Table 1.

Statistical results of kelp responses.

Parameter	Fixed effect	numDF	denDF	F value	P value
Biogenic elemental mass fraction
Aluminium (Al)	Area	2	68	23.1	< 0.001
	Station	8	61	10.6	< 0.001
Iron (Fe)	Area	2	66	30.7	< 0.001
	Station	8	61	9.1	< 0.001
Manganese (Mn)	Area	2	67	20.6	< 0.001
	Station	8	61	20.7	< 0.001
Copper (Cu)	Area	2	69	13.2	< 0.001
	Station	8	63	5.8	< 0.001
Cobalt (Co)	Area	2	68	1.2	0.3
	Station	8	60	5.3	< 0.001
Cadmium (Cd)	Area	2	69	5.6	0.006
	Station	8	63	2.9	0.007
Lead (Pb)	Area	2	68	16.1	< 0.001
	Station	8	62	8.2	< 0.001
Mercury (Hg)	Area	2	68	53.1	< 0.001
	Station	8	61	28.8	< 0.001
Biochemistry
Chlorophyll a	Area	2	69	6.5	0.002
	Station	8	62	3.1	0.006
De-epoxidation state of xanthophyll cycle pigments (DPS)	Area	2	68	14.5	< 0.001
	Station	8	63	5.1	< 0.001
Antioxidant activity	Area	2	69	8.5	< 0.001
	Station	8	63	3.8	0.001
Biodiversity indices
Shannon entropy	Area	2	64	7.0	0.002
	Station	8	57	5.4	< 0.001
Pielou evenness	Area	2	63	15.5	< 0.001
	Station	8	57	6.2	< 0.001
Relative abundance of microbial taxa
Bacteroidetes	Area	2	64	9.4	< 0.001
	Station	5	58	5.77	0.001
Proteobacteria	Area	2	64	4.4	0.02
	Station	8	55	9.5	< 0.001
Alphaproteobacteria	Area	2	64	0.07	0.93
	Station	8	56	4.82	< 0.001
Gammaproteobacteria	Area	2	64	4.55	0.01
	Station	8	58	5.05	< 0.001
Flavobacteria	Area	2	64	12.2	< 0.001
	Station	8	58	6.8	< 0.001
Tiotrichales	Area	2	62	18.2	< 0.001
	Station	8	56	4.42	< 0.001
Pirellulales	Area	2	61	17.3	< 0.001
	Station	8	55	5.74	< 0.001
Planctomycetes	Area	2	61	17.3	< 0.001
	Station	8	55	5.74	< 0.001
Saprospirales	Area	2	64	3.7	0.03
	Station	8	56	3.3	0.003
Rhodobacterales	Area	2	64	0.07	0.93
	Station	8	56	4.8	< 0.001

Results of analysis of variance (ANOVA). As the data met all requirements (normality, homoscedasticity), a linear model was fit on each response parameter. Sampling area and station (Fig. 1a) were modelled as single fixed effect to analyse spatial differences of kelp responses. Analysis of variance was tested on the model using the “anova” function (type I sums of squares). Significant results are marked in bold. Note: tested values are the means of replicates (Area: N = 3; Station: N = 6–9) numDF: numerator degrees of freedom. denDF: denominator degrees of freedom.