Bacillaria paxillifera

General Close


(diatoms) A type of diatom that has longitudinal symmetry with valves that are linear or oval shaped. Some pennate diatoms possess a raphe, which allows them to be motile.

Shape Elongated, rectangular and Close


Lance-shaped. Having a wider rounded base and tapering towards the tip.

Size Length 70 - 200 μm, width 5 - 8 μm
Colour Yellow-brown
Connection Direct contact of Close


In diatoms, the structurally distinct halves of the cell wall (Becker 1996).

Covering Silica Close


In diatoms, the hard and porous silica cell wall (Horner 2002).



(plural: flagella) A tail-like projection that sticks out from the cell body and enables movement.



An organelle in the cell that contains the cell pigments (Horner 2002). This is where photosynthesis occurs. A chloroplast is a specialized chromatophore.

Two, large, plate-like
Lifestyle Close


The chemical process by which light energy, water and carbon dioxide are combined to produce oxygen and organic compounds. Photoautotrophic organisms (plants and algae) use this reaction to produce their own food.

. Sexual/asexual.


A rapid increase or accumulation of algal populations in an aquatic system. This will likely involve one or a few dominant phytoplankton species. This follows seasonal patterns (i.e., spring, summer or fall bloom) with dominant species being those that are best adapted to the environmental conditions of that time period. Discolouration of the water may be observed because of the algae's pigmentation. Blooms are often green but may be yellow-brown or red depending on the species present.

Does not usually form blooms
Harmful effects None known
Habitat Close


The ecological zone at the bottom of a body of water.

, but common in Close


Organisms that drift at the mercy of the currents.

. Marine/brackish/freshwater
Geographic Close


Widely distributed; occurring in many parts in the world.

Seasonal Rare off BC, but more abundant in spring and early summer
Growth Conditions


The dissolved ion content of a body of water. Can be measured in the following units: parts per thousand (PPT or ‰), practical salinity units (PSU), and absolute salinity (g/kg). PPT is measured by weight, denoting the number of parts salt per thousand total parts or a value of 10-3. PSU measures the conductivity of saltwater and compares it in a ratio to a standard KCl solution (because this is a ratio, salinity measured in this way can also be written without units). The newest unit of salinity is absolute salinity, which uses the mass fraction of salt in seawater (g salt per kg seawater) rather than its conductivity (TEOS-20 2010).

32 - 38
Temperature 2 - 25 °C (optimal)


Homoeocladia paxillifer (O.F. Müller) Elmore 1921 Close


Expressing the same fundamental type or structure; may or may not be symmetrical (e.g., the two valves of a diatom, where they are the same shape and appearance, but one is bigger than the other). In naming species, a homotypic synonym is one that comes into being when a taxon gets a new name (without being added to an already existing taxon).

Bacillaria paxillifer (O.F. Müller) T. Marsson 1901 (homotypic)
Oscillatoria paxillifera (O.F. Müller) Schrank ex Gomont 1892 (homotypic)
Nitzschia paradoxa (J.F. Gmelin) Grunow 1880 Close


A difference in type. In naming species, a heterotypic synonym is one that comes into being when a taxon becomes part of a different taxon. Compare to homotypic.

Nitzschia paxillifer (O.F. Müller) Heiberg 1863 (homotypic)
Diatoma paxillifera (O.F. Müller) Brébisson 1838 (homotypic)
Oscillatoria paxillifer (O.F. Müller) Schrank 1823 (homotypic)
Oscillaria paxillifera (O.F. Müller) Schrank 1823 (homotypic)
Bacillaria paradoxa J.F. Gmelin 1791 (heterotypic)
Vibrio paxillifer O.F. Müller 1786 Close


The original name for an organism. In botany, the original published nomenclature from which a new binomial nomenclature is derived for a particular group of organisms (Tindall 1999).

, homotypic)
(Guiry and Guiry 2012)


Empire Eukaryota
Kingdom Chromista
Subkingdom Harosa
Infrakingdom Heterokonta
Phylum Ochrophyta
Subphylum Khakista
Class Bacillariophyceae
Subclass Bacillariophycidae
Order Bacillariales
Family Bacillariaceae
Genus Bacillaria
Species B. paxillifera (O. F. Müller) T. Marsson 1901

(Guiry and Guiry 2012)


Photosynthetic. Reproduces sexually and asexually.


Cells are elongated and motile, sliding along each other in stacked colonies. Cells are rectangular in Close


In diatoms, the portion of the cell wall between the two valves of a cell; made up of intercalary bands (bands closest to the valves) and connecting bands (bands in the middle of the girdle). In dinoflagellates, the equivalent of a cingulum or transverse furrow (Horner 2002).

view (when in colonies), and lanceolate in valve view (Cupp 1943). Close


"In some pennate diatoms, one or two longitudinal slits along the [long] axis or around the valve margins" (Horner 2002). Secretion of mucilage allows a pennate diatom to attach itself to or glide on a substrate (Regents of the University of California 2006).

system is slightly keeled and runs from pole to pole (Hasle and Syvertsen 1997). Two large plate-like chloroplasts are present, one near each end of the cell (Horner 2002, Kraberg et al. 2010). The Close


(plural: nuclei) In eukaryotic cells, a membrane-bound organelle that contains the cell's genetic information; the nucleus controls the activities of the cell by controlling gene expression.

is located centrally (Cupp 1943). Cells are yellow-brown in colour.
Fibulae are strong, and the valve surface is covered in transverse parallel Close


(referring to pores in diatoms) In diatoms, a striation or row of pores on the valve face. "In centric diatoms, striae may be radial, running from the centre of the valve to the margin ... In pennate diatoms, striae may be parallel to the median line of the valve or raphe" (Horner 2002).

(Hasle and Syvertsen 1997).


Length Close


(axis, spine) The region of the apex or point. Refers to the most anterior point or region of the cell (HPP 2003).

axis): 70 - 200 μm
Width Close

Transapical axis

In diatoms, the longitudinal axis of the valve.

(transapical axis
): 5 - 8 μm
Height Close

Pervalvar axis

The axis through the centre point of the two valves of a frustule. This axis is perpendicular to the valve face.

(pervalvar axis
): 5 - 10 μm
Fibulae: 7 - 9 in 10 μm


(referring to pores in diatoms) In diatoms, a striation or row of pores on the valve face. "In centric diatoms, striae may be radial, running from the centre of the valve to the margin ... In pennate diatoms, striae may be parallel to the median line of the valve or raphe" (Horner 2002).

: 20 - 21 in 10 μm
(Cupp 1943, Hasle and Syvertsen 1997, Kraberg et al. 2010)

Similar species


Harmful effects

Not known.


Benthic, marine and brackish/freshwater species, but is also commonly found in plankton (Cupp 1943).


Cosmopolitan (Hasle and Syvertsen 1997).
Present throughout the year with higher abundance in winter and spring in Northern European seas (Kraberg et al. 2010) and in the rivers of SE Iraq (Hameed 2003). Most abundant during the summer in northern Japan (Kasim and Mukai 2006) and during the fall in southern Korea (Yoon and Koh 1995).
Relatively rare in BC waters, but more abundant during spring and early summer.

Growth conditions

May prefer salinities around 15 (Redekar and Wagh 2000). Can grow well under high phosphorous conditions (Blinn and Bailey 2001).

Environmental Ranges

Depth range (m): 0 - 40
Temperature range (°C): 0.015 - 24.625
Nitrate (μmol L-1): 1.640 - 12.045
Salinity: up to 37.775
Oxygen (mL L-1): 4.855 - 8.067
Phosphate (μmol L-1): 0.210 - 0.630

Silicic acid

A general term to describe chemical compounds containing silicon, oxygen and hydrogen with a general formula of [SiOx(OH)4-2x]n. Diatoms polymerize silicic acid into biogenic silica to form their frustules (Azam and Chisholm 1976).

(μmol L-1): 1.595 - 7.103
(OBIS 2012, cited in EOL 2012)

Bloom characteristics

Does not usually form blooms (Kraberg et al. 2010).


Blinn, D. W. and Bailey, P. C. E. 2001. Land-use influence on stream water quality and diatom communities in Victoria, Australia: a response to secondary salinization. Hydrobiologia. 466: 231-244.

Cupp, E. E. 1943. Marine Plankton Diatoms of the West Coast of North America. University of California Press. Berkeley, California. 238.

Encyclopedia of Life (EOL). 2012. Bacillaria paxillifer. Accessed 06 Apr 2012.

Guiry, M. D. and Guiry, G. M. 2012. Bacillaria paxillifera (O. F. Müller) T. Marsson. Accessed 06 Apr 2012.

Hameed, H. A. 2003. The colonization of periphytic diatom species on artificial substrates in the Ashar canal, Basrah, Iraq. Limnologica - Ecology and Management of Inland Waters. 33(1): 54-61.

Hasle, G. R. and Syvertsen, E. E. 1997. Marine diatoms. In: Tomas, C. R. (ed.) Identifying Marine Phytoplankton. Academic Press, Inc., San Diego. 5-385.

Horner, R. A. 2002. A Taxonomic Guide To Some Common Phytoplankton. Biopress Limited, Dorset Press, Dorchester, UK. 200.

Kasim, M. and Mukai, H. 2006. Contribution of benthic and epiphytic diatoms to clam and oyster production in the Akkeshi-ko Estuary. Journal of Oceanography. 62: 267-281.

Kraberg, A., Baumann, M. and Durselen, C. D. 2010. Coastal Phytoplankton: Photo Guide for Northern European Seas. Verlag Dr. Friedrich Pfeil, Munchen, Germany. 204.

Ocean Biogeographic Information System (OBIS). 2012. Bacillaria paxillifer. Accessed 06 Apr 2012.

Redekar, P. D. and Wagh, A. B. 2000. Growth of fouling diatoms from the Zuari estuary, Goa (West coast of India) under different salinities in the laboratory. Seaweed Research and Utilisation. 22(1-2): 121-124.

Yoon, Y. H. and Koh, N. P. 1995. Studies on the environmental characteristics of the breeding ground in the Kogum-sudo, southern part of Korean peninsula. 1. Seasonal succession of phytoplankton population. Korea Inter-University Institution of Ocean Sciences. 27: 116-127.

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