DIATOMEAS BENTÓNICAS ASOCIADAS A TROMBOLITOS VIVOS

D. A. Siqueiros-Beltrones

Abstract


Se determinó el primer elenco florístico de diatomeas asocia das a trombolitos vivos (protrombolitos). Estos sustratos que exhiben condiciones particulares de estabilidad, fueron descubiertos en playas de la Ensena da de La Paz, B.C.S. y representan un nuevo sustrato para el desarrollo de diatomeas bentónicas marinas. Se examinaron fragmentos de protrombolitos recolectados mensualmente, de agosto a noviembre de 2005, en cuatro sitios de la Ensenada. La envoltura de los protrombolitos consiste en un complejo de cianofitas: Microcoleus chthonoplastes, Oscillatoria limosa/Lyngbia aestuarii y otras formas filamentosas. Se identificaron 150 taxa de diatomeas, principalmente formas pennadas. La presencia de ciertos taxa evidencia la influencia de los manglares y ambientes hipersalinos aledaños. Aunque la composición de especies no difiere de otras asociaciones de la región, los taxa dominantes son distintos; los más frecuentes son: Mastogloia pumila (Grun.) Cleve, Mastogloia obliqua Hagelstein, Navicula formenterae Cleve, Nitzschia frustulum var. perminuta Grunow, Nitzschia scalpelliformis (Grun.) Grunow, Nitzschia sigma (Kütz.) W. Smith, Psammodyction constricta (Kütz.) Ralfs, Rhopalodia gibberula (Ehr.) O. Müller, Seminavis sp. 1. La riqueza de especies es considerada alta, dada la estabilidad y homogeneidad del sistema protrombolítico.

Benthic diatoms associated to living thrombolites

The first floristic account of benthic diatoms associated to recent (living) thrombolites or protrombolites was determined. These sedimentary formations generated by cyanophytes that exhibit particular conditions of stability were discovered in beaches of Ensenada de La Paz. These represent new substrata for the growth of marine benthic diatoms. Fragments of pro-thrombolites collected monthly from August to November in four sites of the Ensenada were examined. The pro-thrombolite cover consisted of a cyanophyte complex where Microcoleus chthonoplastes, Oscillatoria limosa/Lyngbia aestuarii, and other filamentous forms are the main components. A total of 150 diatom taxa were identified, mainly pennate forms. The presence of certain taxa shows the influence of nearby mangroves and hypersaline environments. Although the species composition does not seem to differ from other assemblages in the region, dominant taxa are different. The most frequent taxa were: Mastogloia pumila (Grun.) Cleve, Mastogloia obliqua Hagelstein, Navicula formenterae Cleve, Nitzschia frustulum var. perminuta Grunow, Nitzschia scalpelliformis (Grun.) Grunow, Nitzschia sigma (Küt z.) W. Smith, Psammodyction constricta (Kütz.) Ralfs, Rhopalodia gibberula (Ehren berg) O. Müller, Seminavis sp. 1. The species richness is high considering the stability and homogeneity of the pro-thrombolithic system.

Keywords


Bahía de La Paz; bathymetry

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DOI: http://dx.doi.org/10.37543/oceanides.v21i1-2.30

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CICIMAR Oceánides,  Av. Instituto Politécnico Nacional s/n Col. Playa Palo de Santa Rita, CP. 23096 La Paz, Baja California Sur, México. Teléfono (52)6121230350 ext. 81527.   ISSN: 2448-9123,  otorgado por el Instituto Nacional del Derecho de Autor.