the deep ocean (general)

Question 1

how are organisms adapted to pressure

Answer 1

• Organisms adapted to the deep don’t have to worry about it
• Organisms w air pockets have issues with pressure - humans
• Organisms in the deep have issues being brought up
○ Less pressure = they expand, internal organs exit
Some organisms can go deep even if they arent always there ie seals

Question 2

effect of pressure in the deep

Answer 2

• Effect of pressure in deeper depths:
○ Decreased dissolved O2
○ Decreased enzyme function - protein unfolds
○ disrupts membrane structure - cells
Ex. Put a Styrofoam cup outside of an immersible - immersible gets pressurized

Question 3

organism internal adaptations

Answer 3

• Enzymes more stable
• Cell membranes more fluid - higher water content, water isnt compressible
• Cell communication adapted e.g. barophilic bacteria, different pathways and signals
High H2O content of deep organisms prevents damage

Question 4

salinity in the deep?

Answer 4

• Higher near surface

More constant below 200m

Question 5

temperature and the deep

Answer 5

• More constant deeper you go (less than 1 degree C varience/year)
○ Beyond intertidal region has less temp. variation
Biggest change 0-1000m (20 degrees C - 5 degrees C)

Question 6

oxygen in the deep

Answer 6

lLargely oxygenated except low circulation areas (trenches)

Question 7

food in the deep

Answer 7

• Not readily available - most organisms have adaptations related to getting food
• Chronically short - e.g. Ophiuroids - 24000m - dead organisms fall deep into the ocean - feeds the deep water organisms, these ophiuroids have sensory systems in their arms
Benthic biomass is very reduced - organisms constantly scavenging

Question 8

why is food scarce?

Answer 8

• Why?
○ Distance from coast and depth down - food is not necessarily reaching deep ocean
○ Patchy benthic feeders - distribution is patchy, might be due to local anoxic environment (i.e. carcass) in these patches - kills off some of these feeders in low numbers
§ Could also be because of patchy larval settlement or dispersing adults - settle as adults
○ Stress in the sediment kills benthic and detritus feeders - sediment is soft and easily moved, can bury and kill
§ Lack of aeration of sediments
Continued erosion by currents

Question 9

deep sea organisms food adaptations

Answer 9

• Deep sea organism adaptations
1. Lower metabolism - there is a lack of food
a. Lower than expected metabolism at 4 degrees C
2. Consumption of prey
a. Use sit and wait approach
b. Can consume same size as predator due to large mouths and stomach
There are active predatores ie. Bristlemouth, lantern fish

Question 10

deep sea biota distribution

Answer 10

• Low animal density BUT high diversity
• Studies compare continental shelf benthos to deep sea
• Still finding new species
DNA studies show similar speciation to organisms in shallow H2O

Question 11

How can so many species coexist in the deep

sea sediments with little environmental variability?

Answer 11

“Possible” answers:
• not homogeneous currents disturb it
• increased local heterogeneity & microhabitats
• reduced dispersal mechanisms at depth
• deep sea an “older”; “more stable” habitat vs shelfs
• lower extinction rates (not exposed or glaciated).