For the last two and a half years, 15 scientists have been scouring the oceans in search of some of earth's smallest but most important organisms - Plankton. The exhaustive research has revealed some great news and some, not so encouraging.

The Tara Oceans expedition was the eighth in a series of research trips undertaken by a group of the world's best physical oceanographers, marine biologists, imaging specialists and molecular biologists to observe and document our changing environment and also, learn more the Earth's complex yet fragile ecosystem.

While past expeditions have focused on particular areas like Greenland, Antarctica and Patagonia, this latest one that lasted 938 days was an excursion all around the world. Its mission was to understand the evolution and ecology of the many tiny organisms collectively known as plankton. The expedition returned to Lorient, France on March 31st, 2012 after which, began the arduous task of analyzing the data.

In total, the researchers collected about 27,000 samples from 152 areas - all the way from the Mediterranean Sea to the Pacific, Atlantic and even the Antarctic Ocean and, from 35 depths ranging from the surface of the water all the way down to a kilometer deep. The scientists first sorted out the organisms by size and then classified them with the help of automated imaging systems.

What they unveiled was encouraging - Over 1.5 million new species of Plankton. The smaller ones were of course more abundant in the number of species, as well as, count. They also found some unexpected cohabitant patterns - Some of the organisms liked to live together, while others, not so much. As one would expect the diversity also varied depending on the temperature, depth and acidity levels of the water.

The scientists are hoping that further research will reveal the exact factors that determine the diversity and denseness in population, which in turn may allow them deduce the impact that global warming and ocean acidification has had on marine ecosystems. While not confirmed yet, they do suspect that the species are very sensitive to temperature change!

Though the discovery of so many new species of these important organisms was exciting, what was not so thrilling was the amount of plastic debris discovered even in areas like the Antarctica, which the researchers had assumed would be pristine, given how far it is from any kind of civilization. The scientists are quite fearful about the impact these will have on marine life especially given that the brightly colored debris do not disintegrate for centuries and are often mistaken for food. To read more about this amazing expedition and their future trips check out

Plankton, which means wanderer or drifter in the Greek language, is the name assigned to any micro-organism that drifts around in the oceans or freshwater. They can be divided into two categories - the Phytoplankton ('light-loving' plankton) that include small algae and fungi and the Zooplankton, which includes tiny crustaceans, krill and even the eggs and larvae of larger animals. While tiny, both are crucial to the survival of humans and marine animals. If estimates are to believed the light-loving plankton that conduct photosynthesis just like their counterparts on land, are responsible for producing between 40-80% of the world's supply of oxygen. As for the Zooplankton? They are what keep most of the marine life, ranging from the tiny shrimp to the massive whale - Well-fed and happy!