Lecture 5 Flashcards

Reef

Underwater ecosystem formed around corals

Mimic shallow-water environments, organisms exploit these environments

Barrier Reef

Ridge of sediment separated from a major landmass by water

Great Barrier Reef

2000km long, 150km wide

40km offshore of Australia

Corals

Live in shallow, warm, tropical seawater

Solitary or colonial organisms

Have a life cycle

Coral Reefs

Can grow from one polyp

Limestone skeleton grows 2cm/yr

Continents

Continental crust above mean sea level

Continental Margin

Continental crust under shallow water

Deep Ocean Basins

Deeper areas further from land

Mid-Ocean Ridges

Where new oceanic crust added

Where are the deepest parts of the ocean?

Commonly just offshore of the continental margin

Continental Shelf

Flat and shallow part of the continental margin

Average extends 70km offshore

Average slope is 2 degrees

Shelf Break

Where the continental shelf ends and the continental slope begins

Continental Slope

Steeply sloped area offshore of the shelf break

Average: 4 degrees

Continental Rise

Transition zone between slope and deep ocean floor

Commonly cut by submarine canyons

Made by mix of water and sediment

Turbidity Currents

Mix of water and sediment, that fills submarine canyon

Creates underwater avalanche

Graded Bedding

Larger grains at bottom, finer grains at top

Abyssal Plain

Flat surfaces in deep ocean

Cover 1/3 of planet, very deep

Ocean Trench

Deep linear depression on the ocean floor

Forms from tectonic plate collision

Deepest places on Earth

Volcanic Arcs

Lines of volcanoes that form on overriding tectonic plate

Associated with convergent margins

Hydrothermal Vent

Fissure on seafloor where heated water is expelled

Cold water is heated by magma and re-emerges

Often host unconventional ecosystems

Hydrothermal Vents

Opening in the ocean floor that emits hot water and dissolved minerals

Usually associated with divergent plate margins

Hydrothermal Vent Biocommunity

Bottom-dwelling community of organisms associated with a hydrothermal vent

Rely on sulfur-oxidizing bacteria

Hyperthermophiles

Organisms able to grow at 90 degrees or greater

400 species now known

Survive through detoxifying sulfide via chemosynthesis

Chemosynthesis

A process where bacteria or archaea synthesize organic molecules by oxidizing inorganic molecules

Typical Hydrothermal Vent

Emits fluid that are hot, acidic, and toxic

High concentration of dissolved hydrogen sulfide and heavy metals

Black Smoker Hydrothermal Vents

Emits a black cloud of hot water and suspended metal particles

Copper sulfides, zinc, silver

White Smoker Hydrothermal Vents

Emits a white cloud of hot water filled with dissolved metals

Water is not as hot as in black smokers

Biomass at Hydrothermal Vents

Have high metabolic rates and mature rapidly

Well adapted to the temporary nature of these vents

Giant Deep Sea Tubeworms (Riftia Pachyptila)

2.5m long, 10 cm diameter, no mouth

Absorb nutrients via symbiotic bacteria in their tissues, have no digestive tract

Giant Bivalves

Calyptogena Magnifica: Giant White Clam

Bathymodiolus Thermophilus: Large deep water mussel

Catch suspended particles in their gills

Vulcanoctopus Hydrothermalis

Near black smokers, eats crustaceans, small eyes

Small octopus thing, 200 mm long

What is the difference between a seamount and a tablemount?

Seamounts are volcanoes that may or may not rise above sea level, where tablemounts are seamounts that have been exposed to elements and therefore become flat topped

Seamounts = cone shaped

Tablemounts = flat topped

What are the ways that coral reproduces?

2 ways

‘Budding’ (Asexual reproduction)

Egg + sperm fertilization