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24 Cards in this Set

  • Front
  • Back
Depth Zones in the Ocean

Sublittoral, Bathyal, Abysmal, Hadal, Trenches
Deep Sea physical environment

Deep sea is the largest habitat. Temperature, very cold. Warmer in Mediterranean and red sea + hydrothermal vents with higher temperatures. Pressure is extremely high. Light is dark

Completely inhabitable to us.

Food availability
Nutrient Poor. Dependent on outside energy sources. Falling debris, fecal pellets, carasses

Bone eating worms. Close relative to hydrothermal vents

Little or no seasonal variation in temperature. Infrequent disturbances - bioturbation, benthic storms, whale falls
Deep Sea Expeditions

First. - HMS Lightning and HMS Porcupine

Dredged 4km around Britain

Challenger expedition - circumnavigated the earth and dredged upto 5.5 km depth

1960s development of modern equipment and submersibles

Deep Sea Biodiversity
Difficult to sample. Most diverse is mid deep level not the lowest for benthic invertebrates. Patchy distribution of species - richness can vary substantially. Low latitudes are more rich in species
Low Latitude Biodiversity

Many species have evolutionized to lost swim bladder and eyes

Echinoderms, arthropods, mollusks, fishes

Large moving or seaside7.2km depth

Lost swim bladders and negatively buoyant


Smaller than megafauna, very high diversity

Polychaetes, small crustaceans, mollusks


Smaller than 1mm, very diverse but still poorly known

Nematodes, copepods, ostracods, flatworms

Deep sea diversity causes hypothesis

1. Stability-time hypothesis

2. Biological Disturbances

3. Patchy food resources

4. Large Area

5. Source sink hypothesis

Stability Time Hypothesis

Constant environment causes stable biological interactions and specialization

Biological Disturbances

Predation by megafauna reduces competition among macrofauna, coexistence, Macrofauna in turn crops meiofauna
Patchy food resources

Food falls are generally patchy and can support high species diversity

Large Area

Large are should be able to support many species
Source sink hypothesis
Abundance goes up as you go deeper down. The deeper areas are sustained by the up top areas
Vent Fauna

Large variety of organisms on the vent: giant mussels bivalve, tubeworms, crab and other crustaceans


Different vent sites differ in fauna compositions

Vent Fauna Feeding

Basic energy source - chemautotrophic bacteria receive energy by oxidizing reduced suphur and other compounds. Microbial production on some vents 2-3 times

Macrofauna have evolved symbiotic relationships with bacteria.

Cold Seeps

Area were hydrocarbon, methane, hydrogen sulphide, and other fluids seep out of the ocean floor. Common in gulf of Mexico. A concern is that when the ocean is getting warmer, then these will melt and methane will be released into the ocean

Anthropogenic Impacts on the Deep Sea

Disposal, Exploitation, Ocean Acidification/Climate Change


Sewage, Chemicals, CO2

Mining, Fossil Fuels

Warming temp, acidification, hypoxia