Deep Sea Pelagic and Benthic

Where does the dark ocean start?

200m

What is the largest habitat on Earth

Pelagic dark ocean

The ocean below 200 m is how much of Earth’s total volume?

95%

How much of earth’s surface does dark ocean cover

66%

how much of the total microbial production is in the dark ocean

50%

What is the temp range

1-4 C

What makes up 80-90% of energy sources for deep sea/dark ocean organisms?

Fluxes on particulate matter

List sources of energy for deep sea/dark ocean organisms

Fluxes of particulate matter, DOM from overturning convection, Vertical migration of zooplankton and micronekton, In-situ chemoautotrophic production

How much of energy in deep sea does DOM make up

10-20%

Two types of chemoautotrophic production in deep sea

Pelagic: inorganic carbon to organic carbon

Benthic: hydrothermal vents

What is the largest benthic habitat?

Abyssal plane (60% of ocean floor)

Mean depth of abyssal plane

4500 m

Is the abyssal plane mostly sediment or rocks?

sediment

How much surface production reaches the abyssal plane?

1-2%

What temperature is abyssal plane

less than 3C

Salinity of abyssal plane

33-35 ppt

How much oxygen in abyssal plane

almost saturated

Which invertebrates dominate the Abyssal Plane?

echinoderms: brittle stars, sea stars, sea cucumbers, sea urchins, crinoids

What fish in abyssal plane?

rat tails, sharks, hagfish

What other invertebrates are in the abyssal plane?

Sea pens, stalked sea squirt, crustacea: amphipods, isopods, annelids: polychaetes

What happens to the average biomass as you increase depth?

exponentially decreases

countershading

bioluminescence on belly makes body silhouettes blend in with light from durface

Adaptations of deep sea animals

camouflage, attract prey with bioluminescent lures, avoid prey (biolum for startling predators), large mouths, find mate

Two types of Hydrothermal Vents

Warm diffuse flow (5-100) and superheated plumes (250-400)

How is H2S toxic to cytochromes?

It stops cell respiration

Where are vestimentifera found?

Black smokers in Pacific

Why are riftia red

lots of hemoglobin

What group is riftia in

Annelida

How fast do riftia grow

85 cm per year

How large can they be

1.5 m long

Biomass of bivalves and riftia

20-30 kg/m2

How does riftia eat

has a trophosome with symbiotic bacteria

How can they have oxygen and H2S

Hemoglobin can carry both

Hydrothermal vents

coldwater sinks into crust

has dissolved metals and H2S

site of sulfide oxidation

produce organic molecules from CO2

What other bacteria are imp at hydrothermal vents

methane and ammonium oxidizers

Alvinella pompejana

Lives in tubes close to hot vents, up to 80 C (brief 100C). Bacteria live on surface

Macrofauna on vents

molluscs, annelids, and crustaceans

How tall lost city

60 m

What is lost city made from

calcium carbonate

Dif between hot vent and lost city

lost city cooler, methane and H rich (only small amounts of CO2 and Sulfide) and is alkaline (9-11 pH), Releases CH4 and H2. Only small invertebrates

What alternative metabolism is happening at a lost city

Menthanotrophs with anaerobic oxidation of methane (sulfate reduction) deposit carbonate

Cold seeps

Subduction zones, also shallower water. Chemosynthetic production and limpets graze on bacterial mats

Similarities between hot vents and cold seeps

biomass is high but species diversity is low, and they influence metal content in the water

what do hydrothermal vents provide in the pacific

micronutrients, which can be upwelled to create phytoplankton blooms