Benthic diatoms from shallow environments deposited at 300 m depth in a southern Gulf of California basin.

Benthic diatoms collected with a Technicap model PPS-3/3 trap with an aperture of 0.125 m2 were recorded, which consists of a programmable carousel motorized with twelve 250 mL bottles installed at 300 m deep in Cuenca Alfonso, Bahía de La Paz. The hypothesis that diatoms deposited in the trap sediment would be related to mangrove environments from the Bay of La Paz. Thus, in order to identify the benthic diatoms and infer their origin, a sample for the period December 2011 to January 2012. The identification was made from images taken with a Zeiss Supra Vp55 scanning electron microscope. I know identified 38 diatom taxa, 32 of which were benthic forms including the species: Actinoptychus vulgaris, Halamphora coffeaeformis, Delphineis surirella, Fragilariopsis doliolus and Nitzschia amabilis. What these, the observed diatoms correspond mainly to benthic taxa commonly represented in habitats of shallow intertidal and subtidal zones. Although the hypo- thesis was supported, the species composition of diatoms it did not allow greater precision on the environment of origin.