Average porewater ratios of [alkalinity]/[Cl], and [Ca]/[Cl] in winter and summer, before and after inundation.

<p>Average porewater ratios of [alkalinity]/[Cl], and [Ca]/[Cl] in winter and summer, before and after inundation.</p

Effects of location, season, vegetation type and their interactions on the water table and porewater chemistry at <i>T</i> = 0 of each yearly experiment.

<p>Effects of location, season, vegetation type and their interactions on the water table and porewater chemistry at <i>T</i> = 0 of each yearly experiment.</p

o-PO₄ (A), NO₃^- (B) and NH₄⁺ (C) concentrations per vegetation type in porewater 2 days before the experiment, in inundation water during the experiment, and in porewater 2 days after the experiment.

<p>Sample means with standard deviations are indicated (<i>n</i> = 5). Statistical information is provided in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0144006#pone.0144006.t003" target="_blank">Table 3</a>. For abbreviations see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0144006#pone.0144006.t001" target="_blank">Table 1</a>.</p

Water table (A) and Cl-concentrations (B) per vegetation type in porewater 2 days before the experiment, in inundation water during the experiment, and in porewater 2 days after the experiment.

<p>Sample means with standard deviations are indicated (<i>n</i> = 5). Statistical information is provided in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0144006#pone.0144006.t003" target="_blank">Table 3</a>. For abbreviations see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0144006#pone.0144006.t001" target="_blank">Table 1</a>.</p

Effects of inundation, season, vegetation type and their interactions on porewater chemistry during the experiments.

<p>Effects of inundation, season, vegetation type and their interactions on porewater chemistry during the experiments.</p

Initial water tables and porewater characteristics for the different areas and vegetation types for combined seasons.

<p>Initial water tables and porewater characteristics for the different areas and vegetation types for combined seasons.</p

Interacting effects of <i>Azolla</i>, rain and wind on salinity stratification. A

<p>) Salinity (mg L⁻¹ ± standard error) in the top water layers (solid lines) and in the bottom water layers (dotted lines) of the beakers in the absence of <i>Azolla</i> (rounds), in the presence of <i>Azolla</i> (squares), with no influence of wind (closed figures) or with influence of wind (open figures) hours after the rain event. <b>B</b>) Salinity (mg L⁻¹) profiles in the beakers 20 hours after the rain event.</p

Mesocosm experiment.

<p><b>A</b>) Development of the biomass density of <i>Azolla filiculoides</i> (g dry weight m⁻² ± standard error) grown in freshwater or brackish water basins. <b>2B</b>) Chloride concentrations and <b>2C</b>) phosphate concentrations (µM ± standard error) in the top, middle and bottom water layers of the freshwater and brackish water basins during the mesocosm experiment. Significant differences between water layers are indicated by different letters. The cumulative amount of rainfall during the experiment (mm) is shown on the right axis in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0050159#pone-0050159-g002" target="_blank">figure <b>2B</b></a>.</p

Calibration and validation statistics of partial least-squares regression models.

<p>Calibrations were evaluated as follows (Saeys et al (2005): excellent (R²/r² ≥ 0.9, RPD ≥ 3.0), reliable quantitative predictions (R²/r² ≥ 0.75 and <0.9, RPD ≥ 2.0 and <3.0), differentiation between high and low values (R²/r² ≥ 0.65 and <0.75, RPD ≥ 1.5 and <2.0, unsuccessful (R²/r² <0.65, RPD <1.5).</p><p>Transf: transformations for regression analyses.</p><p>Abs: Log1/R (R = reflectance).</p><p>1D: first derivative.</p><p>R²: coefficient of multiple determination (calibration).</p><p>SEC: standard error of calibration.</p><p>SECV: standard error of cross validation.</p><p>r²: regression coefficient NIRS predicted vs. observed values.</p><p>SEP: standard error of prediction (validation).</p><p>RPD: ratio of SD of reference values (validation) to SEP.</p><p>RPIQ: ratio of the interquartile distance IQ ( = Q3–Q1) of reference values (validation) to SEP.</p><p>Corr. OM: Pearson correlation with organic matter content.</p

Exemplary observed vs. NIR predicted values for NaCl-extractable Ca and N-NH₄ and oxalate-extractable Fe and P.

<p><i>Open circles</i> calibration data set, <i>filled circles</i> external validation.</p