Introduction
Methods
Study site
In situ water measurement
Sampling of macrophytes, water, and bed sediment
Chemical analysis
Data analyses
Growth rate
Habitat categorizing
Results
Biomass, growth rate, and pH distributions
DO and free CO2 concentrations of spring water
Principal components derived from principal component analysis
PC1 (32.7%) | PC2 (17.4%) | PC3 (16.3) | |
---|---|---|---|
Water quality | |||
pH | −0.107 | 0.524 | 0.327 |
Water temperature | 0.393 | 0.322 | 0.126 |
Dissolved oxygen (DO) | −0.369 | 0.269 | 0.276 |
Electric conductivity (EC) | −0.411 | −0.203 | −0.067 |
Dissolved inorganic carbon (DIC) | 0.105 | −0.136 | −0.112 |
Dissolved inorganic nitrogen (DIN) | 0.434 | −0.031 | −0.088 |
Phosphate (PO4-P) | 0.306 | 0.067 | 0.011 |
Bed sediment | |||
Particle diameter (d50) | −0.091 | −0.158 | −0.477 |
Nitrogen content (TN) | 0.362 | −0.275 | 0.185 |
Phosphorous content (TP) | 0.076 | −0.427 | 0.357 |
Sediment layer thickness | −0.018 | 0.355 | −0.304 |
Land use types | |||
Riparian forests or paddy fields | 0.053 | 0.141 | −0.543 |
Comparison of bed-sediment characteristic between reaches adjacent to different land-use types
TP content (%) | Particle diameter [d50] (mm) | |||
---|---|---|---|---|
Reach adjacent to riparian forests (St. 2–6) | Reach adjacent to paddy fields (St. 7–17) | Reach adjacent to riparian forests (St. 2–6) | Reach adjacent to paddy fields (St. 7–17) | |
Summer | 0.088 ± 0.035b
| 0.141 ± 0.054a
| 0.253 ± 0.185 | 0.302 ± 0.158 |
Autumn | 0.094 ± 0.024b
| 0.142 ± 0.060a
| 1.991 ± 2.2504a
| 0.491 ± 0.129b
|
Relationship between free CO2 and growth rate
Variable | Correlation coefficient |
---|---|
Water quality | |
pH | −0.77** |
Water temperature | −0.07 |
Dissolved oxygen (DO) | −0.98** |
Electric conductivity (EC) | −0.48 |
Dissolved inorganic carbon (DIC) | −0.22 |
Dissolved organic carbon (DOC) | 0.85** |
Dissolved inorganic nitrogen (DIN) | 0.14 |
Phosphate (PO4-P) | 0.06 |
Bed sediment | |
Particle diameter (d50) | 0.07 |
Nitrogen content (TN) | 0.22 |
Phosphorous content (TP) | −0.04 |
Sediment-layer thickness | 0.55 |