Underwater Universe Uncovered With Completion Of First Global Atlas Of Marine Plankton

The first ever global atlas of marine plankton — cataloging the wheres, whens, and hows of the world’s oceanic plankton populations — has now completed thanks to an international collaboration between many of the world’s premier marine research centers.

"The MAREDAT atlas catalogues marine plankton including single-celled animals, foraminifera." Image Credit: Ralf Schiebel, Universite d'Angers
“The MAREDAT atlas catalogues marine plankton including single-celled animals, foraminifera.”
Image Credit: Ralf Schiebel, Universite d’Angers

When seen under the microscope — the microscopic organisms that are present in the world’s oceans in near infinite seeming numbers — can look quite strange, even alien, as compared to the world that humans are used to seeing. While most people go through their lives without ever actually being consciously aware of these organisms, they exert an enormous influence on the ecosystems of the world, and even on the environment — but despite their ecological importance there is still much that remains unknown about them. That’s where the new atlas and research comes in.

The atlas — the Marine Ecosystem Biomass Data (MAREDAT) — is the first step “towards a comprehensive inventory of the marine biota based on counts of individual cells or organisms. It will help researchers better understand marine biodiversity for conservation and monitoring.

“One of the more surprising findings from the study is that phytoplankton and zooplankton biomass are roughly the same size in the upper ocean. Compare that to more familiar land ecosystems where the biomass of plants greatly exceeds that of animals and it’s pretty illuminating,” states WHOI Senior Scientist and Marine Chemist Scott Doney, a collaborator on the project.

So far, “it has catalogued about half a million measurements of plankton biomass, which are subdivided into 12 broad plankton groups. Each group has a separate database.”

“The data and documentation can be downloaded by any researcher so that they can explore their own scientific questions,” Doney states. “Over time we hope to grow the database by adding other historical and newly collected data for plankton groups already in the database as well as extend into different plankton groups.”

"Marine plankton diatom, Chaetoceros decipiens, is catalogued in the MAREDAT atlas." Image Credit: Karine Leblanc, Mediterranean Institute of Oceanography
“Marine plankton diatom, Chaetoceros decipiens, is catalogued in the MAREDAT atlas.”
Image Credit: Karine Leblanc, Mediterranean Institute of Oceanography

The Woods Hole Oceanographic Institution continues:

One group of microorganisms Doney and his colleague Yawei Luo have focused on cataloguing in MAREDAT is marine nitrogen-fixing bacteria called “diazotrophs.” These unique microbes can literally make the nutrients they need for growth out of thin air, or at least from dissolved nitrogen gas. They play an essential role in subtropical ocean gyres providing a source of nitrogen in the otherwise nutrient-poor surface waters. The nitrogen fixation rates and diazotroph cell counts are being used to study the environmental conditions that determine nitrogen fixation and diazotroph community structure.


Working with more than 45 other scientists from WHOI and around the world, Luo and Doney built the first-ever global dataset on nitrogen-fixers by collecting data from historical scientific literature and existing databases. The past decade has seen a virtual explosion in new ocean field data on marine nitrogen-fixers spanning a wide range of taxonomic groups including free-living cells and filamentous organisms as well as symbiotic organisms that live inside other plankton. Luo and Doney study ocean microbes as part of the Center for Microbial Oceanography, Research, and Education (C-MORE), a National Science Foundation Science and Technology Center based at the University of Hawaii.


The first edition of the MAREDAT global plankton atlas took three years to compile and combines information from half a million data points. The data will have a wide-range of application across ocean and climate science including helping scientists create computer models to predict the impact of climate change and ocean acidification.

The research was a collaboration between scientists at the Woods Hole Oceanographic Institution (WHOI), the University of East Anglia, ETH Zurich, University of Manchester, Université d’Angers and CNRS, the US National Oceanic and Atmospheric Administration (NOAA), and a variety of other scientific institutions around the globe.

The atlas was just published in a special issue of the journal Earth System Science Data.

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