The Tara ship crossed the Atlantic, Pacific, Southern and Indian oceans on a 112,654 kilometres journey and while previously scientists thought there were fewer than 500,000 species of plankton, the expedition revealed 1.5 million.
The underwater creatures will be revealed at London's Science Museum by scientist Chris Bowler who spent three years aboard the ship.
The new species include what looks like brightly coloured sea centipedes, ghostly fish, technicolour squid and siphonophores.
A siphonophore is made up of countless tiny creatures, each with a specific function such as swimming, eating, floating or reproduction, linked together by a long hollow tube similar to an umbilical cord.
It lurks about 3,000 feet below the surface of the sea trapping prawns and shrimps in its poisonous tentacles.
The study also revealed the fragile state of the oceans. It carried out the first ever sampling for plastic contamination in waters off the world's last pristine continent, Antarctica.
It found thousands of plastic fragments per square kilometre which can pose a threat to the environment.
"These fragments can cause serious damage to the ecosystem by releasing toxins into the food chain and being eaten by fish, sea mammals and sea birds that think that it is jellyfish," a Science Museum spokesman, said.
"Because the southern ocean phytoplankton is so important for regulating the wellbeing of our planet by removing CO2 from the atmosphere and generating oxygen for us to breathe, this news from the Antarctic is particularly alarming," the spokesman added.
London: A French research ship has found one million new species, mainly plankton, and the world's longest animal - a siphonophore which can extend for up to 150 feet, lurking in the world's oceans.
First Published: Wednesday, September 26, 2012, 15:19