Extreme Marine Ecosystems

Question 1

What are examples of extreme marine environments?

Answer 1

-Hydrothermal vents
-Whale falls
-Cold water reefs

Question 2

What factors drive deep sea ecosystems?

Answer 2

-High pressures
-Low temperatures
-Depth (Lack of sunlight/ food)
-Expanse of deep sea (large volume of water- finding food/ mates

Question 3

The deep sea is…

Answer 3

Dark and cold

Question 4

What weakly supports deep sea food webs?

Answer 4

Organic matter raining from above

Question 5

Is photosynthetic production possible?

Answer 5

No, no new organic matter is not possible due to lack of light

Question 6

What are deep-sea communities are adapted to?

Answer 6

-Sparse food availability
-Low population density

Question 7

Describe deep-sea benthic ecosystems
(habitats are diverse)

Answer 7

-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

Question 8

What alternate energy sources exist in deep sea?

Answer 8

-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

Question 9

What does chemosynthesis run on?

Answer 9

Runs on chemical energy

Question 10

What does chemosynthesis rely on?

Answer 10

Requires high concentrations of chemicals like hydrogen sulfide and methane

Question 11

What are cold seeps?

Answer 11

-Occur at tectonic active plates in the seafloor where hydrogen sulfide, oil, highly saline water and methane leak out to form brine pools

Question 12

Describe brine pools

Answer 12

-Are underwater lakes
-Salt concentrations denser than ocean
-Can be high or low sulphide concentrations

Question 13

What forms hydrothermal vents?

Answer 13

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

Question 14

Describe hydrothermal vents

Answer 14

-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

Question 15

Describe hydrothermal vent chimneys

Answer 15

-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

Question 16

Where is there a large number of active hydrothermal vents?

Answer 16

The Pacific ring of fire and around boundaries of plate tectonics

Question 17

Describe black smokers

Answer 17

Are chimneys formed from deposits of iron sulfide, which is black

Question 18

Describe white smokers

Answer 18

Are chimneys formed from deposits of barium, calcium and silicon which are white

Question 19

What is an example of a chemosynthetic reaction:

Answer 19

6CO2 + 6H2O + 3H2S = C6H12O6 + 3H2SO4

Question 20

What is an example of chemosynthetic reaction in words:

Answer 20

Carbon dioxide + water + hydrogen sulphide = sugar + sulphur compounds

Question 21

What are the basis of hydrothermal vent food chain?

Answer 21

Chemolithoautotrophic bacteria
Microbes that use chemicals from the bedrock as an energy source for making their own food

Question 22

Break down chemolithoautotrophic bacteria

Answer 22

Chemo -chemical
Bedrock - litho
Auto - own
Troph- food

Question 23

What factors drive hydrothermal vent communities?

Answer 23

-Chemosynthetic bacteria (primary producers)
-Hot, mineral rich water
-Location (advantages and disadvantages)

Question 24

Describe grey whales (eschrichtius robustus) in relation to whale falls

Answer 24

-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

Question 25

What do whale remains sustain?

Answer 25

Support a thriving community of extraordinary species, some of which had only ever been noted at deep-sea hydrothermal vents

Question 26

What organisms feed on whale falls

Answer 26

-Hagfish
-Lithodid crabs
-Several species of crabs
-Osedax worms
-A rattail
-Sea anemones
-Squat lobsters
-Octopus

Question 27

What feeds on the oils in whale bones?

Answer 27

Osedax worms

Question 28

Where do cold water corals occur?

Answer 28

Oceanic waters and temperatures between 4 and 12 degrees

Question 29

What depths are cold water corals found at?

Answer 29

50 to 1000 m at high latitudes
Up to 4000m (beneath warm water masses) at low latitudes

Question 30

What build reefs?

Answer 30

Scleractinians
-800 species are described in shallow waters
-10 are known to make substantial deep-water reef frameworks

Question 31

What is the distribution of cold water corals?

Answer 31

1300 species living on Lophelia pertusa reefs in the North East Atlantic
There is a striking relationship of Scleractinia occurrences and the depth of the Aragonite Saturation Horizon (ASH)

Question 32

Describe cold water corals

Answer 32

-Gonochoristic (have separate sexes)
-Seasonally enhanced food flux (phytoplankton blooms) greatly influence reproductive periodicity in deep-sea fauna