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

Die Tiefsee, in Tiefen von mehr als 1.000 Metern, ist gekennzeichnet durch kalte Temperaturen von 2–3 Grad Celsius, einen enormen hydrostatischen Druck, der etwa alle 10 Meter um etwa 1 Atmosphäre zunimmt, sowie niedrige Nährstoffgehalte.Piezotolerante Mikroben sind solche, die Hochdruckbedingungen vertragen und unter diesen lebensfähig bleiben, wie zum Beispiel Mitglieder der Gattung Colwellia.Wahre Piezophile wie Moritella-Arten hingegen wachsen und überleben am besten unter hohem Druck durch spezifische zelluläre Mechanismen.Zum Beispiel erhöhen Piezophile den Anteil ungesättigter Fettsäuren in ihren Membranen zur Erhaltung der Membranflüssigkeit und Proteinstabilität unter hohem Druck. Einige Arten exprimieren druckregulierte Proteine wie OmpH durch druckempfindliche Transkriptionssysteme.Unterhalb von 2.000 Metern beherbergen Sedimente Sulfatreduzierende und methanoxidierende Organismen sowie andere Mikroben, die an extreme Energiebegrenzung angepasst sind.Diese Knappheit führt dazu, dass die Zelldichte deutlich geringer ist als in flacheren Regionen.

mikrobielle Ökologie der tiefsee

Deep Sea Microbial Ecology

Der Tiefozean und seine darunterliegenden Sedimente stellen weitläufige, weitgehend unerforschte mikrobielle Lebensräume dar, die weit über die sonnenbeschienene Bodenzone hinausgehen. Die photische (euphotische) Zone erstreckt sich typischerweise über die oberen ~100–200 Meter pelagischen Gewässer im offenen Ozean, variiert jedoch geografisch und saisonal, sofern ausreichend Licht photosynthetisches Leben unterstützt. Darunter liegt das Tiefsee, das sich über etwa 1000–6000 Meter erstreckt (bathypelagische bis abgrundliche Zonen), mit tieferen Hadalgräben, die über 6000 Meter hinausgehen. Diese Region ist geprägt von völliger Dunkelheit, eisigen Temperaturen (2–3 °C, die an hydrothermalen Quellen etwas höher sein können), hohem hydrostatischem Druck, der von der Oberfläche um ~1 atm pro 10 m ansteigt (z. B. ~100 atm bei 1000 m), und starken Nährstoffbeschränkungen.Mikroorganismen, die diese Tiefen bewohnen, zeigen einzigartige physiologische Anpassungen. Einige, wie piezotolerante Mikroben, können hohen Druck tolerieren, wachsen aber optimal bei einer Atmosphäre. Andere, als Piezophile bezeichnet, wachsen am besten unter hohem Druck, typischerweise um 300–400 Atmosphären, und extreme Piezophile wie Moritella-Arten aus dem Marianengraben benötigen Druck über 700 Atmosphären für das Wachstum. Zur Anpassung entwickeln diese Organismen mehrere einzigartige zelluläre Prozesse, wie die Erhöhung ungesättigter Fettsäuren zur Aufrechterhaltung der Membranflüssigkeit unter Druck und die Expression druckempfindlicher Proteine wie OmpH.Unter dem Meeresboden lebt mikrobielles Leben in Tiefseesedimenten weiter und bildet eine der größten mikrobiellen Biosphären der Erde. Die mikrobielle Dichte des Sediments nimmt mit der Tiefe ab, von etwa 10⁹ Zellen/g an der Oberfläche auf weniger als 10³ Zellen/g bei mehreren hundert Metern Tiefe. Dieser Rückgang entspricht einer verminderten Energieverfügbarkeit aufgrund der Erschöpfung organischer Substanz und terminaler Elektronenakzeptoren wie Sulfat. In nährstoffreichen kontinentalen Rändern wird Sulfat schnell verbraucht, was zur Methanogenese führt. Andererseits kann in organisch-armen Tiefseesedimenten Sulfat bis zur basaltischen Grundlage erhalten bleiben.Trotz niedriger Zelldichte enthält das schiere Sedimentvolumen schätzungsweise 5,4 × 10²⁹ prokaryotische Zellen. Der mikrobielle Stoffwechsel in diesen Zonen basiert auf langsam abbaubarer organischer Substanz und geochemisch erzeugten Verbindungen wie Methan, Wasserstoff und Acetat. Phylogenetische Studien zeigen eine Dominanz von unkultivierten Archaeen, darunter Bathyarchaeota, und sulfatreduzierende Proteobakterien, die sich alle durch langsames Wachstum, kompakte Genome und spezialisierte anaerobe Signalwege an extreme Energiebeschränkungen anpassen.

Mikrobielle Ökologie der Tiefsee

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

Lehre

JoVE Core

Microbiology

Mikrobiologie

Unit

Einheit

Microbial Ecology

Mikrobielle Ökologie

KEY TERMS AND CONCEPTS

ZENTRALE BEGRIFFE UND KONZEPTE

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

introduction to microbial ecology

Microbial Communities in Soil and Extremes

Microbial ecology looks at how microorganisms live, interact, and adapt in different ecosystems. It also shows how these tiny organisms help shape nutrient cycling, energy flow, and environmental balance. An ecosystem includes living parts and non-living parts, and microbes respond to both. Microorganisms can form populations, which are groups of the same species living together at the same time. When populations from different species live and interact in the same place, they form a microbial...

ecological niche

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methods to assess microbial communities

Measuring Microbial Diversity and Activity

Microbial communities include bacteria, archaea, and eukaryotic microorganisms. They live in many ecosystems and affect important environmental and biological processes. Scientists study these communities by looking at how many species are present, how many individuals each species has, and how evenly the species are spread out. Species richness is the number of different species in a sample. Species abundance is the relative amount of each species. Species evenness describes how uniformly the...

the winogradsky column

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How Microbes Hunt and Defend

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microbial interactions: competition

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microbial interactions: parasitism

Microbial Parasites and Host Dependence

Microbial parasites depend on a host for nutrients and shelter, and this dependence often harms the host. In parasitism, only the parasite benefits. This is different from mutualism, where both organisms gain from the relationship. Microbial parasites are classified by where they live in or on the host. Ectoparasites stay on the host’s surface, such as the skin or outer tissues, and take in nutrients from outside. Endoparasites live inside the host’s body and invade tissues or organs.

microbe-plant interactions

How Plant Microbes Affect Growth

Plant microbes can help, harm, or simply live alongside their hosts. These microbe-plant interactions shape plant growth, health, and ecosystem function. The plant microbiome includes bacteria, fungi, archaea, protists, and viruses, and these organisms may live on the plant surface, inside plant tissues, or in symbiosis throughout the plant. Some of the most important beneficial partnerships involve mycorrhizal fungi. These fungi form close connections with roots and are grouped as arbuscular...

microbes and the carbon cycle

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microbes and methanogenesis

How Microbes Produce Methane

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Microbial Steps in the Nitrogen Cycle

Microbes drive the nitrogen cycle by changing nitrogen into forms that plants and other organisms can use. This biogeochemical cycle keeps nitrogenous compounds balanced in ecosystems. It also supports plant growth and microbial growth. Nitrogen fixation begins the cycle by converting inert atmospheric nitrogen gas, N2, into ammonia, NH3. This step depends on nitrogenase enzymes. Free-living diazotrophs do this on their own. Aerobic bacteria such as Azotobacter spp. and anaerobic bacteria such...

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Microbial Life in the Ocean

Marine microbial life is shaped by salinity, low nutrients, and changing oxygen levels. These physical and chemical limits influence which microbes can survive and how they function. They also affect how ocean microbes help drive nutrient and carbon cycling. Small cell size is common in these environments because it gives microbes a larger surface-to-volume ratio. That helps them take up nutrients more efficiently when nutrients are scarce. In estuaries, where salinity changes often,...

deep sea microbial ecology

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...

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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.

Deep Sea Microbes and Extreme Conditions | JoVE K12

JoVE Core Microbiology provides an engaging introduction to the microbial world and its influence on health, industry, and the environment. This comprehensive collection covers key concepts such as microbial structure, metabolism, genetics, and ecology. It introduces essential laboratory techniques and microscopy methods through visually engaging animations. Corresponding scientist-in-action videos bridge classroom concepts with real-world research and applications.

microbiology

Deep Sea Microbes and Extreme Conditions

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