— — . 



By Kathy Hart 



Photo by Jefferson T. Turner 



Red tide di 

 organism 



Photo by Scott Taylor 



Pat Tester, right, 

 organism 



helps identify red tide 



The toxic tide put 

 ciammers like these 

 out of business 



•■"-vr. 



nvasion of the Red Tide 



ctober 31, 1987, was D-Day in 

 coastal North Carolina. 



atches of yellow-green organisms in- 

 vaded the waters of North Carolina's 

 coast. 



cientists at the state's three marine 

 laboratories scurried to sample and 

 magnify the organisms under their 

 microscopes. They quickly identified 

 the intruding organisms as "red tide." 



ed tide in North Carolina? 



his isn't Florida, Texas or Long 

 Island Sound where red tide is com- 

 mon. Besides, there was nothing red 

 about the yellowish slicks that clouded 

 the waters. 



ut the prognosis proved right. The 

 tiny organisms were a subtropical 

 species of a red tide dinoflagellate 

 called Ptychodiscus brevis. 



ore simply, they are single-celled 

 plants. But they have a few animal 

 characteristics such as the tiny hair- 

 like flagella that permit them to swim. 



espite their name, all red tide 

 dinoflagellates are not red. This par- 

 ticular tide was yellow-green, although 

 some patches were brick red. 



nd it left beachcombers coughing, 

 fish suffocating and shellfishermen out 

 of work. 



hat could be in organisms 20 

 microns (a micron is one thousandth of 

 a millimeter) big that could do such 

 damage? 



eurotoxins. This dinoflagellate con- 



tained neurotoxins that affected the 

 nervous systems of other creatures, in- 

 cluding man. 



ther types of red tide possess 

 paralytic and diarrheic toxins that 

 cause paralysis and diarrhea, respec- 

 tively. Some red tides carry no toxins 

 at all. 



long the surf, crashing waves 

 crushed the red tide organisms and 

 sent their toxins airborne. That's what 

 caused surf and boat fishermen to 

 cough and feel dizzy and nauseous. 



he toxins can paralyze the gills of 

 fish, making it impossible for them to 

 pass water over their gills. They soon 

 suffocate. 



ut the toxins do not taint their flesh. 

 It is safe to eat fish, crabs and shrimp 

 taken from North Carolina's red tide 

 waters. 



ysters, clams and scallops are a dif- 

 ferent matter. 



hese shellfish, which filter their food 

 from the surrounding habitat, concen- 

 trate the toxins in their digestive 

 systems. And since oysters and clams 

 are eaten whole, they are dangerous to 

 consume even if cooked. 



f tainted shellfish are accidentally 

 eaten, this type of red tide will not 

 cause death, says Dan Kamykowski, a 

 red tide expert at North Carolina State 

 University. But Kamykowski says that 

 red tides found along the Canadian 

 and Central American coasts can be 

 deadly. 



