Wonderful information Sandra -- you are truly an EXCELLENT teacher! I look forward to further posts as even I am going to learn from your very informative postings.
Yesterday was World Oceans Day and I watched some of the Google street-views, pretty amazing. I can't wait to read your next post and I will tell Ruben & Eli about it.
I believe there are cyanobacteria that have some effect on the final color along with the symbiotic algae as well ,in some coral.