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<\/a>artistic rendering of tiarina fusus’ movement, grazing behavior, and metabolic process<\/p><\/div>\n
Taxonomy<\/h4>\n
Eukaryota<\/em><\/p>\n Kingdom: Chromista<\/em><\/p>\n Phylum: Ciliophora<\/em><\/p>\n Class: Ciliatea<\/em><\/p>\n Order: Gymnostomatida<\/em><\/p>\n Family: Colepidae<\/em><\/p>\n Genus: Tiarina<\/em><\/p>\n Species: fusus<\/em><\/p>\n The Tiarina fusus<\/em> is a prostomatid ciliate zooplankton known for its abundant populations during the occurance of red tides. \u00a0While it is not the cause of red tides, it appears to prey on the various dinoflagelletes that are responsible for the phenomenon.\u00a0 T. fusus<\/em> is a common zooplankton that appears in pelagic coastal regions in all parts of the world.\u00a0 The species does not have a common name besides its scientific name, and it is generally referred to simply as a ciliate from its class Ciliatea.\u00a0 Cilia are organelles with hairlike structures that serve a motile function for cilliates.\u00a0 The ciliates are a group of heterotrophic protozoans, unicellular eukaryotes whose famous characteristic is its cilia that are primarily utilized in its interactions with the world around the organism.\u00a0 In T. fusus<\/em>\u2019 case, these interactions include feeding and swimming (Guiry, M.D. & Guiry, G.M. 2015). \u00a0The T. fusus<\/em>\u00a0has been observed to ingest a maximum of seven different species of dinoflagellates, and has been found to contain multiple semi-digested prey cells within its protoplasm simultaneously.\u00a0 As it is common for a behavior known as grazing, the T. fusus<\/em> takes only four to five minutes after ingesting a prey cell before it ingests another (Jin-Jeong et al. 2002).<\/p>\n Tiarina fusus diagram<\/p><\/div>\n a- macronucleus<\/p>\n b- prey cell and food vacuole<\/p>\n c- oral cilia ring<\/p>\n d- mouth\/anterior protruberances<\/p>\n e- anus (posterior)<\/p>\n f- outer membrane cilia<\/p>\n The T. fusus<\/em>\u2019 body takes on a more or less spindle-shaped form with longitudinal and lateral ridges, an oral cilia ring with anterior protuberances, and it contains one circular macronucleus with a food vacuole.\u00a0 Swimming in spiral tracks, the T. fusus<\/em>\u2019 movements are analogous to a drill, with its pointed anterior and posterior acting as an axis to its swiveling round barrel-esque body.\u00a0 Erratic and unpredictable, it seems to glide through the water indiscriminately, sometimes moving backwards or swimming in a circle with the help of the abundant cilia around its outer membrane.\u00a0 The T. fusus<\/em> measures at a length between 60-90 \u00b5m and at a width between 20-35 \u00b5m.\u00a0 It prefers to reside in an ecological temperature around 5-10 \u00baC and salinity of 12-16 \u2030 (Faur\u00e9-Fremiet E. 1951).<\/p>\n While not a lot is known about the overall grazing impact of Tiarina fusus<\/em> on marine red tidal waters, the ciliate is known to have a significant variety of natural prey that include red-tide dinoflagellates which can be consumed by T. fusus<\/em> up to its own size.\u00a0 In Japan, T. fusus<\/em> has a significant grazing impact on the populations of autotroph\u00a0Akashiwo sanguinea<\/em> when red tides occur in Tokyo Bay every May (Jin-Jeong et al. 2002).\u00a0 The T. fusus<\/em> travels at a maximum speed of 3125 \u00b5m\/s-1\u00a0<\/sup>which relative to other plankton its size is fast, therefore it must consume frequently to compensate for the great energy loss.\u00a0 The oral cilia ring is an effective adaptation for its demanding energy conversion needs. \u00a0It has a special ability to ingest prey of its own size, including Dinophysis.\u00a0 However, when T. fusus<\/em> comes in contact with heterotrophic Dinophysis rotundata<\/em> or D. hastata<\/em>, the reversal of roles occur.\u00a0 At first, the dinoflagellate releases a discharge that attaches itself to the ciliate, binding the two together, and T. fusus<\/em> continues on swimming with the Dinophysis connected to it.\u00a0 Then, the Dinophysis extends its pseudopodium onto the ciliate, rendering T. fusus<\/em> immobile and allowing the dinoflagellate control over movement.\u00a0 The Dinophysis gradually consumes T. fusus<\/em> as it swims around, swelling substantially and assuming a more rotund shape.\u00a0 Dinophysis rotundata<\/em> essentially absorbs Tiarina fusus<\/em>\u2019 energy during this unique power exchange for two to three hours (Hansen, J. 1991).\u00a0 These two species have the uncommon relationship of being able to prey on each other, where the predator becomes the prey.<\/p>\nDescription<\/h4>\n
<\/a>Movement<\/h4>\n
Role in Ecosystem and Feeding<\/h4>\n