That pic was nasty - apparently Punta Cana had a bad issue like that too - 20 feet out - couldn't swim in the ocean. I am a beach girl but I am not going to TTR for the beach - going for everything else as hubby and I have not been away together before (him stuck working and me solo or girl trips) - So I wanted something fun and special for our first trip!
Currently staying at Riu Palace Las Americas. Seaweed is not bad at all at RPLA! Ext door at the Riu Cancun it is awful nasty brown water and seaweed. That is only a 300-400 yard walk and you go from clear blue water to that is brown. However I did walk to the main beach in Cancun by Krystal and seaweed was piled up on the beach and into the water a good 15-20 feet out. No one was in the ocean swimming and walked a good half of mile down the beach and there were probably 40-50 people total on the beach due to the seaweed being so bad.
Water currents in the Gulf around the... is it a "bay" at Cancun? Anyway, those currents do weird things with the collection and...distribution of the seaweed which comes ashore in some places... and in other places not at all. Does weird things to the groth/loss of beach sands as well. Time lapse on it would be cool to see.