''Struvea'' is a genus of green macroalgae (or seaweed) in the family

Boodleaceae Boodleaceae is a family of green algae in the order Cladophorales Cladophorales are an order of green algae, in the class Ulvophyceae The Ulvophyceae or ulvophytes are a class of green algae, distinguished mainly on the basis of ultrastru ...

Taxonomy and Nomenclature

This genus was founded by

Otto Wilhelm Sonder Otto Wilhelm Sonder (18 June 1812, Bad Oldesloe – 21 November 1881) was a German botanist and pharmacist. Life A native of Holstein, Sonder studied at Kiel University, where he sat pharmaceutical examinations in 1835, before becoming the prop ...

in 1845 and was named in honor of the Russian ambassador H. de Struve. Initially, the genus name was in conflict with ''Struvea'' Reichenbach, a heterotypic synonym of ''Torreya'' Arnott but P.C. Silva formally conserved ''Struvea'' Sonder in 1952 to prevent further taxonomic problems. Currently, there is only four confirmed species for this genus. This low species number was due to the segregation of '' Phyllodictyon'' from ''Struvea sensu lato'' based on differences in cell division processes and later on supported by molecular data. The ''Struvea plumosa'' sample collected by

Ludwig Preiss Johann August Ludwig Preiss (21 November 1811 – 21 May 1883) was a German-born British botanist and zoologist. Early life Preiss was born in Herzberg am Harz. He obtained a doctorate, probably at Hamburg, then emigrated to Western Australia. ...

from western Australia was described by Sonder and now serves as the

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

species for this genus. The voucher specimen for the type species is housed at the Royal Botanic Gardens Melbourne (MEL).

Morphology

The

thallus Thallus (plural: thalli), from Latinized Greek (), meaning "a green shoot" or "twig", is the vegetative tissue of some organisms in diverse groups such as algae, fungi, some liverworts, lichens, and the Myxogastria. Many of these organisms wer ...

of ''Struvea'' is composed of a single to numerous (clumped) blades borne from a monosiphonous or

aseptate In biology, a septum (Latin for ''something that encloses''; plural septa) is a wall, dividing a cavity or structure into smaller ones. A cavity or structure divided in this way may be referred to as septate. Examples Human anatomy * Interatri ...

stipe (''i.e.'', stipitate in nature); moreover, the blades form a stellate or criss-cross network of 2–3 ranks of distichously-arranged pinnae (laterals) lying on one plane. Members of this genus exhibit one of the four major types of

cytokinesis Cytokinesis () is the part of the cell division process during which the cytoplasm of a single eukaryotic cell divides into two daughter cells. Cytoplasmic division begins during or after the late stages of nuclear division in mitosis and meios ...

within the order Cladophorales—segregative cellular division (SCD)—wherein the

cytoplasm In cell biology, the cytoplasm is all of the material within a eukaryotic cell, enclosed by the cell membrane, except for the cell nucleus. The material inside the nucleus and contained within the nuclear membrane is termed the nucleoplasm. The ...

of a mother cell divides simultaneously into several independent cytoplasms that would later on produce

cell walls 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 mech ...

and become daughter cells. Differences between the type of cell division process has been used to delineate the members of Cladophorales'','' most notably the delineation between ''Struvea'' and ''Phyllodictyon''—the latter of which exhibits centripetal invagination by a primordial septum (CI). In terms of its cellular ultrastructure, the cell walls of ''Struvea'' are composed of crystalline inclusions forming single crystals that are broad, prismatic, and hexagonal, diamond, needle-shaped, or triangular in shape. Chloroplasts are also reticulate or net-like with numerous

pyrenoids Pyrenoids are sub-cellular micro-compartments found in chloroplasts of many algae,Giordano, M., Beardall, J., & Raven, J. A. (2005). CO2 concentrating mechanisms in algae: mechanisms, environmental modulation, and evolution. Annu. Rev. Plant Bio ...

Distribution

''Struvea'' are widely distributed in the tropics and subtropics, mainly

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

and the tropical Western Pacific. ''Struvea elegans'' is the most widely distributed species encompassing the

Caribbean islands Almost all of the Caribbean islands are in the Caribbean Sea, with only a few in inland lakes. The largest island is Cuba. Other sizable islands include Hispaniola, Jamaica, Puerto Rico and Trinidad and Tobago. Some of the smaller islands are re ...

Oman Oman ( ; ar, عُمَان ' ), officially the Sultanate of Oman ( ar, سلْطنةُ عُمان ), is an Arabian country located in southwestern Asia. It is situated on the southeastern coast of the Arabian Peninsula, and spans the mouth of t ...

, and

Fiji Fiji ( , ,; fj, Viti, ; Fiji Hindi: फ़िजी, ''Fijī''), officially the Republic of Fiji, is an island country in Melanesia, part of Oceania in the South Pacific Ocean. It lies about north-northeast of New Zealand. Fiji consists ...

. Meanwhile, ''S. plumosa'' and ''S. thoracica'' are only found in

Oceania Oceania (, , ) is a region, geographical region that includes Australasia, Melanesia, Micronesia, and Polynesia. Spanning the Eastern Hemisphere, Eastern and Western Hemisphere, Western hemispheres, Oceania is estimated to have a land area of ...

. Lastly, ''S. okamurae'' seems to be restricted within the tropical Western Pacific with

Micronesia Micronesia (, ) is a subregion of Oceania, consisting of about 2,000 small islands in the western Pacific Ocean. It has a close shared cultural history with three other island regions: the Philippines to the west, Polynesia to the east, and ...

as the limit of its westernmost range. However, this distribution data on ''Struvea'' could just be an artefact of poor taxon sampling.

Ecology

Members of this genus are found on the

intertidal zone The intertidal zone, also known as the foreshore, is the area above water level at low tide and underwater at high tide (in other words, the area within the tidal range). This area can include several types of habitats with various species o ...

down to

mesophotic A Mesophotic coral reef or mesophotic coral ecosystem (MCE), originally from the Latin word ''meso'' (meaning middle) and ''photic'' (meaning light), is characterised by the presence of both light-dependent coral and algae, and organisms that can b ...

depths. ''Struvea plumosa'' inhabit limestone areas of the intertidal zone down to 33 meters deep. ''S. elegans'' are only restricted to mesophotic depths. ''S. okamurae'' is epilithic and found between 4–6 meters in depth. Lastly, ''S. thoracica'' thrive in subtidal channels and/or reef flats of about 15–18 m in depth with substrate primarily composed of shell fragments and coral debris.

Life history

Unfortunately, research on the life history of this genus is centered around its growth (SCD) rather than reproduction. However, being a member of family Boodleaceae the general cycle is believed to be diplontic and presence of zoospores have been observed.

Exploitation/Harvesting/Cultivation

Due to its unknown life cycle, relatively few representative species, and its tendency to inhabit subtidal areas—this genus is not harvested from the wild and there is no known culture technology.

Chemical composition/Natural products chemistry

Most chemistry research work on this genus is mainly centered around the calcium oxalate crystals present within the cell walls of the blades. Out of the four species, ''S. elegans'' does not possess any crystals while ''S. plumosa'' has diamond, triangular or pentagonal-shaped crystals and ''S. thoracica'' has needle-shaped ones.

Utilization and Management

Due to a lack of general interest and use, there is currently no utilization and management strategy for the members of this genus.

References

External links

Cladophorales genera Boodleaceae Taxa named by Otto Wilhelm Sonder {{Ulvophyceae-stub