Table 2 Independent variables selected by the boosted general additive model (boosted GAM) for the full area and polygon area models

1

bspatial (Lon, Lat)

DD

1.45

18.90

2

bbs (Total depth, S)

m

-

4.80

3

bbs (Temperature, W)

°C

0.09

5.40

4

bbs (Salinity, W)

UPS

0.13

0.60

5

bbs (Oxygen, W)

(mg/L)

0.17

5.00

6

bbs (Alkalinity, W)

meq/l

0.13

2.10

7

bbs (CO2, W)

mmol/l

0.13

2.10

8

bbs (Nitrate, W)

μMolar

0.21

3.00

9

bbs (Phosphate, W)

μMolar

0.09

0.70

10

bbs (Silicate, W)

μMolar

-

1.10

11

bbs(Sigma T, W)

Kg/m3

0.30

-

12

bbs(Sand, S)

%

-

0.50

13

bbs (Silt, S)

%

-

1.10

14

bbs (Clay, S)

%

0.04

-

15

bbs (Phosporus, S)

micromol/g

0.04

0.60

16

bbs (Nitrogen, S)

micromol/g

-

1.30

17

bbs (PAHL, S)

μg/g

0.47

5.70

18

bbs (PAHH, S)

μg/g

94.70

6.90

19

bbs (Aliphatic PAHs, S)

μg/g

-

0.60

20

bbs (PCNM2)

DD

0.30

24.00

21

bbs (PCNM21)

DD

0.47

3.70

22

bbs (PCNM58)

DD

0.68

11.90