A $1.3 million grant from the Gordon and Betty Moore Foundation will allow UGA researchers to uncover answers about an important metabolic link that takes place in the Earth’s oceans.
Microorganisms in the largest microbial habitat on Earth, the ocean microbiome, function similarly to microorganisms in the human gut; they perform chemical transformations that keep the whole system healthy.
Phytoplankton, the microbial primary producers of the ocean, take up carbon dioxide and provide the building blocks for all marine life, while bacteria use these building blocks to direct the carbon to different functions in the ocean.
The billions of marine microorganisms present in every liter of seawater represent a structured ecological community that regulates how the Earth functions, from energy consumption to respiration, and including the operation of carbon and nitrogen cycles. However, the precise metabolic links between phytoplankton and bacteria have proven difficult to analyze.
Now, thanks to the Moore Foundation grant, UGA researchers are working to uncover the details of these metabolic transformations to assess the rates at which metabolites move between microbial primary producers and consumers in the surface ocean.
“The flux of key phytoplankton-derived metabolites into other marine organisms is the foundation of ocean biology,” said Mary Ann Moran, Distinguished Research Professor of Marine Sciences in the Franklin College of Arts and Sciences and principal investigator on the grant. “We’re looking at the step after marine phytoplankton use CO2 to create the building blocks: How fast are specific metabolites released from these primary producers cycled by bacteria?”
The importance of carbon cycling on Earth is clear, but understanding how carbon is obtained by bacteria, sustains bacterial growth and respiration, and connects the various microbial communities of the ocean has proven surprisingly elusive. How much carbon gets stored in the ocean and what sets that amount is also difficult to quantify because of the challenging chemistry involved and the fact that current techniques are hindered by the presence of salt in seawater.
“Half of the carbon fixation on Earth is carried out by marine phytoplankton, and half of that gets released to bacteria. So for a full quarter of the world’s total photosynthesis, we are missing information about how metabolites are transformed at the earliest stages,” said Arthur Edison, Georgia Research Alliance Eminent Scholar in the Franklin College department of biochemistry and molecular biology, department of genetics, Institute of Bioinformatics and Complex Carbohydrate Research Center.
The UGA team designed a research plan that tracks chemicals of interest into bacterial cells, requiring a combination of new technologies and recent innovations in conventional spectroscopy.
“But the game changer that will really give us a sensitive signal is called dissolution dynamic nuclear polarization,” Edison said. “This tool, plus a lot of patience in the lab, will allow us to see one molecule change into another, change into another, change into another, as long as the signal lasts.”
