Table 1.

Abiotic variables of the examined marinas and control areas. See Appendix S1 for method description

Variables	Category	Pairs														t/F-valuesa	p values
		1		2		3		4		5		6		7
		$\overline{x}$	± SE	$\overline{x}$	± SE	$\overline{x}$	± SE	$\overline{x}$	± SE	$\overline{x}$	± SE	$\overline{x}$	± SE	$\overline{x}$	± SE
Berths (no.)	Marina	13		26		391		160		39		45		25
	Control	1		1		9		3		2		0		0
Jetties (no.)	Marina	6		6		11		13		7		6		4
	Control	1		0		3		1		1		0		0
Water surface area (ha)	Marina	4.38		5.66		8.52		9.74		2.07		3.40		3.02		0.47	0.655
	Control	8.15		1.24		5.57		10.2		3.38		1.75		3.13
Water retention time (days)	Marina	8.0		1.4		0.08		0.06		15.7		1.5		1.8		− 1.30	0.240
	Control	15.1		0.4		0.02		0.11		25.6		1.6		1.0
Wave exposure (Log10 m2 s−1)	Marina	3.1		3.4		3.3		3.4		3.2		4.6		3.2		− 1.41	0.209
	Control	3.6		3.5		3.9		3.6		2.9		4.7		3.0
Maximum depth (m)	Marina	3		6		20		6		3		3		3		1.00	0.356
	Control	3		6		15		6		3		3		3
Sampling depth (m)	Marina	1.5	± 0.2	1.9	± 0.2	1.5	± 0.3	1.8	± 0.1	1.3	± 0.2	1.4	± 0.2	1.2	± 0.2	6.09	0.016
	Control	1.7	± 0.1	2.6	± 0.2	1.7	± 0.3	1.8	± 0.2	2.2	± 0.3	1.4	± 0.2	1.5	± 0.1
Salinity (PSU)	Marina	6.6	± < 0.1	4.8	± < 0.1	4.8	± < 0.1	5.4	± < 0.1	5.2	± < 0.1	6.1	± < 0.1	5.5	± < 0.1	1.68	0.242
	Control	6.6	± < 0.1	5.2	± < 0.1	6.4	± < 0.1	5.7	± < 0.1	5.0	± < 0.1	6.4	± < 0.1	5.3	± < 0.1
Total nitrogen conc. (µmol L−1)	Marina	23.3	± 0.9	20.7	± 1.6	20.5	± 1.0	19.9	± 0.4	63.5	± 1.8	21.3	± 1.3	32.2	± 2.1	1.14	0.326
	Control	21.8	± 0.8	20.5	± 0.5	23.6	± 0.4	19.1	± 0.7	33.2	± 0.8	22.7	± 1.9	27.7	± 0.9
Total phosphorous conc. (µmol L−1)	Marina	0.90	± 0.11	0.51	± 0.05	0.59	± 0.06	0.42	± 0.02	3.48	± 0.07	1.04	± 0.09	1.73	± 0.14	1.03b	0.350
	Control	0.90	± 0.05	0.49	± 0.01	0.98	± 0.01	0.54	± 0.02	1.07	± 0.02	0.80	± 0.06	0.57	± 0.02
Turbidity (NTU)	Marina	2.7	± 0.3	6.5	± 0.1	4.9	± 0.1	7.7	± 0.1	5.3	± 0.1	2.0	± 0.1	2.8	± 0.3	0.61b	0.464
	Control	3.4	± 0.2	2.6	± 0.3	1.8	± 0.1	1.7	± 0.1	2.6	± 0.6	2.5	± 0.5	6.5	± 0.1
Dominant substrate (> 90%)	Marina	M, ST, B, BR		M, G		M, SA		M, SA		M		M, SA, G		M		0.25	0.784
	Control	M		M, G		M, SA, ST		M, SA, G, ST		M, BR		M, SA, ST		M

M mud, SA sand, G gravel, ST stones, B boulders, BR bedrock

^aDifferences between marina and control sites in area, retention time, wave exposure and maximum depth were tested with paired t-tests (inlets as replicates), while differences in sampling depth, salinity, nutrient concentrations and turbidity were tested with mixed effects models (stations as replicates), where the random factor inlet was nested within marina–control pairs. Differences in substrate composition were tested with a PERMANOVA with marina–control pairs as random strata

^bTests were performed on log₁₀-transformed values