:Ditylum brightwellii

{{Speciesbox

| image = Ditylum_brightwellii2.jpg

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| genus = Ditylum

| species = brightwellii

| authority = (T.West) Grunow in Van Heurck

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Ditylum brightwellii is a species of cosmopolitan marine centric diatoms. It is a unicellular photosynthetic autotroph that has the ability to divide rapidly and contribute to spring phytoplankton blooms.{{cite journal|last1=Rynearson|first1=Tatiana A.|author-link1=Tatiana Rynearson|last2=Armbrust|first2=E. Virginia |author-link2=E. Virginia Armbrust|year=2005 |title=Maintenance of clonal diversity during a spring bloom of the centric diatom Ditylum brightwellii |journal=Molecular Ecology |volume=14 |issue=6 |pages=1631–1640 |doi=10.1111/j.1365-294X.2005.02526.x |pmid=15836638|bibcode=2005MolEc..14.1631R |s2cid=39671471 }}

Description

The D. brightwellii cell has a high length to diameter ratio. The cell wall is silicified, as is characteristic of all diatoms. This hard, porous covering is known as the frustule and causes the cell to be more dense than the surrounding water. Oceanic currents and surface winds prevent D. brightwellii cells from sinking beneath the euphotic zone. Cells range in size from 25–100μm in diameter and 80–130μm in length. The valve is most often triangular in shape, but can also be biangular or quadrangular.{{cite web|url=http://www.algaebase.org/search/genus/detail/?genus_id=44389 |title=Ditylum J.W.Bailey, 1861: 163 |publisher=Algaebase |date= |accessdate=4 November 2013}} A long hollow tube called the rimoportula is located centrally and extends from each valve

Distribution

Ditylum brightwellii is found in all global oceans except in polar waters.{{cite web|url=http://www.sms.si.edu/irlspec/Ditylu_bright.htm |title=Ditylum brightwellii |publisher=Smithsonian Institution |date=25 September 2011 |accessdate=4 November 2013}} Genetically distinct populations were observed over the course of a spring bloom in Puget Sound, suggesting that certain genetic lineages are better adapted to certain environmental conditions.

Life cycle

File:Dytilum Brightwelli 3.jpg]]

Ditylum brightwellii reproduces primarily asexually, creating clonal lineages. Vegetative cells are capable of enlargement and may also produce resting spores.Hargraves PE (1984) Resting spore formation in the marine diatom Ditylum brightwellii (West) Grun. ex V.H. In: Proceedings of the Seventh International Diatom Symposium, Philadelphia, 22–27 August 1982 (ed. Mann DG), pp. 33–46. Otto Koeltz-Science, Koenigstein. However, samples from Puget Sound, WA display high genetic diversity.{{cite journal |last1=Rynearson |first1=T. A. |author-link1=E. Virginia Armbrust|last2=Newton |first2=J. A. |last3=Armbrust |first3=E. V. |year=2006 |title=Spring bloom development, genetic variation, and population succession in the planktonic diatom Ditylum brightwellii |journal=Limnology and Oceanography |volume=51 |issue=3 |pages=1249–1261 |doi=10.4319/lo.2006.51.3.1249 |bibcode=2006LimOc..51.1249R |doi-access= }} This is indicative of sexual reproduction (auxospore formation). Clonal isolates have observed to produce both sperm and eggs.{{cite journal|last1=Koester|first1=Julie A.|last2=Brawley|first2=Susan H.|author-link2=Susan Brawley|last3=Karp-Boss|first3=Lee|last4=Mann|first4=David G.|title=Sexual reproduction in the marine centric diatom Ditylum brightwellii (Bacillariophyta)|journal=European Journal of Phycology|volume=42|issue=4|year=2007|pages=351–366|issn=0967-0262|doi=10.1080/09670260701562100|s2cid=80737380 |doi-access=free|bibcode=2007EJPhy..42..351K }} Two eggs are produced from each oogonium and 64 sperm are produced from each spermatogonangium. The frequency of sexual reproduction in D. brightwellii is not clear, although conditions including increased nutrients, temperatures ranging from 10 °C-14 °C, and a short photoperiod may be favorable for sexual reproduction.

:Ditylum brightwellii

Description

Distribution

Life cycle

References

Further reading