Interactions between oceans and the coastal places

**Marine** = the **sea** does the work (waves, hydraulic action, abrasion). **Subaerial** = the **land/air** does it above the waterline (weathering, mass movement).

The **zig-zag transport of sediment along a coast** by waves that hit the shore at an angle.

The **rock type and its resistance** — hard rock erodes slowly, soft rock fast.

Crack -> cave -> **arch** -> **stack** -> **stump**; the cliff also retreats to leave a **wave-cut platform**.

A gently sloping **rock bench at the cliff foot**, left behind as the cliff is undercut and retreats.

**Freeze-thaw weathering**, **salt weathering** and **mass movement** (slumping/rockfall). NOT wave action.

A drying beach + onshore wind move sand; an obstacle traps it; **vegetation** colonises and fixes it into a tall dune.

It **traps wind-blown sand** (slowing the wind) and **binds the sand with roots** (marram grass), so the dune grows and stays fixed.

**Emergent** (sea falls/land rises) -> **raised beaches + relict cliffs**. **Submergent** (sea rises/land sinks) -> **rias + fjords**.

Ice melts -> land is unloaded -> it **rebounds upward (isostatic uplift)**, stranding an old beach **above** the present sea.

A glacier carves a deep **U-shaped valley** below sea level; the ice melts and **sea level rises**, drowning the valley.

**Two+ developed factors/processes**, a **named coast**, a weighing of their **relative importance**, and a clear **judgement**.

A ridge built by tiny **coral polyps** that need warm, clear, shallow, sunlit, salty water.

When sea water gets too warm, corals **expel the algae** that feed and colour them, turning white and often dying.

Extra **CO2** dissolving in seawater makes it more acidic, so corals struggle to build their **skeletons**.

**Salt-tolerant trees** rooted in the sheltered, shallow **intertidal zone** of tropical coasts.

Sheltered, **low-energy** shallow water in warm tropical seas (e.g. estuaries and lagoons).

Reefs **break wave energy**; mangrove roots **absorb storm-surge** and trap sediment - shielding the shore.

They are **breeding and nursery grounds** for fish, giving fishers a steady catch and income.

**Tourism** (diving/snorkelling jobs) and **fisheries** (reef-fish income); also coastal protection saving repair costs.

**Overfishing/dynamite fishing** and **pollution/run-off** (also coastal development, tourism damage).

**Climate change** - warming causes bleaching and extra CO2 causes acidification.

**Less storm protection** and **lost fish nurseries/biodiversity** (also lost carbon store and more pollution reaching the sea).

Two+ developed threats (natural AND human), a named example, a weighing of relative seriousness, and a clear judgement.