Other than outer space, the Earth’s oceans may very well be one of the last unexplored frontiers. In fact, we know more about the moon and our solar system than what all lies beneath the waves. However, our knowledge is slowly expanding thanks to new advances in science and technology. On May 22nd, a special article in Science Magazine released the amazing discoveries and findings of a six year study surveying micro-organisms found in oceanic waters all around the world.
In 2009, a research schooner called, “The Tara” began to sail the Earth’s seas while collecting water samples for the next three years. Marine Scientists then spent three more years studying and analyzing those water samples and what they discovered hiding between molecules of H2O. The results? A massive, hidden galaxy of microscopic creatures that has opened our eyes to the amazing biodiversity contained within all marine ecosystems. In fact, it took a team of 160 scientists from various disciplines to organize and publish the results of this study!
From the larvae of fish to single-celled algae, members of the Tara expedition collected, “over 35,000 samples of water containing micro-organisms from 200 marine stations up to depths of 3.280 feet over a period of 1, 140 days.”
Using the latest technology in genetics from the European Molecular Biology Laboratory (EMBL) and the French National Centre for Scientific Research (CNRS), the Tara team was able to collect, analyze and compile genetic material from the collected micro-organisms into a massive DNA database. This database is the largest ever created in the field of marine research. A whopping 40 million different genes were discovered in the database indication that the biodiversity of plankton and other marine micro-organisms is much larger than previously thought. This, in turn, revealed 150,000 genetic types.
One finding of the survey that was quite unexpected was the astronomical diversity of single-celled marine eukaryotes. Eukaryotes are micro-organisms that contain special organelles bound by a membrane within their physical make-up. These organelles act as cellular sub-units with special functions and jobs within the eukaryote. The Tara expedition was able to sequence the genetic bar codes of nearly a billion single-celled eukaryotes! This has led to the conclusion that there is more eukaryotic biodiversity than that which is found in plankton, bacteria or other animals!
Now you may be wondering why there is so much hype over organisms that can’t even be seen with the naked eye. Even though they may seem insignificant, marine plankton and micro-organisms make up for most of the biomass, or total mass of living organisms, within the world’s oceans. “For each milliliter of seawater, micro-organisms account for about 10,000 to one million cells.” Just like other animals, these creatures come together and form various communities. However, these communities can be affected and dependent on various factors such as water depth, temperature and level of sunlight for their food and survival. For instance, Zoo-plankton (plankton that feed on other micro-organisms) are dependent on using ocean currents to rise close to the ocean surface where it is warmer and more food is available for them to consume.
An example of how non-living forces impact micro-organism communities is seen in the phenomenon known as Agulhas rings. The Agulhas current, located in the southwestern Indian Ocean, creates huge rings or swirls that rotate counter-clockwise. These swirls break off from the Agulhas current off of the tip of South Africa and drift across the South Atlantic ocean creating barriers between communities of plankton. These rings are so large, they can be seen from space!
The complexity and nature of marine micro-organism communities is still poorly understood. However, the Tara expedition has opened a window into this tiny but significant universe. The types of species found in the micro world plus how those species interact with each other and their environment will give insight into the greater issues of climate change that has been observed in more recent decades. And who knows? The discoveries of the Tara expedition may even allow us to figure out how to lessen the negative future impacts of climate change on the world’s oceans. Big things do indeed come in little packages!
1. Starr, Michelle. “Hidden life of the Ocean revealed in New Giant Survey.” Cnet. http://www.cnet.com/news/hidden-life-of-the-ocean-revealed-in-new-giant-survey/. 25 May, 2015, Accessed 27 May, 2015.
1. Peijnenberg and Goetze 2013 (Ecology and Evolution)
3. Dr. Richard Kirby (Royal Society/BNPS)