Ecological Archives E096-084-A2

Lucía Vivanco, Irina C. Irvine, and Jennifer B. H. Martiny. 2015. Nonlinear responses in salt marsh functioning to increased nitrogen addition. Ecology 96:936–947. http://dx.doi.org/10.1890/13-1983.1

Appendix B. Detailed description of the principal component analysis of biogeochemical variables that describe baseline conditions among three Californian salt marshes and a table showing the eigenvector scores of 12 biogeochemical variables in three main PCA axes in control plots at 7 months of fertilization.

Table B1. Eigenvector scores of 13 biogeochemical variables in three main PCA axes in control plots at 7 months of fertilization. The highest eigenvector scores for each PCA axis are indicated in bold. Values in parentheses indicate variance accounted for by each axis. See associated Fig. 1.

 

PCA 1

PCA 2

PCA 3

 

(24.5%)

(21.9%)

(17%)

Plant characteristics

 

 

 

Plant biomass

0.080

-0.035

0.353

Leaf N content

0.148

0.143

-0.559

Leaf C content

0.233

0.288

-0.382

Microbial processes

 

 

 

Methane flux

0.056

0.279

0.376

Sediment respiration

0.460

-0.213

0.017

Carbon mineralization

0.357

-0.011

0.197

Potential net N mineralization

0.074

0.453

0.257

Potential net nitrification

-0.132

-0.040

-0.390

Sediment characteristics

 

 

 

Total C

0.420

0.206

-0.011

Total N

0.392

0.263

-0.005

Extractable ammonium

-0.344

0.065

0.061

pH

0.180

-0.527

0.103

Gravimetric water content

-0.267

0.415

0.061


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