A team of researchers from the University of California, Irvine (UCI) has traveled the world to monitor oceans to assess the waters' conditions based on changes in plankton genomes.
The UCI team analyzed gains and losses in the genetic structure of phytoplankton samples gathered in the world's major ocean regions such as the Atlantic, Pacific, and Indian oceans. Data gathered in these locations were then used to generate a high-resolution map that shows where these phytoplankton populations could thrive, and where they are forced to survive with scarce amounts of nutrients like nitrogen, iron, and phosphorus.
Researchers published their findings in the journal Science, in the article "Metagenomic analysis reveals global-scale patterns of ocean nutrient limitation," April 15.
Part of the Bio-GO-SHIP Initiative
UCI researchers made eight deployments across six different research vessels, spending a total of 228 days at sea. The new study was a part of the Global Ocean Ship-Based Hydrographic Investigations Program (GO-SHIP), which is a collaborative effort among researchers of different fields to "develop a globally coordinated network of sustained hydrographic sections."
Following their deployment, researchers were able to collect almost 1,000 ocean genome samples - particularly from the phytoplankton species "Prochlorococcus" - which they used as an indicator of ocean health and productivity.
The oceanographers in the team aim to understand how these photosynthetic algae adapt to "nutrient stress," or the difficulty in securing essential nutrients phytoplankton needs to grow and reproduce.
"Phytoplankton are foundational to the marine food web, and they are responsible for as much as half of global carbon dioxide fixation on an ongoing basis, so the health and distribution of these organisms is very important," said Adam Martiny, senior co-author of the paper and a professor of Earth system science at UCI, in a news release from the university.
He adds that the knowledge they gained from these ocean studies will help climatologists make "more sound predictions" about the role of phytoplankton in regulating the carbon levels in the ocean and in the atmosphere.
Researchers explain that since phytoplankton are usually found in large populations and have rapid life cycles, changes in their community composition and genetic makeup could offer insights into environmental conditions at an even faster rate compared to existing methods of ocean physics and chemistry analysis.
Phytoplankton Genetic Component for Ocean Water Analysis
Researchers noted that the Prochlorococcus genome contains a specific component that allows them to directly assimilate inorganic phosphate abundant in seawater. However, when this phosphate is in extremely low amounts, phytoplankton adapts by developing a gene that allows them to consume dissolved organic phosphorus instead. This adaptive gene was observed by researchers in the genomes of the collected phytoplankton.
The study also covered other genome adaptations for varying levels of nutrients in the environment to examine the trade-offs made by the phytoplankton to survive. It resulted in a global map that captures cases of nutrient stress to different populations, including regions where phytoplankton experiences co-stress between two or more elements - with one of these elements most often being nitrogen.
Check out more news and information on Planktons in Science Times.
