Cerataulina pelagica

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 Diameter 7-60 μm, length 25-120 μm
Colour Yellow-brown
Connection Hair-like Close


A natural projection or appendage on an organism.

on blunt projections
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
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. Forms 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.

Variable characteristics between seasons/years.
Harmful effects Mechanical irritation to gills of fish and Close


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

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 Temperate to warm waters
Seasonal Late spring to 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).

26 - 36
Temperature -1 - 29°C


Cerataulina bergonii (H. Peragallo) Schütt 1896 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.

Cerataulus bergonii H. Peragallo 1892 (heterotypic)
Zygoceros pelagicum Cleve 1889 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)


Empire Eukaryota
Kingdom Chromista
Subkingdom Harosa
Infrakingdom Heterokonta
Phylum Ochrophyta
Subphylum Khakista
Class Mediophyceae
Subclass Biddulphiophycidae
Order Hemiaulales
Family Hemiaulaceae
Genus Cerataulina
Species C. pelagica (Cleve) Hendey 1937

(Guiry and Guiry 2011)


Photosynthetic. Reproduction sexual and asexual (Guiry 2011). Forms auxospores (Kustenko 1979). May form 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 stage
cells (Ishii et al. 2009).


Cells are cylindrical and usually in chains. Close


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

are slightly arched, with two blunt projections on opposite margins, each with a fine, small, curved, hair-like process. Cells are connected via these hair-like processes (Cupp 1943). Valves twist around the 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
, making the connections on one end roughly perpendicular to the other end (Kraberg et al. 2010). "Chloroplasts are numerous and small. 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.

sits against the cell wall" (Cupp 1943). Cells are yellow-brown in colour (Guiry 2011).


"In some diatoms, the space between the valves of adjacent cells in chains" (Horner 2002).

between cells are often very small. Close

Intercalary bands

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

Intercalary bands
are numerous and Close



. Cell walls are soft and weakly Close


Describing the character (i.e., white, shimmery) or chemical presence silicon dioxide (SiO2) as a component of phytoplankton cell covering.

, collapsing when dried. Sculpturing very delicate" (Cupp 1943). "The 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
is central or subcentral. 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 indistinct" (Horner 2002). "A Close


Features that provide support to other structures in the cell.

and Close


Describing a surface that contains many holes. Synonym: areolated.

plate Close

Costate ocellus

"A plate of silica pierced by closely packed pores" with siliceous ribs between each row of pores (Tomas 1997).

(costate ocellus
) is located at the base of the process (not seen 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).

light microscopy
)" (Kraberg et al. 2010).


Length (pervalvar axis): 25 - 120 μm
Diameter: 7 - 60 μm
Valve 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).

: 14 - 25 in 10 μm
(Hasle and Syvertsen 1980, Kraberg et al. 2010)

Similar species

Other cylindrical diatoms, such as Guinardia delicatula. C. pelagica can be distinguished by the conspicuous cell connections that twist around the pervalvar axis, making the connections on one end roughly perpendicular to the other end (Kraberg et al. 2010).

Harmful effects

Can cause mechanical irritation in fish gills, possibly resulting in mortalities (Taylor et al. 1985). Suspected to produce oxylipins (oxygenase-derived metabolites), other than PUAs (polyunsaturated aldehydes), that can negatively affect copepod reproduction (Ianora et al. 2008). After Close


(settling out) The tendency for particles to settle out of the water column and come to rest at the bottom due to gravitational forces. Factors that influence the rate of sedimentation are particle size, water density and currents.

, blooms can inhibit growth of benthic shellfish by clogging the gills (Lorrain et al. 2000).


Neritic (Cupp 1943).




Widely distributed; occurring in many parts in the world.

in coastal regions, concentrating in temperate to warm waters (Kraberg et al. 2010).
Blooms in late spring and summer (Gayoso 1999).
"Common off California, in the Gulf of California, and north to Alaska" (Cupp 1943).

Growth conditions

Blooms often occur when 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.

are depleted by previous diatom blooms and temperature rises (Ault et al. 2000, cited in Ianora et al. 2008). Requires salinities above 20 (Carstensen et al. 2007). May be able to store nutrients and would therefore be adapted to living in environments where available nutrients are inconsistent (Pinckney et al. 1999, Tozzi et al. 2004, Katz et al. 2005, all cited in Philips et al. 2010). May be more common in areas with more intense turbulence, which is needed to keep the larger non-motile diatoms in the Close


The zone near the surface of the water where the light intensity is sufficient to support net photosynthesis (Letelier et al. 2004). Defined as the area above "the depth at which the photon flux equals 1% of the flux measured just above the air-sea interface" (Ryther 1956).

zone (Lauria et al. 1999). Often appears together with Guinardia delicatula, Leptocylindrus danicus, and Dactyliosolen fragilissimus (Hasle and Syvertsen 1997).

Environmental Ranges

Depth range (m): 0 - 305
Temperature range (°C): -1.023 - 29.468
Nitrate (μmol L-1): 0.053 - 9.622
Salinity: 25.730 - 36.252
Oxygen (mL L-1): 4.444 - 8.419
Phosphate (μmol L-1): 0.046 -1.177

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): 1.153 - 22.728
(OBIS 2011, cited in EOL 2011)

Bloom characteristics

Bloom characteristics are often quite variable between different seasons and years (Gayoso 1999).


Ault, T., Velzeboer, R. and Zammit, R. 2000. Influence of nutrient availability on phytoplankton growth and community structure in the Port Adelaide River, Australia: bioassay assessment of potential nutrient limitation. Hydrobiologia. 429: 89-103.

Carstensen, J., Henriksen, P. and Heiskanen, A. S. 2007. Summer algal blooms in shallow estuaries: Definition, mechanisms, and link to eutrophication. Limnology and Oceanography. 52(1): 370-384.

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. Cerataulina pelagica (Cleve) Hendey. http://www.eol.org/pages/912091. Accessed 08 Jul 2011.

Gayoso, A. M. 1999. Seasonal Succession Patterns of Phytoplankton in the Bahía Blanca Estuary (Argentina). Botanica Marina. 42: 367-375.

Guiry, M. D. 2011. Cerataulina pelagica (Cleve) Hendey, 1937. World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=149619. Accessed 08 Jul 2011.

Guiry, M. D. and Guiry, G. M. 2011. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org. Accessed 08 July 2011.

Hasle, G. R. and Syvertsen, E. E. 1980. The diatom genus Cerataulina: morphology and taxonomy. Bacillaria. 3: 79-113.

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.

Ianora, A., Casotti, R., Bastianini, M., Brunet, C., D'Ippolito, G., Acri, F., Fontana, A., Cutignano, A., Turner, J. T. and Miralto, A. 2008. Low reproductive success for copepods during a bloom of the non-aldehyde-producing diatom in the North Adriatic Sea. Marine Ecology. 29(3): 399-410.

Ishii, K., Ishikawa, A. and Imai, I. 2009. Marine diatoms emerged from in situ surface sediment in a temperate embayment. Phycologia. 48(4, suppl.): 48.

Katz, M. E., Finkel, Z. V., Grzebyk, D., Knoll, A. H. and Falkowski, P. G. 2005. Evolutionary trajectories and biogeochemical impacts of marine eukaryotic phytoplankton. Annual Reviews of Ecology and Systematics. 35: 523-556.

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

Kustenko, N. G. 1979. Characteristic features of ontogenesis in the alga Cerataulina bergonii. Biologiya Morya. 2: 79-82.

Lauria, M. L., Purdie, D. A. and Sharples, J. 1999. Contrasting phytoplankton distributions controlled by tidal turbulence in an estuary. Journal of Marine Systems. 21: 189-197.

Lorrain, A., Paulet, Y. M., Chauvaud, L., Savoye, N., Nezan, E., Guerin, L. Growth anomalies in Pecten maximus from coastal waters (Bay of Brest, France): relationship with diatom blooms. Journal of Marine Biological Association of the United Kingdom, 80(4): 667-673.

Ocean Biogeographic Information System (OBIS). 2011. Cerataulina pelagica. http://www.iobis.org/mapper/?taxon_id=418638. Accessed 08 Jul 2011.

Philips, E. J., Badylak, S., Christman, M. C. and Lasi, M. A. 2010. Climatic Trends and Temporal Patterns of Phytoplankton Composition, Abundance, and Succession in the Indian River Lagoon, Florida, USA. Estuaries and Coasts. 33(2): 498-512.

Pinckney, J. L., Paerl, H. W. and Harrington, M. B. 1999. Responses of the phytoplankton community growth rate to nutrient pulses in variable estuarine environments. Journal of Phycology. 35: 1455-1463.

Taylor, F. J., Taylor, N. J. and Walsby, J. R. 1985. A bloom of the planktonic diatom, Cerataulina pelagica, off the coast of northeastern New Zealand in 1983, and its contribution to an associated mortality of fish and benthic fauna. Internationale Revue der gesamten Hydrobiologie. 70(6): 773-795.

Tozzi, S., Schofield, O. and Falkowski, P. 2004. Historical climate change and ocean turbulence as selective agents for key phytoplankton functional groups. Marine Ecology Progress Series. 274: 123-132.

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