Lecture 11 - The Deep Sea Flashcards
What is the biggest ecosystem on the Earth?
The deep sea
What percentage of the deep sea is beyond shallow margins?
90%
When does deep sea begin?
At the shelf break, approximately 200m
Give the zonation of the ocean floor.
1) Continental shelf
2) Continental slope
3) Continental rise
4) Abyssal plain
5) Mid-ocean ridge
6) Deep ocean trenches
What is the deepest part of the ocean?
The Mariana trench
What is ALVIN?
A deep-sea submersible operated by WHOI, built in 1964.
How many large submarines operate in the deepest parts of the ocean?
Three
What does most of our knowledge of the deep sea come from?
Videos.
What light is found in the abyssal plane?
- No light from the surface
- Background light that comes from decay of certain compounds
- Bioluminescence
What percentage of mesopelagic organisms have a form of bioluminescence?
90%
Why do deep sea species often have large eyes?
To maximise their ability to see each other’s signals
How do organisms produce bioluminescence?
Using the chemical luciferin, which is oxidised by lucifers to form blue-green light
What is the temperature range of the abyssal plane?
-1 to 4 degrees
Mostly constant around 2 degrees
True or false:
There is a fast current across the abyssal plane.
FALSE.
There is a slow and steady current; cold water from poles sinks and moves gently across the ocean bed in one single direction.
What is the most important group of fish in deep sea environments?
Lanternfish
