Detonula pumila

General Close


(diatoms) Having radial symmetry, i.e., cell is shaped like a coin or a tuna can or a soup can.

Shape Cylindrical
Size Length 15 - 120 μm, diameter 15 - 45 μm
Colour Yellow-brown
Connection Single central Close


In some diatoms, "closed or solid structures projecting from the cell wall;" in dinoflagellates, solid projections that usually taper to a point.

with ring of smaller Close


The outline or border that defines the shape of an organism or cell.

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.

Numerous, small, star-shaped plates
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. Close


In diatoms, the special cells that restore normal size following cell division. Auxospores are associated with sexual reproduction (Horner 2002).



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.

Information not available
Harmful effects None known
Habitat Close


Describing shallow, near-shore areas and the organisms that live there. Refers to shallow marine waters ranging from the low tide mark to the continental shelf. Varying amounts of sunlight penetrate the water, allowing photosynthesis by both phytoplankton and bottom-dwelling organisms. Close proximity to land favours high nutrient content and biological activity (Encyclopedia Britannica 2011).

and Close


Describing an ecosystem or species that is far from the bottom or shore of a water body. In an open aquatic environment.

Geographic Close


Widely distributed; occurring in many parts in the world.

, may prefer warmer waters
Seasonal Summer and autumn in Northern European seas
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).

16 - 36
Temperature 2 - 29 °C (optimal)


Schroederella schroederi (Bergon) Pavillard 1925
Schroederella delicatula (H. Péragallo) Pavillard 1913 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.

Thalassiosira condensata Cleve 1900 (heterotypic)
Lauderia delicatula H. Péragallo 1888 (heterotypic)
Lauderia pumila Castracane 1886 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).

, 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).

(Guiry and Guiry 2011, Guiry 2011)


Empire Eukaryota
Kingdom Chromista
Subkingdom Harosa
Infrakingdom Heterokonta
Phylum Ochrophyta
Subphylum Khakista
Class Mediophyceae
Subclass Thalassiosirophycidae
Order Thalassiosirales
Family Skeletonemaceae
Genus Detonula
Species D. pumila (Castracane) Gran 1900

(Guiry and Guiry 2011)


Photosynthetic. Reproduces sexually and asexually (Guiry 2011). Auxospores present (see description) (Cupp 1943).


Cells are cylindrical and are joined as straight chains. Close


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

are slightly convex with a depression in the centre, where a single distinct spine connects adjacent cells. Cells are also connected marginally by a ring of small spines, each of which splits off into two gelatinous threads joined to the spines of adjacent cell, forming a distinct zigzag pattern. Chloroplasts are numerous, small, star-shaped plates (Cupp 1943). Cell colour is yellow-brown (Guiry 2011).
The cell's central spine also has a polysaccharide thread that can sometimes be seen extending from corners of cells. Marginal spines are shaped as half-tubes. The valve surface has Close


(symmetry) Describing a shape that many axes of symmetry. That is, it does not have a left and right like humans do (bilateral symmetry), but can be divided into equal halves no matter where you place the axis. Some examples of radially symmetrical organisms include sea stars and centric diatoms like Thalassiosira.



Features that provide support to other structures in the cell.

and a few well-developed Close


In diatoms, the regularly repeated hexagonal holes on the valve walls (HPP 2003).

. Close

Girdle bands

The connecting elements between two valves of a diatom cell. "They enclose and protect the cell and also accommodate the increase in cell volume during the cell cycle" (Horner 2002).

Girdle bands
are numerous and collar-shaped with rows of areolae, forming incomplete loops. There are very small Close


(plural: puncta) A sharp tip or small point on any part of an organism's anatomy.

on the girdle bands (Horner 2002). Each valve has one marginal Close

Labiate process

In diatoms, a simple slit in the valve wall with two internal lips, one on each side of the slit. They can be useful in identification because they are positioned differently in different species (Horner 2002).

labiate process
(Kraberg et al. 2010). Auxospores are elliptical, single, and lay in the girdle-band zone. They are much larger in diameter than the mother cell (Cupp 1943).


Length 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
): 15 - 120 μm
Diameter: 15 - 45 μm
Areolae on Close


In diatoms, "the part of a valve that extends from the valve face, forming the valve edge." It is visible when the frustule is viewed in girdle view (Spaulding 2010).

surface: 18 - 20 in 10 μm
Marginal spines: 6 - 8 in 10 μm
(Cupp 1943, Hasle and Syvertsen 1997, Kraberg et al. 2010)

Similar species

Other cylindrical diatoms, such as Lauderia annulata and Skeletonema costatum. Adjacent cells of L. annulata are directly in contact with each other, whereas those of D. pumila are not (Kraberg et al. 2010). D. pumila can also be distinguished by the central spine fitting into the depression on the adjacent cell and also by the ring of smaller marginal spines forming the zigzags between cells.

Harmful effects

None known.


Neritic (Cupp 1943) and pelagic/oceanic (Gameiro et al. 2004, Cai et al. 2004).


Cosmopolitan, may prefer warmer waters (Hasle and Syvetsen 1997).
Summer and autumn in Northern European seas (Kraberg et al. 2010). Late spring around Portugal (Gameiro et al. 2004, Silva et al. 2008).
"Fairly common off southern California and in Gulf of California" (Cupp 1943).

Growth conditions

May be favoured by Close


A wind-driven mechanism of mixing the water column. Cold, dense, nutrient-rich, and often oxygen-poor water from depths rises to replace the warmer nutrient-poor surface water. This input of nutrients can have a significantly increase primary productivity in a region (Dugdale 1985).

events (Zúñiga 2011) and mixing of the Close

Water column

Referring to a water system from the surface to the bottom sediments. This can be used to understand processes of stratification, mixing and their relationship to nutrient transport. Temperature, salinity, pH, and nutrient levels often vary along the length of the water column.

water column
(Cabeçadas et al. 1999). Salinity ranges from 16 - 35 (Gameiro et al. 2004)

Environmental Ranges

Depth range (m): 0 - 470
Temperature range (°C): 2.387 - 29.386
Nitrate (μmol L-1): 0.061 - 11.093
Salinity: up to 36.252
Oxygen (mL L-1): 4.515 - 7.808
Phosphate (μmol L-1): 0.078 - 1.293

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): 0.754 - 25.562
(OBIS 2011, cited in EOL 2011)

Bloom characteristics

Information not available.


Cabeçadas, L., Brogueira, M. J. and Cabeçadas, G. 1999. Phytoplankton spring bloom in the Tagus coastal waters: hydrological and chemical conditions. Aquatic Ecology. 33(3): 243-250.

Cai, W. G., Jia, X. P. and Li, C. H. 2004. GIS-based analysis of the spatial-temporal variation of phytoplankton in the Western Guangdong Waters. Shengtai Xuebao. 24(10): 2143-2148.

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). 2011. Detonula pumila (Castracane) Gran. Accessed 14 Aug 2011.

Gameiro, C., Cartaxana, P., Cabrita, M. T. and Brotas, V. 2004. Variability in Chlorophyll and Phytoplankton Composition in an Estuarine System. Hydrobiologia. 525(1-3): 113-124.

Guiry, M. D. 2011. Detonula pumila (Castracane) Gran, 1900. Accessed 14 Aug 2011.

Guiry, M. D. and Guiry, G.M. 2011. Detonula pumila (Castracane) Gran. Accessed 14 Aug 2011.

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.

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). 2011. Detonula pumila. Accessed 14 Aug 2011.

Silva, A., Mendes, C. R., Palma, S. and Brotas, V. 2008. Short-time scale variation of phytoplankton succession in Lisbon bay (Portugal) as revealed by microscopy cell counts and HPLC pigment analysis. Estuarine, Coastal and Shelf Science. 79(2): 230-238.

Zúñiga, D., Alonso-Pérez, F., Castro, C. G., Arbones, B. and Figueiras, F. G. 2011. Seasonal contribution of living phytoplankton carbon to vertical fluxes in a coastal upwelling system (Ría de Vigo, NW Spain). Continental Shelf Research. 31(5): 414-424.

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