1. The Deep
Chapters 3, 18, 19

2. World Ocean Primitive earth and formation of the ocean
early earth thought to be composed of silicon compounds, iron, magnesium oxide, and other elements
gradually, the earth heated, causing melting and separation of elements
water vapor locked within minerals released to the surface, where it cooled, condensed, and formed the ocean

3. World Ocean Ocean and the origin of life
atmosphere formed by gases escaping from the planet
no accumulation of oxygen until evolution of photosynthesis—free oxygen forms oxides
Stanley Miller’s apparatus

4. World Ocean The ocean today
4 major ocean basins: Pacific, Atlantic, Indian and Arctic
seas and gulfs

5. Continental Drift Layers of the earth
solid inner core—iron- and nickel-rich
liquid outer core (same composition)
mantle—thickest layer with greatest mass, mainly magnesium-iron silicates
crust—thinnest and coolest, outermost

6. Continental Drift Moving continents Alfred Wegener
Pangaea, Laurasia and Gondwanaland

7. Continental Drift Forces that drive continental movement
magma convection currents
midocean ridges form along cracks where magma breaks through the crust
at subduction zones, old crust sinks into the mantle where it is recycled
seafloor spreading causes continental drift

8. Continental Drift Evidence for continental drift
fit of continental boundaries
earthquakes
seafloor temperatures highest near ridges
age of crust, as determined by samples drilled from the ocean bottom, increases with distance from a ridge

9. Continental Drift Theory of plate tectonics
lithosphere is viewed as a series of rigid plates separated by earthquake belts
divergent plate boundaries—midocean ridges where plates move apart
convergent plate boundaries—trenches where plates move toward each other
faults—regions where plates move past each other (e.g. transform faults)
rift zones—where lithosphere splits

10. Continental Drift Rift communities
depend on specialized environments found at divergence zones of the ocean floor
first was discovered by Robert Ballard and J.F. Grassle in 1977, in the Galápagos Rift
primary producers are chemosynthetic bacteria

11. Ocean Bottom Continental margins
continental shelf, continental slope, and shelf break
submarine canyons and turbidity currents
continental rises
shaping the continental shelves
glaciers
sediments

12. Ocean Bottom Ocean basin Life on the ocean floor
abyssal plains and hills
seamounts
ridges and rises
trenches and island arcs
Life on the ocean floor
continental shelves are highly productive
life on the abyssal plains is not abundant owing to the absence of sunlight

13. Composition of the Seafloor
Sediment—loose particles of inorganic and organic material

14. Composition of the Seafloor
Hydrogenous sediments
formed from seawater through a variety of chemical processes
e.g. carbonates, phosphorites
Biogenous sediments
formed from living organisms
mostly particles of corals, mollusc shells, shells of planktonic organisms

15. Composition of the Seafloor
Terrigenous sediments
produced from continental rocks by the actions of wind, water, freezing, thawing
e.g. mud (clay + silt)
Cosmogenous sediments
formed from iron-rich particles from outer space which land in the ocean and sink to the bottom

16. Salt and Water
30% of the salt supply comes from the sea; 70% from deposits left when ancient seas evaporated
Extraction of salt from seawater
seawater is directed into shallow ponds where it is concentrated, then evaporated
in cold regions, ice (which is nearly pure water) is removed, leaving concentrated seawater which is heated to evaporate the remaining pure water

17. Salt and Water
Desalination—process of removing salts from seawater (so it is potable)
process is energetically/financially expensive
usually more expensive than obtaining water from groundwater or surface sources
used in Israel, Saudi Arabia, Morocco, Malta, Kuwait, Caribbean islands, parts of Texas and California

18. Mineral Resources Sulfides Manganese
formed when mineral-rich solutions from fractures in rift valleys come into contact with colder seawater, and precipitate
no technology exists for sampling/mining
Manganese
used as a component of several alloys
nodules are found on the ocean floor
attempts to develop mining technology were largely suspended in the 1980s

19. Sand and Gravel
Most widespread seafloor mining operations extract sand and gravel for use in cement, concrete and artificial beaches
Calcium carbonate deposits
lime, cement, calcium oxide for removing magnesium from seawater, gravel
Tin is extracted from sand in coastal regions of Southeast Asia

20. Sand and Gravel
Uranium extracted from bottom sediments of the Black Sea
Platinum extracted from coastal sands in the U.S., Australia, South Africa
Mining sands/gravel can cause pollution and habitat destruction in the marine environment

21. Energy Sources: Coal, Oil, Natural Gas, and Methane Hydrate
formed from prehistoric swamp plants
coal is mined from under the sea in Japan
Oil and natural gas
represent 90% of the mineral value taken from the sea
formed from remains of diatoms and other microorganisms
oil is mined in the Persian Gulf, North Sea, Gulf of Mexico, northern coast of Australia, southern coast of California, and around the Arctic ocean

22. Energy Sources: Coal, Oil, Natural Gas, and Methane Hydrate
methane hydrate—ice crystals that trap methane, and can be burned
world’s largest known fuel reserve
methane gas rapidly escapes from the crystals when they are brought to the surface
experiments indicate it may be possible to exploit this resource, but geologists and biologists have concerns

23. Finding Your Way around the Sea
Maps and charts
Mercator projections
bathymetric charts
physiographic charts

24. Finding Your Way around the Sea
Reference lines
latitude
longitude
divisions of latitude and longitude

25. Finding Your Way around the Sea
Navigating the ocean
principles of navigation
a sextant was used to determine latitude based on the angle of the North Star with reference to the horizon
longitude determined using chronometer

26. Finding Your Way around the Sea
Navigating the ocean
global positioning system (GPS)
utilizes a system of satellites to determine position
GPS measures the time needed to receive a signal from 3 satellites, and calculates position

27. Survival in the Deep Sea
The deep sea is an inhospitable place
frigid temperatures throughout the year
tremendous pressure
total darkness
Conditions have remained stable over many years
Some creatures have evolved to survive in this harsh environment

28. Survival in the Deep Sea
Adaptations to pressure
fluid pressure within the animal’s tissues matches the pressure of the seawater
Adaptations to cold
nearly all have body temperatures close to that of the surrounding water
slow metabolism – slow movement, growth; less reproduction, longer life
high density of cold water matches that of animal’s bodies – they don’t sink

29. Environmental Factors Affect Organism Distribution
pressure
760 mm Hg or 1 atmosphere at sea level
increases 1 atmosphere for every 10 meters below sea level

30. Life in the Dark Color in deep-sea organisms
countershading employed in the disphotic zone—region of dim light (twilight)
photophores (light-producing organs) may be used to make the ventral surface lighter
many species are bright red or orange
appear black or gray in dim light
many are bioluminescent

31. Life in the Dark Roles of bioluminescence how bioluminescence works
a protein called luciferin is combined with oxygen in the presence of an enzyme called luciferase and adenosine triphosphate (ATP)
chemical energy of ATP converted to light
camouflage
bioluminescence matches the intensity of sunlight, and thus contributes to countershading, in the twilight zone

32. Life in the Dark Roles of bioluminescence (continued)
mating and species recognition
identifies the sex of an individual
allows for identification of species
attracting prey
anglerfish and stomiatoids attract prey with bioluminescent lures
light may be used to locate prey in the dark
defense
deepwater squid and shrimp release clouds of bioluminescent materials to confuse predators

33. Life in the Dark Seeing in the dark
many deep-sea fishes have tubular eyes containing 2 retinas instead of 1
1 retina views distant objects, while the other views closer objects

34. Life in the Dark Seeing in the dark
deep-sea squid have barrel-shaped, stalked or unequally-sized eyes
some animals have slightly-functional eyes or are totally blind, relying on chemical stimuli instead

35. Life in the Dark Finding mates in the dark Finding food in the dark
male becomes a parasite on the female in some species of anglerfish
Finding food in the dark
benthic organisms and scavengers eat detritus which drifts down from above
many small fishes and invertebrates migrate upward at night to feed
adaptations include large mouths and expandable stomachs

36. Life in the Dark Finding food in the dark (continued)
some can eat prey larger than themselves
stomiatoids have barbels (fleshy projections) that may be used as lures, probes or for species recognition
anglerfishes have a spine used as a fishing pole, tipped with a luminous lure

37. Giants of the Deep Giant squids New species of deepwater squid
large, unnamed species discovered 1988
have longer arms than other squid, bent downward at sharp angles
exhibit different behaviors
hide in their ink clouds instead of fleeing
pairs have been observed attached, towing each other through the water

38. Relicts from the Deep Spirula Vampire squid
small molluscs resembling squid and octopuses with spiral-shaped internal shells
similar to belemnites common in the sea million years ago
Vampire squid
dark-colored, webbing between its arms
thought to be descendents of an intermediate organism between squids and octopuses

39. Relicts from the Deep Coelacanth Neopilina
fish with large, thick scales and fleshy bundles between its body and fins
thought to be extinct for 70 million years until 1 was caught alive in 1938
Neopilina
limpet-like mollusc
thought to be extinct for 350 million years until 1 was found in 1952

40. Life on the Sea Bottom Benthic communities
sources of food for benthic organisms
organic matter rains down from surface waters and accumulates on the ocean floor
a large carcass will occasionally drift down
food chains
bacteria are consumed by meiofauna (e.g. foraminiferans and nematodes)
infauna (e.g. worms, bivalves) eat meiofauna
deposit feeders and suspension feeders
predators include fishes, squids, sea stars

41. Life on the Sea Bottom Benthic communities (communities)
diversity of benthic organisms of the deep
low numbers, but high diversity
ineffective dispersion of young may lead to isolation, which contributes to speciation
stable conditions may prevent extinction of species, so species proliferate

42. Life on the Sea Bottom Vent communities
self-contained communities that are some of the most productive in the sea
formation of vents
vents form at spreading centers
seawater seeps down to where it contacts magma
water is superheated, and loses some minerals while it picks up others, such as sulfur, iron, copper and zinc

43. Life on the Sea Bottom Vent communities (continued) types of vents
white smokers—produce a stream of milky fluid rich in zinc sulfide; water temperature is normally less than 300o C
black smokers—narrow chimneys that emit a clear water with temperatures of 300o to 450o C that is rich in copper sulfides (which precipitate with contact with cold seawater, to produce the black color)

44. Life on the Sea Bottom Vent communities (continued) vent communities
residents include large clams, mussels, anemones, barnacles, limpets, crabs, worms and fishes
primary producers are chemosynthetic bacteria
primary consumers filter-feed or graze bacteria from the water
clams (Calyptogena), mussels (Bathymodiolus) and vestimentiferan worms (Riftia) host symbiotic chemosynthetic bacteria

45. Life on the Sea Bottom Vent communities (continued)
rise and fall of vent communities
vents are colonized by organisms shortly after they are formed
when geological changes inactivate the vent (an estimated 20 years later), these organisms all die
vent inhabitants are thought to produce large numbers of larvae which drift to other vent sites