[Todos] Seminario 20 de Octubre Correcion 10hs!!!

[Adrián Turjanski]

Seminario El miercoles 20 de Octubre a las 10hs en el INQUIMAE
3er PisoPabellon II.
Correccion es a las 10hs!

Stromatolites: Archaic ecosystems in the modern puna (4,000 m asl) genomic
biodiversity from an extreme environment

Dra Maria Eugenia Farias
PROIMI-CONICET- LIMLA
Laboratorio de Investigaciones Microbiologicas de Lagunas Andinas
www.limla.com.ar

High-altitude Andean lake (HAAL) ecosystems of the South American Andes
are almost unexplored systems of shallow lakes formed during the Tertiary
geological period, distributed in the geographical area called the
Puna-High Andes at altitudes from 3,000 to 6,000 m above sea level, and
isolated from direct human activity (Seufferheld et al., 2008). The HAAL
ecosystems are unique not only for their geographical characteristics and
broad range of extreme environments but also for their abundant
biodiversity. The microbial communities that have evolved within these
high-altitude aquatic ecosystems tolerate chemical and physical stresses
such as wide fluctuations in daily temperatures, hypersalinity, and
variable pH and have proved to be adapted to high levels of UV radiation,
a low level of nutrient availability, and high concentrations of heavy
metals, especially arsenic (Zenoff et al., 2006; Ordoñez et al., 2009).
So far these outstanding microbial diversity and resistance mechanisms to
extreme factors have been described in most Lakes at these locations, i.e.
Laguna Azul, Laguna Verde, Laguna Negra, Laguna Vilama, Laguna Aparejos,
Laguna Chaxas (Fernandez Zenoff et al., 2006; Dib et al., 2008; 2009,
Flores et al., 2009; Farías et al., 2009) where microbes have been
isolated mainly from shallow water and sediments. In a recent exploration,
it has been obvious the presence of modern stromatolite-like ecosystems at
hypersaline lakes: i.e. Socompa Lake, “Sea Eyes” at Tolar Grande and Lake
Diamante (Belluscio, 2009; 2010). Stromatolites are internally-laminated,
macroscopic sedimentary structures, commonly of biological origin that
form the dominant part of Earth’s early fossil record and so provide a
potentially important source of information about early life (Allwood et
al., 2006). The oldest examples of these preserved formations are more
than 3 billion years old and are found mainly in Western Australia and
South Africa (Lowe, 1980; Walter et al., 1980; Byerly et al., 1986).
Recent studies have reflected a widespread and growing acceptance of the
oldest stromatolites from the Pilbara region of Western Australia as
biogenic (Allwood et al., 2006). In turn, modern stromatolites have been
so far recorded in four locations: i) an hypersaline region of Hamelin
Pool, Shark Bay in Western Australia (Goh et al., 2009), ii) shallow
subtidal regions at the margin of Exuma Sound in the Bahamas (Foster et
al., 2009), iii) fresh-water areas at the Cuatro Ciénagas basin in Mexico
(Desnues et al., 2008); and iv) Yellowstone Hot Spring (Lau et al., 2005).
All of these locations are situated at the sea level where microorganisms
cope with little or no stress conditions.
In the dessertic region of Salta, Northwestern Argentina, we have found
characteristic stromatolite-like ecosystems laying and developing in
shallow hypersaline lakes located above 4,000 metters, under the pressure
of harsh conditions, very similar to the ones present in the Early´s Earth
atmosphere (Farias 2011).
Here we present chemical microbiological, morphological and Genomic
Analysis of these extreme environments


El trabajo de la Dra. Farias ha despertado gran interes en la comunidad
cientifica y en la sociedad en general. Para mas informacion vean las
notas:

http://www.nature.com/news/2009/090917/full/news.2009.924.html

http://www.conicet.gov.ar/NOTICIAS/portal/noticia.php?n=4725&t=5

http://www.lanacion.com.ar/nota.asp?nota_id=1179746