Marine Zooplankton

The Census of Marine Zooplankton (CMarZ), a project of the Census of Marine Life, aimed to identify and study the biodiversity of animal plankton around the world, including ~6,800 described species in fifteen phyla.

The comb jelly (ctenophore) Thalassocalyce inconstans was photographed in the Sargasso Sea by Census of Marine Zooplankton researchers.

Credit: L. Madin, Woods Hole Oceanographic Inst. (WHOI) (www.cmarz.org)

Holozooplankton (hereafter called "zooplankton") are small animals that drift in the ocean waves through their entire lives. As such, they are not very easy to count or even identify to species -- but that was the goal of CMarZ. The scientists working on the project aimed to study the species diversity, genetic diversity, geographic distribution and total biomass of zooplankton worldwide, focusing on the ~7,000 species that had previously been described.

The scientists focused on the deep sea, under-sampled regions (such as the waters of Southeast Asia), and biodiversity hotspots, identifying species based on both morphology and DNA barcoding. The scientists collected zooplankton at the deepest regions yet -- more than 16,000 feet (5,000 meters) -- and developed technology to perform DNA barcoding at sea.

Overall, these efforts produced the most comprehensive global view of zooplankton diversity, distribution, and abundance to date, including numbers of species and their biogeographical distributions, abundance, and genetic diversity, as well as an estimate of how much we don't yet know. This knowledge will provide a benchmark against which future changes resulting from climate change or other anthropogenic or natural variation can be measured, affected the study of ocean health, fisheries management, and the detection of introduced and invasive species.

Some of the project's achievements include:

  • CMarZ scientists carried out more than 90 cruises, collecting samples from every ocean basin at more than 12,000 stations.
  • Despite their efforts to study only known species, CMarZ researchers discovered 85 new species over the course of the Census of Marine Life. Of these, 47 new species in 7 new genera and 2 new families were formally described and published.
  • Images of more than 150 species of living zooplankton were prepared by CMarZ, which can be used by scientists for species identification, by educators to teach students about zooplankton diversity, and generally to increase public interest and appreciation for marine biodiversity.
  • "Gold-standard" DNA barcodes for at least 2,000 species (nearly 30%) of the ~7,000 described species of holozooplankton were identified by CMarZ researchers, with the help of collborating DNA barcoding centers. The growing DNA barcode database helps scientists identify the species of individual specimens faster and more accurately for individual specimens, and enable environmental sequencing of bulk samples for years to come.
  • CMarZ produced new deep-sea sampling technologies, including high-volume sampling below 5,000 meters for accurate sampling of rare zooplankton, and new aboard-ship analytical approaches, including DNA sequencing during oceanographic research cruises.
  • Related Video

    In a decade long project, which ended in October 2010, scientists with the Census of Marine Life traveled the world cataloging the ocean’s life forms. From...
    Caption: 

    Histioteuthis squid larva, collected in the Sargasso Sea.

    Credit: L. Madin, Woods Hole Oceanographic Inst. (WHOI) (www.cmarz.org)

    Want to see more photos of cool zooplankton collected by CMarZ? Check out the following galleries produced by the researchers:

    Photo Gallery

    Zooplankton Biodiversity

    This swimming snail is transparent and has shiny black eyes.

    More Information

    Census of Marine Zooplankton HomepageCMarZ at the Census of Marine Life

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