the deep sea floor

Question 1

shape of the deep sea floor

Answer 1

○ Imperceptible gradient
○ Single largest environment on the planet - not accessible, costs a lot to access
Interrupted by mountain chains (bigger than we see on terrestrial habitat)

Question 2

corals of the deep

Answer 2

• Grow beyond light (filter feed) but can contain symbiodinum - dinoflagellate, endosymbionts transferring carbohydrates to coral (e.g. black coral)
• Many have a reef system with other organisms
• Found between 30 to 1000m, even 10,000+ m
• Diverse fauna, most off NE atlantic
• Support demersal fisheries
High diversity in organisms
• 2000* sp. per mound
• repeated colonization and extinction
• Mounds ver old (oldest organisms in the sea)
DNA differences between open ocean and fjord/coastal populations

Question 3

how are corals connected

Answer 3

Colonial organism - individuals connected - grows new skeleton

Question 4

describe fishes of the deep sea

Answer 4

• Rat tailed fish bathysaurus (250 m + to hadal)
○ Have swim bladders and searchlight anal photophore - searches for food, has bioluminescence, can be used to protect
• Tripod fish bathypterois grallator
Stationary, sit and wait predator
• uses elongated fin rays, perched, facing current
• hermaphroditic

Question 5

deposit feeders?

Answer 5

• Deposit feeders - gather sediment
○ Live in muds or on sediment, common in deeper depths
• Explored less than 1% of the deep sea bottom
• Suspension feeders are rare in the mud
• New amphipod species - supergiant amphipods
• Go back to this slide
Deep sea sediments found to have a high water content = low stability

Question 6

•

Trophic group mentalism

Answer 6

negative effect of deposit feeder on suspension feeders

○ Bad for corals , can clog their filter feeders

Question 7

sediment cycling? why is there reduced decomp here?

Answer 7

• Low organic content to sediment bottom
○ Continental shelf botton 2-5%
○ Open ocean bottom 0.5-1.5%
○ Abyssal bottom <0.25%
• Reduced decomposition
○ Not because of temp or pressure, likely bc of scarcity of bacteria or lower metabolism
• Larger organisms can disrupt sediment and deposit feeders
○ e.g. mysticete grey whale
Particle cycle over sediment can effect deposit feeders

Question 8

carcass breakdown stages

Answer 8

• Aphipods, crusaceans, hagfish, sleep sharks will feed on it
• Then, colonization of brittle stars, polychaete worms, crabs, clams, mussels, bacteria - break it down to the bone
• Stages of breakdown
1. Scavenger state: 1st year, sharks, bony fish, crabs
2. Enriched sediment: 2nd yr, inverts live on enriched sediment
3. Sulfide stage: chemoautotrophic bacteria and clams with symbiotic bacteria
Reef stage: epibenthic suspension feeding animals on bones