Effects of red tide
Name: Mrs. Corwin's 5th grade class
My 5th grade class would like to know why is it that red tide only affects
humans and not lobsters, fish, etc. Why is the micro-organism so toxic to humans?
Waiting to learn....
Without going into too much detail, the microorganisms responsible for
causing red tide can live within the shellfish without killing them because the
chemicals they produce which imbue everything with the characteristic red color
aren't toxic to the shellfish. It's just our bad luck that those very same chemicals
happen to interact with our body chemistries in the ways that can't occur in shellfish.
As it turns out, red tides do affect other vertebrates (animals with
backbones), in fact, they are responsible for huge, stinky die-offs of fish that
wash up on shore during a "red tide". The microorganism responsible for the
occurrence of a red tide is the "dinoflagellate", there are different types of
dinoflagellates, and as I understand it, they produce different types of toxins,
but usually the toxin responsible for the die-offs is what is called a "neurotoxin",
which affects the heart , slowing it down. This reduces blood circulation, and the
reduced blood circulation to the gills results in oxygen starvation, and the fish dies.
As far as I know, however, this toxin only affects vertebrates, and not invertebrates
(animals without backbones) like the clam and lobster.
Tom F Ihde
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Update: June 2012