Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Coexisting in a sea of competition

14.04.2015

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.

Credit

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 http://www.whoi.edu.

Media Contact

WHOI Media Relations Office
media@whoi.edu
508-289-3340

 @WHOImedia

http://www.whoi.edu 

WHOI Media Relations Office | EurekAlert!

More articles from Earth Sciences:

nachricht Hundreds of bubble streams link biology, seismology off Washington's coast
22.03.2019 | University of Washington

nachricht Atmospheric scientists reveal the effect of sea-ice loss on Arctic warming
11.03.2019 | Institute of Atmospheric Physics, Chinese Academy of Sciences

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: The taming of the light screw

DESY and MPSD scientists create high-order harmonics from solids with controlled polarization states, taking advantage of both crystal symmetry and attosecond electronic dynamics. The newly demonstrated technique might find intriguing applications in petahertz electronics and for spectroscopic studies of novel quantum materials.

The nonlinear process of high-order harmonic generation (HHG) in gases is one of the cornerstones of attosecond science (an attosecond is a billionth of a...

Im Focus: Magnetic micro-boats

Nano- and microtechnology are promising candidates not only for medical applications such as drug delivery but also for the creation of little robots or flexible integrated sensors. Scientists from the Max Planck Institute for Polymer Research (MPI-P) have created magnetic microparticles, with a newly developed method, that could pave the way for building micro-motors or guiding drugs in the human body to a target, like a tumor. The preparation of such structures as well as their remote-control can be regulated using magnetic fields and therefore can find application in an array of domains.

The magnetic properties of a material control how this material responds to the presence of a magnetic field. Iron oxide is the main component of rust but also...

Im Focus: Self-healing coating made of corn starch makes small scratches disappear through heat

Due to the special arrangement of its molecules, a new coating made of corn starch is able to repair small scratches by itself through heat: The cross-linking via ring-shaped molecules makes the material mobile, so that it compensates for the scratches and these disappear again.

Superficial micro-scratches on the car body or on other high-gloss surfaces are harmless, but annoying. Especially in the luxury segment such surfaces are...

Im Focus: Stellar cartography

The Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT) in Arizona released its first image of the surface magnetic field of another star. In a paper in the European journal Astronomy & Astrophysics, the PEPSI team presents a Zeeman- Doppler-Image of the surface of the magnetically active star II Pegasi.

A special technique allows astronomers to resolve the surfaces of faraway stars. Those are otherwise only seen as point sources, even in the largest telescopes...

Im Focus: Heading towards a tsunami of light

Researchers at Chalmers University of Technology and the University of Gothenburg, Sweden, have proposed a way to create a completely new source of radiation. Ultra-intense light pulses consist of the motion of a single wave and can be described as a tsunami of light. The strong wave can be used to study interactions between matter and light in a unique way. Their research is now published in the scientific journal Physical Review Letters.

"This source of radiation lets us look at reality through a new angle - it is like twisting a mirror and discovering something completely different," says...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International Modelica Conference with 330 visitors from 21 countries at OTH Regensburg

11.03.2019 | Event News

Selection Completed: 580 Young Scientists from 88 Countries at the Lindau Nobel Laureate Meeting

01.03.2019 | Event News

LightMAT 2019 – 3rd International Conference on Light Materials – Science and Technology

28.02.2019 | Event News

 
Latest News

Solving the efficiency of Gram-negative bacteria

22.03.2019 | Life Sciences

Bacteria bide their time when antibiotics attack

22.03.2019 | Life Sciences

Open source software helps researchers extract key insights from huge sensor datasets

22.03.2019 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>