Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Disappearance of Coral Reefs, Drastically Altered Marine Food Web on the Horizon

If current climate trends follow historical precedent, ocean ecosystems will be in state of flux for next 10,000 years, according to Scripps Oceanography researchers

If history’s closest analog is any indication, the look of the oceans will change drastically in the future as the coming greenhouse world alters marine food webs and gives certain species advantages over others.

Coral Gardens: A school of surgeonfish cruise coral reefs near Palmyra Atoll.

Scripps Institution of Oceanography, UC San Diego, paleobiologist Richard Norris and colleagues show that the ancient greenhouse world had few large reefs, a poorly oxygenated ocean, tropical surface waters like a hot tub, and food webs that did not sustain the abundance of large sharks, whales, seabirds, and seals of the modern ocean. Aspects of this greenhouse ocean could reappear in the future if greenhouse gases continue to rise at current accelerating rates.

The researchers base their projections on what is known about the “greenhouse world” of 50 million years ago when levels of greenhouse gases in the atmosphere were much higher than those that have been present during human history. Their review article appears in an Aug. 2 special edition of the journal Science titled “Natural Systems in Changing Climates.”

For the past million years, atmospheric CO2 concentrations have never exceeded 280 parts per million, but industrialization, forest clearing, agriculture, and other human activities have rapidly increased concentrations of CO2 and other gases known to create a “greenhouse” effect that traps heat in the atmosphere. For several days in May 2013, CO2 levels exceeded 400 parts per million for the first time in human history and that milestone could be left well behind in the next decades. At its current pace, Earth could recreate the CO2 content of the atmosphere in the greenhouse world in just 80 years.

In the greenhouse world, fossils indicate that CO2 concentrations reached 800-1,000 parts per million. Tropical ocean temperatures reached 35º C (95º F), and the polar oceans reached 12°C (53°F)—similar to current ocean temperatures offshore San Francisco. There were no polar ice sheets. Scientists have identified a “reef gap” between 42 and 57 million years ago in which complex coral reefs largely disappeared and the seabed was dominated by piles of pebble-like single-celled organisms called foraminifera.

“The ‘rainforests-of-the-sea’ reefs were replaced by the ‘gravel parking lots’ of the greenhouse world,” said Norris.

Changing marine life characteristics: Comparison of present, past, and future ocean ecosystemstates. Click on image for larger view. Image courtesy of Science

The greenhouse world was also marked by differences in the ocean food web with large parts of the tropical and subtropical ocean ecosystems supported by minute picoplankton instead of the larger diatoms typically found in highly productive ecosystems today. Indeed, large marine animals—sharks, tunas, whales, seals, even seabirds—mostly became abundant when algae became large enough to support top predators in the cold oceans of recent geologic times.

“The tiny algae of the greenhouse world were just too small to support big animals,” said Norris. “It’s like trying to keep lions happy on mice instead of antelope; lions can’t get by on only tiny snacks.”

Within the greenhouse world, there were rapid warming events that resemble our projected future. One well-studied event is known as the Paleocene-Eocene Thermal Maximum (PETM) 56 million years ago, which serves as a guide to predicting what may happen under current climate trends.

That event lasted about 200,000 years and warmed the earth by 5-9° C (9-16° F) with massive migrations of animals and plants and shifts in climate zones. Notably, despite the disruption to Earth’s ecosystems, the extinction of species was remarkably light, other than a mass extinction in the rapidly warming deep ocean.

“In many respects the PETM warmed the world more than we project for future climate change, so it should come as some comfort that extinctions were mostly limited to the deep sea,” said Norris. “Unfortunately, the PETM also shows that ecological disruption can last tens of thousands of years.”

Indeed, Norris added that continuing the fossil fuel economy even for decades magnifies the period of climate instability. An abrupt halt to fossil fuel use at current levels would limit the period of future climate instability to less than 1,000 years before climate largely returns to pre-industrial norms. But, if fossil fuel use stays on its current trajectory until the end of this century, then the climate effects begin to resemble those of the PETM, with major ecological changes lasting for 20,000 years or more and a recognizable human “fingerprint” on Earth’s climate lasting for 100,000 years.

Co-authors of the review are Sandra Kirtland-Turner of Scripps Oceanography, Pincelli Hull of Yale University, and Andy Ridgwell of the University of Bristol in the United Kingdom.

Robert Monroe | EurekAlert!
Further information:

More articles from Ecology, The Environment and Conservation:

nachricht Invasive Insects Cost the World Billions Per Year
04.10.2016 | University of Adelaide

nachricht Malaysia's unique freshwater mussels in danger
27.09.2016 | The University of Nottingham Malaysia Campus

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

First-time reconstruction of infectious bat influenza viruses

25.10.2016 | Life Sciences

Novel method to benchmark and improve the performance of protein measumeasurement techniques

25.10.2016 | Life Sciences

Amazon rain helps make more rain

25.10.2016 | Life Sciences

More VideoLinks >>>