Comprehensive Oceanography Final Exam Study Guide

Ocean Geography

• Water-to-Land Ratios:

  • Northern Hemisphere: 61% water, 39% land.

  • Southern Hemisphere: 81% water, 19% land.

  • Earth Overall: 71% water, 29% land.

• Major Oceans by Size:

  • Pacific Ocean: 165.2 million km^2 (46% of world ocean).

    • Deepest point: Challenger Deep in Mariana Trench (10,994m).

    • Widest point: ~17,700 km from Indonesia to Panama.

  • Atlantic Ocean: 82.4 million km^2 (23.5%).

    • Deepest point: Puerto Rico Trench (8,605m).

    • Narrowest point: Strait of Denmark (~290 km).

  • Indian Ocean: 73.4 million km^2 (20%).

    • Deepest point: Java Trench (7,725m).

  • Southern Ocean: 20.3 million km^2 (5.4%).

    • Surrounds Antarctica, defined by Antarctic Convergence.

  • Arctic Ocean: 14.1 million km^2 (4.3%).

    • Shallowest ocean (average depth 1,038m).

Earth's Coordinate System

• Latitude:

  • Parallel lines running east-west.

  • Measured in degrees north/south of the equator (0°).

  • North Pole: 90°N, South Pole: 90°S.

  • One degree = 60 nautical miles = 111 km.

• Longitude:

  • Lines running north-south (meridians).

  • Measured in degrees east/west of the Prime Meridian (0°).

  • Opposite of Prime Meridian: International Date Line (180°).

  • Lines converge at the poles.

• Finding Locations:

  • Latitude always given first, then longitude.

  • Example: New York City (40.7°N, 74.0°W).

  • Each degree divided into 60 minutes ('), each minute into 60 seconds (").

Earth's Seasons

• Earth's Tilt:

  • 23.5° tilt on the axis creates seasons.

  • The tilt direction remains fixed as Earth orbits the sun.

• Equinox:

  • Sun directly above the equator.

  • Equal day/night worldwide (12 hours each).

  • Spring (Vernal) Equinox: ~March 21.

  • Fall (Autumnal) Equinox: ~September 23.

• Solstice:

  • Maximum tilt toward/away from the sun.

  • Summer Solstice (N. Hemisphere): ~June 21.

    • Sun directly over the Tropic of Cancer (23.5°N).

    • Longest day in the Northern Hemisphere.

  • Winter Solstice (N. Hemisphere): ~December 21.

    • Sun directly over the Tropic of Capricorn (23.5°S).

    • Shortest day in the Northern Hemisphere.

The Hydrologic Cycle

• Definition: Continuous movement of water throughout Earth's systems.

• Major Processes:

  • Evaporation: Liquid water → water vapor (ocean to atmosphere).

    • ~434,000 km^3/year from oceans.

    • ~71,000 km^3/year from land.

  • Transpiration: Water vapor release from plants.

  • Condensation: Water vapor → liquid water (cloud formation).

  • Precipitation: Water falls to Earth (rain, snow, etc.).

    • ~398,000 km^3/year over oceans.

    • ~107,000 km^3/year over land.

  • Infiltration: Water soaks into the ground.

  • Runoff: Surface water flow to the ocean.

    • ~36,000 km^3/year from land to ocean.

  • Groundwater Flow: Subsurface water movement.

• Residence Times:

  • Atmosphere: ~9 days.

  • Rivers: ~2 weeks.

  • Soil moisture: ~2 months.

  • Lakes: ~10 years.

  • Groundwater: ~300 years.

  • Oceans: ~3,000 years.

Plate Tectonics

• Theory of Plate Tectonics:

  • Earth's lithosphere (crust + upper mantle) divided into plates.

  • Plates move over the plastic asthenosphere.

  • Motion driven by convection in the mantle.

• Earth's Layers:

  • Crust: 5-70 km thick (oceanic 5-10 km, continental 30-70 km).

  • Mantle: 2,885 km thick (upper/lower).

  • Core: 3,486 km radius (liquid outer, solid inner).

• Major Tectonic Plates:

  • Pacific Plate

  • North American Plate

  • South American Plate

  • Eurasian Plate

  • African Plate

  • Antarctic Plate

  • Indo-Australian Plate (sometimes considered as Indian Plate and Australian Plate)

  • Nazca Plate

  • Caribbean Plate

  • Cocos Plate

  • Arabian Plate

  • Philippine Plate

  • Juan de Fuca Plate

• Plate Boundaries:

  • Divergent Boundaries (spreading centers):

    • Plates move apart.

    • Magma rises, creates new crust.

    • Examples: Mid-Atlantic Ridge, East Pacific Rise.

    • Features: Rift valleys, volcanic activity.

  • Convergent Boundaries (collision zones):

    • Plates move toward each other.

    • Oceanic-Continental: Oceanic subducts, forms volcanic arc.

      • Example: Andes Mountains (Nazca under South American).

    • Oceanic-Oceanic: One subducts, forms island arc.

      • Example: Aleutian Islands (Pacific under North American).

    • Continental-Continental: Mountain building, no subduction.

      • Example: Himalayas (Indian-Eurasian collision).

    • Features: Deep trenches, volcanoes, earthquakes.

  • Transform Boundaries (fault zones):

    • Plates slide past each other horizontally.

    • Example: San Andreas Fault (Pacific-North American).

    • Features: Shallow earthquakes, offset features.

Continental Drift

• Evidence:

  • Matching coastlines (Africa-South America).

  • Similar rock formations across oceans.

  • Matching fossil records.

  • Paleomagnetic patterns.

  • Seafloor spreading.

• Seafloor Spreading:

  • New oceanic crust forms at mid-ocean ridges.

  • Oldest crust (~180 million years) far from ridges.

  • Rate: 1-20 cm/year depending on location.

• Ocean Basin Evolution Cycle:

  • Embryonic Stage: Continental rifting (Red Sea).

  • Juvenile Stage: New ocean basin forms (Atlantic).

  • Mature Stage: Subduction begins (Pacific).

  • Declining Stage: Ocean narrows (Mediterranean).

  • Terminal Stage: Continental collision (Himalayan region).

• Hot Spots:

  • Fixed mantle plumes of rising magma.

  • Create volcanic island chains as a plate moves over.

  • Examples:

    • Hawaiian-Emperor Seamount Chain.

    • Galapagos Islands.

    • Iceland.

    • Yellowstone (continental).

  • Used to track plate motion.

Oceanic Sediments

• Types of Marine Sediments:

  • Lithogenous (Terrigenous):

    • Source: Weathering of continental rocks.

    • Composition: Quartz, clay minerals, feldspar.

    • Distribution: Near continents, abundant in the Atlantic.

    • Examples: Sand, silt, clay.

  • Biogenous:

    • Source: Skeletal remains of marine organisms.

    • Composition:

      • Calcareous: Calcium carbonate (CaCO_3).

        • Foraminifera, coccolithophores, pteropods.

      • Siliceous: Silicon dioxide (SiO_2).

        • Diatoms, radiolarians.

    • Distribution: Areas of high productivity.

    • Minimum 30% biological material to be classified as biogenous.

  • Hydrogenous (Authigenic):

    • Source: Chemical precipitation from seawater.

    • Examples:

      • Manganese nodules (deep ocean).

      • Phosphorites (continental shelves).

      • Metal sulfides (hydrothermal vents).

      • Evaporites (salt, gypsum in enclosed basins).

  • Cosmogenous:

    • Source: Extraterrestrial (meteorites, cosmic dust).

    • Rare except in deep ocean or low sedimentation areas.

    • Examples: Tektites, micrometeorites, spherules.

• Major Biogenous Oozes:

  • Calcareous Ooze: Most common.

    • Found above Carbonate Compensation Depth (CCD, ~4,500m).

    • Below CCD, calcium carbonate dissolves.

  • Siliceous Ooze: More resistant to dissolution.

    • Diatom ooze (high latitudes).

    • Radiolarian ooze (equatorial regions).

• Sediment Distribution Factors:

  • Distance from the source.

  • Organism productivity.

  • Water depth (dissolution).

  • Current patterns.

  • Seafloor topography.

Ocean Basin Structure

• Continental Margins:

  • Passive Continental Margins (Atlantic-type):

    • Not associated with plate boundaries.

    • Gradual transition from continent to ocean basin.

    • Components:

      • Continental Shelf: Shallow, gently sloping (0.1°).

        • Average width: 80 km.

        • Average depth at edge: 130 m.

      • Continental Slope: Steeper descent (3-6°).

        • From shelf edge to deep ocean.

      • Continental Rise: Sediment accumulation at the base of the slope.

        • Formed by turbidity currents.

    • Examples: Eastern North America, Western Europe.

  • Active Continental Margins (Pacific-type):

    • Associated with plate boundaries (usually convergent).

    • Narrow shelf, steep slope, deep trenches.

    • Often have coastal mountain ranges.

    • Examples: Western South America, Japan.

• Deep Ocean Basin Features:

  • Abyssal Plains: Flat sediment-covered areas.

    • Most extensive in the Atlantic.

  • Seamounts: Underwater volcanoes (>1,000m height).

    • Often form at hot spots.

  • Guyots: Flat-topped seamounts (eroded at the surface).

  • Mid-Ocean Ridges: Undersea mountain ranges.

    • Longest feature on Earth (~65,000 km).

    • Site of seafloor spreading.

  • Ocean Trenches: Deepest parts of the ocean.

    • Form at subduction zones.

Water Properties

• Molecular Structure:

  • H_2O: Two hydrogen atoms bonded to one oxygen atom.

  • Bent structure (104.5° angle).

  • Polar molecule (negative at oxygen, positive at hydrogen).

  • Hydrogen bonds between molecules.

• Four Critical Properties:

  • High Heat Capacity:

    • Amount of heat needed to raise the temperature.

    • Water: 4.184 J/g·°C (highest of common substances).

    • Results in thermal stability of oceans.

    • Moderates Earth's climate.

  • Universal Solvent Capability:

    • Dissolves more substances than any other liquid.

    • Due to the polar nature of the water molecule.

    • Salinity: Average 35 ppt (parts per thousand).

    • Major ions: Cl^⁻ (55%), Na^+ (30.6%), SO_4^{2-}
      (7.7%), Mg^{2+} (3.7%).

  • Surface Tension:

    • Cohesive force at the air-water interface.

    • Creates a "skin" effect on the water surface.

    • Supports small organisms, water striders.

    • Essential for capillary action in plants.

  • Density Anomaly:

    • Most substances contract when cooling.

    • Water expands when freezing (ice less dense than water).

    • Maximum density at 4°C (39.2°F).

    • Causes ice to float, protects aquatic life.

• Water Density Factors:

  • Temperature (inverse relationship).

  • Salinity (direct relationship).

  • Pressure (direct relationship).

• Light Attenuation:

  • Open ocean: Blue light penetrates deepest (~200m).

  • Coastal waters: Green/yellow penetrates furthest due to particles.

  • Red light absorbed within first 10m.

  • Attenuation increased by:

    • Dissolved organic matter.

    • Suspended sediments.

    • Plankton blooms.

• Ocean Chemistry:

  • pH scale: 0-14 (logarithmic).

  • Ocean average: 8.1 (slightly basic).

  • Decreasing due to CO_2 absorption (ocean acidification).

  • Buffer Systems:

    • Resist pH changes.

    • Oceanic buffer: Carbonate system.

    • CO2 + H2O ↔ H2CO3 ↔ HCO3⁻ + H^+ ↔ CO3^{2-} + 2H^+

    • Maintains pH stability.

  • Gas Dissolution:

    • Optimal conditions: Cold, high-pressure water.

    • Follows Henry's Law: Solubility proportional to partial pressure.

    • Oxygen, CO_2 most important dissolved gases.

Atmosphere and Heat Budget

• Solar Radiation:

  • Solar constant: ~1,368 W/m^2.

  • Varies with:

    • Latitude: Higher at equator, lower at poles.

    • Season: Varies with Earth's tilt.

    • Time of day: Maximum at local noon.

• Earth's Heat Budget:

  • Solar input balanced by Earth's output.

  • Energy distribution:

    • 30% reflected (albedo).

    • 19% absorbed by the atmosphere.

    • 51% absorbed by land/ocean.

• Ice-Albedo Feedback Loop:

  • Positive feedback mechanism.

  • Process:

    • Cooling → More ice.

    • More ice → Higher albedo.

    • Higher albedo → More reflection.

    • More reflection → Less absorption.

    • Less absorption → More cooling.

  • Important in climate change scenarios.

• Primary Heat Distribution Forces:

  • Atmospheric Circulation:

    • Distributes ~2/3 of heat.

  • Ocean Currents:

    • Distributes ~1/3 of heat.

• Atmospheric Composition:

  • Nitrogen (N_2): 78.08%.

  • Oxygen (O_2): 20.95%.

  • Argon (Ar): 0.93%.

  • Carbon Dioxide (CO_2): 0.04% (increasing).

  • Water Vapor (H_2O): 0-4% (variable).

  • Trace Gases: Methane, ozone, etc.

• Air Density Factors:

  • Temperature: Density decreases as temperature increases.

  • Pressure: Density increases with pressure.

  • Humidity: Moist air less dense than dry air.

  • Altitude: Density decreases with height.

• Weather vs. Climate:

  • Weather: Short-term atmospheric conditions (days).

  • Climate: Long-term average patterns (30+ years).

Wind Patterns

• Global Wind Belts:

  • Driven by uneven heating and the Coriolis effect.

  • Trade Winds (0-30° N/S):

    • Northeast in the Northern Hemisphere.

    • Southeast in the Southern Hemisphere.

    • Flow toward the equator.

  • Westerlies (30-60° N/S):

    • Southwest in the Northern Hemisphere.

    • Northwest in the Southern Hemisphere.

    • Flow toward the poles.

  • Polar Easterlies (60-90° N/S):

    • Northeast in the Northern Hemisphere.

    • Southeast in the Southern Hemisphere.

    • Flow from the poles.

• Global Pressure Systems:

  • Equatorial Low (ITCZ): 0°

    • Intertropical Convergence Zone

    • Rising air, high rainfall

  • Subtropical Highs: 30° N/S

    • Descending air, clear skies

    • World's deserts typically here

  • Subpolar Lows: 60° N/S

    • Rising air, stormy conditions

  • Polar Highs: 90° N/S

    • Descending air, dry conditions

• Coastal Wind Patterns:

  • Sea Breeze (daytime):

    • Land heats faster than water.

    • Air rises over land, pulls in from sea.

    • Cooler temperatures along the coast.

  • Land Breeze (nighttime):

    • Land cools faster than water.

    • Air rises over water, pulls in from land.

    • Can bring humidity inland.

Ocean Structure and Circulation

• Vertical Temperature Structure:

  • Mixed Layer: Surface to ~100m

    • Uniform temperature due to wind mixing

    • Varies seasonally in depth

  • Thermocline: Rapid temperature change

    • Seasonal Thermocline: Forms in summer at mid-latitudes

    • Permanent Thermocline: 100-1000m in tropics

    • Absent in polar regions

  • Deep Zone: Below thermocline

    • Cold, stable temperatures (~2-4°C)

  • Impact on Phytoplankton

    • Spring/Fall blooms at mid-latitudes when:

      • Nutrients brought up from mixing

      • Light sufficient for photosynthesis

      • Thermocline not yet established/broken down

• Ocean Conveyor Belt (Thermohaline Circulation):

  • Global circulation pattern driven by:

    • Temperature differences (thermo-)

    • Salinity differences (-haline)

  • Major Components:

    • North Atlantic Deep Water (NADW)

      • Cold, salty water sinks in North Atlantic

    • Antarctic Bottom Water (AABW)

      • Coldest, densest water forms around Antarctica

    • Antarctic Intermediate Water (AAIW)

      • Forms at Antarctic Convergence

    • Surface Currents

      • Return flow to maintain balance

  • Significance:

    • Regulates climate

    • Redistributes heat globally

    • Cycle time: ~1,000 years

• Surface Currents:

  • Driven primarily by wind

  • Influenced by the Coriolis effect and continental boundaries

  • Major gyres:

    • North Atlantic Gyre (clockwise)

    • South Atlantic Gyre (counterclockwise)

    • North Pacific Gyre (clockwise)

    • South Pacific Gyre (counterclockwise)

    • Indian Ocean Gyre (counterclockwise)

• Western Boundary Currents:

  • Narrow, deep, fast currents on western sides of oceans

  • Examples: Gulf Stream, Kuroshio Current

  • Warm water transported poleward

• Eastern Boundary Currents:

  • Broad, shallow, slow currents on eastern sides of oceans

  • Examples: California Current, Benguela Current

  • Cold water transported equatorward

Waves

• Wave Characteristics:

  • Wavelength: Distance between successive crests

  • Wave Height: Vertical distance from trough to crest

  • Amplitude: Half the wave height

  • Period: Time between successive crests passing a fixed point

  • Frequency: Number of waves passing per second (1/period)

  • Wave Speed: Wavelength/period

• Wave Formation Factors:

  • Wind Speed: Stronger winds = larger waves

  • Wind Duration: Longer blowing = larger waves

  • Fetch: Distance wind blows over water

    • Longer fetch = larger waves

• Types of Waves:

  • Capillary Waves: Small ripples (wavelength <1.7 cm)

  • Wind Waves: Locally generated, chaotic

  • Swell: Regular waves that have traveled from generation area

  • Internal Waves: Form between water layers of different densities

  • Tsunamis: Generated by seismic activity, not wind

• Wave Behavior:

  • Deep-Water Waves: Depth > 1/2 wavelength

    • Circular water motion

    • No bottom interaction

    • Speed depends on wavelength

  • Shallow-Water Waves: Depth < 1/20 wavelength

    • Elliptical water motion

    • Bottom interaction

    • Speed depends on depth

  • Transitional Waves: Between deep and shallow conditions

• Wave Breaking:

  • Occurs when wave height ratio exceeds 1:7

  • Or when depth < 1.3 x wave height

  • Types:

    • Spilling: Gentle slope, wave crests tumble down

    • Plunging: Steep slope, wave curls over

    • Surging: Very steep slope, wave surges up the beach

• Wave Interactions:

  • Constructive Interference: Waves combine, height increases

  • Destructive Interference: Waves cancel

  • Refraction: Waves bend in shallow water

  • Diffraction: Waves bend around obstacles

  • Reflection: Waves bounce back from barriers

Tides

• Tide-Generating Forces:

  • Caused by the gravitational pull of the Moon and Sun

  • Modified by the centrifugal force of Earth-Moon rotation

• Tidal Patterns:

  • Diurnal Tides: One high and one low per day

    • Example: Gulf of Mexico

  • Semidiurnal Tides: Two equal highs and lows per day

    • Example: Atlantic Coast

  • Mixed Semidiurnal Tides: Two unequal highs and lows

    • Example: Pacific Coast

• Spring and Neap Tides:

  • Spring Tides: Larger tidal range

    • Occur during full and new moons

    • Sun, Earth, and Moon aligned

    • Solar and lunar tides add together

  • Neap Tides: Smaller tidal range

    • Occur during quarter moons

    • Sun, Earth, and Moon form a right angle

    • Solar and lunar tides partly cancel

• Tidal Cycles:

  • Daily Cycle: 24 hours 50 minutes (one lunar day)

  • Monthly Cycle: 29.5 days (one lunar month)

  • Annual Cycle: Affected by Earth's orbit

  • 18.6 Year Cycle: Due to Moon's orbital plane

• Tidal Currents:

  • Flood Current: Rising tide, water moves inland

  • Ebb Current: Falling tide, water moves seaward

  • Slack Water: Brief period between flood and ebb

• Amphidromic Points:

  • Points of zero tidal range

  • Tides rotate around these points due to the Coriolis effect

  • About a dozen major amphidromic points globally

Marine Life Organization

• Three Domains of Life:

  • Bacteria: Prokaryotes, no nucleus, single-celled

  • Archaea: Prokaryotes, no nucleus, often extremophiles

  • Eukarya: Eukaryotes, have nucleus, includes all multi-cellular life

• Biological Hierarchy:

  • Domain

  • Kingdom

  • Phylum

  • Class

  • Order

  • Family

  • Genus

  • Species

• Evolution, Taxonomy, and Phylogeny:

  • Evolution: Process of genetic change over generations

  • Taxonomy: Science of classifying organisms

  • Phylogeny: Evolutionary history and relationships

  • All connected: Taxonomy attempts to reflect evolutionary relationships

• Cell Size Relationships:

  • As cell radius (r) increases:

    • Surface area increases as r^2

    • Volume increases as r^3

    • Surface area to volume ratio decreases

  • Small cells are more efficient at nutrient/gas exchange

  • Large organisms need specialized systems (circulatory, respiratory)

• Organism Size and Abundance:

  • Inverse relationship: smaller organisms are more abundant

  • Microscopic organisms vastly outnumber larger ones

  • Marine life abundance pyramid:

    • Bacteria/Archaea: Most abundant (~10^{29} cells in ocean)

    • Phytoplankton: Very abundant

    • Zooplankton: Abundant

    • Fish/Nekton: Less abundant

    • Mammals: Least abundant

• Energy Flow:

  • Autotrophs (Producers):

    • Make organic compounds from inorganic materials

    • Examples: Phytoplankton, algae, some bacteria

    • Primary production methods:

      • Photoautotrophs: Use sunlight (photosynthesis)

      • Chemoautotrophs: Use chemical energy (chemosynthesis)

  • Heterotrophs (Consumers):

    • Obtain energy by consuming other organisms

    • Categories:

      • Herbivores: Consume plants/algae

      • Carnivores: Consume animals

      • Omnivores: Consume both

      • Detritivores: Consume dead organic matter

      • Decomposers: Break down organic matter to nutrients

• Photosynthesis/Respiration Equation:

  • Photosynthesis:

    • 6CO2 + 6H2O + \text{light energy} → C6H{12}O6 + 6O2

    • Converts light energy to chemical energy

  • Respiration:

    • C6H{12}O6 + 6O2 → 6CO2 + 6H2O + \text{energy}

    • Releases stored chemical energy

Ocean Zones

• Pelagic Zones (Water Column):

  • Epipelagic (0-200m)

    • Sunlit zone, photosynthesis occurs

    • Most productive, highest biodiversity

    • Temperature varies with location and season

  • Mesopelagic (200-1000m)

    • Twilight zone, minimal light

    • Site of daily vertical migrations

    • Strong oxygen minimum zone

  • Bathypelagic (1000-4000m)

    • Midnight zone, no light penetration

    • Cold (~4°C), high pressure

    • Specialized organisms (bioluminescence common)

  • Abyssopelagic (4000-6000m)

    • Abyssal zone, complete darkness

    • Very cold, extreme pressure

    • Limited food, sparse populations

  • Hadopelagic (>6000m)

    • Trench zone, greatest depths

    • Most extreme conditions

    • Highly specialized organisms

• Benthic Zones (Ocean Floor):

  • Littoral/Intertidal: Between high and low tide

    • Harsh conditions, specialized adaptations

    • Divided into:

      • Supralittoral: Spray zone

      • Upper Intertidal: Rarely submerged

      • Middle Intertidal: Regularly submerged/exposed

      • Lower Intertidal: Rarely exposed

  • Sublittoral/Neritic: Continental shelf (0-200m)

    • Highest benthic productivity

    • Various habitats: kelp forests, seagrass beds, coral reefs

  • Bathyal: Continental slope (200-4000m)

    • Transitional zone

    • Limited primary production, relies on surface inputs

  • Abyssal: Abyssal plains (4000-6000m)

    • Vast flat areas

    • Food-limited, low metabolism organisms

  • Hadal: Deep trenches (>6000m)

    • Most extreme benthic environment

    • Specialized high-pressure adaptations

Marine Organism Categories

• Plankton: Organisms that drift with currents

  • Phytoplankton: Photosynthetic plankton

    • Examples: Diatoms, dinoflagellates, coccolithophores

  • Zooplankton: Animal plankton

    • Examples: Copepods, krill, jellyfish, larvae

  • Bacterioplankton: Bacterial plankton

• Virioplankton: Viral Plankton

  • Holoplankton: Entire life cycle as plankton

    • Examples: Copepods, radiolarians, foraminifera

  • Meroplankton: Temporary planktonic phase

    • Examples: Fish larvae, crab larvae, coral larvae

• Nekton: Active swimmers

  • Examples: Fish, marine mammals, squid, sea turtles

• Benthos: Bottom-dwelling organisms

  • Epifauna: Live on the substrate surface

    • Examples: Crabs, sea stars, coral

  • Infauna: Live within the substrate

    • Examples: Clams, worms, burrowing urchins

  • Sessile: Attached to the substrate

    • Examples: Sponges, barnacles, mussels

  • Vagile: Mobile on/near bottom

    • Examples: Crabs, lobsters, flatfish

Adaptations to Marine Environment

• Light Adaptations:

  • The photic zone varies with water clarity:

    • Open ocean: up to 200m

    • Coastal waters: often <20m

  • Color adaptations:

    • Red organisms appear black at depth (red light absorbed first)

    • Many deep-sea organisms red for camouflage

    • Bioluminescence is common below 200m

• Temperature Adaptations:

  • Homeotherms: Maintain constant body temperature

    • Examples: Marine mammals, seabirds

    • Adaptations: Blubber, counter-current heat exchange

  • Poikilotherms/Ectotherms: Temperature varies with environment

    • Most marine organisms

    • Adaptations:

      • Antifreeze proteins in polar species

      • Enzyme systems optimized for temperature range

      • Behavioral thermoregulation

• Osmoregulation Adaptations:

  • Osmoconformers: Internal fluids match the environment

    • Most marine invertebrates

    • Example: Starfish, approximately 35 ppt salinity

  • Osmoregulators: Maintain different internal salinity

    • Marine vertebrates

    • Examples: Fish (~10-12 ppt), sharks (~25 ppt)

    • Mechanisms: Special gills, kidneys, salt glands

  • Anadromous Fish: Live in ocean, spawn in freshwater

    • Examples: Salmon, sturgeon, shad

    • Undergo physiological changes during migration

  • Catadromous Fish: Live in freshwater, spawn in the ocean

    • Examples: American eel, European eel

    • Also undergo physiological changes

• Buoyancy Control Methods:

  • Gas Bladders/Swim Bladders

    • Most bony fish

    • Adjust gas volume to maintain neutral buoyancy

  • Oil/Lipid Storage

    • Sharks (squalene in liver)

    • Deep-sea fish (wax esters)

  • Ion Regulation

    • Replacing heavy ions (sodium) with lighter ones (ammonium)

    • Example: Squid use ammonium chloride

  • Water Content

    • Jellyfish (95-98% water)

    • Provides near-neutral buoyancy

  • Morphological Adaptations

    • Flattened bodies (flatfish)

    • Fins/appendages for lift

The Biological Pump

• Definition: Process transporting carbon from surface to deep ocean

• Process Steps:

  1. Phytoplankton (primary producers) fix CO_2 via photosynthesis.

  2. Phytoplankton consumed by zooplankton (grazing).

  3. Carbon moves up the food web (larger organisms eat smaller).

  4. Organic matter produced as:

     • Fecal pellets from zooplankton/fish.

     • Marine snow (detritus, dead organisms).

     • Dissolved organic matter (DOM) released by organisms.

  5. Sinking of organic matter transports carbon to the deep ocean.

  6. Decomposition/remineralization releases nutrients, CO_2 in the deep.

     • Some carbon buried in sediments (long-term storage).

• Efficiency Factors:

  • Size and density of organic matter (sinking rate).

  • Remineralization rates (temperature, oxygen levels).

  • Water column stratification (mixing).

  • Food web structure and efficiency.