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Spatially robust estimates of biological nitrogen (N) fixation imply substantial human alteration of the tropical N cycle

Overview of attention for article published in Proceedings of the National Academy of Sciences of the United States of America, May 2014
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About this Attention Score

  • In the top 5% of all research outputs scored by Altmetric
  • High Attention Score compared to outputs of the same age (95th percentile)
  • Good Attention Score compared to outputs of the same age and source (74th percentile)

Mentioned by

news
3 news outlets
blogs
1 blog
twitter
13 tweeters

Citations

dimensions_citation
111 Dimensions

Readers on

mendeley
226 Mendeley
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Title
Spatially robust estimates of biological nitrogen (N) fixation imply substantial human alteration of the tropical N cycle
Published in
Proceedings of the National Academy of Sciences of the United States of America, May 2014
DOI 10.1073/pnas.1320646111
Pubmed ID
Authors

B. W. Sullivan, W. K. Smith, A. R. Townsend, M. K. Nasto, S. C. Reed, R. L. Chazdon, C. C. Cleveland

Abstract

Biological nitrogen fixation (BNF) is the largest natural source of exogenous nitrogen (N) to unmanaged ecosystems and also the primary baseline against which anthropogenic changes to the N cycle are measured. Rates of BNF in tropical rainforest are thought to be among the highest on Earth, but they are notoriously difficult to quantify and are based on little empirical data. We adapted a sampling strategy from community ecology to generate spatial estimates of symbiotic and free-living BNF in secondary and primary forest sites that span a typical range of tropical forest legume abundance. Although total BNF was higher in secondary than primary forest, overall rates were roughly five times lower than previous estimates for the tropical forest biome. We found strong correlations between symbiotic BNF and legume abundance, but we also show that spatially free-living BNF often exceeds symbiotic inputs. Our results suggest that BNF in tropical forest has been overestimated, and our data are consistent with a recent top-down estimate of global BNF that implied but did not measure low tropical BNF rates. Finally, comparing tropical BNF within the historical area of tropical rainforest with current anthropogenic N inputs indicates that humans have already at least doubled reactive N inputs to the tropical forest biome, a far greater change than previously thought. Because N inputs are increasing faster in the tropics than anywhere on Earth, both the proportion and the effects of human N enrichment are likely to grow in the future.

Twitter Demographics

The data shown below were collected from the profiles of 13 tweeters who shared this research output. Click here to find out more about how the information was compiled.

Mendeley readers

The data shown below were compiled from readership statistics for 226 Mendeley readers of this research output. Click here to see the associated Mendeley record.

Geographical breakdown

Country Count As %
United States 9 4%
Brazil 5 2%
Panama 1 <1%
Mexico 1 <1%
Japan 1 <1%
Germany 1 <1%
Unknown 208 92%

Demographic breakdown

Readers by professional status Count As %
Researcher 59 26%
Student > Ph. D. Student 49 22%
Student > Master 40 18%
Student > Bachelor 22 10%
Student > Doctoral Student 13 6%
Other 30 13%
Unknown 13 6%
Readers by discipline Count As %
Agricultural and Biological Sciences 92 41%
Environmental Science 61 27%
Earth and Planetary Sciences 30 13%
Biochemistry, Genetics and Molecular Biology 3 1%
Engineering 3 1%
Other 11 5%
Unknown 26 12%

Attention Score in Context

This research output has an Altmetric Attention Score of 36. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 09 June 2014.
All research outputs
#756,501
of 18,922,407 outputs
Outputs from Proceedings of the National Academy of Sciences of the United States of America
#13,078
of 91,974 outputs
Outputs of similar age
#8,939
of 199,335 outputs
Outputs of similar age from Proceedings of the National Academy of Sciences of the United States of America
#250
of 962 outputs
Altmetric has tracked 18,922,407 research outputs across all sources so far. Compared to these this one has done particularly well and is in the 96th percentile: it's in the top 5% of all research outputs ever tracked by Altmetric.
So far Altmetric has tracked 91,974 research outputs from this source. They typically receive a lot more attention than average, with a mean Attention Score of 32.7. This one has done well, scoring higher than 85% of its peers.
Older research outputs will score higher simply because they've had more time to accumulate mentions. To account for age we can compare this Altmetric Attention Score to the 199,335 tracked outputs that were published within six weeks on either side of this one in any source. This one has done particularly well, scoring higher than 95% of its contemporaries.
We're also able to compare this research output to 962 others from the same source and published within six weeks on either side of this one. This one has gotten more attention than average, scoring higher than 74% of its contemporaries.