Weckström, K., Massé, G., Collins, L. G., Hanhijärvi, S.,
Bouloubassi, I., Sicre, M.-A., Seidenkrantz, M.-S., Schmidt, S.,
Andersen, T. J., Andersen, M. L., Hill, B., and Kuijpers, A.,
2013. Evaluation of the sea ice proxy IP 25 against observational
and diatom proxy data in the SW Labrador Sea. Quaternary Science Reviews, 79, 53–62.
Cross-references
Marine Microfossils
Modelling Past Oceans
North Atlantic Oscillation (NAO)
Paleoceanographic Proxies
Paleoceanography
DINOFLAGELLATES
Jens Matthiessen
1 and Michael Schreck
2
1
Alfred Wegener Institute, Helmholtz Centre for Polar and
Marine Research, Bremerhaven, Germany
2
Arctic Research Centre, Korea Polar Research Institute,
Incheon, Korea
Definition
Dinoflagellates (Greek, dinh, dino, “whirl” and Latin flagellum, “whip, scourge”) are unicellular protists that have
two distinctive flagella during at least part of their life
cycle.
Introduction
Dinoflagellates are a biologically complex group of protists that comprise planktonic, meroplanktonic, and benthic species. They have different modes of nutrition
making it difficult to attribute the group as a whole to animals or plants. Some species produce toxins that impact
human health through consumption of contaminated seafood or water or aerosol exposure (Hackett et al., 2004).
Toxic algae blooms are increasingly documented over
the past decades (http://oceanservice.noaa.gov/hazards/
hab) and may have a considerable economic impact.
Extensive blooms of dinoflagellates may cause a coloration of water known as red tide. Some species are an
important source of bioluminescence (Hackett et al.,
2004). Since it has been finally accepted more than
50 years ago that the fossil hystrichospheres in Mesozoic
and Cenozoic sediments are cysts of dinoflagellates
(e.g., Dale, 1983), dinoflagellate cysts have become
important in stratigraphy and understanding past
environments.
General characteristics
Dinoflagellates (c. 2 to 2,000 mm) are primarily unicellular
eukaryotes but some species are colonial, and chain formation is common (Taylor et al., 2008). Organisms are
assigned to the division Dinoflagellata (kingdom
Alveolata) based on possession of one or more of a suite
of characters including an amphiesma, two dissimilar flagella, and a unique type of nucleus (Taylor, 1987). The
amphiesma is the complex outer region of the cell wall,
usually containing a single layer of flattened vesicles.
These amphiesmal vesicles may contain thecal plates usually composed of cellulose (thecate or armored forms). Six
basic types of tabulation, i.e., arrangement of amphiesmal
vesicles, are known (Fensome et al., 1993). Dinoflagellates without thecal plates are called athecate, naked, or
unarmored.
A distinctive flagellar apparatus consisting of a coiled
transverse flagellum within a cingular groove and a posterior flagellum within a sulcal groove enables a spiral
motion and to move freely in the water column (Taylor,
1987). Swimming speeds range from centimeters to a
few meters per hour. Vertical migration is a result of
endogenous rhythms. This motility permits to optimize
position in the euphotic zone to a limited extent to take full
advantage of light and nutrients and avoids sinking under
very stable water conditions.
The unique type of nucleus, the dinokaryon, is characterized by chromosomes that remain condensed between
cell divisions, and a lack of histones. Dinoflagellates
may have special vacuole-like structures of unknown
function called pusules (usually two per cell). The accessory pigment peridinin that enables energy transfer may
be present in photosynthetic cells.
Ecology of dinoflagellates
Dinoflagellates live in all aquatic environments and have
been observed both in snow and sea ice (Taylor et al.,
2008). They are most abundant in shallow marine settings
but also occur in fully oceanic environments. The biogeographic distribution is primarily determined by temperature, and the same species occur within similar climatic
zones in both hemispheres. True endemism is rare, and
some species have a bipolar distribution. More than
2,300 species have been described (Gómez, 2012) of
which more than 180 are marine benthic (Hoppenrath
et al., 2014) and 350 freshwater species (Mertens et al.,
2012).
Dinoflagellates have diverse feeding mechanisms and
utilize various modes of nutrition: they may be
phototrophic, heterotrophic, and mixotrophic and may be
free living, endosymbionts, or parasites (Jeong et al.,
2010). Most species are probably mixotrophic or heterotrophic feeding on diverse preys such as bacteria,
picoeukaryotes, nanoflagellates, diatoms, other dinoflagellates, heterotrophic protists, and metazoans or ingest
particulate matter or dissolved substances. They are
important in planktonic marine food webs since they
may have both a considerable grazing impact on natural
populations and are excellent prey for mixotrophic protists
and metazoans. Together with diatoms and
coccolithophores, dinoflagellates are among the most
prominent marine primary producers today, thus playing
an important role in the global carbon cycle.
DINOFLAGELLATES
189
Bouloubassi, I., Sicre, M.-A., Seidenkrantz, M.-S., Schmidt, S.,
Andersen, T. J., Andersen, M. L., Hill, B., and Kuijpers, A.,
2013. Evaluation of the sea ice proxy IP 25 against observational
and diatom proxy data in the SW Labrador Sea. Quaternary Science Reviews, 79, 53–62.
Cross-references
Marine Microfossils
Modelling Past Oceans
North Atlantic Oscillation (NAO)
Paleoceanographic Proxies
Paleoceanography
DINOFLAGELLATES
Jens Matthiessen
1 and Michael Schreck
2
1
Alfred Wegener Institute, Helmholtz Centre for Polar and
Marine Research, Bremerhaven, Germany
2
Arctic Research Centre, Korea Polar Research Institute,
Incheon, Korea
Definition
Dinoflagellates (Greek, dinh, dino, “whirl” and Latin flagellum, “whip, scourge”) are unicellular protists that have
two distinctive flagella during at least part of their life
cycle.
Introduction
Dinoflagellates are a biologically complex group of protists that comprise planktonic, meroplanktonic, and benthic species. They have different modes of nutrition
making it difficult to attribute the group as a whole to animals or plants. Some species produce toxins that impact
human health through consumption of contaminated seafood or water or aerosol exposure (Hackett et al., 2004).
Toxic algae blooms are increasingly documented over
the past decades (http://oceanservice.noaa.gov/hazards/
hab) and may have a considerable economic impact.
Extensive blooms of dinoflagellates may cause a coloration of water known as red tide. Some species are an
important source of bioluminescence (Hackett et al.,
2004). Since it has been finally accepted more than
50 years ago that the fossil hystrichospheres in Mesozoic
and Cenozoic sediments are cysts of dinoflagellates
(e.g., Dale, 1983), dinoflagellate cysts have become
important in stratigraphy and understanding past
environments.
General characteristics
Dinoflagellates (c. 2 to 2,000 mm) are primarily unicellular
eukaryotes but some species are colonial, and chain formation is common (Taylor et al., 2008). Organisms are
assigned to the division Dinoflagellata (kingdom
Alveolata) based on possession of one or more of a suite
of characters including an amphiesma, two dissimilar flagella, and a unique type of nucleus (Taylor, 1987). The
amphiesma is the complex outer region of the cell wall,
usually containing a single layer of flattened vesicles.
These amphiesmal vesicles may contain thecal plates usually composed of cellulose (thecate or armored forms). Six
basic types of tabulation, i.e., arrangement of amphiesmal
vesicles, are known (Fensome et al., 1993). Dinoflagellates without thecal plates are called athecate, naked, or
unarmored.
A distinctive flagellar apparatus consisting of a coiled
transverse flagellum within a cingular groove and a posterior flagellum within a sulcal groove enables a spiral
motion and to move freely in the water column (Taylor,
1987). Swimming speeds range from centimeters to a
few meters per hour. Vertical migration is a result of
endogenous rhythms. This motility permits to optimize
position in the euphotic zone to a limited extent to take full
advantage of light and nutrients and avoids sinking under
very stable water conditions.
The unique type of nucleus, the dinokaryon, is characterized by chromosomes that remain condensed between
cell divisions, and a lack of histones. Dinoflagellates
may have special vacuole-like structures of unknown
function called pusules (usually two per cell). The accessory pigment peridinin that enables energy transfer may
be present in photosynthetic cells.
Ecology of dinoflagellates
Dinoflagellates live in all aquatic environments and have
been observed both in snow and sea ice (Taylor et al.,
2008). They are most abundant in shallow marine settings
but also occur in fully oceanic environments. The biogeographic distribution is primarily determined by temperature, and the same species occur within similar climatic
zones in both hemispheres. True endemism is rare, and
some species have a bipolar distribution. More than
2,300 species have been described (Gómez, 2012) of
which more than 180 are marine benthic (Hoppenrath
et al., 2014) and 350 freshwater species (Mertens et al.,
2012).
Dinoflagellates have diverse feeding mechanisms and
utilize various modes of nutrition: they may be
phototrophic, heterotrophic, and mixotrophic and may be
free living, endosymbionts, or parasites (Jeong et al.,
2010). Most species are probably mixotrophic or heterotrophic feeding on diverse preys such as bacteria,
picoeukaryotes, nanoflagellates, diatoms, other dinoflagellates, heterotrophic protists, and metazoans or ingest
particulate matter or dissolved substances. They are
important in planktonic marine food webs since they
may have both a considerable grazing impact on natural
populations and are excellent prey for mixotrophic protists
and metazoans. Together with diatoms and
coccolithophores, dinoflagellates are among the most
prominent marine primary producers today, thus playing
an important role in the global carbon cycle.
DINOFLAGELLATES
189