Before the Oligocene epoch some 33.6 million years ago, the Earth was a warm place with a tropical climate. In this region, plankton diversity was high until glaciation - the Antarctic continental ice cap - reduced the populations leaving only those capable of surviving in the new climate.
Since that time, we have had seasonal primary productivity of plankton communities. This ice-cap is associated with the ice-pack, the frozen part that disappears and reappears as a function of seasonal climate changes. This phenomenon, still active today, influences global food webs, according to a paper in Science which used information contained in ice sediments from different depths.
Pre-glaciation sediment contained highly varied dinoflagellate communities, with star-shaped morphologies. When the ice appeared 33.6 million years ago, this diversity was limited and their activity subjected to the new seasonal climate.
The Integrated Ocean Drilling Program international expedition has obtained this information from the paleoclimatic history preserved in sediment strata in the Antarctic depths. Andalusian Institute of Earth Sciences researcher Carlota Escutia, who led the expedition, explains that “the fossil record of dinoflagellate cyst communities reflects the substantial reduction and specialization of these species that took place when the ice cap became established and, with it, marked seasonal ice-pack formation and melting began.”
A typical, simple dinoflagellate associated with the early Oligocene epoch and found in 33 million year-old sediments. Credit: University of Granada
The article reports that when the ice-pack melts as the Antarctic summer approaches, this marks the increase in primary productivity of endemic plankton communities. When it melts, the ice frees the nutrients it has accumulated and these are used by the plankton. Dr Escutia says “this phenomenon influences the dynamics of global primary productivity”.
Since ice first expanded across Antarctica and caused the dinoflagellate communities to specialize, these species have been undergoing constant change and evolution. However, the IACT researcher thinks “the great change came when the species simplified their form and found they were forced to adapt to the new climatic conditions”.
Reference: Alexander J. P. Houben, Peter K. Bijl, Jörg Pross, Steven M. Bohaty, Sandra Passchier, Catherine E. Stickley, Ursula Röhl, Saiko Sugisaki, Lisa Tauxe, Tina van de Flierdt, Matthew Olney, Francesca Sangiorgi, Appy Sluijs, Carlota Escutia Henk Brinkhuis and the Expedition 318 Scientists. Reorganization of Southern Ocean Plankton Ecosystem at the Onset of Antarctic Glaciation. Science. DOI: 10.1126/science.1223646
- PHYSICAL SCIENCES
- EARTH SCIENCES
- LIFE SCIENCES
- SOCIAL SCIENCES
Subscribe to the newsletter
Stay in touch with the scientific world!
Know Science And Want To Write?
- How Gut Bacteria Ensure A Healthy Brain – and Could Play A Role In Treating Depression
- Researchers Created A Laser Bullet To See What It Would Look Like - And Here It Is
- The Strange Organic Molecules In Titan's Atmosphere
- We're Too Late To Prevent 137,000 More Ebola Cases, Says Epidemiology Paper
- The Quote Of The Week - Shocked And Disappointed
- Type 1 Diabetes Surges In White Kids
- It Takes More Than Singing To Strike A Chord In Music Education
- "I found the AMO/PDO charts to be very broad, and hard to tell (at least with the limited knowledge..."
- "I have dabbled with AMO and PDO, but it really needs to be more of a comparison to SST's, at which..."
- "The UN with it's small direct Ebola budget is hiring Ebola survivors to take care of sick kids..."
- "Ebola patients are sometimes thought of as Zombies returning from the dead. If one is low in fluids..."
- "In a universe of infinite realities, maybe there is one where homeopathy works. Just not in this..."
- Leftist dystopia? Anti-technology fever animates opposition to GMOs and other ‘disruptive’ technologies
- CDC faced a nearly impossible balancing act with Ebola, and failed
- Why Chobani reversed course, making yoghurt only from milk from cows not fed GMO grain
- Monterey, California, hotbed of anti-GMO activism, home to new GMO corn farm
- Evolution is sometimes messy or even outright ridiculous
- Rich and famous embrace Vandana Shiva, wealthy self-described savior of the poor