Algae & me

I had my first close encounter with Red Tide recently, and it isn't pretty.  On the Gulf, the culprit is Karenia brevis, a naturally-occurring organism seen as far back as the 15th C.  The algae is not particularly villainous until it has a population explosion.  That's recently happened in these parts,  and it's asphyxiating fish in vast quantities.  My sunset walk on the beach last night?