Shifts in the pelagic ammonia-oxidizing microbial communities along the eutrophic estuary of Yong River in Ningbo City, China.

Qiufang Zhang,Yangjing Zhou,Hendrikus J Laanbroek,Jirong Xu,Heping Chen,Mingkuang Wang,Fangyuan Tang

doi:10.3389/fmicb.2015.01180

Qiufang Zhang, Yangjing Zhou + Show 5 more

Open Access

https://doi.org/10.3389/fmicb.2015.01180

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Abstract

Aerobic ammonia oxidation plays a key role in the nitrogen cycle, and the diversity of the responsible microorganisms is regulated by environmental factors. Abundance and composition of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) were investigated in the surface waters along an environmental gradient of the Yong River in Ningbo, East China. Water samples were collected from three pelagic zones: (1) freshwaters in the urban canals of Ningbo, (2) brackish waters in the downstream Yong River, and (3) coastal marine water of Hangzhou Bay. Shifts in activity and diversity of the ammonia-oxidizing microorganisms occurred simultaneously with changes in environmental factors, among which salinity and the availabilities of ammonium and oxygen. The AOA abundance was always higher than that of AOB and was related to the ammonia oxidation activity. The ratios of AOA/AOB in the brackish and marine waters were significantly higher than those found in freshwaters. Both AOA and AOB showed similar community compositions in brackish and marine waters, but only 31 and 35% similarity, respectively, between these waters and the urban inland freshwaters. Most of AOA-amoA sequences from freshwater were affiliated with sequences obtained from terrestrial environments and those collected from brackish and coastal areas were ubiquitous in marine, coastal, and terrestrial ecosystems. All AOB from freshwaters belonged to Nitrosomonas, and the AOB from brackish and marine waters mainly belonged to Nitrosospira.

Highlights

Excessive inorganic nitrogen is often the cause of eutrophication, which is a key important factor contributing to habitat variation and to catastrophic algal bloom expansion in aquatic ecosystems (Glibert et al, 2005)
Being the first step of a coupled nitrification/denitrification process, which enables the removal of a large part of anthropogenically produced reactive nitrogen, aerobic ammonia oxidation is of pivotal significance in aquatic ecosystems (Seitzinger, 1988; Francis et al, 2007)
Ammonia oxidation is controlled by the enzyme ammonia monooxygenase, which is partly encoded by the amoA gene (Rotthauwe et al, 1997; Kowalchuk and Stephen, 2001)

Summary

Introduction

Excessive inorganic nitrogen is often the cause of eutrophication, which is a key important factor contributing to habitat variation and to catastrophic algal bloom expansion in aquatic ecosystems (Glibert et al, 2005). Many worldwide studies in estuaries have reported that spatial variation in environmental factors drive shifts in abundance and community composition of ammonia-oxidizing microorganisms in sediments, i.e., in the Sacramento San Joaquin Delta (Damashek et al, 2015), the Scheldt estuary (Sahan and Muyzer, 2008), the Chesapeake Bay (Francis et al, 2003), the Plum Island Sound (Bernhard et al, 2005, 2007, 2010), the Ythan Estuary (Freitag et al, 2006), the Tokyo Bay (Urakawa et al, 2006), the Bahía del Tóbari estuary (Beman and Francis, 2006), the San Francisco Bay (Mosier and Francis, 2008), the Huntington Beach (Santoro et al, 2008), the Barn Island salt marsh (Moin et al, 2009), the Jiaozhou Bay (Dang et al, 2010), the Pearl River estuary (Cao et al, 2011; Jin et al, 2011; Xie et al, 2014), the Elkhorn Slough estuary (Wankel et al, 2011), and the Qiantang River (Liu et al, 2013). The series of studies have indicated that environmental factors such as salinity, trophic status, oxygen and temperature are likely to be potential selective factors shaping ammonia-oxidizing microbial communities

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