SAVE THE PLANKTON: So much more than whale food

Gotta love those life-sustaining and genetically diverse little critters

Marineboffins have spent three and half years at sea analysing plankton (singular: plankter) in the most comprehensive analysis of the organisms to have ever taken place.

Plankton are, by all accounts, a mysterious bunch of creatures. They are not defined by a phylogenetic or taxonomic classification, but rather by their ecological niche.

The grouping includes complicated animals, unicellular protists, algae, and archaea, which inhabit the pelagic zone (essentially everywhere except the floor and the coast) of most bodies of water.

These organisms are fundamental to the largest ecosystem on earth, but relatively little is known about them.

In the largest study into the secret world of plankton, researchers boarded their 110-foot research schooner, Tara, to sample microscopic plankton at 210 sites, and at depths of up to 2,000 metres, in all of the planet's major oceanic regions.

As plankton are very rarely capable of independent movement (and when they are it is only what is called diel vertical migration, in which a plankter may swim vertically towards (or away from) the surface) the location of plankton is primarily determined by environmental factors, such as the immediate concentration of ambient nutrients and, as they say, the motion of the ocean.

The multinational Tara Oceans consortium therefore had to travel around the world to get a decent sample of the critters.

Its work, explained in a short piece published in Science magazine today, involved not only science but also:

Outreach and education as well as negotiation through the shoals of legal and political regulations, funding uncertainties, threats from pirates, and unpredictable weather.

At various times, journalists, artists, and teachers were also on board. Visitors included Ban Ki-moon (Secretary-General of the United Nations) and numerous youngsters.

Their work dominates this issue of Science magazine, in which five Research Articles describe the samples, data, and analysis from their 87,000 mile trip — equivalent to more than three times the circumference of the planet.

Chris Bowler, a research director at France's National Center for Scientific Research, and one of the scientists involved in the study, said "Plankton are much more than just food for the whales. Although tiny, these organisms are a vital part of the Earth's life support system, providing half of the oxygen generated each year on Earth by photosynthesis and lying at the base of marine food chains on which all other ocean life depends."

The scientist's work culminated in conducting the largest DNA sequencing effort ever attempted in marine boffinry, and managed to pinpoint 40 million plankton genes, revealing an incredible genetic diversity amongst plankton — and an equally incredible homogeneity amongst marine viruses.

"Since the most numerous members of the plankton are bacteria, the majority of viruses in the ocean are thought to infect bacteria," University of Arizona oceanographer Jennifer Brum, another of the researchers, said.

"A good way of thinking about this is that there are roughly 200 million viruses in every mouthful of seawater, and most of those viruses are infecting the roughly 20 million bacteria found in every mouthful of seawater."

According to Science, among the resources the project has produced is "an ocean microbial reference gene catalog; a census of plankton diversity covering viruses, prokaryotes, and eukaryotes; and methodologies to explore interactions between them and their integration with environmental conditions. Although many more such analyses will follow, life in the ocean is already a little less murky than it was before." ®

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