Spatial and temporal variability in the nitrogen cyclers of hypereutrophic Lake Taihu.
Harmful cyanobacterial blooms (cyanoHABs) are a major threat to freshwater ecosystems worldwide. Evidence suggests that both nitrogen and phosphorus are important nutrients in the development and proliferation of blooms, yet much less is known about nitrogen cycling dynamics in these systems. To assess the potential nitrogen cycling function of the cyanoHAB community, surface water samples were collected in Lake Tai (Taihu), China over a 5-month bloom event in 2014. The expression of six nitrogen cycling genes (nifH, hzsA, nxrB, nrfA, amoA, nosZ) was surveyed using a targeted microarray with probes designed to provide phylogenetic information. N-Cycling gene expression varied spatially across Taihu, most notably near the mouth of the Dapu River. Expression of nifH was observed across the lake and attributable to both Proteobacteria and Cyanobacteria: Proteobacteria were major contributors to nifH signal near shore. Other N transformations such as anaerobic ammonia oxidation and denitrification were evident in the surface waters as well. Observations in this study highlight the potential importance of heterotrophic bacteria in N-cycling associated with cyanoHABs.
Department of Microbiology, The University of Tennessee, Knoxville, TN 37919, USA.
Lauren E
LE
Krausfeldt
Taihu Laboratory for Lake Ecosystem Research, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
Xiangming
X
Tang
CSIRO Oceans and Atmosphere, Castray Esplanade, Hobart, Tasmania 7004, Australia.
Jodie
J
van de Kamp
Taihu Laboratory for Lake Ecosystem Research, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
Guang
G
Gao
CSIRO Oceans and Atmosphere, Castray Esplanade, Hobart, Tasmania 7004, Australia.
Levente
L
Bodrossy
Department of Chemistry, State University of New York, College of Environmental Science and Forestry, Syracuse, NY 13210, USA.
Gregory L
GL
Boyer
Department of Microbiology, The University of Tennessee, Knoxville, TN 37919, USA.
Steven W
SW
Wilhelm
D002681:China; D000458:Cyanobacteria / Q000235:genetics; D017753:Ecosystem; D004784:Environmental Monitoring; D005068:Eutrophication; D052836:Heterotrophic Processes; D060106:Lakes / Q000382:microbiology*; D009584:Nitrogen / Q000378:metabolism*; D058458:Nitrogen Cycle; D010758:Phosphorus / Q000032:analysis; D010802:Phylogeny; D045483:Rivers
D010758:Phosphorus; D009584:Nitrogen
Harmful algal blooms; Microcystis; heterotrophic bacteria; microarray; nitrogen fixation