Name: deep sea microbes and extreme conditions
Uploaded: 2026-03-12T13:57:45.000Z
Duration: 1 min 18 s
Channel: JoVE

Las profundidades marinas, a profundidades superiores a 1.000 metros, se caracterizan por temperaturas frías de 2–3 grados Celsius, una inmensa presión hidrostática que aumenta aproximadamente 1 atmósfera cada 10 metros y bajos niveles de nutrientes.Los microbios piezotolerantes son aquellos que pueden tolerar condiciones de alta presión y mantenerse viables bajo ellas, como los miembros del género Colwellia.Por otro lado, los verdaderos piezófilos, como las especies de Moritella , crecen y sobreviven mejor bajo alta presión gracias a mecanismos celulares específicos.Por ejemplo, para mantener la fluidez de las membranas y la estabilidad de las proteínas bajo alta presión, los piezófilos aumentan la proporción de ácidos grasos insaturados en sus membranas. Algunas especies expresan proteínas reguladas por presión, como el OmpH, a través de sistemas de transcripción sensibles a la presión.Por debajo de los 2.000 metros, los sedimentos albergan reductores de sulfatos y organismos oxidadores de metano, junto con otros microbios adaptados a limitaciones extremas de energía.Esta escasez hace que las densidades celulares sean mucho menores que en regiones más superficiales.

deep sea microbial ecology

Deep Sea Microbial Ecology

El oc&#xE9;ano profundo y sus sedimentos subyacentes representan vastos h&#xE1;bitats microbianos, en gran parte inexplorados, que se extienden mucho m&#xE1;s all&#xE1; de la zona f&#xF3;tica iluminada por el sol. La zona f&#xF3;tica, o euf&#xF3;tica, suele abarcar los primeros ~100&#x2013;200 m de las aguas pel&#xE1;gicas en mar abierto, pero su profundidad var&#xED;a geogr&#xE1;fica y estacionalmente, y en ella la luz es suficiente para sostener vida fotosint&#xE9;tica. Debajo de esta se encuentra el oc&#xE9;ano profundo, que abarca aproximadamente entre 1.000 y 6.000 m, desde las zonas batipel&#xE1;gica hasta abisal, con fosas hadales m&#xE1;s profundas que se extienden m&#xE1;s all&#xE1; de 6.000 m. Esta regi&#xF3;n se caracteriza por la oscuridad total, temperaturas g&#xE9;lidas (2&#x2013;3&#xB0;C, que pueden ser ligeramente superiores en las fuentes hidrotermales), una alta presi&#xF3;n hidrost&#xE1;tica que aumenta desde la superficie en ~101.33 Kpa por cada 10 m (por ejemplo, ~10.13 Mpa a 1.000 m) y graves limitaciones de nutrientes.
Los microorganismos que habitan estas profundidades presentan adaptaciones fisiol&#xF3;gicas &#xFA;nicas. Algunos, como los microorganismos piezotolerantes, pueden tolerar altas presiones, pero su crecimiento &#xF3;ptimo se produce a 101.33 Kpa. Otros, denominados piez&#xF3;filos, crecen mejor bajo alta presi&#xF3;n, por lo general en torno a 30.40&#x2013;40.53 Mpa, y los piez&#xF3;filos extremos, como Moritella spp. de la Fosa de las Marianas, requieren presiones superiores a 70.93 Mpa para crecer. Para adaptarse, estos organismos desarrollan varios procesos celulares &#xFA;nicos, como el aumento de &#xE1;cidos grasos insaturados para mantener la fluidez de la membrana bajo presi&#xF3;n y la expresi&#xF3;n de prote&#xED;nas sensibles a la presi&#xF3;n, como OmpH.
Bajo el lecho marino, la vida microbiana contin&#xFA;a en los sedimentos marinos profundos, formando una de las mayores biosferas microbianas de la Tierra. La densidad microbiana de los sedimentos disminuye con la profundidad, desde alrededor de 10&#x2079; c&#xE9;lulas/g en la superficie hasta menos de 10&#xB3; c&#xE9;lulas/g a cientos de metros de profundidad. Esta disminuci&#xF3;n se corresponde con una menor disponibilidad de energ&#xED;a debido al agotamiento de la materia org&#xE1;nica y de los aceptores terminales de electrones, como el sulfato. En los m&#xE1;rgenes continentales ricos en nutrientes, el sulfato se consume r&#xE1;pidamente, dando paso a la metanog&#xE9;nesis. Por otro lado, en los sedimentos oce&#xE1;nicos profundos pobres en materia org&#xE1;nica, el sulfato puede persistir hasta el basamento bas&#xE1;ltico.
A pesar de las bajas densidades celulares, el enorme volumen de sedimento alberga una cantidad estimada de 5.4 &#xD7; 10&#xB2;&#x2079; c&#xE9;lulas procariotas. El metabolismo microbiano en estas zonas depende de la materia org&#xE1;nica de degradaci&#xF3;n lenta y de compuestos producidos geoqu&#xED;micamente, como metano, hidr&#xF3;geno y acetato. Los estudios filogen&#xE9;ticos revelan el predominio de Archaea no cultivadas, incluidas Bathyarchaeota, y de Proteobacteria reductoras de sulfato, todas las cuales se adaptan a limitaciones energ&#xE9;ticas extremas mediante un crecimiento lento, genomas compactos y v&#xED;as anaerobias especializadas.

The deep ocean and its underlying sediments represent vast, largely unexplored microbial habitats that extend far beyond the sunlit photic zone. The ...

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Education

Educación

JoVE Core

Microbiology

Microbiología

Unit

Unidad

Microbial Ecology

Ecología microbiana

KEY TERMS AND CONCEPTS

TÉRMINOS Y CONCEPTOS CLAVE

deep sea microbes and extreme conditions

Deep sea microbes live in one of Earth’s harshest environments. The deep ocean is far below the sunlit photic zone, which usually reaches the upper 100 to 200 meters of open water. Below that layer, the bathypelagic and abyssal zones stretch from about 1,000 to 6,000 meters, and hadal trenches go even deeper.

This region is dark, cold, and highly pressurized. Temperatures are usually around 2 to 3°C, although hydrothermal vents can be slightly warmer. Pressure rises by about 1 atmosphere for every 10 meters of depth, so it reaches about 100 atmospheres at 1,000 meters. Nutrients are also scarce, which makes life difficult for microbes.

Some deep sea microorganisms are piezotolerant. This means they can handle high pressure but still grow best at 1 atmosphere. Others are piezophiles, which grow best under high pressure, often around 300 to 400 atmospheres. Extreme piezophiles, such as Moritella species from the Mariana Trench, need pressures above 700 atmospheres to grow.

These microbes survive through special cell changes. Many increase the amount of unsaturated fatty acids in their membranes so the membranes stay fluid under pressure. Some also express pressure-sensitive proteins such as OmpH. These adaptations help cells function in conditions that would damage most surface-dwelling life.

Life also continues beneath the seafloor in deep-sea sediments. This subsurface habitat is one of the largest microbial biospheres on Earth. Microbial density drops with depth, from about 10^9 cells per gram near the surface to fewer than 10^3 cells per gram at hundreds of meters down.

That decline reflects lower energy supply. Organic matter becomes depleted, and terminal electron acceptors such as sulfate are used up. On nutrient-rich continental margins, sulfate disappears quickly and methanogenesis begins. In organic-poor deep-ocean sediments, sulfate can remain all the way to the basaltic basement.

Even with very low cell numbers, the total sediment volume is enormous. It may contain an estimated 5.4 × 10^29 prokaryotic cells. These microbes use slowly degradable organic matter and compounds made geochemically, including methane, hydrogen, and acetate.

Many of the organisms found there are still uncultured. Phylogenetic studies often show Archaea, including Bathyarchaeota, and sulfate-reducing Proteobacteria. They are adapted to extreme energy limits through slow growth, compact genomes, and specialized anaerobic pathways.

Deep Sea Microbes and Extreme Conditions

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key terms and concepts

Explore how deep sea microbes survive cold, dark, high-pressure waters and nutrient-poor sediments through special adaptations and slow metabolism.

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microbiology

Deep Sea Microbes and Extreme Conditions

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