Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists Discover Huge Phytoplankton Bloom in Ice Covered Waters

08.06.2012
A team of researchers, including scientists from Woods Hole Oceanographic Institution (WHOI), discovered a massive bloom of phytoplankton beneath ice-covered Arctic waters. Until now, sea ice was thought to block sunlight and limit the growth of microscopic marine plants living under the ice.
The amount of phytoplankton growing in this under-ice bloom was four times greater than the amount found in neighboring ice-free waters. The bloom extended laterally more than 100 kilometers (62 miles) underneath the ice pack, where ocean and ice physics combined to create a phenomenon that scientists had never seen before.

The study, published June 8 in the journal Science, concluded that ice melting in summer forms pools of water that act like transient skylights and magnifying lenses. These pools focused sunlight through the ice and into waters above the continental shelf north of Alaska, where currents steer nutrient-rich deep waters up toward the surface. Phytoplankton under the ice were primed to take advantage of this narrow window of light and nutrients.

“Way more production is happening under the ice than we previously thought, in a manner that’s very different than we expected,” said WHOI biologist Sam Laney, who was part of the multi-institutional team led by Kevin Arrigo of Stanford University.

Just as a rainstorm in the desert can cause the landscape to explode with wildflowers, this research shows that events like pooling melt water can happen on very short timescales in the Arctic yet have major effects on the ecosystem.

“If you don’t catch these ephemeral events, you’re missing a big part of the picture,” Laney said.

The unexpected discovery occurred during a 2011 expedition aboard the U.S. Coast Guard icebreaker Healy. It was part of the NASA-funded ICESCAPE program to investigate the impact of climate change in the polar Chukchi and Beaufort seas.

The scientists found themselves in the right place at the right time in early July of 2011, as the Healy made its way above the Arctic Circle and into year-old ice. Atop the meter-thick ice, pools of sky-blue melt water were accumulating as the Arctic summer progressed.

Researchers expected that, as in years past, the waters beneath the ice would have minimal amounts of chlorophyll—the fluorescing hallmark of photosynthetic marine plants. Instead, they observed the opposite. As the ship broke further into the ice, chlorophyll in the dark waters below shot up to levels rarely observed even in the most productive ocean regions. It became evident that there was a phytoplankton bloom of astonishing magnitude happening under the ice. Optical measurements showed that four times as much light penetrated ice covered by meltwater ponds than ice covered by snow.

“Although the under-ice light field was less intense than in ice-free waters, it was sufficient to support the blooms of under-ice phytoplankton, which grew twice as fast at low light as their open ocean counterparts,” the study notes.

The ship conducted transects into the ice pack to determine how far and deep the bloom extended. Measurements of biomass showed the largest part of the bloom occurred far away from the open ocean, under thick ice and close to water upwelling at the continental shelf break, where the shallow coastal shelf plunges steeply into deeper water.

Another member of the ICESCAPE team, WHOI physical oceanographer Bob Pickart showed that easterly winds churned out by monster storm systems along the Aleutian Islands can reverse the current along the shelf break. The change in circulation drives cold, nutrient-rich water up from the abyss and refreshes the supply of nutrients available to phytoplankton growing near the surface.

“Without a doubt the bloom was enhanced at the shelf break,” Pickart said.

As the melt pools introduced light through the ice, phytoplankton in shelf break waters likely experienced something akin to an all-you-can-eat buffet.

What types of organisms participated in the bloom? Laney caught them on camera with an instrument he had brought to sea—the Imaging FlowCytobot, an automated microscopic imaging system invented at WHOI and built by Laney and co-developer Dr. Rob Olson.

Since their return, Laney and MIT/WHOI Joint Program graduate student Emily Brownlee have been working with the Imaging FlowCytobot’s other co-developer and ICESCAPE team member, WHOI biologist Heidi Sosik, to sort through and classify organisms in the millions of images collected by the instrument and unravel intricacies of the under-ice bloom. The images showed that the bloom was not caused by fallout from algae growing on the ice, but rather it contained different organisms that seized the confluence of currents, light, and nutrients.

The Imaging FlowCytobot offers tantalizing insights into the microbial dynamics and food web of this dramatic Arctic algal boom. For example, the images consistently showed some phytoplankton in the bloom in a half-munched state, offering clues to the planktonic grazers that might be eating them.

Discovering the under-ice bloom “was very serendipitous,” Pickart said, but the difficulty of exploring the harsh, remote region also leaves it wide open for surprises.

The Woods Hole Oceanographic Institution is a private, non-profit organization on Cape Cod, Mass., dedicated to marine research, engineering, and higher education. Established in 1930 on a recommendation from the National Academy of Sciences, its primary mission is to understand the oceans and their interaction with the Earth as a whole, and to communicate a basic understanding of the oceans’ role in the changing global environment. For more information, please visit www.whoi.edu.

Originally published: June 7, 2012

WHOI Media Relations Office | EurekAlert!
Further information:
http://www.whoi.edu/main/news-releases?tid=3622&cid=139069

More articles from Ecology, The Environment and Conservation:

nachricht Preservation of floodplains is flood protection
27.09.2017 | Technische Universität München

nachricht Conservationists are sounding the alarm: parrots much more threatened than assumed
15.09.2017 | Justus-Liebig-Universität Gießen

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: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Terahertz spectroscopy goes nano

20.10.2017 | Information Technology

Strange but true: Turning a material upside down can sometimes make it softer

20.10.2017 | Materials Sciences

NRL clarifies valley polarization for electronic and optoelectronic technologies

20.10.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>