top of page
  • Writer's pictureAustin Pugh

Meet the Critters: Foraminifera

3 foramifiera skeletons laid in a row against a black background
Foraminifera skeletons Author: Siim Sepp (Sandatlas) licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.

Critter Fun Facts:

Foraminifera (sometimes called just "forams") are tiny single celled creatures with wither external or internal shells that support most of the ocean's food chains. These critters can range from sizes of less than 1mm up to 20cm (this small size allows the oceans to support lots of individuals). They are found all over the planet, in every ocean and in every marine habitat. Most adapted for living in the ocean, but some species have been reported to live in brackish (mix of salt and fresh) and even freshwater. Some species are planktonic, they float through the water column and collect detritus as food, however most species are benthic and lie in or on the sediment at the ocean floor. Their abundance and small size make foraminifera a vital part of ocean food webs as they take tiny organic detritus and introduce it back into the ecosystem when they are eaten by their predators like fish, snails, sand dollars, and even larger foraminifera.

Foraminifera have an extensive fossil record and can be used to measure conditions of past environments. Foraminifera have been used to show shifting of temperature and locate ancient shorelines. Foraminifera can also be used in biostratigraphy to help geologists distinguish relative age of layers of rock, and are used as indicator species in petroleum geology to find oil and gas. There are over 50,000 species recognized both live and fossilized.

Photomicrographs of 30 living planktonic foraminifera against a black background
Photomicrographs of living planktonic foraminifera. Scale bars are 200 µm. Authors: Haruka Takagi, Katsunori Kimoto, Tetsuichi Fujiki, Hiroaki Saito, Christiane Schmidt4 , Michal Kucera and Kazuyoshi Moriya5 (file is licensed under the Creative Commons Attribution-Share Alike 4.0 International license.)

OA Impact: Preliminary research indicates a negative affect on the survival of foraminifera under OA conditions, however this effect could also be attributed to other factors like temperature. More Canadian research is needed to understand the impacts that OA is having on Canadian foraminifera.

Diet: Detritus, other foraminifera, and anything smaller than them that they can digest.

Habitat: Every marine environment some pelagic (found in the upper water column) most benthic (living on the seafloor). Species have been reported from brackish water, and from freshwater

Predators: invertebrates, seabirds, other foraminifera, fish, and many more! These creatures are a major food source for marine animals all over the world!

Geographic Distribution: All oceans

Various species of foraminifera lie against the purple/blue background  of the slide with grains of sand surrounding them
Foraminifera under 300x magnification viewed with a Differential inference contrast optical microscopy technique Author: Doc. RNDr. Josef Reischig, CSc. from the archive of Joseld Reischig licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.

Linnaean Classification:

Kingdom: Chromista

Subkingdom: Harosa

Infrakingdom: Rhizaria

Phylum: Foraminifera

Etymology: (Latin) Hole bearers. This was given to them due to the holes that can be found when looking at the shells of some species up close as can be seen in the above images.

Past Names: None

Recent Posts

See All


bottom of page