In your own words, explain john martin s theory about iron dumping.

Basically the theory centers on the idea that an atom of iron dumped into the sea results in the conversion of 10,000 molecules of carbon dioxide to carbohydrates. John Martin's hypothesis is that the growth of phytoplankton is limited by the amount of iron dissolved in sea water. Lab experiments done by him then showed that indeed, adding a small amount of iron accelerated the growth of plankton.

No. an alpha particle is a pair of protons and a pair of neutrons, i.e. a helium