中科院南京土壤研究所褚海燕團(tuán)隊(duì)和中科院青藏高原研究所的研究人員合作,，深入研究了青藏高原堿性湖底沉積物細(xì)菌群落的空間分布及其驅(qū)動(dòng)機(jī)制,。相關(guān)成果近期發(fā)表在《環(huán)境微生物學(xué)》雜志上,。
據(jù)了解，生物地理學(xué)是研究生物多樣性時(shí)空分布規(guī)律的一門學(xué)科,，是生態(tài)學(xué)的核心問(wèn)題之一,。目前，對(duì)于微生物分布是受當(dāng)代環(huán)境因子還是歷史因素（用空間距離表征）的影響以及它們的相對(duì)貢獻(xiàn)率,，還存在很大爭(zhēng)議,。已有研究表明，pH是酸性土壤中微生物空間分布的關(guān)鍵驅(qū)動(dòng)因子,，但在堿性條件下pH是否同樣重要還未見(jiàn)報(bào)道,。
此次研究人員通過(guò)454高通量測(cè)序技術(shù)，對(duì)青藏高原堿性湖底沉積物細(xì)菌群落進(jìn)行研究發(fā)現(xiàn),，與酸性土壤相似,，堿性沉積物中pH同樣是控制細(xì)菌群落空間變異的關(guān)鍵因子，同時(shí)盡管環(huán)境因子控制了更多的細(xì)菌群落變異,，但空間距離作為單一因子,，解釋了最高的群落變異,。
據(jù)悉,，此項(xiàng)研究首次證明了pH是驅(qū)動(dòng)堿性湖泊沉積物細(xì)菌生物地理分布的關(guān)鍵因子,，并提出了當(dāng)代環(huán)境與歷史因素共同驅(qū)動(dòng)青藏高原湖泊沉積物的細(xì)菌空間分布。同時(shí),，研究也建議,，在微生物生物地理分布研究中應(yīng)選擇足夠的樣本數(shù)以提高統(tǒng)計(jì)的可靠性、受到較少擾動(dòng)的生態(tài)系統(tǒng)以減少隨機(jī)傳播,、不同的空間尺度以提高結(jié)果的適用性,。
評(píng)審專家認(rèn)為，該研究將pH驅(qū)動(dòng)微生物群落分布的重要作用從酸性拓展到堿性,，對(duì)于更好地理解微生物群落結(jié)構(gòu)的驅(qū)動(dòng)因子和空間地理分布機(jī)制具有重要意義,。（生物谷Bioon.com）
doi: 10.1111/j.1462-2920.2012.02799.x
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Geographic distance and pH drive bacterial distribution in alkaline lake sediments across Tibetan Plateau
Xiong J, Liu Y, Lin X, Zhang H, Zeng J, Hou J, Yang Y, Yao T, Knight R, Chu H
Continent-scale biogeography has been extensively studied in soils and marine systems, but little is known about biogeographical patterns in non-marine sediments. We used barcode pyrosequencing to quantify the effects of local geochemical properties and geographic distance for bacterial community structure and membership, using sediment samples from 15 lakes on the Tibetan Plateau (4-1670 km apart). Bacterial communities were surprisingly diverse, and distinct from soil communities. Four of 26 phyla detected were dominant: Proteobacteria, Bacteroidetes, Firmicutes and Actinobacteria, albeit 20.2% of sequences were unclassified at the phylum level. As previously observed in acidic soil, pH was the dominant factor influencing alkaline sediment community structure, phylotype richness and phylogenetic diversity. In contrast, archaeal communities were less affected by pH. More geographically distant sites had more dissimilar communities (r=0.443, P=0.030). Variance partitioning analysis showed that geographic distance (historical contingencies) contributed more to bacterial community variation (12.2%) than any other factor, although the environmental factors explained more variance when combined (28.9%). Together, our results show that pH is the best predictor of bacterial community structure in alkaline sediments, and confirm that both geographic distance and chemical factors govern bacterial biogeography in lake sediments.
