Researchers have discovered amazing diversity among plankton, a group of microscopic plants, fish, and viruses responsible for a significant portion of the world’s oxygen and a favorite snack food of whales.
Though small, plankton serve an important part of the marine food chain while also supplying, via photosynthesis, half of the oxygen generated on Earth.
Despite appearing so simple and being so small, scientists have discovered a world of complexity beyond their wildest imaginations, courtesy of a multi-year operation known as the Tara Oceans project.
From 2009 to 2013, scientists aboard the French Schooner, Tara, took about 35,000 samples of plankton. These samples included bacteria, viruses, single-cell algae, fish larvae from major oceanic regions while collecting information about depth, temperature, and salinity of the waters they inhabited.
“This is the largest DNA sequencing effort ever done for ocean science: analyses revealed around 40 million genes, the vast majority of which are new to science, thus hinting towards a much broader biodiversity of plankton than previously known,” according to Patrick Wincker of the French National Sequencing Center, Genoscope.
“When we mapped how planktonic organisms — from viruses to small animal larvae — interact with each other, we discovered that most of those interactions are parasitic, recycling nutrients back down the food chain,” according to Jeroen Raes from the Flanders Institute for Biotechnology and Free University of Brussels.
Even viruses, usually thought of as nothing more than a nuisance by most people, were identified to have more than 5,000 viral populations in the upper areas of the world’s oceans.
“Surprisingly despite several decades of prior marine viral research, only 39 of these 5,000 viral populations were similar to previously known viruses,” according to Jennifer Brum from the University of Arizona.
This discovery “has generated a treasure trove of data available to anyone willing to dive in,” E. Virginia Armbrust of the University of Washington, Seattle and Stephen R. Palumbi of Stanford University said in an accompanying Perspective article in the Science journal.
“Together, these studies deliver compelling evidence for extensive networks of previously hidden biological interactions in the sea.” — AFP