Microbe Profiles: Tintinnids
Eukarya:Ciliophora:Spirotrichea:Choreotrichi:Ciliate
About Tintinnids
Tintinnids are ciliates that live in detachable, trumpet-shaped shells called loricae. This outer shell serves as protection and helps Tintinnids find food sources. Tintinnids without loricae have been shown to encounter food less often than those that are encased. Having a hard outer shell made of proteins and minerals also allows tintinnids to be preserved in the fossil record, which is a rare feat for ciliates.
Age
The first Tintinnid-like organisms appear in fossils from the Ordovician period, but they contain loricae made of calcite (chalk). Because modern Tintinnids have shells made largely of protein, most scientists believe that their official first appearance was in the Jurassic period (around 200 million years ago). Still, Tintinnids didn’t become abundant or common until the Cretaceous period.
Feeding and Die
Tintinnids feed with cilia-covered mouths. Their bodies are sparsely covered in these hairlike projections, but most cilia are concentrated around the mouthparts. In water, these whirring tentacles create a small current that sucks in food — usually diatoms, dinoflagellates, or other phytoplankton. Their mouths have the ability to reject larger prey, but tintinnids do not stalk or seek out their food. Instead, they locate food through random movement throughout their aquatic habitat.
Habitats
Tintinnids are aquatic heterotrophs — meaning they live in water and get their nutrients from organic matter. Tintinnids live in a diverse set of aquatic habitats — from freshwater and marine, to coastal and arctic. They are more common in saltwater where they can reach concentrations of thousands of individuals, sometimes of different species, in just a liter of water.
Species Diversity
There are around 1000 described species of Tintinnid. There can be multiple species of tintinnid in each given environment, and some of those species are environment-specific. In a locale, there may be dozens of different species, distinguishable by their shells.
Ecological Role
As primary producers, Tintinnids play an important role in marine ecosystems. Tintinnids feed on phytoplankton and are prey for copepods — tiny but prevalent crustaceans.
These tiny animals are the food of larger fish, which feed even larger fish, which can feed mammals on land. Ensuring that the smallest actors in the food chain remain in balance helps to maintain the health of aquatic ecosystems.
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Note: This information in this article can be found in the text, “The Biology and Ecology of Tintinnid Ciliates: Models for Marine Plankton.” Unfortunately, the book is not open access.
