AICE Marine Science Study Guide Notes

Anatomy of Fish

  • Cartilaginous vs Bony Fish:

    • Bony Fish (Osteichthyes): Hard, scaly, skeletons made of bones; e.g., goldfish, clownfish, tuna.

    • Cartilaginous Fish (Chondrichthyes): Softer, smoother; skeletons made of cartilage; e.g., sharks, rays.

    • Swim Bladder (Bony Fish): Organ that maintains buoyancy.

Taxonomic Hierarchy

  • Classification from broadest to most specific:

    1. Domain

    2. Kingdom

    3. Phylum

    4. Class

    5. Order

    6. Family

    7. Genus

    8. Species

  • Example: Prionace glauca (blue shark).

Layers of the Ocean

  1. Epipelagic Zone:

    • Depth: 0-200 meters.

    • Characteristics: This zone is well-lit, receiving abundant sunlight, which allows for photosynthesis and supports the growth of phytoplankton, the foundation of the oceanic food web.

    • Organisms: Various marine life, including fish, marine mammals, and some invertebrates, thrive in this zone due to the availability of light and nutrients.

  2. Mesopelagic Zone:

    • Depth: 200-1000 meters.

    • Characteristics: Known as the twilight zone, it receives limited light, diminishing with depth. This results in a gradient of light known as photic to aphotic transition.

    • Organisms: It is populated by organisms such as squids, lanternfish, and other fish that migrate to the epipelagic zone at night to feed, as well as deeper-dwelling species that rely on detritus falling from above for sustenance.

  3. Bathypelagic Zone:

    • Depth: 1000-4000 meters.

    • Characteristics: This zone is devoid of natural light, resulting in complete darkness and high pressure. Temperature drops significantly, nearing freezing levels.

    • Organisms: Many species exhibit bioluminescence, which helps them navigate, search for food, or attract mates. Notable inhabitants include anglerfish, giant squid, and various deep-sea fish.

  4. Abyssopelagic Zone:

    • Depth: 4000 meters and deeper.

    • Characteristics: This zone is characterized by perpetual darkness, with temperatures near freezing and extremely high pressure. The seabed often consists of deep-sea sediments, comprising silt and clay.

    • Organisms: Life in this zone is scarce, but certain organisms, such as tube worms and deep-sea fish, have adapted to survive in these harsh conditions, often relying on chemosynthesis near hydrothermal vents for energy.

  5. Benthic Zone:

    • Depth: The ocean floor varies in depth and includes the intertidal zone, continental shelf, and deep ocean floor habitats.

    • Characteristics: This zone is often rich in biodiversity, providing various habitats like coral reefs, sea grass beds, and rocky substrates.

    • Organisms: Many benthic organisms, including crustaceans, mollusks, and echinoderms, thrive here, playing vital roles in nutrient cycling and sediment turnover.

  6. Hadopelagic Zone:

    • Depth: 6000-11000 meters, encompassing the deepest ocean trenches.

    • Characteristics: This extreme environment experiences the highest pressures found in the ocean, with remarkably low temperatures and limited nutrient availability.

    • Organisms: Only specialized organisms like certain deep-sea jellyfish, amphipods, and extremophiles, capable of coping with these extreme conditions, can survive here, often relying on organic material that sinks from upper zones.

Ecological Relationships

  • Commensalism: One benefits, the other unaffected (e.g., barnacles on whales).

  • Mutualism: Both benefit (e.g., clownfish and sea anemones).

  • Parasitism: One benefits at the other's expense (e.g., barnacles on crabs).

  • Predation: Predator-prey relationship (e.g., sharks eating fish).

  • Competition: Both species negatively affected competing for resources.

Weathering, Erosion & Sedimentation

  • Weathering: Breakdown of rocks into smaller pieces (physical, chemical types).

  • Erosion: Movement of materials from one location to another.

  • Sedimentation: Deposition of particles in new locations, influenced by particle size and water speed.

Molecular Bonds

  1. Covalent Bond: Atoms share electrons (e.g., water - H2O).

  2. Ionic Bond: One atom gives up electrons, becoming positively charged (e.g., sodium chloride - NaCl).

  3. Hydrogen Bond: Weak bonds important for water's properties.

Tides

  • Tides: Periodic rise and fall of ocean surface due to gravitational pull of the moon and sun.

  • Types of Tides: Semi-diurnal (2 high, 2 low), Diurnal (1 high, 1 low).

  • Factors Affecting Tides: Spring tides (sun, moon, earth alignment) and Neap tides (right angle formation).

Water Characteristics

  • Universal Solvency: Water dissolves many substances due to polarity.

  • High Specific Heat: Water requires significant energy to change temperature.

  • Density: Less dense as solid (ice) than as liquid, affecting aquatic life.

  • Cohesion & Adhesion: Important for capillary action.

Coral Reefs

  • Importance: Biodiversity, habitat for marine life, sources of food, and protection against wave energy.

  • Erosion and Threats: Climate change, physical damage, and pollution can lead to detrimental effects on coral reefs.

Echinoderms & Crustaceans

  • Echinoderms: Sea stars and sea cucumbers, maintain ecosystems and coral reefs.

  • Crustaceans: Hard exoskeletons, serve vital roles in marine food chains.

Mangroves

  • Adaptations for salt exclusion, important for coastal protection, and biodiversity.

  • Economic importance includes flood protection and carbon storage.