Use Of Scanning Electron Microscopy (SEM) In Foraminiferal Research

VIOLETA I. TOTAH; FABIÁN G. TRICÁRICO; SILVIA WATANABE

Ciudad Autónoma de Buenos Aires

Congreso; XV Congreso Interamericano de Microscopia CIASEM-SAMIC; 2020

CIASEM SAMIC

Use Of Scanning Electron Microscopy (SEM) In Foraminiferal ResearchTotah1, V. I., Tricárico2*, F. G. y Watanabe3, S.1. Laboratorio de Foraminíferos / Museo Argentino de Ciencias Naturales ?B. Rivadavia? (MACN) -CONICET, CABA, Argentina. 2. Servicio de Microscopía Electrónica de Barrido / Museo Argentino de Ciencias Naturales ?B.Rivadavia? (MACN) - CONICET, CABA, Argentina.3.Laboratorio de Foraminíferos / Museo Argentino de Ciencias Naturales ?B. Rivadavia? (MACN) -CONICET, CABA, Argentina.* Corresponding author: fabitrica@gmail.comForaminifera are marine protists provided with a shell usually less than 1mm in size, made ofcalcium carbonate or agglutinated particles selected from the environment. They include currentplanktonic and benthic species, and a large number of fossil forms. Their taxonomy is almostexclusively based on the morphology of the shell, which is examined under a stereomicroscope atmagnifications up to 80x, but for very small species and/or detailed analyses of their surfacestructures SEM (Scanning Electron Microscopy) is employed.In order to compare the information obtained by Light Microscopy (LM) and SEM, we worked withspecimens from the Foraminiferal National Collection (MACN-Fo), acquiring images of the samespecimens with both techniques. For each species, specimens were selected from a picking trayunder a LM, and mounted on an aluminium stub with double-sided adhesive tape in the desiredposition. LM images were first obtained with a Zeiss Discovery V20 stereomicroscope atmagnifications up to 225x. The specimens were then coated with Pd/Au (60/40%) for 3 minutes in aQuorum Technologies SC7620 sputter coater and examined and photographed with a PHILIPS XL30 SEM at 15 kv.SEM images allowed to better visualize the surface morphology of the shells and to detect structuraldetails poorly visible in LM images, whereas in translucent species LM images reveal internalstructures not visible with SEM. Thus, the two techniques furnish complementary information for theidentification of the species and the study of new taxa.