deep ocean light

Question 1

where is the dark zone

Answer 1

below 1000m

Question 2

light in the deep sea at open oceans

Answer 2

• Open oceans >200m or below effective light penetration
•
80-90% of oceans are deep sea

Question 3

first dredge? today?

Answer 3

hms challenger 1870. used plates

cabeled observatories eg venus monterey

Question 4

divisions of the deep sea?

Answer 4

photic zones:
disphotic zone: twilight, mesopelagic zone
aphotic zone: without light
schemes of zonation:
benthic including: bathyl (1000-4000m), abyssal (4000-6000m), and hadal (6000-10,000m)
pelagic = open watr

Question 5

deepest light? what do disphotic organisms look like

Answer 5

• Little light below 150m or 492’
• Deepest light measured = 1000m
Most disphotic zone organisms are transparent

Question 6

how is light used in the deep sea

Answer 6

• Capture prey with use of red light
• Escape being prey (e.g. copepods)
• Tag predators (eg. Shrimp)
Act as an alamrm ex comb jelly fish

Question 7

what is phytodetritus

Answer 7

• Phytodetritus: large amount of sinking material from surface
• Very important to deep sea
Most research done at inner continental shelf (30-50% of nutrients hit bottom)
• open ocean only 2-7% hits bottom (consumed by
bacteria & transit time), then consumed by benthic org.