Bieb 140 Lecture 12

Front 1

Depth Zones in the Ocean

Back 1

Sublittoral, Bathyal, Abysmal, Hadal, Trenches

Front 2

Deep Sea physical environment

Back 2

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.

Front 3

Food availability

Back 3

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

Front 4

Osedax

Back 4

Bone eating worms. Close relative to hydrothermal vents

Front 5

Predictability

Back 5

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

Front 6

Deep Sea Expeditions

Back 6

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

Front 7

Deep Sea Biodiversity

Back 7

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

Front 8

Low Latitude Biodiversity

Back 8

Many species have evolutionized to lost swim bladder and eyes

Front 9

Megafauna

Back 9

Echinoderms, arthropods, mollusks, fishes

Large moving or seaside7.2km depth

Lost swim bladders and negatively buoyant

Front 10

Macrofauna

Back 10

Smaller than megafauna, very high diversity

Polychaetes, small crustaceans, mollusks

Front 11

Meiofauna

Back 11

Smaller than 1mm, very diverse but still poorly known

Nematodes, copepods, ostracods, flatworms

Front 12

Deep sea diversity causes hypothesis

Back 12

1. Stability-time hypothesis

2. Biological Disturbances

3. Patchy food resources

4. Large Area

5. Source sink hypothesis

Front 13

Stability Time Hypothesis

Back 13

Constant environment causes stable biological interactions and specialization

Front 14

Biological Disturbances

Back 14

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

Front 15

Patchy food resources

Back 15

Food falls are generally patchy and can support high species diversity

Front 16

Large Area

Back 16

Large are should be able to support many species

Front 17

Source sink hypothesis

Back 17

Abundance goes up as you go deeper down. The deeper areas are sustained by the up top areas

Front 18

Vent Fauna

Back 18

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

Benthopelagic

Different vent sites differ in fauna compositions

Front 19

Vent Fauna Feeding

Back 19

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.

Front 20

Cold Seeps

Back 20

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

Front 21

Anthropogenic Impacts on the Deep Sea

Back 21

Disposal, Exploitation, Ocean Acidification/Climate Change

Front 22

Disposal

Back 22

Sewage, Chemicals, CO2

Front 23

Exploitations

Back 23

Mining, Fossil Fuels

Front 24

Climate

Back 24

Warming temp, acidification, hypoxia