The Chrysophyceae, usually called chrysophytes, chrysomonads, golden-brown algae or golden algae are a large group of
algae
Algae (; singular alga ) is an informal term for a large and diverse group of photosynthesis, photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from u ...
, found mostly in freshwater.
Golden algae is also commonly used to refer to a single species, ''
Prymnesium parvum'', which causes
fish kills.
The Chrysophyceae should not be confused with the
Chrysophyta
Chrysophyta or golden algae is a term used to refer to certain heterokonts.
It can be used to refer to:
* Chrysophyceae (golden algae), Bacillariophyceae (diatoms), and Xanthophyceae (yellow-green algae) together. E.g., Pascher (1914).
* Chrysoph ...
, which is a more ambiguous
taxon. Although "chrysophytes" is the anglicization of "Chrysophyta", it generally refers to the Chrysophyceae.
Members
Originally they were taken to include all such forms of the
diatom
A diatom ( Neo-Latin ''diatoma''), "a cutting through, a severance", from el, διάτομος, diátomos, "cut in half, divided equally" from el, διατέμνω, diatémno, "to cut in twain". is any member of a large group comprising se ...
s and multicellular
brown algae
Brown algae (singular: alga), comprising the class Phaeophyceae, are a large group of multicellular algae, including many seaweeds located in colder waters within the Northern Hemisphere. Brown algae are the major seaweeds of the temperate and p ...
, but since then they have been divided into several different groups (e.g.,
Haptophyceae,
Synurophyceae
The synurids (order Synurales) are a small group of heterokont algae, found mostly in freshwater environments, characterized by cells covered in silica scales.
Characteristics
They are covered in silicate scales and spines. In ''Synura'', th ...
) based on pigmentation and cell structure. Some heterotrophic flagellates as the
bicosoecid
Bicosoecida (ICZN) or Bicosoecales/Bicoecea (ICBN) is an order of Bikosea, a small group of unicellular flagellates, included among the heterokonts. Informally known as bicosoecids, they are a small group of unicellular flagellates. The cells ar ...
s and
choanoflagellates
The choanoflagellates are a group of free-living unicellular and colonial flagellate eukaryotes considered to be the closest living relatives of the animals. Choanoflagellates are collared flagellates, having a funnel shaped collar of interconne ...
were sometimes seen as related to golden algae too.
They are now usually restricted to a core group of closely related forms, distinguished primarily by the structure of the
flagella in motile cells, also treated as an order Chromulinales. It is possible membership will be revised further as more species are studied in detail.
The Chrysophyceae have been placed by some in the polyphyletic
Chromista
Chromista is a biological kingdom consisting of single-celled and multicellular eukaryotic species that share similar features in their photosynthetic organelles (plastids). It includes all protists whose plastids contain chlorophyll ''c'', suc ...
. The broader monophyletic group to which the Chrysophyceae belong includes various non-algae including the bicosoecids, not the collar flagellates, opalines, oomycete fungi, proteromonads, actinophryid heliozoa, and other heterotrophic flagellates and is referred to as the
Stramenopiles.
Description
The "primary" cell of chrysophytes contains two
specialized flagella. The active, "feathered" (with
mastigonemes
Mastigonemes are lateral "hairs" that attach to protistan flagella. Flimsy hairs attach to the flagella of euglenid flagellates, while stiff hairs occur in stramenopile and cryptophyte protists.Hoek, C. van den, Mann, D. G. and Jahns, H. M. (1 ...
) flagellum is oriented toward the moving direction. The smooth passive flagellum, oriented toward the opposite direction, may be present only in rudimentary form in some species.
An important characteristic used to identify members of the class Chrysophyceae is the presence of a siliceous cyst that is formed endogenously. Called statospore, stomatocyst or statocyst, this structure is usually globose and contains a single pore. The surface of mature cysts may be ornamented with different structural elements and are useful to distinguish species.
* Most members are unicellular
flagellate
A flagellate is a cell or organism with one or more whip-like appendages called flagella. The word ''flagellate'' also describes a particular construction (or level of organization) characteristic of many prokaryotes and eukaryotes and thei ...
s, with either two visible flagella, as in ''
Ochromonas'', or sometimes one, as in ''
Chromulina
''Chromulina'' is a genus of golden algae in the family Chromulinaceae.
References
External links
*
''Chromulina'' at AlgaeBase''Chromulina'' at NCBI
Chrysophyceae
Heterokont genera
Algae genera
{{Heterokont-stub ...
''. The
Chromulinales as first defined by Pascher in 1910 included only the latter type, with the former treated as the order
Ochromonadales. However, structural studies have revealed that a short second flagellum, or at least a second basal body, is always present, so this is no longer considered a valid distinction. Most of these have no cell covering. Some have loricae or shells, such as ''
Dinobryon
''Dinobryon'' is a type of microscopic algae. It is one of the 22 genera in the family Dinobryaceae. ''Dinobryon'' are mixotroph A mixotroph is an organism that can use a mix of different sources of energy and carbon, instead of having a singl ...
'', which is sessile and grows in branched colonies. Most forms with silicaceous scales are now considered a separate group, the
synurid
The synurids (order Synurales) are a small group of heterokont algae, found mostly in freshwater environments, characterized by cells covered in silica scales.
Characteristics
They are covered in silicate scales and spines. In ''Synura'', thes ...
s, but a few belong among the Chromulinales proper, such as ''
Paraphysomonas''.
* Some members are generally
amoeboid
An amoeba (; less commonly spelled ameba or amœba; plural ''am(o)ebas'' or ''am(o)ebae'' ), often called an amoeboid, is a type of Cell (biology), cell or unicellular organism with the ability to alter its shape, primarily by extending and ret ...
, with long branching cell extensions, though they pass through flagellate stages as well. ''
Chrysamoeba'' and ''
Rhizochrysis'' are typical of these. There is also one species, ''
Myxochrysis paradoxa'', which has a complex life cycle involving a
multinucleate plasmodial stage, similar to those found in
slime molds. These were originally treated as the order
Chrysamoebales. The superficially similar ''
Rhizochromulina
''Rhizochromulina'' is an unusual genus of marine heterokont algae, with one species, ''Rhizocromulina marina''. They are colored amoeboids with a single flagellum, and produce distinctive spindle-shaped zoospores. These have a cell structure ty ...
'' was once included here, but is now given its own order based on differences in the structure of the flagellate stage.
* Other members are non-motile. Cells may be naked and embedded in
mucilage, such as ''
Chrysosaccus'', or coccoid and surrounded by a cell wall, as in ''
Chrysosphaera''. A few are filamentous or even
parenchyma
Parenchyma () is the bulk of functional substance in an animal organ or structure such as a tumour. In zoology it is the name for the tissue that fills the interior of flatworms.
Etymology
The term ''parenchyma'' is New Latin from the word � ...
tous in organization, such as ''
Phaeoplaca''. These were included in various older orders, most of the members of which are now included in separate groups. ''
Hydrurus'' and its allies, freshwater genera which form branched gelatinous filaments, are often placed in the separate order
Hydrurales, but may belong here.
Classifications
Pascher (1914)
Classification of the class Chrysophyceae according to Pascher (1914):
* Division
Chrysophyta
Chrysophyta or golden algae is a term used to refer to certain heterokonts.
It can be used to refer to:
* Chrysophyceae (golden algae), Bacillariophyceae (diatoms), and Xanthophyceae (yellow-green algae) together. E.g., Pascher (1914).
* Chrysoph ...
** Class Chrysophyceae
*** Order
Chrysomonadales
*** Order
Chrysocapsales
*** Order
Chrysosphaerales
Chrysosphaerales is an order of Chrysophyceae
The Chrysophyceae, usually called chrysophytes, chrysomonads, golden-brown algae or golden algae are a large group of algae, found mostly in freshwater. Golden algae is also commonly used to refer ...
*** Order
Chrysotrichales
** Class
Heterokontae
** Class
Diatom
A diatom ( Neo-Latin ''diatoma''), "a cutting through, a severance", from el, διάτομος, diátomos, "cut in half, divided equally" from el, διατέμνω, diatémno, "to cut in twain". is any member of a large group comprising se ...
eae
Smith (1938)
According to
Smith (1938):
* Class Chrysophyceae
** Order
Chrysomonadales
*** Suborder
Cromulinae (e.g., ''
Mallomonas
''Mallomonas'' is a genus comprising unicellular algal eukaryotes and characterized by their intricate cell coverings made of silica scales and bristles. The group was first named and classified by Dr. Maximilian Perty in 1852. These organisms li ...
'')
*** Suborder
Isochrysidineae (e.g., ''
Synura
''Synura'' is a genus of colonial chrysomonad algae covered in silica
Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In m ...
'')
*** Suborder
Ochromonadineae (e.g., ''
Dinobryon
''Dinobryon'' is a type of microscopic algae. It is one of the 22 genera in the family Dinobryaceae. ''Dinobryon'' are mixotroph A mixotroph is an organism that can use a mix of different sources of energy and carbon, instead of having a singl ...
'')
** Order
Rhizochrysidales (e.g., ''
Chrysamoeba'')
** Order
Chrysocapsales (e.g., ''
Hydrurus'')
** Order
Chrysotrichales (e.g., ''
Phaeothamnion'')
** Order
Chrysosphaerales
Chrysosphaerales is an order of Chrysophyceae
The Chrysophyceae, usually called chrysophytes, chrysomonads, golden-brown algae or golden algae are a large group of algae, found mostly in freshwater. Golden algae is also commonly used to refer ...
(e.g., ''
Epichrysis'')
Bourrely (1957)
According to Bourrely (1957):
* Class Chrysophyceae
** Order
Phaeoplacales
** Order
Stichogloeales
** Order
Phaeothamniales
Phaeothamniales is an order of alga in the Ochrophyta
The ochrophytes, subphylum Ochrophytina, is a group of mostly photosynthetic heterokonts. Their plastid is of red algal origin.
The classification of the group is still being worked out. ...
** Order
Chrysapionales
** Order
Thallochrysidales
** Order
Chrysosphaerales
Chrysosphaerales is an order of Chrysophyceae
The Chrysophyceae, usually called chrysophytes, chrysomonads, golden-brown algae or golden algae are a large group of algae, found mostly in freshwater. Golden algae is also commonly used to refer ...
** Order
Chrysosaccales
** Order
Rhizochrysidales
** Order
Ochromonadales
** Order
Isochrysidales
Isochrysidales is an order of Haptophyceae.
References
Haptophytes
Bikont orders
{{Haptophyte-stub ...
** Order
Silicoflagellales
** Order
Craspedomonadales
** Order
Chromulinales
Starmach (1985)
According to Starmach (1985):
* Class Chrysophyceae
** Subclass
Heterochrysophycidae
*** Order
Chromulinales
*** Order
Ochromonadales
** Subclass
Acontochrysophycidae
*** Order
Chrysarachniales
*** Order
Stylococcales
*** Order
Chrysosaccales
*** Order
Phaeoplacales
** Subclass
Craspedomonadophycidae
*** Order
Monosigales
Kristiansen (1986)
Classification of the class Chrysophyceae and splinter groups according to Kristiansen (1986):
* Class Chrysophyceae
:* Order
Ochromonadales
:* Order
Mallomonadales
:* Order
Chrysamoebales
:* Order
Chrysocapsales
:* Order
Hydrurales
:* Order
Chrysosphaerales
Chrysosphaerales is an order of Chrysophyceae
The Chrysophyceae, usually called chrysophytes, chrysomonads, golden-brown algae or golden algae are a large group of algae, found mostly in freshwater. Golden algae is also commonly used to refer ...
:* Order
Phaeothamniales
Phaeothamniales is an order of alga in the Ochrophyta
The ochrophytes, subphylum Ochrophytina, is a group of mostly photosynthetic heterokonts. Their plastid is of red algal origin.
The classification of the group is still being worked out. ...
:* Order
Sarcinochrysidales
* Class
Pedinellophyceae
:* Order
Pedinellales
Pedinellales is a group of single-celled algae found in both marine environments and freshwater.
These are found in both freshwater and marine environments, and most genera are sessile, attached by posterior stalks. The flagellum is at the ante ...
* Class
Dictyochophyceae
Dictyochophyceae sensu lato is a photosynthetic lineage of heterokont algae.
Taxonomy
* Class Dictyochophyceae Silva 1980 s.l.
** Subclass Sulcophycidae Cavalier-Smith 2013
*** Order Olisthodiscales Cavalier-Smith 2013
**** Family Olisthodisca ...
:* Order
Dictyochales
Dictyochales (Silicoflagellates, or Dictyochophyceae ''sensu stricto'') are a small group of unicellular heterokont algae, found in marine environments.
Characteristics
In one stage of their life cycle, they produce a siliceous skeleton, comp ...
Margulis et al. (1990)
Classification of the phylum Chrysophyta according to Margulis et al. (1990):
* Phylum
Chrysophyta
Chrysophyta or golden algae is a term used to refer to certain heterokonts.
It can be used to refer to:
* Chrysophyceae (golden algae), Bacillariophyceae (diatoms), and Xanthophyceae (yellow-green algae) together. E.g., Pascher (1914).
* Chrysoph ...
** Class
Chrysophyceae
The Chrysophyceae, usually called chrysophytes, chrysomonads, golden-brown algae or golden algae are a large group of algae, found mostly in freshwater. Golden algae is also commonly used to refer to a single species, ''Prymnesium parvum'', which ...
** Class
Pedinellophyceae
** Class
Dictyochophyceae
Dictyochophyceae sensu lato is a photosynthetic lineage of heterokont algae.
Taxonomy
* Class Dictyochophyceae Silva 1980 s.l.
** Subclass Sulcophycidae Cavalier-Smith 2013
*** Order Olisthodiscales Cavalier-Smith 2013
**** Family Olisthodisca ...
(=
Silicoflagellata
Dictyochales (Silicoflagellates, or Dictyochophyceae ''sensu stricto'') are a small group of unicellular heterokont algae, found in marine environments.
Characteristics
In one stage of their life cycle, they produce a siliceous skeleton, comp ...
)
van den Hoek ''et al.'' (1995)
According to
van den Hoek, Mann and Jahns (1995):
* Class Chrysophyceae
** Order
Ochromonadales (e.g., ''
Ochromonas,
Pseudokephyrion,
Dinobryon
''Dinobryon'' is a type of microscopic algae. It is one of the 22 genera in the family Dinobryaceae. ''Dinobryon'' are mixotroph A mixotroph is an organism that can use a mix of different sources of energy and carbon, instead of having a singl ...
'')
** Order
Mallomonadales (= Class
Synurophyceae
The synurids (order Synurales) are a small group of heterokont algae, found mostly in freshwater environments, characterized by cells covered in silica scales.
Characteristics
They are covered in silicate scales and spines. In ''Synura'', th ...
, e.g., ''
Mallomonas
''Mallomonas'' is a genus comprising unicellular algal eukaryotes and characterized by their intricate cell coverings made of silica scales and bristles. The group was first named and classified by Dr. Maximilian Perty in 1852. These organisms li ...
,
Synura
''Synura'' is a genus of colonial chrysomonad algae covered in silica
Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In m ...
'')
** Order
Pedinellales
Pedinellales is a group of single-celled algae found in both marine environments and freshwater.
These are found in both freshwater and marine environments, and most genera are sessile, attached by posterior stalks. The flagellum is at the ante ...
(= Class
Pedinellophyceae, e.g., ''
Pedinella
''Pedinella'' is a genus of small, unicellular planktonic or attached, flagellated heterokonts first described in 1888 by A. V. Vysotskij. The genus is monospecific, and the single species is ''Pedinella hexacostata'' Vysotskij. ''Pedinella'' has ...
'')
** Order
Chrysamoebidales (e.g., ''
Rhizochrysis,
Chrysarachnion'')
** Order
Chrysocapsales (e.g., ''
Chrysocapsa,
Hydrurus'')
** Order
Chrysosphaerales
Chrysosphaerales is an order of Chrysophyceae
The Chrysophyceae, usually called chrysophytes, chrysomonads, golden-brown algae or golden algae are a large group of algae, found mostly in freshwater. Golden algae is also commonly used to refer ...
(e.g., ''
Chrysosphaera'')
** Order
Phaeothamniales
Phaeothamniales is an order of alga in the Ochrophyta
The ochrophytes, subphylum Ochrophytina, is a group of mostly photosynthetic heterokonts. Their plastid is of red algal origin.
The classification of the group is still being worked out. ...
(e.g., ''
Phaeothamnion,
Thallochrysis'')
Preisig (1995)
Classification of the class Chrysophyceae and splinter groups according to Preisig (1995):
* Class Chrysophyceae
:* Order
Bicosoecales
:* Order
Chromulinales
:* Order
Hibberdiales
:* Order
Hydrurales
:* Order
Sancinochrysidales
:* Order
Chrysomioridales
* Class
Dictyochophyceae
Dictyochophyceae sensu lato is a photosynthetic lineage of heterokont algae.
Taxonomy
* Class Dictyochophyceae Silva 1980 s.l.
** Subclass Sulcophycidae Cavalier-Smith 2013
*** Order Olisthodiscales Cavalier-Smith 2013
**** Family Olisthodisca ...
:* Order
Pedinellales
Pedinellales is a group of single-celled algae found in both marine environments and freshwater.
These are found in both freshwater and marine environments, and most genera are sessile, attached by posterior stalks. The flagellum is at the ante ...
:* Order
Rhizochromulinales
Rhizochromulinales is an order of Dictyochophyceae. The order includes the genus, ''Rhizochromulina
''Rhizochromulina'' is an unusual genus of marine heterokont algae, with one species, ''Rhizocromulina marina''. They are colored amoeboids wit ...
:* Order
Dictyochales
Dictyochales (Silicoflagellates, or Dictyochophyceae ''sensu stricto'') are a small group of unicellular heterokont algae, found in marine environments.
Characteristics
In one stage of their life cycle, they produce a siliceous skeleton, comp ...
* Class
Synurophyceae
The synurids (order Synurales) are a small group of heterokont algae, found mostly in freshwater environments, characterized by cells covered in silica scales.
Characteristics
They are covered in silicate scales and spines. In ''Synura'', th ...
:* Order
Synurales
Guiry and Guiry (2019)
According to Guiry and Guiry (2019):
* Class Chrysophyceae
** Order
Chromulinales
** Order
Hibberdiales
** Order
Hydrurales
** Order
Rhizochrysidales
** Order
Thallochrysidales
** Chrysophyceae ordo
incertae sedis
' () or ''problematica'' is a term used for a taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertaint ...
(11 genera)
Ecology
Chrysophytes live mostly in
freshwater, and are important for studies of
food web dynamics in
oligotrophic freshwater ecosystems, and for
assessment
Assessment may refer to:
Healthcare
*Health assessment, identifies needs of the patient and how those needs will be addressed
*Nursing assessment, gathering information about a patient's physiological, psychological, sociological, and spiritual s ...
of
environmental degradation resulting from
eutrophication and
acid rain
Acid rain is rain or any other form of precipitation that is unusually acidic, meaning that it has elevated levels of hydrogen ions (low pH). Most water, including drinking water, has a neutral pH that exists between 6.5 and 8.5, but acid ...
.
[Sandgren et al. (1995).]
Evolution
Chrysophytes contain the pigment
fucoxanthin.
Because of this, they were once considered to be a specialized form of
cyanobacteria. Because many of these organisms had a silica capsule, they have a relatively complete fossil record, allowing modern biologists to confirm that they are, in fact, not derived from cyanobacteria, but rather an ancestor that did not possess the capability to photosynthesize. Many of the chrysophyta precursor fossils entirely lacked any type of photosynthesis-capable pigment. The most primitive stramenopiles are regarded as heterotrophic, such as the ancestors of the Chrysophyceae were likely heterotrophic flagellates that obtained their ability to photosynthesize from an endosymbiotic relationship with fucoxanthin-containing cyanobacteria.
References
Bibliography
* Andersen, R. A. 2004
Biology and systematics of heterokont and haptophyte algae.''American Journal of Botany'' 91(10): 1508–1522. 2004.
* Duff, K.E., B.A. Zeeb & J.P. Smol. 1995. ''Atlas of Chrysophycean Cysts'', Vol. 1.
2001, Vol. 2
Kluwer Academic Publishers, Dordrecht.
* Jørgen Kristiansen. 2005. ''Golden algae: a biology of chrysophytes.'' A.R.G. Gantner Verlag, distributed by Koeltz Scientific Books, Königstein, Germany, vii + 167 pp. .
* Kristiansen, J. and R.A. Andersen
ds. 1986. ''Chrysophytes: Aspects and Problems.'' Cambridge University Press, Cambridge, xiv + 337 pp.
* Kristiansen, J. and Preisig, H.
ds. 2001. ''Encyclopedia of chrysophyte genera''. Bibliotheca Phycologica, Vol. 110, J. Cramer, Berlin.
* Medlin, L. K., W. H. C. F. Kooistra, D. Potter, G. W. Saunders, and R. A. Anderson. 1997
Phylogenetic relationships of the “golden algae” (haptophytes, heterokont chromophytes) and their plastids.''Plant Systematics and Evolution'' (Supplement) 11: 187–219.
* Sandgren, C.D., J.P. Smol, and J. Kristiansen
ds. 1995. ''Chrysophyte algae: ecology, phylogeny and development.'' Cambridge University Press, New York. .
* Škaloud, P., Škaloudová, M., Pichrtová, M., Němcová, Y., Kreidlová, J. & Pusztai, M. 2013. www.chrysophytes.eu – a database on distribution and ecology of silica-scaled chrysophytes in Europe. ''Nova Hedwigia'', Beiheft 142: 141-146
link
{{Taxonbar, from=Q1763065
Algae classes