Table 2 Results of simple linear models for temperature, pH and salinity over time categorised by estuary type.

Temperature (°C)

 Coefficient

−0.00017

0.00068

0.000262

0.00089

0.000319

0.00052

 p value

NS

<0.0001

<0.0001

<0.0001

<0.001

<0.0001

 R² (adjusted)

0.0019

0.082

0.0149

0.103

0.0114

0.0466

 Number of observations (n)

625

1892

1751

1054

949

6271

 Change in °C year⁻¹

NS

0.248

0.0954

0.325

0.117

0.192

 Change over the sampling period (°C)

NS

2.79

1.07

3.65

1.31

2.16

pH

 Coefficient

−0.000276

−0.000168

−0.000146

−0.000243

−0.000166

−0.000237

 p value

<0.001

<0.0001

<0.001

<0.0001

<0.01

<0.0001

 R² (adjusted)

0.0325

0.0623

0.00608

0.0586

0.0128

0.0846

 Number of observations (n)

122

1132

644

598

641

3137

 Change in pH units year⁻¹

−0.101

−0.0612

−0.0534

−0.0888

−0.0607

−0.0978

 Change over the sampling period

−0.53

−0.32

−0.28

−0.46

−0.32

−0.51

Salinity (PSU)

 Coefficient

−0.00164

0.000653

−0.000277

−0.00131

0.000242

−0.000238

 p value

<0.0001

<0.001

NS

<0.0001

NS

<0.05

 R² (adjusted)

0.032

0.006

0.0003

0.016

−0.0006

0.0005

 Number of observations (n)

625

1892

1751

1054

949

6271

 Change in PSU year⁻¹

−0.6

0.238

NS

−0.479

NS

−0.0861

 Change over the sampling period (PSU)

−6.74

2.68

NS

−5.38

NS

−0.97