Marine science igcse

• Producers:

  • Make up the first trophic level
  • Also known as autotrophs
  • Make their own food
• Consumers make up the next trophic levels and can be omnivores, eating producers along with primary consumers
• Primary Consumers:

  • Herbivores that feed on producers
• Tertiary Consumers:

  • Eat the secondary consumers, placed at the fourth trophic level
• Continental shelves are the extensions of landmasses that slope gently towards the deep sea.
• The ocean has different zones based on depth, including the intertidal zone (where waves meet land), neritic zone (close to shore), pelagic zone (open water), benthic zone (bottom of the sea floor), and abyssal zone (deepest part).
• Estuaries are semi-enclosed coastal bodies of water with one or more rivers or streams flowing into them, and with a free connection to the open sea.
• The average depth of the world's oceans is approximately 3,812 meters (12,497 feet)
• Beneath the mantle is the core, made almost entirely of metal, particularly iron
• The core is solid in the center and molten around this, creating a magnetic field around the Earth
• We use the Earth's magnetic field for navigation; a compass aligns with the Earth's magnetic field to point to the magnetic North Pole
• The Earth's magnetic field is important for helping some species to navigate during migration
• The Earth's crust is the outermost solid layer, while beneath it is the mantle, made of viscous molten rock called magma
• Tsunamis can do great damage to human communities along coastlines due to their great height and the large amount of energy they transfer
• Coral reefs act as natural breakwaters and coastal defenses against tidal action and tsunamis
• Important marine habitats affected by tsunamis include coastal seagrass beds and mangrove forests
• Tsunamis can cause destruction to the sea floor, destroying habitats and organisms on the seabed
• The theory of plate tectonics explains the movement of tectonic plates over hundreds of millions of years
• Plate boundaries can be divergent, convergent, or transform boundaries
• Divergent plate boundaries involve plates moving away from each other
• Convergent plate boundaries involve plates moving towards each other
• Transform plate boundaries involve plates sliding against each other
• Plate tectonics theory describes how convection currents in the mantle cause the crust to break into tectonic plates
• We use a system of coordinates to form a grid enclosing the Earth, helping us identify and locate places on the Earth
• The system of coordinates has reference lines acting as zero for the coordinate scales:

  • The horizontal reference line is the Equator, with latitude increasing as you move north or south from zero at the Equator to 90° N at the North Pole, or 90° S at the South Pole
  • The vertical reference line is the Prime Meridian, running from the North Pole to the South Pole through the Royal Observatory in Greenwich, England
• Most of the water on Earth (97%) is found in oceans and seas as salt water, with only 3% as freshwater
• Oceans separate most continents and are generally deeper than seas, with seas being smaller areas of water sometimes found within oceans
• The Pacific Ocean is the largest ocean, covering over 160 million km² and having a volume of 660 million km³
• The Earth is a planet with a rocky composition, a thin solid outer crust, a semi-molten mantle, and a core made mostly of iron that creates a magnetic field
• The Earth's crust is divided into large tectonic plates that float and move around due to convection currents in the mantle
• Tectonic plates move against each other in different directions, causing convergent, divergent, and transform plate boundaries that can lead to earthquakes and the formation of features like volcanoes, mid-ocean ridges, and ocean trenches
• The Earth has five interconnected oceans that form the World Ocean, covering more than two-thirds of the planet
• The gravitational effects of the Moon and the Sun on water in oceans and seas create tides, with amplitudes changing as the Moon orbits the Earth, leading to spring tides and neap tides
• Oceanic currents are continuous flows of seawater in specific directions, influenced by prevailing winds, the Earth's rotation, tides, and changes in seawater density
• Gyres are large circular oceanic currents that circulate water around the World Ocean, with five main gyres found in some of the largest oceans
• Rip currents are dangerous narrow currents that can form along beaches and coastlines, posing risks to swimmers who may be pulled far out to sea
• Upwelling is the movement of cold, nutrient-rich water from deep in the ocean to the surface, contributing to the ocean's ecosystem
• Changes in seawater density due to temperature and salinity differences cause vertical currents in the ocean, influencing the movement of water and affecting tides
• Surface currents are linked to vertical currents in the ocean, creating a 'global conveyor belt' that circulates water around the entire globe over approximately 1000 years
• Soluble: the description of a substance that dissolves in a particular solvent