Deep sea environment

Question 1

Deep sea characteristics

Answer 1

75% of all ocean water is deep sea
-Between 1000m-6000m
-consists of:
-low temp
-high pressure
-low nutrient levels
-Complete darkness such that photosynthesis relying on sunlight is impossible and must be chemotrophic

Question 2

Pressure adaptions

Answer 2

-Outer membrane protein H: It is a porin that makes it easier to extract nutrients from the environment
-Cell membrane is composed of unsaturated fatty acid tails that increases the fluidity of membrane: useful for high pressure and cold as it prevents membrane from hardening and freezing
-proteins are predominantely made from alpha helices to give increased felxibility

Question 3

type of microbes

Answer 3

piezophillic or piezotolerant
There are also psychrophilic and phsychrotoelrant as well as thermophilic and thermotolerant

Question 4

Archaea high temp adaptions

Answer 4

Ether linkages in membrane instead of ester linkages which makes them more stable

Question 5

Molecular effects of high pressure

Answer 5

-Piezophiles have mulitple pressure-detecting systems and pressure-regulated genes that are only expressed at high pressure
-Enzymes do not require high pressure to function, only genes
-gram negative piezophiles regulate expression of porins based on pressure

Question 6

Culture these bacteria

Answer 6

must used specialised growth chambers that simulate high pressure and cold

Question 7

Deep-sea sediment samples

Answer 7

-Archaeal and bacterial pop occur at depths greater than 2000m
-Samples are harvested by drilling ocean floor
-There are fewer deep-sea microbes at greater depths than are found closer to the surface of the rock layer as sub-seafloor ecosystems contain 4*10^15g of microbial cellular carbon

Question 8

Phylogenetic diversity of marine sediment Pro

Answer 8

-Proteabacteria dominate
-Bacteroidetes and unclassified/minor groups also present
-minor amounts of cyanobacteria (sulphur-reducing)
-Novel phyla of Archaea unrelated to cultured representatives (not related to any other Archaeal species) are widespread in deep subsurface

Question 9

-Hydrothermal vent formation

Answer 9

Occur due to fissure in earth’s crust or when tectonic plates collide which releases heat from molten rock
-Hydrothermal fluid rich in: Fe, Cu, Ca, S, SO3

Question 10

Warm vent formation

Answer 10

Occur when hydrothermal fluids combine with water before they leave, which causes warm water to be released

Question 11

Hot vent formation

Answer 11

Occur when hydrothermal fluid directly leaves vents in ocean

Question 12

Hydrothermal vents M type

Answer 12

-Chemolithotrophs B predominate at vent
-Thermophiles and hyperthermophiles are present
-Chemolithotrophic Pro utilise inorganic materials from vents

Question 13

Phylogenetic diversity at hydrothermal vents

Answer 13

-Detected by FISH staining
-Pyrolobus and Pyrodictium are thermophillic sulfur-reducing M
-Most M are Proteobacteria such as Alpha, Gamma, Delta and Epsilon
-limited Archae