Phytoplankton may be surprisingly resilient to nutrient stress

An international team of scientists led by UC Irvine (UCI) has created the first high-resolution global map of surface ocean phosphate, a mineral that is key in supporting the marine food chain. Based on their research, the experts discovered that phytoplankton are much more resilient to nutrient stress than previously thought.

Considering that ocean algae absorb a significant amount of carbon dioxide from the atmosphere, the findings have important implications for climate change predictions.

Study lead author Adam Martiny is a professor of Earth System Science and Ecology and Evolutionary Biology at UCI.

“Understanding the global distribution of ocean nutrients is fundamental to identifying the link between changes in ocean physics and ocean biology,” explained Professor Martiny. “One of the outcomes of having this map is that we can show that plankton communities are extremely resilient even in nutrient-deficient environments.”

“As lower ocean nutrient availability is one of the predicted outcomes of climate change, this may be good news for plankton, and for us.”

Dissolved inorganic phosphate plays an important role in the ocean habitat, but it is notoriously difficult to detect. Unlike many of the other nutrients that are used by phytoplankton for survival, the amount of phosphorus is limited on our planet and it is rare in the ocean. 

By understanding how much phosphorus is available and where, scientists can better predict how the dynamics of the ocean food web will be chemically altered by climate change. To investigate, the UCI team analyzed more than 50,500 seawater samples collected on 42 research voyages covering all of Earth’s ocean basins.

Professor Martiny said that in addition to identifying regions where the mineral is in short supply, the team was also able to discover previously unknown patterns of phosphate levels in major ocean basins in the Atlantic and Pacific.

“We have for too long had this simplistic view of a nutrient-rich ocean at high latitudes and ocean deserts at low latitudes,” noted Professor Martiny. “However, in this paper we argue that our current predictions of nutrient stress may be too dire and marine organisms are able to handle a limited supply of phosphate better than we previously thought.”

The study is published in the journal Science Advances.

—

By Chrissy Sexton, Earth.com Staff Writer

Image Credit: Shutterstock/Elovich