Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Coexisting in a sea of competition


Similar diatom species seek out nutrients in different ways

Diversity of life abounds on Earth, and there's no need to look any farther than the ocean's surface for proof. There are over 200,000 species of phytoplankton alone, and all of those species of microscopic marine plants that form the base of the marine food web need the same basic resources to grow--light and nutrients.

The high diversity of phytoplankton has puzzled biological oceanographers for a long time. There are over 200,000 species of of these tiny marine plants that use sunlight and nutrients to grow and reproduce at the ocean's surface.


Courtesy of Samantha DeCuollo,University of Rhode Island

A study by a team of scientists from the Woods Hole Oceanographic Institution (WHOI), University of Rhode Island (URI), and Columbia University, published April 13 in the Proceedings of the National Academy of Sciences reveals how species of diatoms--one of the several major types of marine phytoplankton--use resources in different ways to coexist in the same community.

"The diversity of phytoplankton has puzzled biological oceanographers for a long time," says Harriet Alexander, the study's lead author and a graduate student in the MIT-WHOI Joint Program in Oceanography. "Why are there so many different species coexisting in this relatively stable environment, when they're competing for the same resources? Why hasn't a top competitor forced others into extinction?"

To try and answer those questions, Alexander and her colleagues used a novel approach combining new molecular and analytic tools to highlight how similar species utilize resources differently--known as niche partitioning--in Narragansett Bay, R.I.

"The phytoplankton of Narragansett Bay, which is a dynamic estuarine system, have been investigated on a weekly basis since the 1950's, giving us great insight into long term patterns of change," says Tatiana Rynearson, a coauthor and the director of the Narragansett Bay Plankton Time Series at URI. "This study uses that time series, but takes it in an entirely new direction, providing insights into the inner lives of phytoplankton."

Working with water samples collected in conjunction with surveys for the Plankton Time Series from the R/V Cap'n Bert, the research team extracted genetic material called ribonucleic acid (RNA) from the plankton in the bay. RNA sequencing, which was done at the Columbia University Genome Center, allowed the researchers to use the genetic information to determine what organisms were present and what they were doing.

The annotation of these RNA sequences via "pattern matching" was facilitated by the Gordon and Betty Moore Foundation's Marine Microbial Eukaryote Transcriptome Sequencing Project, which has sequenced the genetic material of more than 300 marine species.

In conjunction with the sequencing analysis, the research team developed a new bioinformatic approach that uses data from nutrient amendment experiments to help interpret signals from the environment.

"By adding nitrogen, we can get an idea of what these organisms look like and how they behave when they have plenty of nitrogen," explains Alexander. "Then we would also do the converse, by adding everything that they could possibly want except nitrogen. Creating these extremes in nutrient environment enabled the identification of known and novel molecular markers of nutrient condition for these organisms."

Using these data the researchers observed two species of chain-forming diatoms--Skeletonema spp. and Thalassiosira rotula--coexisting in the same parcel of water, but doing fundamentally different things with available nutrients, specifically nitrogen and phosphorus.

"Skeletonema was the dominant player during our sampling and goes after inorganic nitrogen sources, like nitrate and nitrite. As the less dominant player, Thalassiosira, is doing a lot of work bringing in nitrogen from organic sources, such as amino acids," Alexander says.

"We have long suspected that even closely related phytoplankton must have ways of distinguishing their needs from that of their neighbors, for example using different forms phosphorus or nitrogen, but this has been hard to track in the environment, as most approaches are not species-specific," adds Alexander's advisor and coauthor on the study, Sonya Dyhrman, an associate professor in the Department of Earth and Environmental Sciences at Columbia University.

"Part of the challenge is that you would need to track species-specific patterns in resource utilization to compare one diatom to another," adds Dyhrman. "In this study, a new database that is part of the MMETSP was leveraged to identify species-specific signals, and then Harriet developed a way to normalize those signals to be able to compare quantitatively between species."

Much like human genome sequencing is expanding our understanding of medicine, microbial genomics gives us new insights into how marine organisms function in the ocean and how they are influenced by environmental factors such as climate. The tools developed in this study, point the way to further work that examines how diverse populations of diatoms and other phytoplankton will respond to changing conditions in the future ocean.


This research was supported by the Department of Defense through the National Defense Science and Engineering Graduate Fellowship Program, and funds from the National Science Foundation Environmental Genomics and Biological Oceanography Programs, and the Joint Genome Institute/Department of Energy Community Sequencing Program. A grant to the National Center for Genome Resources for the MMETSP was provided by the Gordon and Betty Moore Foundation.

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 ocean and its interaction with the Earth as a whole, and to communicate a basic understanding of the ocean's role in the changing global environment. For more information, please visit

Media Contact

WHOI Media Relations Office


WHOI Media Relations Office | EurekAlert!

More articles from Earth Sciences:

nachricht Jacobs University supports new mapping of Mars, Mercury and the Moon
21.03.2018 | Jacobs University Bremen gGmbH

nachricht Thawing permafrost produces more methane than expected
20.03.2018 | GFZ GeoForschungsZentrum Potsdam, Helmholtz Centre

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Researchers at Fraunhofer monitor re-entry of Chinese space station Tiangong-1

In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.

Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...

Im Focus: Alliance „OLED Licht Forum“ – Key partner for OLED lighting solutions

Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.

They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...

Im Focus: Mars' oceans formed early, possibly aided by massive volcanic eruptions

Oceans formed before Tharsis and evolved together, shaping climate history of Mars

A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...

Im Focus: Tiny implants for cells are functional in vivo

For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.

In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...

Im Focus: Locomotion control with photopigments

Researchers from Göttingen University discover additional function of opsins

Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

International Tinnitus Conference of the Tinnitus Research Initiative in Regensburg

13.03.2018 | Event News

Latest News

TRAPPIST-1 planets provide clues to the nature of habitable worlds

21.03.2018 | Physics and Astronomy

The search for dark matter widens

21.03.2018 | Materials Sciences

Natural enemies reduce pesticide use

21.03.2018 | Life Sciences

Science & Research
Overview of more VideoLinks >>>