Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


River Mystery Solved

Scientists discover how "Didymo" algae bloom in pristine waters with few nutrients

The pristine state of unpolluted waterways may be their downfall, according to research results published in a paper this week in the journal Geophysical Research Letters.

A species of freshwater algae that lives in streams and rivers, called Didymo for Didymosphenia geminata, is able to colonize and dominate the bottoms of some of the world's cleanest waterways--precisely because they are so clear.

Didymo does so with a little help from its friends--in this case, bacteria--which allow it to make use of nutrients like phosphorus.

Blooms of Didymo, also known as "rock snot," says scientist P.V. Sundareshwar of the South Dakota School of Mines and Technology, are made up of stalks that form thick mats on the beds of oligotrophic, or low-nutrient, streams and rivers. Sundareshwar is the paper's lead author.

"In recent decades, human activities have led to many uncommon environmental phenomena," he says. "Now we have Didymo."

The freshwater diatom has become notorious. Didymo has taken over low-nutrient rivers in North America and Europe. It has also invaded water bodies in the Southern Hemisphere, including those in New Zealand and Chile.

Because its blooms alter food webs and have the potential to impact fisheries, "Didymo presents a threat to the ecosystem and economic health of these watercourses," says Sundareshwar.

Algae blooms are usually linked with the input of nutrients that fuel the growth of microscopic aquatic plants. Didymo's ability to grow prolifically in waters where nutrients such as phosphorus are in short supply puzzled scientists.

Environmental managers tried to mitigate Didymo blooms and predict their spread. But how the diatoms sustained such high growth in oligotrophic systems was unknown.

In a study funded by the National Science Foundation (NSF) and the State of South Dakota Carbon Scientist fund, Sundareshwar and colleagues revealed that Didymo is able to concentrate phosphorus from the water.

The scientists conducted their research in Rapid Creek, an unpolluted mountain stream in western South Dakota where Didymo was first observed in 2002. The creek regularly has Didymo blooms, with 30 to 100 percent of the streambed covered with Didymo over an area up to ten kilometers (6 miles) long.

Didymo thrives in Rapid Creek through biogeochemical processes in biofilms in the mats. As Didymo mats form, new stalks develop at the surface and older stalks--which have already bound phosphorus--are displaced to the mats' inner regions.

Phosphorus is available to Didymo thanks to the activity of the bacteria that live inside these mats.

"This study solves the puzzle of how Didymo can produce such large blooms in low-nutrient rivers and streams," says Tim Kratz, program director in NSF's Division of Environmental Biology.

"It has uncovered the fascinating mechanism by which Didymo ‘scrubs' phosphorus from a stream or river," says Kratz, "then creates a microenvironment that allows microbes to make this nutrient available for Didymo's growth."

The concentration of phosphorus on Didymo mats far exceeds the level expected based on the nutrient content of surface waters, says Sundareshwar.

"The ability of the mats to store phosphorus is tied to the availability of iron in the water."

Didymo cells adsorb, or condense on their surfaces, both iron and phosphorus. Then bacterial processes in the mat interact with iron to increase the biological availability of phosphorus.

The process results in abundant phosphorus for cell division, "and hence," says Sundareshwar, "a resolution to the paradox of Didymo blooms in oliogotrophic streams and rivers."

The result will help scientists and managers identify water bodies susceptible to Didymo blooms.

"It also has the potential to lead to discoveries that may stem this organism's prolific growth in rivers around the world," says Sundareshwar.

"This is how science is supposed to work--research conducted at one small creek in South Dakota can be translated to places across the globe."

Co-authors of the paper are S. Upadhayay, M. Abessa, S. Honomichl, C. Sandvik, and A. Trennepohl of the South Dakota School of Mines and Technology; B. Berdanier of South Dakota State University and A. Spaulding of the U.S. Geological Survey in Boulder, Colo.

Media Contacts
Cheryl Dybas, NSF (703) 292-7734
The National Science Foundation (NSF) is an independent federal agency that supports fundamental research and education across all fields of science and engineering. In fiscal year (FY) 2010, its budget is about $6.9 billion. NSF funds reach all 50 states through grants to nearly 2,000 universities and institutions. Each year, NSF receives over 45,000 competitive requests for funding, and makes over 11,500 new funding awards. NSF also awards over $400 million in professional and service contracts yearly.

Cheryl Dybas | EurekAlert!
Further information:

More articles from Earth Sciences:

nachricht Receding glaciers in Bolivia leave communities at risk
20.10.2016 | European Geosciences Union

nachricht UM researchers study vast carbon residue of ocean life
19.10.2016 | University of Miami Rosenstiel School of Marine & Atmospheric Science

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

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...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

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

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>