This sponge is probably Chondrilla nucula.
It was yellowish at first, turning brown at the places of an amplifyed roughness. If this would be Aplysina aerophoba sponge I would suggest this has happened because of a symbiotic cyanophita algae, that changes the colour of sponge if getting in touch with an air.
All in all, I've missed shooting golden fields — they have oxidized during the very first storm, in a pair of days.