Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Newly discovered group of algae live in both fresh water and ocean

21.01.2011
... may have worldwide distribution

A team of biologists has discovered an entirely new group of algae living in a wide variety of marine and freshwater environments. This group of algae, which the researchers dubbed "rappemonads," have DNA that is distinctly different from that of other known algae.


A collection of rappemonad cells photographed by a high-powered microscope. Each cell contains at least two chloroplasts (green dots) and a nucleus (blue dots). Images: from Kim, Harrison, Sudek et al. PNAS 2010

In fact, humans and mushrooms are more closely related to each other than rappemonads are to some other common algae (such as green algae). Based on their DNA analysis, the researchers believe that they have discovered not just a new species or genus, but a potentially large and novel group of microorganisms.

The rappemonads were found in a wide range of habitats, in both fresh and salt water, and at temperatures ranging from 52 degrees to 79 degrees Fahrenheit. According to MBARI Senior Research Technician Sebastian Sudek, co-first-author of the paper reporting the discovery of these algae, “Based on the evidence so far, I think it's fair to say that rappemonads are likely to be found throughout many of the world's oceans. We don't know how common they are in fresh water, but our samples were not from unusual sources—they were from small lakes and reservoirs.”

Researchers Sebastian Sudek, Heather Wilcox, and Alexandra Worden of the Monterey Bay Aquarium Research Institute (MBARI), along with collaborators at Dalhousie University and the Natural History Museum (NHM), London, discovered these microscopic algae by following up on an unexpected DNA sequence listed in a research paper from the late 1990s. They named the newly identified group of algae “rappemonads” after Michael Rappé, a professor at the University of Hawaii who was first author of that paper.

Following up on their initial lead, the research team developed two different DNA “probes” that were designed to detect the unusual DNA sequences reported by Rappé. Using these new probes, the researchers analyzed samples collected by Worden’s group from the Northeast Pacific Ocean, the North Atlantic, the Sargasso Sea, and the Florida Straits, as well as samples collected from several freshwater sites by co-author Thomas Richards' group at NHM. To the teams’ surprise, they discovered evidence of microscopic organisms containing the unusual DNA sequence at all five locations.

Although the rappemonads were fairly sparse in many of the samples, they appear to become quite abundant under certain conditions. For example, water samples taken from the Sargasso Sea near Bermuda in late winter appeared to have relatively high concentrations of rappemonads.

When asked why these apparently widespread algae had not been detected sooner, Sudek speculates that it may in part be due to their size. “They are too small to be noticed by people who study bigger algae such as diatoms, yet they may be filtered out by researchers who study the really small algae, known as picoplankton.”

Sudek says, “The rappemonads are just one of many microbes that we know nothing about—this makes it an exciting field in which to work.” Worden, in whose lab the research was conducted, and who first noticed the unique sequence in the 1990 paper, then initiated research to "chase down" the story behind that sequence, continues, “Right now we treat all algae as being very similar. It is as if we combined everything from mice up to humans and considered them all to have the same behaviors and influence on ecosystems. Clearly mice and humans have different behaviors and different impacts!”

Even though DNA analysis demonstrated that rappemonads were present in their water samples, the researchers were still unable to visualize the tiny organisms because they didn't know what physical characteristics to look for. However, by attaching fluorescent compounds to the newly developed DNA probes, and then applying these probes to intact algae cells, Eunsoo Kim at Dalhousie was able to make parts of the rappemonads glow with a greenish light. This allowed the researchers to see individual rappemonads under a microscope.

The greenish glow highlighted the rappemonad’s “chloroplasts,” which contain the unique DNA sequence tagged by the new probes. Chloroplasts are used by plants and algae to harvest energy from sunlight in a process called photosynthesis. Because all of the rappemonads contain chloroplasts, the researchers believe they “make a living” through photosynthesis. However, Worden points out that it still needs to be shown that the chloroplasts are functional.

One of the primary goals of Worden’s research is to study marine algae in the context of their environment. Worden feels that such an approach is imperative to understanding how rappemonads and other microorganisms affect large-scale processes in the ocean and in the atmosphere. In coming years her lab will be building upon their recent insights, including the discovery of the rappemonads, to study the roles that different algal groups play in the cycling of carbon dioxide between the atmosphere and the ocean.

Worden says, “There is a tremendous urgency in gaining an understanding of biogeochemical cycles. Marine algae are key players in these cycles, taking up carbon dioxide from the atmosphere and releasing oxygen, which we breathe. Until we have a true census of marine algae and understanding of how each group thrives, it will be very difficult to model global biogeochemical cycles. Such modeling is essential for predicting how climate change will impact life on earth.”

For additional information or images relating to this news release, please contact:

Kim Fulton-Bennett: (831) 775-1835, kfb@mbari.org

Research paper:

E. Kim, J.W. Harrison, S. Sudek, M.D.M. Jones, H.M. Wilcox, T.A. Richards, A.Z. Worden, J.M. Archibald, Newly identified and diverse plastid-bearing branch on the eukaryotic tree of life. Proceedings of the National Academy of Sciences (PNAS), DOI: 10.1073/pnas.1013337108.

Kim Fulton-Bennett | EurekAlert!
Further information:
http://www.mbari.org
http://www.mbari.org/news/news_releases/2011/rappemonads/rappemonads-release.html

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

Electrode materials from the microwave oven

19.10.2017 | Materials Sciences

New material for digital memories of the future

19.10.2017 | Materials Sciences

Physics boosts artificial intelligence methods

19.10.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>