Marine Biology Midterm

Paleolithic Fishing

Wooden hooks used for catching fish

160,000 Years Ago

Earliest evidence of humans harvesting molluscs and crustaceans

42,000 Years Ago

Age of the oldest fish hook found in Southeast Asia

23,000 Years Ago

Age of the oldest fish hooks found in Japan, made of beaks, bones, claws, and shells

Phoenicians

First accomplished Western navigators who sailed the Mediterranean, Red Sea, Atlantic, and Indian Ocean by 2000 B.C.

Aristotle

First marine biologist; created the "Ladder of Life" classifying ~1,400 marine species, studied gills, and detailed cuttlefish anatomy

Roman Marine Aquaculture

Widespread fish farming practice in ancient Roman villas around Sorrento and the Gulf of Naples

Dark Ages Marine Exploration

Period when European scientific inquiry stalled, but Vikings, Arabians, Chinese, and Polynesians continued ocean navigation

Luigi Ferdinando Marsili

18th-century scientist who developed and popularized the concept of the isobath

Lazzaro Spallanzani

18th-century researcher who conducted early studies on sea urchins and hermit crabs

James Cook

18th-century explorer who led 3 major ocean voyages, was the first to cross the Antarctic Circle, and mapped longitude

HMS Beagle Expedition

1831 voyage where Charles Darwin collected data leading to his Theory of Atolls and natural selection

US Explorer Expedition

1838 American expedition with 11 naturalists that mapped 280 atolls and collected massive biological collections

HMS Challenger Expedition

1872 voyage covering 68,000 nautical miles that discovered thousands of deep-sea species; results filled 50 volumes over 19 years

Stazione Zoologica Anton Dohrn

First permanent Marine Biological Institute in the world, founded in Naples, Italy in 1872 by Anton Dohrn

Bathysphere

Submersible used in 1934 off Bermuda to reach a record depth of 923 meters (3,028 feet)

Bathyscaphe Trieste

Deep-sea vehicle that reached the bottom of the Mariana Trench (10,916 meters) in 1960

Jacques Cousteau

Co-inventor of the open-circuit scuba demand regulator (Aqua-Lung) for underwater exploration

Hans Hass

Pioneer who developed underwater flash cameras and the Dräger oxygen rebreather

Ocean Surface Coverage

The world ocean covers ~70% of Earth's surface (61% Northern Hemisphere, 80% Southern Hemisphere)

Ocean Biosphere Share

The ocean contains 95% of the total livable biosphere volume on Earth

Pacific Ocean

Largest ocean (155.5M km²); mean depth 4,028 m; deepest point Mariana Trench (11,033 m)

Atlantic Ocean

Second largest ocean (76.7M km²); mean depth 3,926 m; deepest point Puerto Rico Trench (8,648 m)

Indian Ocean

Third largest ocean (68.5M km²); mean depth 3,963 m; deepest point Java Trench (7,725 m)

Southern Ocean

Fourth largest ocean (20.3M km²); mean depth 4,000 m; deepest point South Sandwich Trench (8,428 m)

Arctic Ocean

Smallest ocean (14.0M km²); mean depth 1,205 m; deepest point Litke Deep (5,450 m)

Continental Shelf

Gently sloping shallow extension of a continent extending to the shelf break

Continental Slope

Steeply sloping region connecting the continental shelf to the deep ocean floor

Continental Rise

Apron of sediment accumulated at the base of the continental slope

Abyssal Plain

Vast, flat, sediment-covered region of the deep ocean floor

Ocean Trench

Deep, steep-sided canyon formed at convergent subduction zones; deepest ocean areas

Seamount

Undersea volcanic mountain rising from the seafloor that does not break the water surface

Submarine Canyon

V-shaped canyon cut into the continental shelf and slope, ending in a deep-sea fan

Theory of Continental Drift

Hypothesis proposed by Alfred Wegener in 1912 stating that continents were once joined in a supercontinent

Wegener's Evidence

Fit of coastlines, matching fossils across oceans, matching geological formations, and paleoclimate traces

Pangaea

Supercontinent that existed 225 million years ago before splitting into Laurasia and Gondwana

Plate Tectonics

Movement of ~15 rigid lithospheric plates at speeds of 2-18 cm/year driven by mantle convection

Oceanic Crust

Dark, dense, basaltic crust that is thin (~5 km) and geologically young

Continental Crust

Light, less dense, granitic crust that is thick (~35-70 km) and geologically old

Moho Discontinuity

The boundary layer between the Earth's crust and the upper mantle

Lithosphere

Rigid outer layer of Earth comprising the crust and uppermost solid mantle

Asthenosphere

Soft, plastic layer of the upper mantle upon which tectonic plates float

Divergent Boundary

Plate boundary where plates pull apart, creating mid-ocean ridges and new oceanic crust

Oceanic-Continental Subduction

Boundary where dense oceanic crust sinks beneath continental crust, creating trenches and volcanic arcs

Oceanic-Oceanic Subduction

Boundary where older oceanic crust sinks, forming deep trenches and volcanic island arcs

Continental-Continental Collision

Boundary where two continental plates collide, pushing up non-volcanic mountain ranges

SONAR

Sound Navigation and Ranging; uses reflected sound waves to map seafloor depth and topography

Messinian Salinity Crisis

Geological event 5.7 Mya when the Mediterranean Sea evaporated, refilling rapidly 5.3 Mya

Subducting Plate

The denser plate (usually oceanic crust) that bends and sinks downward into the mantle

Overriding Plate

The less dense plate (continental or younger oceanic crust) that remains on top during subduction

Oceanic Trench (Subduction)

The steep-sided, V-shaped depression formed where the subducting plate bends into the mantle

Accretionary Wedge

A complex mass of scraped-off marine sediments and seafloor rock piled up against the front of the overriding plate

Forearc Region

The region between the oceanic trench and the volcanic arc on the overriding plate

Volcanic Arc

A curved chain of volcanoes formed on the overriding plate above the melting subducted slab (continental arc or island arc)

Backarc Region

The area behind the volcanic arc relative to the subduction zone and trench

Benioff Zone

A dipping planar zone of earthquake foci following the descending subducted slab down into the mantle

Water Polarity

Unequal electron sharing making oxygen slightly negative and hydrogens slightly positive, creating hydrogen bonds

Specific Heat of Water

Amount of heat needed to change water's temperature; 3,300x higher heat capacity than air

Ice Density

Ice is less dense than liquid water because hydrogen bonds expand into a crystalline lattice

Average Ocean Salinity

35 grams of dissolved salt per kilogram of seawater (35 PSU or 35 ppt)

Dominant Seawater Ions

Chloride (55%) and Sodium (31%), followed by Sulfate (8%) and Magnesium (4%)

Factors Raising Salinity

Evaporation and sea ice formation (leaves salt behind in liquid water)

Factors Lowering Salinity

Precipitation, river runoff, and melting ice

Halocline

Layer in the ocean water column where salinity changes rapidly with depth

Hydrostatic Pressure

Increases by 1 atmosphere (ATM) for every 10 meters (33 feet) of ocean depth

Dissolved Gas Solubility

Gases like oxygen and carbon dioxide dissolve most readily in cold, low-salinity water

Ocean Acidification

Process where absorbed CO2 forms carbonic acid, lowering pH and dissolving calcium carbonate shells

Light Absorption Spectrum

Red light is absorbed in top meters; blue and violet light penetrate deepest into the ocean

Photic Zone

Sunlit upper layer of the ocean extending from the surface down to ~200 meters

Disphotic Zone

Twilight ocean zone between 200 and 1,000 meters where light is insufficient for photosynthesis

Aphotic Zone

Pitch-black ocean zone located below 1,000 meters where no sunlight penetrates

Thermocline

Layer in the ocean water column where temperature decreases rapidly with depth

Ocean Gyre

Large circular system of ocean currents driven by global winds and continental boundaries

Coriolis Effect

Deflection of moving air/water to the right in the Northern Hemisphere and left in the Southern Hemisphere

Western Boundary Currents

Fast, deep, warm ocean currents moving poleward on the west side of ocean basins (e.g., Gulf Stream)

Eastern Boundary Currents

Slow, shallow, cold ocean currents moving equatorward on the east side of ocean basins (e.g., California Current)

Ekman Transport

Net movement of surface water at 90 degrees to the wind direction due to the Ekman spiral

Thermohaline Circulation

Deep-ocean global circulation driven by temperature and salinity density differences

Upwelling

Wind-driven process bringing cold, nutrient-rich deep water to the surface, boosting productivity

Wave Crest

The highest point of a wave above the still-water level

Wave Trough

The lowest point of a wave below the still-water level

Wave Height (H)

The vertical distance between the wave trough and the wave crest

Wavelength (L or λ)

The horizontal distance between two consecutive crests or two consecutive troughs

Wave Period (T)

The time it takes for two consecutive wave crests to pass a fixed point

Wave Frequency (f)

The number of wave crests passing a fixed point per unit of time (1/Period)

Still-Water Level

The average sea surface elevation in the absence of waves; halfway between crest and trough

Wave Base

The maximum depth to which wave energy penetrates, equal to 1/2 the wavelength (λ/2)

Fetch

The distance of open water over which wind blows unimpeded to generate waves

Shallow-Water Wave

A wave entering water shallower than 1/2 its wavelength, causing bottom friction and breaking

Tsunami

Long-period sea wave caused by undersea earthquakes, volcanic eruptions, or landslides

Spring Tides

Tides with the largest tidal range; occur during New and Full Moons when Sun, Moon, and Earth align

Neap Tides

Tides with the lowest tidal range; occur during 1st and 3rd Quarter moons at 90-degree angles

Diurnal Tide

Tidal pattern featuring one high tide and one low tide per lunar day

Semidiurnal Tide

Tidal pattern featuring two high tides and two low tides of equal height per lunar day

Mixed Semidiurnal Tide

Tidal pattern featuring two high tides and two low tides of unequal height per lunar day

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