Leptocylindrus danicus

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 20 - 50 μm, diameter 5 - 16 μm
Colour Yellow-brown
Connection Direct cell-to-cell contact
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, Close


Oval or egg-shaped.

, distributed throughout cell
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.

in coastal/shelf waters except in polar regions
Seasonal Very abundant in late spring and summer 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).

20 - 36
Temperature 15 - 20 °C (optimal)




Empire Eukaryota
Kingdom Chromista
Subkingdom Harosa
Infrakingdom Heterokonta
Phylum Ochrophyta
Subphylum Khakista
Class Coscinodiscophyceae
Subclass Chaetocerotophycidae
Order Leptocylindrales
Family Leptocylindraceae
Genus Leptocylindrus
Species L. danicus Cleve 1889

(Guiry and Guiry 2011)


Photosynthetic. Reproduces sexually and asexually (Guiry 2011). Close

Resting spore

In diatoms, a cell that requires a dormancy period prior to germination and can survive for several years; usually developed to survive adverse conditions. They are commonly observed in centric but not pennate diatoms. The morphology of the spore may be similar or different from a vegetative cell; they usually have heavily silicified walls and are rich in storage products (Horner 2002).

Resting spores
and Close


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

present (Cupp 1943; see Description and Growth Conditions sections below).


Cells are cylindrical and form long, straight chains. Cells are connected by the whole Close


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

surface. The central parts of the valve face may be slightly convex/concave, fitting into the concavity/convexity of an adjacent valve. Cells are thin-walled and do not have any obvious Close


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

or Close


A natural projection or appendage on an organism.

. Using 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).

, short flap-like spines are visible on the border between the valve face and 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).

(Hasle and Syvertsen 1997). Chloroplasts are numerous small ovoid plates, distributed throughout the cell (Cupp 1943).

Intercalary bands

Girdle bands that are furthest away from the valve (Smithsonian 2011).

Intercalary bands
are not visible with Close


(light microscopy) "Using a microscope in which a beam of light passes through optical lenses to view an image of the specimen" (MCM LTER 2010).

. Resting spores form as a result of sexual reproduction, they consist of two unequal valves and are found in an auxospore (Horner 2002). Resting spores are covered with Close


Small, needlelike structures.

(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
): 20 - 50 μm
Diameter: 5 - 16 μm
(Hasle and Syvertsen 1997, Kraberg et al. 2010)

Similar species

General appearance and size of Guinardia delicatula resemble those of L. danicus, but the former has a distinct Close


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

spine on each valve end. L. danicus can be distinguished from L. minimus by its larger size and also by the chloroplasts: numerous ovoid chloroplasts are distributed throughout the cell in the former, while only two elongated ones are located near the centre of the latter (Hasle and Syvertsen 1997).

Harmful effects

None known.


Neritic (Cupp 1943).


"Cosmopolitan in coastal and shelf waters, common north temperate species" (Horner 2002). Absent or scarce in the subantarctic and Southern Ocean (Hasle and Syvertsen 1997).
Very abundant in late spring and summer in Northern European seas (Kraberg et al. 2010). Abundant during the summer in Norwegian fjords (Hasle and Syvertsen 1997). Peaks in spring and autumn around the South China Sea (Chen 1993).
"Fairly common off southern California. Reported at Scotch Cap, Alaska, and in Gulf of California where it may become even moderately abundant at times" (Cupp 1943).

Growth conditions

Optimal temperature range between 15 and 20 °C (Verity 1982). Common 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).

events (Casas et al. 1999). Cell density directly correlated with Close


(dissolved inorganic phosphorous) The total concentration of all orthophosphates (PO43-, e.g., HPO42-, H2PO4-, H3PO4, etc.) dissolved in the water (Harrison et al. 2005).

dissolved inorganic phosphorus
(Chen 1993). Resting spores quickly form during the Close


Various chemical substances that an organism needs for metabolism (i.e., to live and grow). These are usually taken up from the environment. Some examples include nitrate, phosphate, silica (for diatoms), iron, copper, etc. Some nutrients, like copper, are required for growth, but can also be toxic at high levels.

depletion that follows upwelling events, although the absolute number is still very low (Ishizaka et al. 1987). In the laboratory, nitrogen depletion at 10 and 15 °C caused almost all narrower cells (diameter less than 8 μm) to become sexual (French and Hargraves 1985).

Environmental Ranges

Depth range (m): 0 - 470
Temperature range (°C): -1.779 - 29.468
Nitrate (μmol L-1): 0.053 - 30.487
Salinity: 19.590 - 36.252
Oxygen (mL L-1): 4.444 - 9.116
Phosphate (μmol L-1): 0.046 - 2.337

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 - 59.801
(OBIS 2011, cited in EOL 2011)

Bloom characteristics

Information not available.


Casas, B., Varela, M. and Bode, A. 1999. Seasonal succession of phytoplankton species on the coast of A Coruña (Galicia, northwest Spain). Boletin del Instituto Español de Oceanografia. 15(1-4): 413-429.

Chen, W. 1993. Population ecology of Leptocylindrus danicus in Dapeng Bay, north of South China Sea. Marine Science Bulletin/Haiyang Tongbao. 12(2): 39-45.

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. Leptocylindrus danicus. http://eol.org/pages/911506/overview. Accessed 3 Sep 2011.

French, F. W. III and Hargraves, P. E. 1985. Spore formation in the life cycles of the diatoms Chaetoceros diadema and Leptocylindrus danicus. Journal of Phycology. 21(3): 477-483.

Guiry, M. D. 2011. Leptocylindrus danicus Cleve, 1889. http://www.marinespecies.org/aphia.php?p=taxdetails&id=149106. Accessed 3 Sep 2011.

Guiry, M. D. and Guiry, G. M. 2011. Leptocylindrus danicus Cleve. http://www.algaebase.org/search/species/detail/?species_id=38350. Accessed 3 Sep 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.

Ishizaka, J., Kaichi, M. and Takahashi, M. 1987. Resting spore formation of Leptocylindrus danicus (Bacillariophyceae) during short time-scale upwelling and its significance as predicted by a simple model. Ecological Research. 2(3): 229-242.

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. Leptocylindrus danicus. http://www.iobis.org/mapper/?taxon_id=461972. Accessed 3 Sep 2011.

Verity, P. G. 1982. Effects of temperature, irradiance, and daylength on the marine diatom Leptocylindrus danicus Cleve. IV. Growth. Journal of Experimental Marine Biology and Ecology. 60(2-3): 209-222.

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