, East Beijing Road 71, Nanjing 210008, China State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110164, China Graduate School of the Chinese Academy of Sciences, Beijing 100049, China
a r t i c l e i n f o
a b s t r a c t
Article history: Received 22 February 2012 Received in revised form 18 July 2012 Accepted 21 July 2012 Available online 17 August 2012
The elevational patterns of diversity for plants and animals have been well established over the past century. However, it is unclear whether there is a general elevational distribution pattern for microbes. Changbai Mountain is one of few well conserved natural ecosystems, where the vertical distribution of vegetation is known to mirror the vegetation horizontal zonation from temperate to frigid zones on the Eurasian continent. Here, we present a comprehensive analysis of soil bacterial community composition and diversity along six elevations representing six typical vegetation types from forest to alpine tundra using a bar-coded pyrosequencing technique. The bacterial communities differed dramatically along elevations (vegetation types), and the community composition was significantly correlated with soil pH, carbon/nitrogen ratio (C/N), moisture or total organic carbon (TOC), respectively. Phylogenetic diversity was positively correlated with soil pH (P ¼ 0.024), while phylotype richness was positively correlated with soil pH (P ¼ 0.004), total nitrogen (TN) (P ¼ 0.030), and negatively correlated with C/N ratio (P ¼ 0.021). Our results emphasize that pH is a better predictor of soil bacterial elevational distribution and also suggest that vegetation types may indirectly affect soil bacterial elevational distribution through altering soil C and N status. Ó 2012 Elsevier Ltd. All rights reserved.
Keywords: Soil bacterial community Elevational distribution pH Changbai Mountain Pyrosequencing
1. Introduction Improved knowledge of biological elevational diversity patterns is indispensable to a comprehensive understanding the influences of climate change on ecosystems (Lomolino, 2001; Rahbek, 2005; Grytnes and McCain, 2007; Malhi et al., 2010). Intensive and extensive studies have showed that taxa of macroorganisms, such as trees, mammals, birds, insects, generally exhibit either monotonically decreasing or hump-shaped richness patterns with elevation driven by potential forces, including climatic, spatial, historical and biotic (Herzog et al., 2005; McCain, 2005, 2009; Rahbek, 2005; Cardelus et al., 2006; Lomolino, 2001; Grytnes and McCain, 2007). Climatic factors in particular showed the strongest positive associations with biological elevational diversity patterns (Hawkins et al., 2003; Currie et al., 2004; Storch et al., 2006; Forister et al., 2010). Compared with macrooganisms, we know very
* Corresponding author. Tel.: þ86 25 86881356. ** Corresponding author. Tel.: þ86 25 86881589. E-mail addresses:
[email protected] (X. Lin),
[email protected] (H. Chu). 0038-0717/$ e see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.soilbio.2012.07.013
little about the pattern of microbial diversity across elevational gradients, though microbes drive many important biogeochemical cycles on earth. Though encouraging progress has been made on horizontal distribution of microbial communities recently (Rousk et al., 2010; Hollister et al., 2010; Fierer and Jackson, 2006; Lauber et al., 2009; Chu et al., 2010; Griffiths et al., 2011), only few investigations about their elevational diversity patterns are reported. Bryant et al. (2008) pointed out that Acidobacteria diversity decreased monotonically with elevation, which was driven by soil pH changes, while Wang et al. (2011) observed the inverse bacterial elevational pattern influenced by carbon supply in a stony stream located on Laojun Mountain. These contradictory results have led to more confusions than elucidations. Thus, more studies of the changing microbial patterns along elevational gradients are needed for a better understanding of underlying mechanism (Fierer et al., 2011). The Changbai Mountain is the highest mountain in northeastern China and is the head of three large rivers (the Songhua, Yalu and Tumen) (He et al., 2005). The vertical distribution of vegetation is known to mirror the vegetation horizontal zonation from temperate to frigid zones on the Eurasian continent (Xu et al.,
C. Shen et al. / Soil Biology & Biochemistry 57 (2013) 204e211
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Table 1 Summary of the main characteristics of sampling sites along an elevational gradient on Changbai Mountain. Forest type Broad-leaved forest (BL) Mixed coniferous broadleaved forest (MCB) Dark-coniferous sprucefir forest (DCF) Dark-coniferous spruce forest (DCS) Ermans birch forest (EB) Alpine tundra(AT) a
Elevation (m)
Position
0
pH ranges
0
MAT ( C)a
MAP (mm)a
530 760
42 47 N 128 12 E 42 240 N 128 060 E
5.43e5.85 5.45e6.31
2.9 2.6
632 691
1250
42 090 N 128 080 E
4.79e5.14
0.3
811
1680
42 050 N 128 040 E
4.44e5.57
2.3
967
3.89e4.40 5.06e5.34
3.3 4.8
1038 1154
1950 2200
0
0
42 03 N 128 04 E 42 020 N 128 040 E
Dominant tree species
Soil type
Quercus mongolica Pinus koraiensis Acer tegmentosum Abies nephrolepis Picea jezoensis Picea jezoensis
Albi-Boric Argosols Albi-Boric Argosols
Betula ermanii Dryas octopetala Rhododendron chrysanthum
Permi-Gelic Cambosols Permafrost cold Cambisols
Bori-Udic Cambosols Umbri-Gelic Cambosols
MAT and MAP indicate mean annual temperature and mean annual precipitation.
2004; Zhang et al., 2011). In particular, a typical alpine tundra belt was above 2000 m where the majority of plants are of polar origin from the Quaternary period glacier retreat (Xu et al., 2004), and these soils may be expected to harbor relatively unique bacterial communities. Meanwhile, Changbai Mountain is one of few well conserved natural ecosystems on the earth (He et al., 2005). All the aforementioned provide an optimal environment to investigate microbial elevational patterns. The objectives of this study were (1) to explore the elevational diversity gradient of bacterial communities on Changbai Mountain, (2) to determine key factors controlling the distribution of bacterial communities, (3) and to compare the differences of bacterial communities in tundra and forest ecosystems. 2. Materials and methods 2.1. Site selection and soil sampling Changbai Mountain (126 550 e129 000 E; 41230 e42 360 N) is located in Jilin Province, of northeast China, which extends along the border of China and North Korea. It is the highest mountain in north-eastern China and is the head of three large rivers (the Songhua, Yalu and Tumen). Topographic features differ on the four slopes of the mountain, with the northern slope being relatively moderate (average slope
