In the marine environment Gonyaulax catenella plays some very large roles. They are responsible for the majority of photosynthetic carbon fixation in the ocean. They also make up the base of the food chain. This dinoflagellate prefers salinity levels between 26-32 and temperatures ranging from 17- 23  °C.

     Unfortunately, Gonyaulax catenella is one of the dinoflagellates responsible for red tides. Red tide is described as a great growth of phytoplanton whose pigment cause the discoloration of water. In the event of  red tides, many fish, whales, manatees, and other marine have died in massive numbers because of the anoxic conditions produced by dinoflagellate blooms. G. catenella is believed to bloom in temperatures ranging from 17 to 23 °C and salinities of 15 to 32. Its toxicity is due to its secretion of a strong neurotoxin called saxitoxin— or STX for short. Saxitoxin is a neurotoxin that specifically binds the sodium channels in neural cells. Thus, it physically blocks the opening of the Na+ channel and prevents any sodium molecules from going in or out of the cell. Since neural transmittance of impulses and messages depends on the depolarization of the inside of the cell , action potentials are stopped, impairing a variety of bodily functions. 

Fish Deads by Red Tide. Judy Baxter, Flickr Creative Commons. 2005Saxitoxin Chemical Makeup. Charlesy, Wikimedia Commons. 2009.
                             Judy Baxter, Flickr Creative Commons. 2005                                         Charlesy, Wikimedia Commons. 2009.   

During red tides, the secretionRed Tide in Newport, Rhode Island, Easton Beach. Parl, Flickr Creative Commons. 2008. of saxitoxin is exceptionally dangerous.
Mussels filter feed on the contaminated water, and although mussels themselves are unharmed by saxitoxin, mussel predators quickly develop the poison symptoms. The high concentration of saxitoxin can cause Paralytic Shellfish Poisoning (PSP), which is dangerous to both humans and marine animals. PSP symptoms in humans include dizziness, numbing of the lips and the neck, fatigue, difficulty breathing and ultimately possible respiratory paralysis. If worse comes to worse, this paralysis can cause death!

Click Karenia brevis to learn some shocking details on another red tide forming dinoflagellate!

                                                                                                                                                                     Parl, Flickr Creative Commons. 2008.


To read up on some interesting facts, including how saxitoxin produced by G. catenella an be used for a good cause, click to the Facts page.