Impacts of Phragmites australis Invasion on Soil Enzyme Activities and Microbial Abundance of Tidal Marshes
Impacts of Phragmites australis Invasion on Soil Enzyme Activities and Microbial Abundance of Tidal Marshes
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DOI：
10.1007/s00248-018-1168-2
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发表时间：
2018-03
影响因子：
3.6
通讯作者：
Sung-Hyun Kim;Sung-Hyun Kim;Jiyoung Kang;J. Megonigal;Hojeong Kang;J. Seo;W. Ding
中科院分区：
文献类型：
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作者：
Sung-Hyun Kim;Sung-Hyun Kim;Jiyoung Kang;J. Megonigal;Hojeong Kang;J. Seo;W. Ding
芦苇在美国东海岸半咸水沼泽地的迅速扩张引起了人们的广泛关注，因为它可能改变植被多样性和生态系统功能。特别是，更高的初级生产ofPhragmites比其他本地物种，如米草patents和Schoenoplectus americanus已被注意到，这表明可能的变化，在盐沼的碳储存潜力。然而，为了更好地了解芦苇入侵对碳储存的长期影响，土壤有机质分解速率的信息是必不可少的。为了解决这个问题，我们比较了微生物酶活性和微生物功能基因丰度（真菌，漆酶，发酵菌，产甲烷菌）在三个深度的土壤中的三种不同的植物在美国马里兰州的半咸水沼泽。测定漆酶和酚氧化酶活性以评估柠檬酸碳的分解潜力，而β-葡萄糖苷酶活性测定作为纤维素分解速率的代表。近地表（0-15 cm）的微生物活动在米草群落中最高，其次是芦苇群落和Schoenoplectus群落。土壤和植物叶片稳定同位素（δ 13 C和δ 15 N）的比较表明，土壤深层有机碳主要来源于米草，只有表层土壤可能受到芦苇的影响。相比之下，通过实时qPCR确定的真菌、漆酶和反硝化菌丰度在三种植被类型的表层土壤中没有表现出明显的模式。而深层芦苇群落土壤中甲烷菌的丰度较高。因此，芦苇入侵将加速CH 4排放，在深层土壤中有丰富的产甲烷菌，虽然酶机制揭示了更大的C积累芦苇入侵在美国东海岸的盐沼的潜力。
The rapid expansion ofPhragmites australisin brackish marshes of the East Coast of the USA has drawn much attention, because it may change vegetation diversity and ecosystem functions. In particular, higher primary production ofPhragmitesthan that of other native species such asSpartina patensandSchoenoplectus americanushas been noted, suggesting possible changes in carbon storage potential in salt marshes. To better understand the long-term effect of the invasion ofPhragmiteson carbon storage, however, information on decomposition rates of soil organic matter is essential. To address this issue, we compared microbial enzyme activities and microbial functional gene abundances (fungi, laccase, denitrifier, and methanogens) in three depths of soils with three different plants in a brackish marsh in Maryland, USA. Laccase and phenol oxidase activities were measured to assess the decomposition potential of recalcitrant carbon while β-glucosidase activity was determined as proxy for cellulose decomposition rate. Microbial activities near the surface (0–15 cm) were the highest inSpartina-community sites followed byPhragmites- andSchoenoplectus-community sites. A comparison of stable isotopic signatures (δ13C and δ15N) of soils and plant leaves suggests that deep organic carbon in the soils mainly originated fromSpartina, and only the surface soils may have been influenced byPhragmiteslitter. In contrast, fungal, laccase, and denitrifier abundances determined by real-time qPCR exhibited no discernible patterns among the surface soils of the three vegetation types. However, the abundance of methanogens was higher in the deepPhragmites-community soil. Therefore,Phragmitesinvasion will accelerate CH4emission by greater CH4production in deep soils with abundant methanogens, although enzymatic mechanisms revealed the potential for larger C accumulation byPhragmitesinvasion in salt marshes in the east coast of the USA.