Lecture 20: Hydrothermal Vents

water seeps into the _____ and becomes _____, after if escapes through _____ in the crust

crust; heated; vents

how did scientists find hydrothermal vents?

scanned the ocean floor for spikes in temp

the ocean temperature is very _____

stable

after searching the ocean floor near a potential vent, scientists found evidence of _____

biology

prior to the 1970a, we through that without the energy of _____ to support the food chain, organisms in the deep sea ate only what _____ fell from the _____

sunlight; debris; surface water

what are two examples of debris that provide nutrients?

wale and wood fall

what does oligotrophic mean?

nutrient poor

the ocean floor has very _____ food

scarce

what is the name of the submersible that send down to study the hydrothermal vents?

the Alvin

what are some common organisms that they found to be living in the hydrothermal vent ecosystem?

crabs, clams, limpets, tubeworm, eel-fish

the unusual vent life forms were _____ from any previously discovered organism include species of giant _____ that represent previously unknown _____

different; invertebrates; taxa

what is the foundation of life in the deep sea?

chemosynthesis

what type of microbes are found at the hydrothermal vents that do chemosynthesis?

thermophilic chemolithoautotrophs and methane oxidizers

True or False: only bacteria are found on deep sea thermal vents?

FALSE: bacteria and archaea

cold ocean water first seeps into the _____ where it becomes heated to _____°C. In the crust _____ from the rock seep into the hot water

crust; 400; minerals

dissolved metals such as _____, _____ an _____, as well as compounds like _____ are enriched in vent fluid

Fe; Cu; Zn; H2S

hot water under _____ spews out of the vents. The vent fluid is _____ to most life

pressure; toxic

which type of hydrothermal vents are hotter?

black smokers

black smokers spew out _____ and _____

Fe; sulfide

the Fe and sulfide in black smokers will _____ and _____ giving the smoker its color and forming a black chimney

react; precipitate

_____ and _____ in white smokers give the smoker its color and the vent fluid is rich in _____, _____, and_____

silica; CaSO4; barium; calcium, silicon

black and white smokers are observed at fast spreading _____ characterized by _____ and _____

ridges; high temperature; volcanic activity

although various habitats within vent fields are physically an ecologically connected, their _____ are DIFFERENT

microbial communities

what are the two key gradients of vent fields?

temperature and chemical

Temperatyre as a central role in determining “_____” along the thermal gradient

who is where

the highest temp at which microbial growth is observed is _____°C

122

hydrothermal _____ also strongly influences the _____ and _____ of microbial communities along mixing gradients

geochemistry; composition; metabolism

adaptations to dynamic conditions (gradients) include _____ and _____ which provide the ability to find preferred environments

motility; metabolism versatility

the _____ and _____ of the vent system is critical

temperature; chemistry

what are the 5 main systems of hydrothermal vents?

chimneys, rising plume, buoyant plume, animal symbionts, surface biosphere

ocean water has a temperature of _____°C and is rich in _____ and _____

2; O2; NO3

the oxygen and nitrate in ocean water can be used as _____ for microbial metabolism

terminal electron acceptors

Vent fluid is upwards of _____°C, has an _____ pH, and is an _____ environment

300; acidic; anaerobic

vent fluid is rich in _____ such as: (2)

dissolved metals; Fe2+, Mn2+

__(4)___ are also found in vent fluid and can act as an energy source or source of carbon

H2S; CH3; CO2; H2

as dissolved meals, H2, and H2S decrease, _____ and _____ increase

O2; NO3

what are the primary pyschrophiles or mesophiles found in the cooler waters?

proteobacteria

what are the primary thermophiles and hyperthermophiles?

archaea

_____ are where sea water and vent fluid mix

plumes

True or False; the majority of metabolic reactions occurring in plumes are aerobic?

FALSE: mixture of anaerobic and aerobic

what are 4 main examples of aerobic reactions that occur in the plumes of hydrothermal vents?

sulfide, H2, Fe, and Mn oxidation

_____ are key in this hydrothermal systems because they gain energy from _____ the _____ compounds released from vents

chemolithoautotrophs; oxidizing; reduced

chemolithoautotrophs uses high energy _____ instead of _____ to fix carbon

inorganics; light

what are 3 examples of chemolithoautotrophs?

hydrogen, Fe, and sulfide oxidizers

all chemolithoautotrophs oxidize _____ compounds for energy using _____ as a terminal electron acceptor WHILE they _____

inorganic; O2; fix carbon

Chemolithoautotrophs are the _____ of this ecosystem

primary producers (they fix carbon!)

chemolithoautotrophs use an _____ to generate a _____ that is used to make ATP

ETC; PMF

Beggiatoa is a _____ forming, _____ oxidizer

mat; sulfur

you can actually see Beggiatoa because the filaments store _____

elemental sulfur

what are 4 important ANAEROBIC metabolisms that occur in hydrothermal vent ecosystems?

methaogenesis, sulfur, sulfate, and iron reduction

Autotrophy involves the fixing of _____

CO2

what type of cycle do hydrothermal vent autotrophs use to fix carbon (CO2)?

Calvin-Benson cycle (Calvin cycle)

CO2 fixing pathways are also distributed along _____

thermal gradients

at <20°C what is the common CO2 fixing pathway?

Calvin cycle

what is a cost of the Calvin cycle, what is a benefit?

energetically costly, O2 tolerant

what is the primary CO2 fixing pathway uses between 20-90°C?

reductive TCA cycle

how does the reductive TCA cycle work?

reverse of TCA incorporates CO2 rather than remove it

what is a cost of the reductive TCA cycle? what is a benefit?

energy efficient, O2 sensitive

what CO2 fixation pathway is used at >90°C?

dicarboxylate-4-hydroxybutyrate pathway

the dicarboxylate-5-hydroxybutryate pathway is only used by _____

hyperhydrothermophilic archaea

True or False: photosynthesis cannot occur in hydrothermal vents due to the lack of light (cannot penetrate to these depths)

FALSE: phototrophs have been found! → use faint glow of black smoker

what is the phototrophic bacteria that has been found in hydrothermal vents?

chlorobiaceae

what type of phototroph is Chlorobiaceae?

green sulfur anoxygenic

why is the Chlorobiaceae able to survive at low depths? (with no sunlight)

can grow at low light intensities → uses glow of black smoker

Chlorobiaceae is the only organism discovered in nature to exclusively use a light other than _____ for photosynthesis

sunlight

what is the scientific name for the giant tube worm?

Riftia pachyptila

Riftia tubes are made of _____ and they do not have a _____ or _____

chitin; mouth; stomachf

the gill-like red plumes of Riftia absorb _____ from the vent water and _____ from the cold water

H2S; O2

the gills of Riftia deliver the H2S and oxygen via an exotic form of _____ to its symbiotic _____ bacteria

hemoglobin; chemolithotrophic

do Riftia tube worms eat food?

no! they have no mouth or stomach!

the ultimate destination of the H2S and oxygen in tube worms is the _____, where the bacteria are located

trophosome

_____ in the trophosome distribute the _____ to symbiotic bacteria

capillary beds; H2S

the Riftia symbiotic bacteria _____ the H2S and _____ carbon which allows them to _____. Eventually they are _____ by the tissues of the trophosome

oxidize; fix; grow; phagocytosed

what type of animal are Calyptogena?

vent clams

vent clams (calyptogena) have symbiotic bacteria in their _____ and use _____ to deliver nutrients to their symbionts

thick gills; hemoglobin

despite their thick shells, the vent clams are eaten by _____ and _____

crabs; octopi (another food source!)

vent shrimp live around clumps of _____ and _____

tube worms; mussels

vent shrimp eat mussels and microbes that grow on the _____ and their _____

chimney; bodies

vent shrimp support _____ by being a food source for _____, _____, and _____

higher eukaryotic life; crabs; anemones; fish

some vent shrimps have a _____ on their backs that is colonized with _____

light organ; bacteria

Hydrothermal vents establish the widespread occurrence of _____ and the upper _____ for life. They also require us to reconsider the theories behind the _____

novel symbioses; temperature limit; origins of life

Hydrothermal vents are the the FIRST example of an ecosystem driven by _____

chemosynthesis