{"id":137514,"date":"2011-02-22T11:18:32","date_gmt":"2011-02-22T10:18:32","guid":{"rendered":"http:\/\/www.madrimasd.org\/blogs\/universo\/?p=137514"},"modified":"2011-04-08T18:59:11","modified_gmt":"2011-04-08T17:59:11","slug":"la-actividad-biologica-de-los-microorganismos-en-suelos-helados","status":"publish","type":"post","link":"https:\/\/www.madrimasd.org\/blogs\/universo\/2011\/02\/22\/137514","title":{"rendered":"La Actividad Biol\u00f3gica de los Microorganismos en Suelos Helados"},"content":{"rendered":"

Se ten\u00eda conocimiento de que los microorganismos del suelo<\/span><\/strong> atesoraban una cierta actividad incluso<\/span><\/strong> en los crudos inviernos boreales, cuando el suelo se congela. Se pensaba que<\/span><\/strong> tal hecho era un mero producto de su respiraci\u00f3n<\/strong>, pero no de su crecimiento<\/strong><\/span>, y menos aun que siguieran manteniendo su actividad, tanto anab\u00f3lica como catab\u00f3lica<\/span><\/strong> en lo concerniente a la descomposici\u00f3n de la materia org\u00e1nica del suelo<\/strong>. Investigaciones \u201cfresquitas\u201d refutan tal hip\u00f3tesis y dicen demostrar que la actividad de hongos y bacterias se mantiene muy intensa en los poros que albergan agua en estado l\u00edquido<\/strong><\/span>. De hecho, seg\u00fan los autores de este estudio, tal \u201cvidilla\u201d (y desarrollo) es tan solo un poco m\u00e1s lenta que la que se genera durante el verano<\/span><\/strong>. Al parecer los investigadores implicados desarrollaron una nueva metodolog\u00eda basada\u00a0 en el uso de la espectroscopia de de resonancia magn\u00e9tica nuclear<\/a>. M\u00e1s aun, seg\u00fan ellos, han logrado entender las propiedades del suelo que estimulan tal actividad, as\u00ed como lugares propicios de su\u00a0matriz\u00a0para albergar la presencia de agua l\u00edquida en ese mundo temporalmente helado<\/span><\/strong>.\u00a0 Resumiendo, que estos encomiables bichitos siguen currando durante todo el a\u00f1o<\/span><\/strong> a pesar de los rigores invernales. Todo un ejemplo en nuestra sociedad de holgazanes. La complejidad tiene sus costos. \u00bfSignificar\u00e1 tal hallazgo que en todos los ambientes la descomposici\u00f3n de la materia org\u00e1nica del suelo se mantiene \u201cfr\u00edamente\u201d a lo largo del ciclo anual?<\/span><\/strong>. Ya se, algunos alegar\u00e9is que me olvido de los ambientes o estaciones que padecen un d\u00e9ficit h\u00eddrico. No es as\u00ed. En estos casos, las pel\u00edculas de agua que rodean ciertas part\u00edculas pueden permanecer con frecuencia a lo largo del t\u00f3rrido verano, albergando a estos insaciables comilones o trabajadores (seg\u00fan interpretaci\u00f3n de cada cual).<\/p>\n

\"microorganismos<\/p>\n

Organismos extrem\u00f3filos-cri\u00f3filos. Fuente: NASA<\/a><\/p>\n

<\/p>\n

Parece claro que los microorganismos crecen casi bajo cualquier condici\u00f3n ambiental, a pesar que les llamen extremistas (perd\u00f3n extrem\u00f3filos y m\u00e1s concretamente cri\u00f3filos<\/span><\/strong>). No, ellos no iniciaron la guerra fr\u00eda, por mucho que se les acuse con tanto desatino. Quiz\u00e1s termine siendo cierto que fuimos invadidos desde el espacio, y que as\u00ed floreci\u00f3 la vida en la Tierra, dando raz\u00f3n al N\u00f3bel Francis Crick<\/a>, quien rescato hace unas d\u00e9cadas la antigua hip\u00f3tesis de la panspermia<\/a>. Pero existe un aspecto mucho m\u00e1s mundano que me asalta en estos momentos la mente<\/strong>. Resulta que<\/strong><\/span> (o era, ya que no trabajo en laboratorios desde hace muchos a\u00f1os) en muchos laboratorios se guardaran las muestras de suelo a baja temperatura<\/span><\/strong> (incluso heladas) antes de ser analizadas, con vistas a que sus enanos habitantes no las alteraran. Pues bien: \u00bfY ahora que? \u00bfSe analizan muestras cuyos resultados no corresponder\u00e1n a las condiciones de campo, debido a la incansable actividad de estos canijos? \u00a0Materia para una \u201cfr\u00eda\u201d reflexi\u00f3n: \u00bfO no?.<\/p>\n

Ya os explicamos que, incluso comunidades vegetales que se presupon\u00eda que alcanzaban un paro vegetativo estival, por las crudas condiciones de aridez ed\u00e1fica (por ejemplo en ciertos bosques escler\u00f3filos<\/a> de la cuenca mediterr\u00e1nea), a menudo no lo padecen, seg\u00fan los datos que ofrecen los sensores remotos sobre su clorofila. Se trata de un caso semejante, aunque permanece por esclarecerse si tal incansable actividad de las comunidades de microorganismos ed\u00e1ficos acaece en todos o caso todos los biomas, o si por el contrario hablamos de una adaptaci\u00f3n a los medios boreales y subpolares<\/strong><\/span>.<\/p>\n

Juan Jos\u00e9 Ib\u00e1\u00f1ez<\/span> <\/span> <\/strong><\/p>\n

Microorganisms in the Ground Don\u2019t Slack Off in Winter<\/a><\/h2>\n

ScienceDaily (<\/strong>Nov. 20, 2010<\/strong><\/span>)<\/span> <\/strong>\u2014 It is known that soil microorganisms can maintain some activity during the cold winter months<\/strong>. Scientist at Swedish University of Agricultural Sciences (SLU) and Ume\u00e5 University in Sweden have now shown that the microorganisms in frozen soils are much more viable than previously anticipated and also has large potential for growth<\/strong>.<\/p>\n

In northern forest ecosystems, there is a great deal of carbon stored in the ground<\/strong>. The degradation of this carbon supply is a crucial component in computational models used to describe the effects of future climate changes.<\/p>\n

In recent years it has been noticed that the winter half of the year can also have a great impact on the carbon balance of forests, as microorganisms (fungi and bacteria) continue to degrade organic carbon despite freezing temperatures and frozen ground<\/strong>. Just how microorganisms go about breaking down organic carbon under such adverse conditions has largely been unknown<\/strong>, which has rendered it difficult to carry out reliable calculations of a forest’s carbon balance in wintertime.<\/p>\n

\u00abThe results of previous studies have been interpreted as meaning that microorganisms in frozen ground cannot grow but merely give off a certain amount of carbon dioxide<\/strong>. A research team at SLU in Ume\u00e5 and at Ume\u00e5 University has now shown that this is not the case. Instead, the capacity of microorganisms to grow in frozen ground is astonishingly similar to that of the summer half of the year, although the growth rate is lower<\/strong>,\u00bb says Mats \u00d6quist from SLU, who directed the study.<\/p>\n

These findings are being published this week in the journal PNAS<\/strong>, published by the American Academy of Sciences. The study was performed in close collaboration between Mats \u00d6quist, Mats Nilsson, and Stina Harrysson Drotz at SLU, and J\u00fcrgen Schleucher and Tobias Sparrman (Ume\u00e5 University).<\/p>\n

In previous publications these scientists have established that the activity of microorganisms in frozen ground is mainly regulated by access to unfrozen water, and they have identified what characteristics in the ground govern the availability of water<\/strong>. These studies have been possible thanks to a method for monitoring unfrozen water using nuclear magnetic resonance spectroscopy (NMR), a method that was developed by the team<\/strong>. In combination with the latest findings about the capacity of microorganisms to exploit organic materials and grow in frozen ground<\/strong>, this research makes it possible to develop more reliable computational models of the carbon balance of the northern hemisphere<\/strong>.<\/p>\n

Story Source: <\/strong>The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Expertanswer<\/a>, via AlphaGalileo<\/a>.<\/p>\n

Journal Reference: <\/strong>S. H. Drotz, T. Sparrman, M. B. Nilsson, J. Schleucher, M. G. Oquist. Both catabolic and anabolic heterotrophic microbial activity proceed in frozen soils. Proceedings of the National Academy of Sciences, 2010; DOI: 10.1073\/pnas.1008885107<\/a><\/p>\n

Resumen del trabajo Original<\/span><\/strong><\/p>\n

Both catabolic and anabolic heterotrophic microbial activity proceed in frozen soils<\/a><\/h3>\n

Stina Harrysson Drotz<\/a>a<\/a>, et al. 2010.<\/h3>\n

Abstract<\/strong><\/span><\/p>\n

A large proportion of the global soil carbon pool is stored in soils of high-latitude ecosystems in which microbial processes and production of greenhouse gases proceed during the winter months. It has been suggested that microorganisms have limited ability to sequester substrates at temperatures around and below 0 \u00b0C and that a metabolic shift to dominance of catabolic processes occurs around these temperatures. However, there are contrary indications that anabolic processes can proceed, because microbial growth has been observed at far lower temperatures. Therefore, we investigated the utilization of the microbial substrate under unfrozen and frozen conditions in a boreal forest soil across a temperature range from \u22129 \u00b0C to +9 \u00b0C, by using gas chromatography-isotopic ratio mass spectrometry and 13C magic-angle spinning NMR spectroscopy to determine microbial turnover and incorporation of 13C-labeled glucose. Our results conclusively demonstrate that the soil microorganisms maintain both catabolic (CO2 production) and anabolic (biomass synthesis) processes under frozen conditions and that no significant differences in carbon allocation from [13C] glucose into [13C]CO2 and cell organic 13C-compounds occurred between +9 \u00b0C and \u22124 \u00b0C. The only significant metabolic changes detected were increased fluidity of the cell membranes synthesized at frozen conditions and increased production of glycerol<\/strong> in the frozen samples. The finding that the processes in frozen soil are similar to those in unfrozen soil has important implications for our general understanding and conceptualization of soil carbon dynamics in high-latitude ecosystems.<\/p>\n","protected":false},"excerpt":{"rendered":"

Se ten\u00eda conocimiento de que los microorganismos del suelo atesoraban una cierta actividad incluso en los crudos inviernos boreales, cuando el suelo se congela. Se pensaba que tal hecho era un mero producto de su respiraci\u00f3n, pero no de su crecimiento, y menos aun que siguieran manteniendo su actividad, tanto anab\u00f3lica como catab\u00f3lica en lo concerniente a la descomposici\u00f3n de la materia org\u00e1nica del suelo. Investigaciones \u201cfresquitas\u201d refutan tal hip\u00f3tesis y dicen demostrar que la actividad de hongos y bacterias se mantiene muy intensa en los poros que albergan agua en estado l\u00edquido. De hecho, seg\u00fan los autores de este\u2026<\/p>\n","protected":false},"author":26,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"ngg_post_thumbnail":0},"categories":[596,608,590,600],"tags":[46911,2634,46759,46910],"blocksy_meta":{"styles_descriptor":{"styles":{"desktop":"","tablet":"","mobile":""},"google_fonts":[],"version":4}},"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/posts\/137514"}],"collection":[{"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/users\/26"}],"replies":[{"embeddable":true,"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/comments?post=137514"}],"version-history":[{"count":8,"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/posts\/137514\/revisions"}],"predecessor-version":[{"id":138845,"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/posts\/137514\/revisions\/138845"}],"wp:attachment":[{"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/media?parent=137514"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/categories?post=137514"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/tags?post=137514"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}