Extreme Marine Ecosystems Flashcards
What are examples of extreme marine environments?
-Hydrothermal vents
-Whale falls
-Cold water reefs
What factors drive deep sea ecosystems?
-High pressures
-Low temperatures
-Depth (Lack of sunlight/ food)
-Expanse of deep sea (large volume of water- finding food/ mates
The deep sea is…
Dark and cold
What weakly supports deep sea food webs?
Organic matter raining from above
Is photosynthetic production possible?
No, no new organic matter is not possible due to lack of light
What are deep-sea communities are adapted to?
-Sparse food availability
-Low population density
Describe deep-sea benthic ecosystems
(habitats are diverse)
-Soft-bottom: ooze-rich abyssal plains and abyssal hills
-Hard-bottom: seamounts, oceanic ridges, oceanic trenches, submarine canyons
-Vent habitats: Hydrothermal vents and cold seeps
What alternate energy sources exist in deep sea?
-Phytodetritus: fallen products of algal blooms
-Food falls: Carcasses of animals falling to the seabed
-Chemosynthesis: Methane and sulfur-rich fluids provide energy for chemosynthetic bacteria in some deep-sea communities
What does chemosynthesis run on?
Runs on chemical energy
What does chemosynthesis rely on?
Requires high concentrations of chemicals like hydrogen sulfide and methane
What are cold seeps?
-Occur at tectonic active plates in the seafloor where hydrogen sulfide, oil, highly saline water and methane leak out to form brine pools
Describe brine pools
-Are underwater lakes
-Salt concentrations denser than ocean
-Can be high or low sulphide concentrations
What forms hydrothermal vents?
Are the result of seawater percolating down through fissures in the ocean crust in the vicinity of spreading centres or subduction zones
-The cold seawater is heated by hot magma and re-emerges to form the vents
Describe hydrothermal vents
-Places where hot, mineral and gas-rich fluids are ejected into the ocean
-Seawater emitted may reach temperatures of over 340 degrees (700 f)
-The hot seawater does not boil because of the extreme pressure at these depths
-The longevity of vents (years to decades) make these thriving, diverse ecosystems
Describe hydrothermal vent chimneys
-Discharged vent water contains high concentrations of iron, manganese and other sulfides
-As these sulfides oxidise in seawater they are deposited as a chimney around the vent mouth
Where is there a large number of active hydrothermal vents?
The Pacific ring of fire and around boundaries of plate tectonics
Describe black smokers
Are chimneys formed from deposits of iron sulfide, which is black
Describe white smokers
Are chimneys formed from deposits of barium, calcium and silicon which are white
What is an example of a chemosynthetic reaction:
6CO2 + 6H2O + 3H2S = C6H12O6 + 3H2SO4
What is an example of chemosynthetic reaction in words:
Carbon dioxide + water + hydrogen sulphide = sugar + sulphur compounds
What are the basis of hydrothermal vent food chain?
Chemolithoautotrophic bacteria
Microbes that use chemicals from the bedrock as an energy source for making their own food
Break down chemolithoautotrophic bacteria
Chemo -chemical
Bedrock - litho
Auto - own
Troph- food
What factors drive hydrothermal vent communities?
-Chemosynthetic bacteria (primary producers)
-Hot, mineral rich water
-Location (advantages and disadvantages)
Describe grey whales (eschrichtius robustus) in relation to whale falls
-Relatively frequent in space and time, in particular along migration corridors
-Hundreds sink annually, 12 - 30 km apart
-Die during 18,000 km round trip migration (Arctic to Baja, California
