Title:Murderous Trees

(SFX: mystery music   )
     NO MOTIVE COULD BE FOUND.  CAUSE OF DEATH COULD NOT BE DETERMINED.
BILLIONS HAD BEEN KILLED AND THE MYSTERY STUMPED ALL THE DETECTIVES.  THE MAIN
PROBLEM WAS THE LACK OF CLUES--AFTER ALL THE CRISIS IN QUESTION OCCURRED OVER
350 MILLION YEARS AGO, IN THE EARLY DEVONIAN ERA, A GOOD HUNDRED MILLION
YEARS BEFORE DINOSAURS ROAMED THE EARTH.  THE VICTIMS WERE TINY MARINE
ANIMALS--SOME 50% OF ALL THE CREATURES LIVING IN THE OCEAN SUDDENLY DIED AND
NOBODY KNOWS WHY.  NOW THOMAS ALGEO, A GEOCHEMIST AT THE UNIVERSITY OF
CINCINNATI, THINKS HE MAY HAVE SOLVED THE CASE.  THE CULPRITS, HE SAYS, WERE
PLANTS AND TREES.  IT WAS AN ACCIDENT, THOUGH, ALL THE PLANTS DID WAS START TO
EVOLVE.

     Algeo: "About 410 to 400 million yeras ago land plants strated to diversify and they
started to develop a lot of new structures that permitted them to expand the range of
habitats that they occupied."

     AS PLANTS EVOLVED, INCORPORATING PHOTOSYNTHESIS AND GETTING BIGGER,
THEY BEGAN TO SPREAD OUT OVER THE LAND. THIS IN TURN, PRODUCED NUTRIENT RICH
SOIL, WHICH WASHED INTO THE SEA. 

     Algeo: "A large flux of dissolved nutrientes were transported to the shallow marine
environemtn. . . producing algae plumes, and. . .they robbed the water of oxygen.  . .
these low oxygen conditions caused the demise of many marine organisms.  And this is
the fundamental link betweent he terrestrial and marine environemnt." 

     ALGEO WAS THE FIRST PERSON TO MAKE THE CONNECTION BETWEEN THE GROWTH
OF PLANTS ON LAND AND THE DEATH OF THE ANIMALS IN THE OCEAN, AND HE'S
CURRENTLY TRYING TO CONVINCE OTHER SCIENTISTS THAT HIS HYPOTHESIS IS RIGHT. 
THERE'S NO WAY TO KNOW FOR SURE IF THIS IS EXACTLY WHAT HAPPENED, BUT
ACCORDING TO ALGEO, THE CASE OF THE DEVONIAN DEATHS IS CLOSED.