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Title: Global biogeography of microbial nitrogen-cycling traits in soil

Authors:
; ORCiD logo;
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1264782
Grant/Contract Number:
PS02-09ER0-25
Resource Type:
Journal Article: Published Article
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Journal Volume: 113; Journal Issue: 29; Related Information: CHORUS Timestamp: 2017-06-24 14:41:51; Journal ID: ISSN 0027-8424
Publisher:
Proceedings of the National Academy of Sciences
Country of Publication:
United States
Language:
English

Citation Formats

Nelson, Michaeline B., Martiny, Adam C., and Martiny, Jennifer B. H.. Global biogeography of microbial nitrogen-cycling traits in soil. United States: N. p., 2016. Web. doi:10.1073/pnas.1601070113.
Nelson, Michaeline B., Martiny, Adam C., & Martiny, Jennifer B. H.. Global biogeography of microbial nitrogen-cycling traits in soil. United States. doi:10.1073/pnas.1601070113.
Nelson, Michaeline B., Martiny, Adam C., and Martiny, Jennifer B. H.. 2016. "Global biogeography of microbial nitrogen-cycling traits in soil". United States. doi:10.1073/pnas.1601070113.
@article{osti_1264782,
title = {Global biogeography of microbial nitrogen-cycling traits in soil},
author = {Nelson, Michaeline B. and Martiny, Adam C. and Martiny, Jennifer B. H.},
abstractNote = {},
doi = {10.1073/pnas.1601070113},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
number = 29,
volume = 113,
place = {United States},
year = 2016,
month = 7
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1073/pnas.1601070113

Citation Metrics:
Cited by: 11works
Citation information provided by
Web of Science

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  • In many ecosystems, nitrogen is the most limiting nutrient for plant growth and productivity. However, current Earth System Models (ESMs) do not mechanistically represent functional nitrogen allocation for photosynthesis or the linkage between nitrogen uptake and root traits. The current version of CLM (4.5) links nitrogen availability and plant productivity via (1) an instantaneous downregulation of potential photosynthesis rates based on soil mineral nitrogen availability, and (2) apportionment of soil nitrogen between plants and competing nitrogen consumers assumed to be proportional to their relative N demands. However, plants do not photosynthesize at potential rates and then downregulate; instead photosynthesis ratesmore » are governed by nitrogen that has been allocated to the physiological processes underpinning photosynthesis. Furthermore, the role of plant roots in nutrient acquisition has also been largely ignored in ESMs. We therefore present a new plant nitrogen model for CLM4.5 with (1) improved representations of linkages between leaf nitrogen and plant productivity based on observed relationships in a global plant trait database and (2) plant nitrogen uptake based on root-scale Michaelis-Menten uptake kinetics. Our model improvements led to a global bias reduction in GPP, LAI, and biomass of 70%, 11%, and 49%, respectively. Furthermore, water use efficiency predictions were improved conceptually, qualitatively, and in magnitude. The new model's GPP responses to nitrogen deposition, CO 2 fertilization, and climate also differed from the baseline model. The mechanistic representation of leaf-level nitrogen allocation and a theoretically consistent treatment of competition with belowground consumers led to overall improvements in global carbon cycling predictions.« less
  • Many studies have shown that changes in nitrogen (N) availability affect primary productivity in a variety of terrestrial systems, but less is known about the effects of the changing N cycle on soil organic matter (SOM) decomposition. We used a variety of techniques to examine the effects of chronic N amendments on SOM chemistry and microbial community structure and function in an alpine tundra soil. We collected surface soil (0-5 cm) samples from five control and five long-term N-amended plots established and maintained at the Niwot Ridge Long-term Ecological Research (LTER) site. Samples were bulked by treatment and all analysesmore » were conducted on composite samples. The fungal community shifted in response to N amendments, with a decrease in the relative abundance of basidiomycetes. Bacterial community composition also shifted in the fertilized soil, with increases in the relative abundance of sequences related to the Bacteroidetes and Gemmatimonadetes, and decreases in the relative abundance of the Verrucomicrobia. We did not uncover any bacterial sequences that were closely related to known nitrifiers in either soil, but sequences related to archaeal nitrifiers were found in control soils. The ratio of fungi to bacteria did not change in the N-amended soils, but the ratio of archaea to bacteria dropped from 20% to less than 1% in the N-amended plots. Comparisons of aliphatic and aromatic carbon compounds, two broad categories of soil carbon compounds, revealed no between treatment differences. However, G-lignins were found in higher relative abundance in the fertilized soils, while proteins were detected in lower relative abundance. Finally, the activities of two soil enzymes involved in N cycling changed in response to chronic N amendments. These results suggest that chronic N fertilization induces significant shifts in soil carbon dynamics that correspond to shifts in microbial community structure and function.« less