Asterionellopsis glacialis

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 Needle-like with a triangular base
Size Length 30 - 150 μm
Colour Yellow-brown
Connection Direct contact between Close


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

face of base
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.

1 to 2, plate-like, located in base
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.

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).

Geographic Close


Widely distributed; occurring in many parts in the world.

Seasonal Usually more abundant in spring and 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).

31 - 38
Temperature 2 - 29 °C


Asterionella glacialis Castracane 1886 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).

, 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).

Asterionella japonica Cleve 1882 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.

(Guiry and Guiry 2012)


Empire Eukaryota
Kingdom Chromista
Subkingdom Harosa
Infrakingdom Heterokonta
Phylum Ochrophyta
Subphylum Khakista
Class Bacillariophyceae
Subclass Fragilariophycidae
Order Fragilariales
Family Fragilariaceae
Genus Asterionellopsis
Species A. glacialis (Castracane) Round 1990

(Guiry and Guiry 2012)


Photosynthetic. Reproduces sexually and asexually (Guiry 2012).


Cells are needle-shaped and arranged in star-like and helical chains. 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, cells have a narrow and elongated neck with a broad triangular base (Cupp 1943). The end of the neck is not lobed. Adjacent cells are attached by the valve face of the base; therefore cells are usually seen in girdle view (Kraberg et al. 2010). In valve view, the base is lobed. One or two plate-like chloroplasts are located in the base (Cupp 1943). Cells are yellow-brown in colour (Guiry 2012).
Characteristics observable under Close


(scanning electron microscope) A microscope which applies "a focused beam of high-energy electrons to generate a variety of signals at the surface of solid specimens" (NSF 2011).

: "Slit fields or Close


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

pores at both ends of valve. A single 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
present at the narrow end of the valve" (Horner 2002). Transapical 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).

are very delicate (Cupp 1943).


Total length (apical axis): 30 - 150 μm
Length of base: 10 - 25 μm
Width of base Close

Transapical axis

In diatoms, the longitudinal axis of the valve.

(transapical axis
): 7 - 18 μm
Height of base 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 - 15 μm
Transapical striae: 28 - 34 in 10 μm
(Cupp 1943, Kraberg et al. 2010)

Similar species

Asterionella species, which have a much wider neck, and the end of the neck is not lobed.

Harmful effects

None known.


Neritic (Cupp 1943) and Close


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

(Brown and McLachlan 1990). Sometimes regarded as an Close


Of or relating to estuaries.

species (Jouenne et al. 2007).


Geographic: Cosmopolitan. Sometimes very abundant in cold to temperate regions (Hasle and Syvertsen 1997).
Seasonal: Can be present in high abundances in late spring and summer in Northern European seas (Kraberg et al. 2010). Present throughout the year but more abundant in spring in coastal Belgian waters (Rousseau et al. 2002). Abundant during summer 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).

and Close


The development of distinct non-mixing layers in the water column resulting from a steep gradient in density, which is caused by differences in temperature and/or salinity.

in Northwest Spain (Z&uactue;ñiga et al. 2011). Blooms in spring in the Bay of Bengal, India (Mishra et al. 2006). More abundant in the winter around Southern Brazil due to frequent southerly winds (Rörig and Garcia 2003, cited in Odebrecht et al. 2010).
Local: Sometimes present during the summer in short-lived medium abundance populations.

Growth conditions

Usually highly abundant after upwelling from southerly polar winds (Odebrecht et al. 1995, Rürig and Garcia 2003, cited in Odebrecht et al. 2010). May be favoured by freshwater inputs (Pannard et al. 2008).

Environmental Ranges

Depth range (m): 0 - 133
Temperature range (°C): 2.147 - 29.386
Nitrate (μmol L-1): 0.056 - 20.029
Salinity (PSU): 30.638 - 37.775
Oxygen (mL L-1): 4.515 - 7.716
Phosphate (μmol L-1): 0.061 - 1.656

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): 0.733 - 35.557
(OBIS, cited in EOL)

Bloom characteristics

Information not available.


Brown, A. C. and McLachlan, A. 1990. Ecology of sandy shores. Elsevier, Amsterdam. 328.

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. Asterionellopsis glacialis. Accessed 21 Jan 2012.

Guiry, M. D. 2012. Asterionellopsis glacialis (Castracane) Round, 1990. Accessed 21 Jan 2012.

Guiry, M. D. and Guiry, G. M. 2012. Asterionellopsis glacialis (Castracane) Round. Accessed 21 Jan 2012.

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.

Jouenne, F., Lefebvre, S., Véron, B. and Lagadeuc, Y. Phytoplankton community structure and primary production in small intertidal estuarine-bay ecosystem (eastern English Channel, France). Marine Biology. 151: 805-825.

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

Mishra, S., Sahu, G., Mohanty, A. K., Singh, S. K. and Panigrahy, R. C. 2006. Impact of the diatom Asterionella glacialis (Castracane) bloom on the water quality and phytoplankton community structure in coastal waters of Gopalpur Sea, Bay of Bengal. Asian Journal of Water, Environment and Pollution. 3(2): 71-77.

Ocean Biogeographic Information System (OBIS). 2012. Asterionellopsis glacialis. Accessed 21 Jan 2012.

Odebrecht, C., Bergesch, M., Rörig, L. R. and Abreu, P. C. 2010. Phytoplankton interannual variability at Cassino Beach, Southern Brazil (1992-2007), with emphasis on the surf zone diatom Asterionellopsis glacialis. 33(2): 570-583.

Odebrecht, C., Segatto, A. Z. and Freitas, C. A. 1995. Surf-zone chlorophyll a variability at Cassino Beach, Southern Brazil. Estuarine Coastal and Shelf Science. 41: 81-90.

Pannard, A., Claquin, P., Klein, C., Le Roy, B. and Véron, B. 2008. Short-term variability of the phytoplankton community in coastal ecosystem in response to physical and chemical conditions' changes. Estuarine, Coastal and Shelf Science. 80(2): 212-224.

Rörig, L. R. and Garcia, V. M. T. 2003. Accumulations of the surf-zone diatom Asterionellopsis glacialis (Castracane) Round in Cassino Beach, Southern Brazil, and its relationship with environmental factors. Journal of Coastal Research. 19: 167-177.

Rousseau, V., Leynaert, A., Daoud, N. and Lancelot, C. Diatom succession, silicification and silicic acid availability in Belgian coastal waters (Southern North Sea). Marine Ecology Progress Series. 236: 61-73.

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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