Table 1. Four experimental treatments in the 40-tank open tank experiment.

The PSII mix comprised of diuron, atrazine, hexazinone and tebuthiuron and the non-PSII mix of 2,4-D and metolachlor, each added at ~10 μg l^-1. Each tank contained 120 l coastal seawater, temperature range (21–37°C).

Light conditions	Sediment conditions
	Sediment free	Coastal Sediments
Dark	No herbicides (n = 3) PSII mix (n = 4) non-PSII mix (n = 3)	No herbicides (n = 3) PSII mix (n = 4) non-PSII mix (n = 3)
Light	No herbicides (n = 3) PSII mix (n = 4) non-PSII mix (n = 3)	No herbicides (n = 3) PSII mix (n = 4) non-PSII mix (n = 3)