Geography IGCSE Paper 1

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174 Terms

1

Waves

Marine processes

Erode, transport + deposit material

Formed by winds blowing over surface of sea

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Factors affecting wave strength

  • Wind strength - stronger wind = bigger waves

  • Wind duration - longer period of time = bigger waves

  • Fetch (distance of open sea that wind travels across) - longer fetch = bigger waves

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What causes a wave to break?

  • Wave moves into shallow water

  • Base of wave has increased friction, causing it to slow down

  • Top of wave continues at same speed

  • Wave becomes unstable and collapses

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Swash

Incoming water pushed up the beach, at the same angle as the waves (transfers energy up the beach)

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Backwash

Water moving back down beach, perpendicular to beach due to gravity (returns energy down beach)

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Constructive wave

  • Low energy

  • Strong swash + weak backwash

  • Causes sediment to be deposited on beach

  • Low frequency, 6-8 per min

  • Low wave height but long wavelength

  • Deposit sand so they create flat beaches

<ul><li><p>Low energy</p></li><li><p>Strong swash + weak backwash</p></li><li><p>Causes sediment to be deposited on beach</p></li><li><p>Low frequency, 6-8 per min</p></li><li><p>Low wave height but long wavelength</p></li><li><p>Deposit sand so they create flat beaches</p></li></ul>
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Destructive wave

  • Lots of energy

  • Strong backwash

  • Causes coast to be eroded away

  • High frequency, 10-12 per min

  • High wave height

  • Can remove sand from beaches making them steep

<ul><li><p>Lots of energy</p></li><li><p>Strong backwash</p></li><li><p>Causes coast to be eroded away</p></li><li><p>High frequency, 10-12 per min</p></li><li><p>High wave height</p></li><li><p>Can remove sand from beaches making them steep</p></li></ul>
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Transportation

Material in sea arrives from many sources:

  • Eroded from cliffs

  • Transported by LSD along coastline

  • Brought inland from offshore by constructive waves

  • Carried to coastline by river

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Traction

Large, heavy material dragged along sea floor

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Saltation

Smaller material is bounced along sea floor

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Suspension

Fine material is held in water

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Solution

Dissolved material carried in water

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Longshore Drift (LSD)

  • Main process of deposition + transportation along coast

  • Influenced by prevailing wind, waves approach beach at an angle

  • As waves break, swash carries material up the beach at same angle

  • As swash dies away, backwash carries material down beach at right angles (90°)

  • Process repeats, transporting material along beach in zig-zag movement

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Weathering

Breakdown of rock in-situ

Doesn’t involve movement of material

Weakens cliffs and makes them more vulnerable to erosion

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Sub-aerial weathering

Coastal processes not linked to action of sea

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Mechanical weathering

Physically breaking rock

  • Example is freeze-thaw weathering

  • Water gets into cracks + joints in rock

  • When water freezes, it expands and cracks widen

  • Over time, pieces of rock split off rock face

  • Big boulders are broken into smaller rocks + gravel

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Chemical weathering

Rocks broken down by chemical process

  • Rainwater is slightly acidic through absorbing CO₂ from atmosphere

  • Reacts with minerals in rock creating new material

  • Rock-type affects rate of weathering e.g. limestone chemically weathers faster than granite

  • Warmer temp → faster chemical reaction

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Biological weathering

Rocks worn away by living organisms

  • Trees + other plants grow within cracks in rock

    • As roots grow bigger they push open cracks in rock making them wider + deeper

    • Over time, growing tree prizes rock apart

  • Tiny organisms like bacteria, algae and moss grow on rocks

    • They produce chemicals that break down surface layer of rock

  • Burrowing animals like rabbits disturb the ground

    • Destabilises rock above burrow

    • Increasing pressure on cracks

    • Pieces fall off rock

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Mass movement

Downhill movement of material under influence of gravity

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Factors influencing type of mass movement

  • Angle of slope (steeper = faster)

  • Nature of regolith (weathered material)

  • Amount + type of vegetation

  • Water

  • Type + structure of rock

  • Human activity

  • Climate

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Sliding

Several different terms: rockslides, landslides, debris slides

Rockslides will be large blocks of solid rock, while landslides may consist of solid rock along with soil + fragments of weathered rock (regolith)

  • Rocks that are jointed or have bedding planes roughly parallel to slope/cliff surface are susceptible to landslides

  • An increase in amount of water can reduce friction, causing sliding

  • In a rock or landslide, slabs of rock/blocks can slide over underlying rocks along a slide or slip plane

<p>Several different terms: rockslides, landslides, debris slides</p><p>Rockslides will be large blocks of solid rock, while landslides may consist of solid rock along with soil + fragments of weathered rock (regolith)</p><ul><li><p>Rocks that are jointed or have bedding planes roughly parallel to slope/cliff surface are susceptible to landslides</p></li><li><p>An increase in amount of water can reduce friction, causing sliding</p></li><li><p>In a rock or landslide, slabs of rock/blocks can slide over underlying rocks along a slide or slip plane</p></li></ul>
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Slumping

Similar to slide, also occurs when stress acting on slope overcomes ability of slope to support own weight + resist movement

  • Often occur in saturated conditions

  • Rotational movement (not in sliding)

  • Occur on moderate to steep slopes

  • Common where softer materials (clay/sands) overlie more resistant/impermeable rock, e.g. limestone/granite

  • Causes rotational scars

  • Repeated slumping creates terraced cliff profile

<p>Similar to slide, also occurs when stress acting on slope overcomes ability of slope to support own weight + resist movement</p><ul><li><p>Often occur in saturated conditions</p></li><li><p>Rotational movement (not in sliding)</p></li><li><p>Occur on moderate to steep slopes</p></li><li><p>Common where softer materials (clay/sands) overlie more resistant/impermeable rock, e.g. limestone/granite</p></li><li><p>Causes <strong>rotational scars</strong></p></li><li><p>Repeated slumping creates <strong>terraced cliff </strong>profile</p></li></ul>
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Influence of geology on coastal environments

  • Geology shapes coastline over time, place and space

  • Coastline made of softer rocks (sands/clays) is easily eroded by destructive waves to form low, flat landscapes such as bays and beaches

  • Coastlines of more resistant, harder rock take longer to erode + produce rugged landscapes such as headlands

  • Differences between hard/soft rocks impact shape + characteristics of cliffs

  • Geology shapes coastline vertically through height + profile of cliff and horizontally with bays + headlands

<ul><li><p><strong>Geology </strong>shapes coastline over time, place and space</p></li><li><p>Coastline made of softer rocks (sands/clays) is easily eroded by <strong>destructive</strong> <strong>waves</strong> to form low, flat landscapes such as bays and beaches</p></li><li><p>Coastlines of more resistant, harder rock take longer to erode + produce rugged landscapes such as headlands</p></li><li><p>Differences between hard/soft rocks impact shape + characteristics of cliffs</p></li><li><p>Geology shapes coastline vertically through height + profile of cliff and horizontally with bays + headlands</p></li></ul>
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Influence of vegetation on coastal environments

  • The longer a coastal landform has existed, the more likely it will be colonised by vegetation

  • Over time, vegetation will ‘fix’ a feature (e.g. sand dune)

  • Vegetation adaptation important to survive coastal conditions

  • Vegetation has to cope with high levels of salt in air and soil

  • Largest influence of vegetation is to assist in protecting + preserving coastal landforms such as sand dunes, salt marshes, mangroves

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Influence of people on coastal environments

  • Human activities transform features + landscape of coastline:

    • Settlement - coasts have always been place of attraction + residence for people

    • Economic development - exploitation through fishing, farming, trade, tourism, energy production

    • Coastal management - controlling coastline to protect human interests

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Influence of sea-level changes on coastal environments

  • Rising sea levels produce submergent coastlines, with rias + fjords

  • Falling sea levels produce emergent coastlines, with relic features e.g. raised beaches, cliffs with caves

  • Sea levels have risen + fallen many times in past

  • During last Ice Age, sea levels fell as water locked up in glaciers + ice sheets, rising again as ice melted

  • Sea levels link to global warming, will have significant effect on many low-lying coasts + islands

  • Many Pacific islands, e.g. Kiribati, Tuvalu are at risk of being completely submerged by rising sea levels

  • Issue is worsened as many of world’s densely populated areas are on coastal lowlands

  • New York + Miami are major cities vulnerable to sea-level rise as cities are built at sea level

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Headland and bay

  • Found in areas of alternating bands of resistant (hard) + less resistant (soft) rocks running perpendicular to oncoming waves (discordant coastline)

  • Initially, less resistant rock (e.g. clay) eroded back, forming a bay

  • Bay = inlet of sea where land curves inwards, usually with beach

  • More resistant rock (e.g. limestone) is left protruding out to sea as headland

<ul><li><p>Found in areas of alternating bands of resistant (hard) + less resistant (soft) rocks running <strong>perpendicular</strong> to oncoming waves (<strong>discordant</strong> coastline)</p></li><li><p>Initially, less resistant rock (e.g. clay) eroded back, forming a bay</p></li><li><p>Bay = inlet of sea where land curves inwards, usually with beach</p></li><li><p>More resistant rock (e.g. limestone) is left protruding out to sea as headland</p></li></ul>
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Cove

  • Forms when coastline has bands of resistant + less resistant rock running parallel to oncoming waves (concordant coastline)

  • Usually band of resistant rock facing waves, with band of softer rock behind

  • Wave processes exploit faults in resistant rock + erode through to softer rock

  • Further wave action erodes soft rock quickly, leaving circular cove with narrow entrance to sea

  • Wave refraction within cove spreads out erosion in all directions, creating typical horseshoe shape

  • e.g. Lulworth Cove, Dorset, UK

<ul><li><p>Forms when coastline has bands of resistant + less resistant rock running <strong>parallel</strong> to oncoming waves (<strong>concordant</strong> coastline)</p></li><li><p>Usually band of resistant rock facing waves, with band of softer rock behind</p></li><li><p>Wave processes exploit faults in resistant rock + erode through to softer rock</p></li><li><p>Further wave action erodes soft rock quickly, leaving circular cove with narrow entrance to sea</p></li><li><p>Wave refraction within cove spreads out erosion in all directions, creating typical horseshoe shape</p></li><li><p>e.g. Lulworth Cove, Dorset, UK</p></li></ul>
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Cliff

  • Cliffs shaped through erosion + weathering processes

  • Less resistant rock erodes quickly, forming sloping cliff faces

  • Steep cliffs formed where harder rock faces sea

<ul><li><p>Cliffs shaped through <strong>erosion</strong> + <strong>weathering </strong>processes</p></li><li><p>Less resistant rock erodes quickly, forming sloping cliff faces</p></li><li><p>Steep cliffs formed where harder rock faces sea</p></li></ul>
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Wave-cut platform

Wide, gently-sloped surface found at foot of cliff

  • As sea attacks base of cliff between high and low water mark, wave-cut notch forms

  • Abrasion, corrosion, hydraulic action further extend notch back into cliff

  • Undercutting of cliff → instability + collapse of cliff

  • Backwash of waves carries away eroded material, leaving wave-cut platform

  • Process repeats + cliff continues to retreat, leading to coastal retreat

<p>Wide, gently-sloped surface found at foot of cliff</p><ul><li><p>As sea attacks base of cliff between high and low water mark, <strong>wave-cut notch</strong> forms</p></li><li><p><strong>Abrasion, corrosion, hydraulic action</strong> further extend notch back into cliff</p></li><li><p><strong>Undercutting </strong>of cliff → instability + collapse of cliff</p></li><li><p>Backwash of waves carries away eroded material, leaving <strong>wave-cut platform</strong></p></li><li><p>Process repeats + cliff continues to retreat, leading to coastal retreat</p></li></ul>
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Cave, arch, stack and stump

  • Found on headland due to wave action + sub-aerial weathering

  • Weaknesses in headland are exploited by erosional processes of hydraulic action, abrasion, corrosion

  • As crack widens, abrasion wears away at the forming cave

  • Cave becomes larger and eventually breaks through headland to form arch

  • Base of arch continually becomes wider + thinner through erosion below + weathering above

  • Eventually, roof of arch collapses, leaving isolated column of rock called stack

  • Stack is undercut at base by wave action + sub-aerial weathering above until it collapses to form stump

<ul><li><p>Found on headland due to wave action + sub-aerial weathering</p></li><li><p>Weaknesses in headland are exploited by erosional processes of hydraulic action, abrasion, corrosion</p></li><li><p>As <strong>crack</strong> widens, abrasion wears away at the forming <strong>cave</strong></p></li><li><p>Cave becomes larger and eventually breaks through headland to form <strong>arch</strong></p></li><li><p>Base of arch continually becomes wider + thinner through erosion below + weathering above</p></li><li><p>Eventually, roof of arch collapses, leaving isolated column of rock called <strong>stack</strong></p></li><li><p>Stack is <strong>undercut </strong>at base by wave action + sub-aerial weathering above until it collapses to form <strong>stump</strong></p></li></ul>
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Beach

  • Form in sheltered areas such as bays

  • Deposition occurs through constructive wave movement, where swash is stronger than backwash

  • Beach formation usually occurs in summer when weather is calmer

  • Sometimes sand from offshore bars can blow onto shore by strong winds

  • Blown sand can create sand dunes at backshore of beach

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Spit

  • Extended stretch of sand/shingle that extends from sea to shore

  • Spits occur when there is change in shape of coastline

  • Or the mouth of a river, which prevents spit from forming across estuary

  • Spit may/may not have ‘hooked’ end, depending on opposing winds + currents

  • e.g. Spurn Point, Humber Estuary, England

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Spit formation

  • Sediment transported by LSD

  • Where coastline changes direction, a shallow, sheltered area allows for deposition of sediment

  • Due to increased friction, more deposition occurs

  • Eventually, spit slowly builds up to sea level + extends in length

  • If wind changes direction, wave pattern alters, resulting in hooked end

  • Area behind spit becomes sheltered

  • Silts are deposited here to form salt marshes/mud flats

<ul><li><p>Sediment transported by LSD</p></li><li><p>Where coastline changes direction, a shallow, sheltered area allows for <strong>deposition of sediment</strong></p></li><li><p>Due to <strong>increased friction</strong>, more deposition occurs</p></li><li><p>Eventually, spit slowly builds up to sea level + extends in length</p></li><li><p>If wind changes direction, wave pattern alters, resulting in hooked end</p></li><li><p>Area behind spit becomes sheltered</p></li><li><p>Silts are deposited here to form salt marshes/mud flats</p></li></ul>
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Bar

  • When spit grows across bay and joins two headlands together

  • Bar of sand is formed (sandbar)

  • Sandbars can form offshore due to action of breaking waves from beach

<ul><li><p>When spit grows across bay and joins two headlands together</p></li><li><p><strong>Bar </strong>of sand is formed (<strong>sandbar</strong>)</p></li><li><p>Sandbars can form <strong>offshore</strong> due to action of breaking waves from beach</p></li></ul>
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Coral reef distribution 🪸

  • Generally between 30ᵒ N and S of equator

Examples:

  • Great Barrier Reef (high biodiversity) - off coast of Queensland, AU

  • Maldives - Indian Ocean

  • Red Sea - Egypt

<ul><li><p>Generally between 30<span>ᵒ N and S of equator</span></p></li></ul><p><span>Examples:</span></p><ul><li><p><strong>Great Barrier Reef</strong> (high biodiversity) - off coast of Queensland, AU</p></li><li><p><strong>Maldives</strong> - Indian Ocean</p></li><li><p><strong>Red Sea</strong> - Egypt</p></li></ul>
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Coral reef global features 🪸

  • Temperature (min: 18ᵒC, optimum: 23-29ᵒC)

  • Shallow water (25m or less depth) because…

    • Closer to light

    • Coral can’t grow deeper than 25m because need light for zooxanthellae to photosynthesise

  • Clear water because…

    • Need light to pass through for PSN

    • Sediment blocks normal feeding patterns by reducing light availability

  • Salinity (between 32-42 PSU) because…

    • Coral are marine animals

    • so need salty water to survive

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Coral reef local features 🪸

  • Wave action

    • Coral need well-oxygenated, clean water, which wave action provides

  • Exposure to air

    • Corals need oxygenated water but can’t be exposed to air for too long or will die

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Mangrove distribution 🌳

  • Similar distribution to coral reefs

  • Mostly between 30ᵒ N and S of equator

  • Most common in SE Asia

<ul><li><p>Similar distribution to coral reefs</p></li><li><p>Mostly between 30<span>ᵒ N and S of equator</span></p></li><li><p><span>Most common in SE Asia</span></p></li></ul>
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Mangrove features 🌳

  • Mangroves are trees that live on coastline

  • Sit in water between 0.5-2.5m high

  • Range in size from small shrubs to trees 60m+ high

  • Have tangled roots that grow above ground and form dense thickets

  • Need high humidity (75-80%) and rainfall levels per annum (1500-3000mm)

  • Ideal temp = 27ᵒC

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Sand dune distribution 🏖

  • Found all around the world

  • They are accumulation of sand, shaped into mounds and ridges by wind

  • Found at back of beach, above max reach of tide

  • Large dunes are less likely in tropical + sub-tropical areas because…

    • Lower avg. wind speeds

    • Damper sand

<ul><li><p>Found all around the world</p></li><li><p>They are accumulation of sand, shaped into mounds and ridges by wind</p></li><li><p>Found at back of beach, above max reach of tide</p></li><li><p>Large dunes are less likely in tropical + sub-tropical areas because…</p><ul><li><p>Lower avg. wind speeds</p></li><li><p>Damper sand</p></li></ul></li></ul>
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Sand dune features 🏖

  • Can be small ridge or large hills usually at back of beach

  • Can extend backwards for many miles as well as along beach

  • Are an important ecosystem, supporting unique flora + fauna that have adapted to live in dune system

  • Vulnerable to erosion by natural processes + human activity

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Salt marsh distribution 🧂

  • Found all over the world, not temperature dependent

  • An ecosystem of intertidal zone, like mangroves

  • Typically flat, with numerous channels running through them

  • They form in:

    • Well-sheltered coastal areas, such as inlets/estuaries

    • Areas behind spits and artificial seas defences

    • Brackish water (partly salty, partly fresh)

<ul><li><p>Found all over the world, not temperature dependent</p></li><li><p>An ecosystem of intertidal zone, like mangroves</p></li><li><p>Typically flat, with numerous channels running through them</p></li><li><p>They form in:</p><ul><li><p>Well-sheltered coastal areas, such as inlets/estuaries </p></li><li><p>Areas behind spits and artificial seas defences</p></li><li><p>Brackish water (partly salty, partly fresh)</p></li></ul></li></ul>
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Salt marsh features 🧂

  • Communities of nonwoody, salt-tolerant plants

  • Begin as tidal mud flats, gaining height as more sediment is deposited

  • This builds up to and above the level, and frequency of tidal flooding ensures that soil never dries out, remains muddy + sticky

  • Pioneer species of halophyte plants begin to colonise

  • As plants die and add nutrients to soil, sediment builds up, making conditions more favourable and other species develop

  • Process of development of vegetation over time = succession

  • Lower marshes are flooded daily by rising tide

  • Good coastal defences in some areas, acting as natural buffer against coastal erosion + flooding

  • However, in many areas they’ve been reclaimed for agriculture/development, and are threatened by human activities

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Abiotic characteristics of coral reefs 🪸

  • Light - need sunlight to survive:

    • Too little = zooxanthellae can’t photosynthesise to produce food for corals

    • Too much = corals may expel zooxanthellae, causing bleaching

  • Depth - need light, so are typically found at approx. 25m

  • Water temp - corals thrive in warm tropical waters

  • Salinity - need salty water

  • Air - can survive out of water for short periods

  • Water - need clean, clear water that doesn’t block light

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Biotic characteristics of coral reefs 🪸

  • Coral reef is well-organised food web comprising of:

    • Producers

    • Consumers

    • Scavengers

    • Decomposers

  • Producers in coral reef include seaweed, seagrass and phytoplankton

  • Consumers are organisms that eat other organisms for energy
    There are three main types of consumers in food web: primary (e.g. sea turtle eating seagrass), secondary (e.g. stingrays, octopuses), tertiary (help maintain balance of ecosystem, e.g. sharks, dolphins)

  • Scavengers feed on dead + decaying plants and animals - e.g. crabs + lobsters

  • Decomposers bring nutrients back into ecosystem for another cycle - e.g. bacteria, fungi

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Value of coral reefs 🪸

  • Biodiversity - Great Barrier Reef has 700 coral species, 1500 fish species and 4000 mollusc species

  • Protection to low-lying coasts from tropical storms

  • Rich fish stocks - supply basic food requirements of developing countries

  • Appeal to tourists + recreational opportunities, such as snorkelling + scuba diving - over 150m people each year take holidays in areas with coral reefs

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How industry threatens coral reefs 🪸

  • Coral reefs are easily stressed by human action
    If stress persists, death of reef soon follows

  • Pollution, overfishing and quarrying of coral for building stone

  • Industrialisation responsible for rising sea temp + sea-level rise, putting coral under threat

  • Rising sea temps increase levels of coral bleaching

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How agriculture threatens coral reefs 🪸

  • Overfishing reduces number of grazing fish that keep coral clear of algae

  • Fishing using explosives that damage coral reefs

  • Commercial farming

  • Fertiliser runoff

  • Pesticide overspray

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How tourism threatens coral reefs 🪸

  • Tourism is biggest threat globally and locally to coral reefs

  • 58% of coral reefs at threat from human activity

  • Any contact with human body will likely kill coral immediately around point of contact

  • Propellers + anchors directly damage coral from boat tours

  • Pollution through diesel spills

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How deforestation threatens coral reefs 🪸

  • Clearance of coral forests + mangroves disturbs natural flows of water + nutrients, leading to stress + coral bleaching

  • Removal of coral reef for stone building/tourist sales

  • Any destruction of coral reef leaves coastline open to coastal flooding + storm surges

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Value of mangroves 🌳

  • Nurseries for fish + crustaceans; rich in wildlife

  • Roots trap silt → help create new land

  • Timber provides fuel + building material

  • Protection from storm surges

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How industry threatens mangroves 🌳

  • Pollution, overfishing and deforestation for aquaculture

  • Clearance for land development, particularly in developing countries

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How agriculture threatens mangroves 🌳

  • Aquaculture - intense fish + shrimp farms

  • Pesticide use

  • Antibiotics used in aquaculture practices

  • Clearance for farm development, particularly in developing countries

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How tourism threatens mangroves 🌳

  • Clearance of mangroves to build hotels + other tourist attractions

  • Diversion of fresh water to hotels etc.

  • Disturbance of habitats

  • Collection of souvenirs by tourists

  • Tours in waterways

  • Pollution through boat fuel spills

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How deforestation threatens mangroves 🌳

  • Removal of trees → collapse of ecosystem

  • Leaves coast open to storms, flooding and coastal retreat

  • Mangrove wood used for timber + fuel

  • Cleared to reduce malaria - unsupported evidence that this works

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Value of sand dunes 🏖

  • Coastal protection from flooding

  • Recreational activities e.g. trail biking + horse riding

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How industry threatens sand dunes 🏖

  • Least threatened at global level (value is mainly tourism + leisure)

  • Local level - biggest threat = sand mining

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How agriculture threatens sand dunes 🏖

  • Destabilisation due to animals grazing on dunes

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How tourism threatens sand dunes 🏖

  • Largest threat to sand dunes due to trampling of delicate, unfixed dunes

  • Driving using 4×4/quadbikes over dunes

  • Sporting events - sand surfing etc.

  • Collecting shells + driftwood

  • Pollution from rubbish left by tourists

  • Car parks

  • Sand mining to build hotels

  • Development of seaside towns

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How deforestation threatens sand dunes 🏖

  • Removal of trees destroys mature dunes + allows for dune migration

  • Leaves coast open to storms + flooding

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Value of salt marshes🧂

  • Collectors of silt + organic matter

  • Nursery areas for fish + crustaceans

  • Protection against wave erosion + sea-level rise

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How industry threatens salt marshes🧂

  • Industrial pollution

  • Ideal sites for nuclear power stations

  • Clearance for development - commercial + private

  • Development can lead to increased noise + light pollution, may affect wildlife behaviour + nesting

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How agriculture threatens salt marshes🧂

  • Drained + cleared for farming

  • Eutrophication through heavy use of fertilisers

  • Pollution from pesticides + herbicides

  • Slurry run-off from cattle

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How tourism threatens salt marshes🧂

  • Tourism limited to local level + nature reserves

  • Roads have divided salt marshes, cutting off parts of it

  • Trampling by visitors

  • Dog walkers letting dogs roam + disturb wildlife

  • Noise from local tourist areas may disturb wildlife

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Wildlife’s needs on coast

  • Unpolluted, safe, quiet environment

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Local residents’ needs on coast

  • Jobs

  • Clean beaches

  • Affordable housing

  • Schools

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Tourists’ needs on coast

  • Beaches

  • Hotels

  • B&Bs

  • Entertainment

  • Holiday homes

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Employers’ needs on coast

  • Building space

  • Offices

  • Factories

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Developers’ needs on coast

  • Areas by sea for tourists - hotels, duplexes, golf courses

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Fishermen’s needs on coast

  • Harbours

  • Unpolluted waters

  • Ease of access to sea

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Farmers’ needs on coast

  • Well-drained land, sheltered from prevailing winds

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Govt + council’s needs on coast

  • Build offshore wind farms, coastal defences

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Transport companies’ needs on coast

  • Good road networks

  • Well-connected ports + terminals

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Issues with Agriculture in coastal zone

Consequences

  • Fertiliser and pesticide overuse

  • Increased livestock density

  • Overwater abstraction

  • Animal waste disposal

  • Land reclamation

Outcomes

  • Species and habitat loss

  • Eutrophication

  • Water pollution

  • Coastal squeeze

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Issues with Urbanisation and Transport in coastal zone

Consequences

  • Change of land use (car parks, ports etc.)

  • Waste disposal

  • Pollution

  • Water abstraction

  • Hard road surfaces

Outcomes

  • Increased flooding

  • Congestion

  • Pollution

  • Loss of habitats

  • Increase in weeds + invasive species

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Issues with Tourism and Recreation in coastal zone

Consequences

  • Harbours, marinas

  • Waste disposal

  • Fuel spillages

  • Change of land use

  • Water abstraction

  • Effluent disposal

Outcomes

  • Congestion + pollution (noise, light, visual, aroma)

  • Loss of habitats

  • Loss of species

  • Litter + fuel spills

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Issues with Fisheries and Aquaculture in coastal zone

Consequences

  • Ports

  • Fish processing facilities

  • Trawlers

  • Road networks

  • Lorries

  • Fishing gear

  • Fish farm pollution

  • Water abstraction

Outcomes

  • Overfishing

  • Pollution on beaches

  • Habitat damage

  • Water pollution

  • Aroma, visual and noise pollution from trawlers

  • Increased seagull activity

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Issues with Industry in coastal zone

Consequences

  • Land use change

  • Change in tidal range

  • Power stations (nuclear + gas)

  • Natural resource extraction

  • Road networks

  • Cooling water/abstraction

  • Waste pollution - chemical, biological, nuclear etc.

Outcomes

  • Thermal pollution

  • Habitat destruction, change and loss

  • Water eutrophication

  • Water pollution

  • Visual eyesore

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Causes of coastal flooding

  • Storm surges - rapid rise in sea level caused by very low-pressure storms

  • Storm tides - occur when there’s combination of high tide + low-pressure storm

  • Tsunamis - large sea waves due to underwater EQs, closer to coast = bigger impact

  • Climate change - causes rising sea levels

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Prediction of flooding

  • Early warning systems allow communities to prepare before flooding occurs

  • Past records (diaries, newspapers etc.) - identify areas at high risk of flooding and their frequency

  • Modern technology (GIS, satellite and computer monitoring, weather stations) - allow for forecasting + tracking potential hazards, i.e.

    • Tropical storms - track storm’s path + associated storm surge

    • EQs - size + position if underwater and possible tsunami outcome

  • These methods indicate possible strength + scale of flooding, and likelihood of damage + death

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Prevention of flooding

  • Flood defences

    • Built along high-risk stretches of coast

  • Emergency centres

    • Centrally placed on higher ground where people can be safe from flooding

  • Early warning systems

    • Allows for preparation/evacuation of an area

  • Education

    • Informing locals on what to do if/when flood occurs

  • Building design

    • Planning new development away from high-risk areas

    • Designing buildings to cope with low-level flooding

      • Elevating buildings so flood water can pass underneath

      • Floodproof buildings with raised foundations

      • Reinforced barriers

      • Dry floodproofing - sealing property so floodwater can’t enter

      • Wet floodproofing - allows some flooding of building

  • Buffer zones

    • Areas of land are allowed to flood before reaching settlements

    • Allows energy in surge to dissipate, reducing the distance floodwater travels

    • Can mean moving people away from coast (could be controversial)

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Shoreline Management Plans

  • Shoreline Management Plans (SMP) set out approach to managing coastline from flooding + erosional risk

  • Plans aim to reduce risk to people, settlements, agricultural land and natural environment

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Hold the line (approach to coastal mgmt)

  • Long term approach + most costly

  • Build + maintain coastal defences so current position of shoreline remains same

  • Hard engineering is most dominant method used, with soft engineering used to support

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Advance the line (approach to coastal mgmt)

  • Build new defences to extend existing shoreline

  • Involves land reclamation

  • Hard + soft engineering used

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Managed realignment (approach to coastal mgmt)

  • Coastline allowed to move naturally

  • Processes monitored + directed when and where necessary

  • Most natural approach to coastal defence

  • Mostly soft engineering with some hard engineering to support

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Do nothing (approach to coastal mgmt)

  • Cheapest method, but most controversial

  • Coast is allowed to erode + retreat landward

  • No investment made in protecting coastline or defending against flooding, regardless of previous intervention

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Factors affecting which coastal mgmt approach to apply

  • Economic value of resources to protect e.g. land, homes etc

  • Engineering solutions - might not be possible to ‘hold the line’ for moving landforms such as spits

  • Cultural + ecological value of land - historic sites + areas of unusual diversity

  • Community pressure - local campaigns to protect region

  • Social value of communities - long-standing, historic communities

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Hard engineering

  • Involves building some form of sea defence, usually from concrete, wood or rock

  • Structures and expensive to build and need to be maintained

  • Defences work against power of waves

  • Protecting one area can impact regions further along coast, resulting in faster erosion + flooding

  • Used when settlements + expensive installations (power stations etc) are at risk - economic benefit greater than cost of building

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Groynes

Hard engineering method

Wood, rock or steel piling built at right angles to shore, trapping beach material being moved by LSD

  • Slows down beach erosion

  • Creates wider beaches

  • Stops material moving down coast where material may have been building up + protecting base of cliff elsewhere

  • Starves other beaches of sand

  • Wood groynes need maintenance to prevent wood rot

  • Makes walking along shoreline difficult

<p><strong>Hard engineering method</strong></p><p>Wood, rock or steel piling built at right angles to shore, trapping beach material being moved by LSD</p><ul><li><p><span style="color: green">Slows down beach erosion</span></p></li><li><p><span style="color: green">Creates wider beaches</span></p></li><li><p><span style="color: red">Stops material moving down coast where material may have been building up + protecting base of cliff elsewhere</span></p></li><li><p><span style="color: red">Starves other beaches of sand</span></p></li><li><p><span style="color: red">Wood groynes need maintenance to prevent wood rot</span></p></li><li><p><span style="color: red">Makes walking along shoreline difficult</span></p></li></ul>
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Revetments

Hard engineering method

Sloping wooden/concrete fence with open plank structure

  • Work to break force of waves

  • Traps beach material behind them

  • Set at base of cliffs/in front of sea wall

  • Cheaper than sea walls but not as effective

  • Ineffective in stormy conditions

  • Can make beach inaccessible for people

  • Regular maintenance is necessary

  • Visually unattractive

<p><strong>Hard engineering method</strong></p><p>Sloping wooden/concrete fence with open plank structure</p><ul><li><p><span style="color: green">Work to break force of waves</span></p></li><li><p><span style="color: green">Traps beach material behind them</span></p></li><li><p><span style="color: green">Set at base of cliffs/in front of sea wall</span></p></li><li><p><span style="color: green">Cheaper than sea walls but not as effective</span></p></li><li><p><span style="color: red">Ineffective in stormy conditions</span></p></li><li><p><span style="color: red">Can make beach inaccessible for people</span></p></li><li><p><span style="color: red">Regular maintenance is necessary</span></p></li><li><p><span style="color: red">Visually unattractive</span></p></li></ul>
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Sea wall

Hard engineering method

Wall, usually concrete, curved outwards to deflect power of waves

  • Most effective at preventing erosion + flooding (if wall is high enough)

  • Very expensive to build + maintain

  • Can be damaged if material isn’t maintained in front of wall

  • Restricts access to beach

  • Unsightly

<p><strong>Hard engineering method</strong></p><p>Wall, usually concrete, curved outwards to deflect power of waves</p><ul><li><p><span style="color: green">Most effective at preventing erosion + flooding (if wall is high enough)</span></p></li><li><p><span style="color: red">Very expensive to build + maintain</span></p></li><li><p><span style="color: red">Can be damaged if material isn’t maintained in front of wall</span></p></li><li><p><span style="color: red">Restricts access to beach</span></p></li><li><p><span style="color: red">Unsightly</span> </p></li></ul>
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Gabions

Hard engineering method

Wire cages filled with stone, concrete, sand etc

  • Cheapest coastal defence

  • Cages absorb wave energy

  • Can be stacked at base of sea wall/cliffs

  • Wire cages can break + need to be securely tied down

  • Not as efficient as other coastal defences

<p><strong>Hard engineering method</strong></p><p>Wire cages filled with stone, concrete, sand etc</p><ul><li><p><span style="color: green">Cheapest coastal defence</span></p></li><li><p><span style="color: green">Cages absorb wave energy</span></p></li><li><p><span style="color: green">Can be stacked at base of sea wall/cliffs</span></p></li><li><p><span style="color: red">Wire cages can break + need to be securely tied down</span></p></li><li><p><span style="color: red">Not as efficient as other coastal defences</span></p></li></ul>
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Rip-rap

Hard engineering method

Large boulders piled up to protect stretch of coast

  • Cheaper method

  • Works to absorb wave energy from base of cliff + sea walls

  • Boulders can be eroded/dislodged during heavy storms

<p><strong>Hard engineering method</strong></p><p>Large boulders piled up to protect stretch of coast</p><ul><li><p><span style="color: green">Cheaper method</span></p></li><li><p><span style="color: green">Works to absorb wave energy from base of cliff + sea walls</span></p></li><li><p><span style="color: red">Boulders can be eroded/dislodged during heavy storms</span></p></li></ul>
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Soft engineering

  • Works with natural processes rather than against them

  • Usually cheaper + don’t damage appearance of coast

  • Considered to be more sustainable appraoch to coastal protection

  • Not as effective as hard engineering

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Beach replenishment

Soft engineering method

Pumping/dumping sand + shingle back onto beach to replace eroded material

  • Beaches absorb wave energy

  • Widens beachfront

  • Must be repeated regularly - expensive

  • Can impact sediment transportation down coast

<p><strong>Soft engineering method</strong></p><p>Pumping/dumping sand + shingle back onto beach to replace eroded material</p><ul><li><p><span style="color: green">Beaches absorb wave energy</span></p></li><li><p><span style="color: green">Widens beachfront</span></p></li><li><p><span style="color: red">Must be repeated regularly - expensive</span></p></li><li><p><span style="color: red">Can impact sediment transportation down coast</span></p></li></ul>
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Cliff regrading

Soft engineering method

Angle of cliff reduced to reduce mass movement

  • Prevents sudden loss of large sections of cliff

  • Regrading can slow down wave cut notching at base of cliffs as wave energy is slowed

  • Doesn’t stop cliff erosion

<p><strong>Soft engineering method</strong></p><p>Angle of cliff reduced to reduce mass movement</p><ul><li><p><span style="color: green">Prevents sudden loss of large sections of cliff</span></p></li><li><p><span style="color: green">Regrading can slow down wave cut notching at base of cliffs as wave energy is slowed</span></p></li><li><p><span style="color: red">Doesn’t stop cliff erosion</span></p></li></ul>
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Fencing, hedging, revegetation

Soft engineering method

Helps stabilise sand dunes/beaches + reduces wind erosion

  • Cheap method against flooding + erosion

  • Hard to protect larger areas of coastline cliffs

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Managed retreat

Soft engineering method

Existing coastal defences are abandoned, allowing sea to flood inland until it reaches higher land or a new line of defences

  • No expensive construction costs

  • Creates new habitats, such as salt marshes

  • Disruption to people where land + homes are lost

  • Cost of relocation can be expensive

  • Compensation to people + businesses may not be paid

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Coastal problems in developed country (Abbotts Hall Farm, Essex, UK)

  • Essex coast in SE England is flat + low-lying

  • Abbotts Hall Farm = 282 hectare nature reserve and head office of Essex Wildlife Trust

  • Area was previously defended by 3km stretch of sea wall.
    By 1990s, needed repairing, at considerable expense.

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