Enzyme Activities and Microbial Communities in Subtropical Forest Soil Aggregates to Ammonium and Nitrate-Nitrogen Additions

Abstract. Nitrogen (N) and phosphorus (P) additions to forest ecosystems are known to influence various above-ground properties, such as plant productivity and composition, and below-ground properties, such as soil nutrient cycling. However, our understanding of how soil microbial communities and their functions respond to nutrient additions in subtropical plantations is still not complete. In this study, we added N and P to Chinese fir plantations in subtropical China to examine how nutrient additions influenced soil microbial community composition and enzyme activities. The results showed that most soil microbial properties were responsive to N and/or P additions, but responses often varied depending on the nutrient added and the quantity added. For instance, there were more than 30 % greater increases in the activities of β-Glucosidase (βG) and N-acetyl-β-D-glucosaminidase (NAG) in the treatments that received nutrient additions compared to the control plot, whereas acid phosphatase (aP) activity was always higher (57 and 71 %, respectively) in the P treatment. N and P additions greatly enhanced the PLFA abundanceespecially in the N2P treatment, the bacterial PLFAs (bacPLFAs), fungal PLFAs (funPLFAs) and actinomycic PLFAs (actPLFAs) were about 2.5, 3 and 4 times higher, respectively, than in the CK. Soil enzyme activities were noticeably higher in November than in July, mainly due to seasonal differences in soil moisture content (SMC). βG or NAG activities were significantly and positively correlated with microbial PLFAs. There were also significant relationships between gram-positive (G+) bacteria and all three soil enzymes. These findings indicate that G+ bacteria is the most important microbial community in C, N, and P transformations in Chinese fir plantations, and that βG and NAG would be useful tools for assessing the biogeochemical transformation and metabolic activity of soil microbes. We recommend combined additions of N and P fertilizer to promote soil fertility and microbial activity in this kind of plantation.

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Patterns of extracellular enzyme activities among pelagic marine microbial communities: implications for cycling of dissolved organic carbon

Aquatic Microbial Ecology ◽

10.3354/ame038135 ◽

2005 ◽

Vol 38 ◽

pp. 135-145 ◽

Cited By ~ 55

Author(s):

C Arnosti ◽

S Durkin ◽

WH Jeffrey

Keyword(s):

Organic Carbon ◽

Dissolved Organic Carbon ◽

Microbial Communities ◽

Enzyme Activities ◽

Extracellular Enzyme ◽

Extracellular Enzyme Activities ◽

Marine Microbial Communities

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Associations between human impacts and forest soil microbial communities

Elem Sci Anth ◽

10.1525/elementa.005 ◽

2020 ◽

Vol 8 (1) ◽

Author(s):

Yongjian Chen ◽

Jialiang Kuang ◽

Pandeng Wang ◽

Wensheng Shu ◽

Albert Barberán

Keyword(s):

Microbial Communities ◽

Forest Soil ◽

Human Activity ◽

Eastern China ◽

Soil Microbial Communities ◽

Nitrifying Bacteria ◽

Rrna Gene ◽

Internal Transcribed Spacer Region ◽

Soil Microbial ◽

Soil Variables

We are living in a new epoch—the Anthropocene, in which human activity is reshaping global biodiversity at an unprecedented rate. Increasing efforts are being made toward a better understanding of the associations between human activity and the geographic patterns in plant and animal communities. However, similar efforts are rarely applied to microbial communities. Here, we collected 472 forest soil samples across eastern China, and the bacterial and fungal communities in those samples were determined by high-throughput sequencing of 16S rRNA gene and internal transcribed spacer region, respectively. By compiling human impact variables as well as climate and soil variables, our goal was to elucidate the association between microbial richness and human activity when climate and soil variables are taken into account. We found that soil microbial richness was associated with human activity. Specifically, human population density was positively associated with the richness of bacteria, nitrifying bacteria and fungal plant pathogens, but it was negatively associated with the richness of cellulolytic bacteria and ectomycorrhizal fungi. Together, these results suggest that the associations between geographic variations of soil microbial richness and human activity still persist when climate and soil variables are taken into account and that these associations vary among different microbial taxonomic and functional groups.

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Extracellular Enzyme Activity and Microbial Diversity Measured on Seafloor Exposed Basalts from Loihi Seamount Indicate the Importance of Basalts to Global Biogeochemical Cycling

Applied and Environmental Microbiology ◽

10.1128/aem.01038-14 ◽

2014 ◽

Vol 80 (16) ◽

pp. 4854-4864 ◽

Cited By ~ 18

Author(s):

Myrna E. Jacobson Meyers ◽

Jason B. Sylvan ◽

Katrina J. Edwards

Keyword(s):

Enzyme Activity ◽

Microbial Communities ◽

Enzyme Activities ◽

Leucine Aminopeptidase ◽

Extracellular Enzyme ◽

Basaltic Rock ◽

Rrna Gene ◽

Content Type ◽

Shelf Sediments ◽

Potential Enzyme Activity

ABSTRACTSeafloor basalts are widely distributed and host diverse prokaryotic communities, but no data exist concerning the metabolic rates of the resident microbial communities. We present here potential extracellular enzyme activities of leucine aminopeptidase (LAP) and alkaline phosphatase (AP) measured on basalt samples from different locations on Loihi Seamount, HI, coupled with analysis of prokaryotic biomass and pyrosequencing of the bacterial 16S rRNA gene. The community maximum potential enzyme activity (Vmax) of LAP ranged from 0.47 to 0.90 nmol (g rock)−1h−1; theVmaxfor AP was 28 to 60 nmol (g rock)−1h−1. TheKmof LAP ranged from 26 to 33 μM, while theKmfor AP was 2 to 7 μM. Bacterial communities on Loihi basalts were comprised primarily ofAlpha-,Delta-, andGammaproteobacteria,Bacteroidetes, andPlanctomycetes. The putative ability to produce LAP is evenly distributed across the most commonly detected bacterial orders, but the ability to produce AP is likely dominated by bacteria in the ordersXanthomonadales,Flavobacteriales, andPlanctomycetales. The enzyme activities on Loihi basalts were compared to those of other marine environments that have been studied and were found to be similar in magnitude to those from continental shelf sediments and orders of magnitude higher than any measured in the water column, demonstrating that the potential for exposed basalts to transform organic matter is substantial. We propose that microbial communities on basaltic rock play a significant, quantifiable role in benthic biogeochemical processes.

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