''Thalassiosira weissflogii'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...

of centric

diatom A diatom ( Neo-Latin ''diatoma''), "a cutting through, a severance", from el, διάτομος, diátomos, "cut in half, divided equally" from el, διατέμνω, diatémno, "to cut in twain". is any member of a large group comprising se ...

s, a unicellular microalga. It is found in marine environments and also in inland waters in many parts of the world. It is actively studied because it may use C4-plant style strategies to increase its photosynthetic efficiency.

Taxonomy

rDNA evidence suggests that ''Thalassiosira weissflogii'' is a

species complex In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...

and that several different genetic populations exist. There was found to be a divergence between one

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English ter ...

from the east and west Atlantic Ocean and California and another from

Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only stat ...

and

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Gui ...

. The latter was considered to consist of two different biological species, one from Hawaii and one from the Indonesian archipelago.

Description

''Thalassiosira weissflogii'' is a short cylinder in shape and varies in size from 4 to 32 µm in diameter. It tends to be larger in winter, typically 15 µm in diameter, but smaller in summer (5 µm).TW1200
Reed Mariculture Inc. Retrieved 2011-11-18. It occurs both singly and in groups and may be embedded in a gelatinous matrix. There is a

silica Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is ...

ceous

cell wall A cell wall is a structural layer surrounding some types of cells, just outside the cell membrane. It can be tough, flexible, and sometimes rigid. It provides the cell with both structural support and protection, and also acts as a filtering mec ...

with two

frustule A frustule is the hard and porous cell wall or external layer of diatoms. The frustule is composed almost purely of silica, made from silicic acid, and is coated with a layer of organic substance, which was referred to in the early literature on ...

s or valves, a larger epivalve and a smaller hypovalve. The face of the valves vary in shape but are basically irregular rings with one labiate and two or more central

processes A process is a series or set of activities that interact to produce a result; it may occur once-only or be recurrent or periodic. Things called a process include: Business and management *Business process, activities that produce a specific se ...

. Other features that may be present include an irregularly shaped areola or pore, further processes on the rim of the valves, marginal spines, striations and thick radial ribs.''Thalassiosira weissflogii'' (Grunow) G. Fryxell & Hasle, (1896) 1977
USGS. Retrieved 2011-11-18.

Distribution and habitat

The native range of ''Thalassiosira weissflogii'' is unclear, but it is found in marine, brackish and freshwater environments. It seems to grow best at higher

salinities Salinity () is the saltiness or amount of salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensionless and equal ...

and occurs in coastal waters in the

Atlantic The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...

and

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the conti ...

s and in rivers and lakes in Europe, Asia, South and North America, including the

Great Lakes The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes in the mid-east region of North America that connect to the Atlantic Ocean via the Saint Lawrence River. There are five lakes ...

, where it was thought to have been introduced in ballast water.

Ecology

''Thalassiosira weissflogii'' is non-toxic but it is sometimes associated with other microalgae that cause

algal bloom An algal bloom or algae bloom is a rapid increase or accumulation in the population of algae in freshwater or marine water systems. It is often recognized by the discoloration in the water from the algae's pigments. The term ''algae'' encompass ...

s or

red tide A harmful algal bloom (HAB) (or excessive algae growth) is an algal bloom that causes negative impacts to other organisms by production of natural algae-produced toxins, mechanical damage to other organisms, or by other means. HABs are sometimes ...

s. It is very tolerant to poor water quality. It flourishes in environments with high

carbon dioxide Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is t ...

levels, high

chlorine Chlorine is a chemical element with the symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine i ...

, high

cadmium Cadmium is a chemical element with the Symbol (chemistry), symbol Cd and atomic number 48. This soft, silvery-white metal is chemically similar to the two other stable metals in group 12 element, group 12, zinc and mercury (element), mercury. Li ...

and high pH. Its growth may be limited by the availability of iron, nickel, zinc, nitrogen and silicon. Cadmium is actually a nutrient for the diatom, and not just a toxin. If zinc is deficient in the environment, the diatom switches to a different version of

carbonic anhydrase The carbonic anhydrases (or carbonate dehydratases) () form a family of enzymes that catalyze the interconversion between carbon dioxide and water and the dissociated ions of carbonic acid (i.e. bicarbonate and hydrogen ions). The active sit ...

enzyme, which uses cadmium instead of zinc as a cofactor. *

Biology

Reproduction in ''Thalassiosira weissflogii'' can be by either asexual or sexual means. The asexual phase involves cell division with each of the new individuals receiving one of the valves. This means that the offspring are of unequal sizes and successive generations tend to decrease in size. Large individuals can also reproduce sexually. This event may be triggered by some external factor such as a variation in light intensity, temperature or day length.

Uses

aquaculture Aquaculture (less commonly spelled aquiculture), also known as aquafarming, is the controlled cultivation ("farming") of aquatic organisms such as fish, crustaceans, mollusks, algae and other organisms of value such as aquatic plants (e.g. lot ...

, ''Thalassiosira weissflogii'' is used to feed to

shrimp Shrimp are crustaceans (a form of shellfish) with elongated bodies and a primarily swimming mode of locomotion – most commonly Caridea and Dendrobranchiata of the decapod order, although some crustaceans outside of this order are ref ...

and

shellfish Shellfish is a colloquial and fisheries term for exoskeleton-bearing aquatic invertebrates used as food, including various species of molluscs, crustaceans, and echinoderms. Although most kinds of shellfish are harvested from saltwater environ ...

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. ...

e in hatcheries. It is considered preferable for this purpose to the other commercially available microalgae, ''

Chaetoceros ''Chaetoceros'' is probably the largest genus of marine planktonic diatoms with approximately 400 species described, although many of these descriptions are no longer valid. It is often very difficult to distinguish between different ''Chaeto ...

'' and ''

Tetraselmis ''Tetraselmis'' is a genus of phytoplankton. ''Tetraselmis'' is a green algal genus within the order Chlorodendrales, and they are characterized by their intensely-colored green chloroplast, their flagellated cell bodies, the presence of a pyreno ...

'', because of its larger size which means it can continue to be used at more advanced larval stages. It is available as a culture of "Instant Algae" which can be stored at 0-4 °C.