Continental shelf and deep sea Flashcards
What is the continental shelf?
Shoreline up to 200 m depth
What is the continental shelf influenced by?
Waves Tides Currents Erosion Inputs from land
What physical processes influence the continental shelf?
1) Glaciation events
2) Waves and flow
3) Fronts and production
4) Light and turbidity
How many regional ecosystem types are there?
7
Based on what are flora and fauna of continental shelf seabed classified?
1) Body size and position
2) Life mode > sessile or mobile
3) Functional role (predator,etc.)
4) Ecosystem function (engineers, sediment processor, etc.)
What characterizes deep sea?
1) depth > 200 m
2) Constant environment: cold, dark, soft and deep muds
3) Limited food supply
4) Diversity hotspots: vents, seamounts, coral mounds, whale-fish fall
Seamount
underwater mountain formed by volcanic activity
Mid-ocean ridge
Site of crust formation with volcanic activity
Trench
Deepest part of the sea
Euphotic zone
Top layer which receives enough light for photosynthesis
Dysphotic zone
Above 1000m, enough light for some vision
Aphotic zone
Below 1000m, no light
What is bioluminescence?
Method of generating light by ogranisms
Used to find mates, food and avoid predators
Blue-green light
How much does hydrostatic pressure increase every 10 m?
1 atmosphere
What is the main sediment of deep sea?
Soft and fine mud
What are the two types of deep-sea sediments?
Clay particles (under oligotrophic surface waters) Biogenic oozes (under productive waters)
Allochthonous system
Relies on food imputs from another source
What kind of food reaches deep sea?
POM = particulate organic matter
When is the main production/input of food during the year?
Spring/Summer
Does species diversity decrease linearly with depth?
No, it shows a significant increase at 1500-2000 m depth, and decreases again below 2000 m
What are deep sea island hotspots of biodiversity?
Cold-water deep coral mounds Seamounts Hydrothermal vents Cold seeps Whale-fish falls
