The alga, called Didymo for Didymosphenia geminata, 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," are made up of stalks that form thick mats on the beds of oligotrophic (low-nutrient) streams and rivers, says scientist P.V. Sundareshwar of the South Dakota School of Mines and Technology in Rapid City. Sundareshwar is the lead author of the paper, published on 28 May in Geophysical Research Letters, a journal of the American Geophysical Union.
"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 oligotrophic 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 had puzzled scientists.
Environmental managers had tried to mitigate Didymo blooms and predict their spread. But how the diatoms sustained such high growth in oligotrophic systems was unknown.
In the study, 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 (6.2 miles) long.
Didymo thrives in Rapid Creek through biogeochemical processes in biofilms in the mats. As Didymo mats develop, 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 the National Science Foundation's (NSF) 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 that was expected based on the nutrient content of surface waters, says Sundareshwar. "The ability of the mats to store phosphorus is in turn tied to the availability of iron in the water."Didymo cells adsorb (collect 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 may help managers identify water bodies susceptible to Didymo blooms, and develop management strategies.
"It also has the potential to lead to discoveries that may stem this organism's prolific growth in rivers around in the world," says Sundareshwar.
This study was funded by NSF and the State of South Dakota Carbon Scientist fund.Notes for Journalists
Or, you may order a copy of the paper by emailing your request to Maria-Jose Vinas at email@example.com. Please provide your name, the name of your publication, and your phone number.
Neither this paper nor this press release are under embargo.Title:
Institute of Atmospheric Sciences, South Dakota School of Mines and Technology, Rapid City, South Dakota, USA;
B. Berdanier: Deparment of Civil and Environmental Engineering, South Dakota State University, Brookings, South Dakota, USA;
S. A. Spaulding: INSTAAR, U.S. Geological Survey, Boulder, Colorado, USA.Contact information for the author:
Maria-Jose Vinas | American Geophysical Union
World's first solar fuels reactor for night passes test
21.02.2018 | SolarPACES
Geophysicists and atmospheric scientists partner to track typhoons' seismic footprints
16.02.2018 | Princeton University
For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.
In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...
Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale
Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...
For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.
But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...
Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.
The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...
Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters
Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...
15.02.2018 | Event News
13.02.2018 | Event News
12.02.2018 | Event News
21.02.2018 | Life Sciences
21.02.2018 | Life Sciences
21.02.2018 | Materials Sciences