Rhizosolenia

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Rhizosolenia
Systematics
without rank: Stramenopiles (stramenopiles) without rank: Diatomea Class : Coscinodiscophyceae Order : Rhizosolenianae Family : Rhizosoleniaceae Genre : Rhizosolenia
Scientific name
Rhizosolenia
Brightw.

Rhizosolenia is a genus of diatoms (diatoms). Rhizosolenia belongs to the centric diatoms and dominates the phytoplankton in some nutrient-rich tropical regions .

features

Rhizosolenia is a unicellular, needle-shaped diatom with a diameter of 2.5 to 170  µm . The shell consists of two separate frustules . Rhizosolenia reproduces asexually by dividing the frustules in half. With each asexual reproduction, the size of the cells halves. Only sexual reproduction restores the original size.

In addition, Rhizosolenia is known for a conspicuous cyclomorphosis . The ends of the shells are short and blunt in winter, but long and pointed in summer.

Way of life

Rhizosolenia occurs in algae mats from different Rhizosolenia species, e.g. B. from Rhizosolenia castracanei and Rhizosolenia imbricata var. Shrubsolei in the central North Pacific (October 1980). The aggregates can reach a size of up to 30 cm.

Rhizosolenia mats regularly migrate into water layers up to 300 m deeper in order to absorb nutrients ( nitrates ) that are depleted in the surface water. The buoyancy is controlled by the creation of carbohydrate reserves, which lead to the sinking. The rate of descent in Rhizosolenia setigera was determined to be 0.16–1.77 m d ⁻¹ (meters per day), the maximum rate of descent was 22.71 m d ⁻¹ . Consuming these ballast supplies creates buoyancy. Ascent rates for Rhizosolenia debyana were determined to be 37–166 m d ⁻¹ . A migration cycle lasts several days or weeks.

Aggregates of Rhizosolenia with other organisms occur. For example, chains of Rhizosolenia debyana were found in association with Oscillatoria , which reached a thickness of 1–2 m when there was little wind (<1–2 m s ⁻¹ ).

An estimated 9–13% of global biogenic silica production is due to Rhizosolenia species.

Systematics

The genus Rhizosolenia was established in 1843 by Christian Gottfried Ehrenberg with Rhizosolenia americana as the type species . Due to recent research results, the genus Rhizosolenia has been divided into the genera Rhizosolenia i.eS , Neocalyptrella , Pseudosolenia , Urosolenia and Proboscia .

Web links

• Rhizosolenia in algaebase.org

Individual evidence

1. ↑ First description ( memento of the original from June 23, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. 
2. ↑ ^{a b c d e} Entry in MicrobeWiki
3. ↑ RE Coker: The sea - the largest living space . Paul Parey, 1966, p. 138 .
4. ^ RS Wimpenny: The Size of Diatoms. I. The Diameter Variation of Rhizosolenia Styliformis Brightw. and R. Alata Brightw. in Particular and of Pelagic Marine Diatoms in General . In: Journal of the Marine Biological Association of the United Kingdom . tape 21 , no. 01 , November 1936, p. 29 , doi : 10.1017 / S0025315400011188 (English).
5. ↑ AL Alldredge, MW Silver: Abundance and production rates of floating diatom mats (Rhizosolenia castracanei and R. imbricata var shrubsolei.) In the eastern Pacific Ocean. In: Marine Biology 66, No. 1, 1982, pp. 83-88, doi : 10.1007 / BF00397258 .
6. ^ ^{A b} Inés Sunesen, Eugenia A. Sar: Marine diatoms from Buenos Aires coastal waters (Argentina). IV. Rhizosolenia s. str., Neocalyptrella, Pseudosolenia, Proboscia . In: Phycologia . tape 46 , no. 6 , November 2007, pp. 628 , doi : 10.2216 / 07-13.1 ( PDF ).
7. ↑ Theodore J. Smayda, Brenda J. Boleyn: Experimental observations on the flotation of marine diatoms. II. Skeletonema costatum and Rhizosolenia setigera. In: Limnology and Oceanography 11, No. 1, 1966, pp. 18-34, doi : 10.4319 / lo.1966.11.1.0018 (PDF).
8. ^ ^{A b} Tracy A. Villareal: Positive buoyancy in the oceanic diatom Rhizosolenia debyana H. Peragallo. In: Deep Sea Research Part A. Oceanographic Research Papers 35, No. 6, 1988, pp. 1037-1045, doi : 10.1016 / 0198-0149 (88) 90075-1 .
9. ↑ Suk-Min Yun, Sang-Deuk Lee, Jin-Hwan Lee: Morphology and distribution of some marine diatoms, family Rhizosoleniaceae, genus Rhizosolenia, in Korean coastal waters . In: ALGAE . tape 26 , no. 2 , June 15, 2011, p. 141 , doi : 10.4490 / algae.2011.26.2.141 (English, PDF ). PDF ( Memento of the original from June 23, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.