Unit 7: Coastal Environments Flashcards

Question

Swell vs storm waves

Answer 1

Waves can be up to 15m high in the open ocean When these aves travel long distances form where they were created (generation area) and reach far away shores they are swell waves. Have a lower height and longer wavelength. Will occur no matter what the local weather Storm waves occur because of more local extreme weather conditions and are characterised by shorter wavelengths, greater heights and higher frequency

Answer 2

When wavelengths are reduced and wave height increases as a wave enters shallower water. At this point it is a breaker wave

Answer 3

Associated with gentle beach gradients and steep waves. Characterised by a gradual peaking of the wave until the crest becomes unstable causing a gentle spilling forward of the crest

Answer 4

Occur on steeper beaches with waves of intermediate steepness. Distinguished by the shoreward face of the wave becoming vertical, curling over and plunging forward and downward as an intact mass of water

Answer 5

Found on steep beaches with low steepness waves. The front face and crest remain relatively smooth and the wave slides directly up the beach without breaking. A large proportion of the wave energy is reflected at the beach

Answer 6

Once a wave breaks and travels onshore it is a wave of translation -Constructive -Destructive Both have a swash and backwash

Answer 7

Tend to occur when wave frequency is low (6-8) per minute especially when these waves advance over a gently shelving sea floor. Have been generated far offshore. The gentle offshore slope creates a gradual increase in friction which will cause a gradual steepening of the wave front. A spilling breaker is formed where water movement is elliptical. As the breaker collapses the powerful swash surges up the gentle gradient. Due to low frequency the backwash has time to return to he sea before the next wave breaks. The swash os not impeded and retains maximum energy

Answer 8

Are the result of locally generated winds which create waves of high frequency (12-14 per minute). Rapid approach of waves especially if moving onshore up a steady shelving coastline creates a rapid increase in friction and a very steep, plunging breaker where water movement is circular. Due to rapid steepening and curling of wave breaker, the wave energy is transmitted down the beach on breaker collapse accelerated by the steeper gradient so the waves becomes destructive, breaking down beach material

Answer 9

Shore platforms Cliffs Beaches Splits, tombolos Deltas High energy

Answer 10

Mudflats Sandflats Saltmarshes Mangroves Deltas Low energy

Answer 11

Sand dunes High energy

Answer 12

Regular movements in the seas surface caused by the gravitational pull of the moon and sun on the oceans The moon accounts for most of the pull

Answer 13

Occur just after a new moon

Answer 14

Occur after a full moon when the sun and moon are aligned

Answer 15

Occurs when the sun and moon are at right angles to the earth

Answer 16

Size and shape of ocean basins Characteristics of shoreline Coriolis force caused by the spinning on the earth Meteorological conditions Tides are greatest in bays and funnel shaped coastlines In the NH flows of water are directed to the right. In the SH to the left During low pressure systems water will rise by 10 cm of every decrease of 10 millibars of pressure

Answer 17

The difference between high and low tide This can vary Classified as -microtidal ( less than 2m) -mesotidal (2-4m) -macrotidal ( over 4m)

Answer 18

The place where there is no tidal range. Tides may increase with distance from the point

Answer 19

Controls the vertical range of erosion and deposition Weathering and biological activity is affected by the time between tides Velocity of tidal currents impact levels of erosion

Answer 20

A large wave or bore caused by the constriction of the spring tide as it enters a long, narrow, shallow inlet

Answer 21

An intermittent strong surface current flowing seaward from the shore Can be caused by a combination of tides and the uneven breaking of waves along a shoreline Once formed they modify the beach creating cusps which makes the current more likely to occur again in the future

Answer 22

An abnormal rise in sea level accompanying a hurricane or intense storm significantly above astronomical tide. Can cause extreme flooding in coasts

Answer 23

Low atmospheric pressure Strong winds Wave action Coastal topography Tides

Answer 24

Loss of life Property damage Displacement Environmental damage Economic costs

Answer 25

Early warning systems Infrastructure improvements Community preparedness Environmental management

Answer 26

Occurs as waves break onto cliffs. As they break against the cliff face any air trapped in cracks, joints and bedding planes is put under great pressure. As the wave retreats the pressure is released with explosive force. This is cavitation. Stress weakens the coherence of the rock aiding erosion. Particularly obvious in well bedded and jointed rocks like limestones, sandstones, granite and chalk as well as rocks poorly consolidated like clay and glacial deposits. Also notable during storm wave activity

Answer 27

Where a breaking wave can hurl pebbles and shingle against a coast

Answer 28

Occurs as other forms of erosion continue. The eroded material is worn down by attrition explaining the variety of sizes of beach material

Answer 29

Is a form of chemical erosion. With calcareous rock waves remove material by acidic water. The source of acidity is from organisms. These make the water more acidic especially in rock pools at low tide

Answer 30

Wave steepness: Steep destructive waves formed locally have more erosive power than less steep constructive waves Wave breaking point: Waves breaking at a cliff base cause maximum erosion whereas waves breaking off shore lose energy

Answer 31

Neap and spring tides vary the zone of wave attack. Strong tidal currents can scaur estuary channels

Answer 32

Longshore and rip currents can move large quantities of material

Answer 33

Onshore winds erode rine beach sane to form dunes Offshore winds may erode dunes and nourish the beach The longer the fetch the greater the wave energy potential

Answer 34

Continual supply is necessary for abrasion whereas an oversupply can protect the coast

Answer 35

Beaches/rock platforms influence wave energy by absorbing waves before they can attack cliffs

Answer 36

Rock type influences the rate of erosion. Granites are very resistant whereas unconsolidated volcanic ash has little resistance to wave attack. Erosion is rapid where rocks of different resistance overlie one another

Answer 37

Well jointed or faulted rocks are very susceptible to erosion Horizontal or vertical structures produce steep cliffs Rocks dipping away from the sea produce gentle cliffs

Answer 38

A teep seabed creates higher and steeper waves than one with a gentle gradient Longshore bars cause waves to break offshore and lose energy

Answer 39

Headlands with vertical cliffs tend to concentrate wave energy by refraction Degree of exposure to waves influence erosion rates

Answer 40

The longer the fetch the greater the potential for erosion by waves

Answer 41

Wave action works between HWM and LWM so causes undercutting of a cliff face forming a notch and overhang. Breaking waves especially during storms and spring tides can erode the coast above HWM. As the undercutting continues the notch becomes deeper and the overhang more pronounced. The overhand will collapse causing the cliff line to retreat. The base of the cliff will be left behind as a broadening platform often covered with deposited material with the coarsest near the cliff base gradually becoming smaller towards the open sea

Answer 42

Salt is where sodium and magnesium compounds expand in joints and cracks weakening rock structures Freeze-thaw is where water freezes expands and degrades jointed rocks Biological is carried out by molluscs, sponges and sea urchins Solution is the chemical weathering of calcium by acidic water which occurs in rock pools due to the presence of organisms secreting organic acids Slaking is where materials disintegrate when exposed to water by hydration cycles Mass movements like slumping and rockfalls are also important in coasts

Answer 43

Sediment sources vary. They include reworked beach deposits, offshore marine deposits, river deposits, glacial deposits, material from cliff mass movements, wind blown deposits and artificial beach nourishment. SOme beaches are formed of volcanic ash and others are formed of shingle. Shingle beaches are of glacial and periglacial deposits. Sandy beaches are the result of river sediment reworked by waves. Others are artificial and use sand from elsewhere

Answer 44

Grains transported by bedload are moved in continuous contact or discontinuous contact. In traction gains slide or roll. Weak currents may transport sand and strong currents transport pebbles and boulders. In saltation grains hop along the seabed. Moderate currents transport sand and strong transport pebbles

Answer 45

Grains carried by turbulent flow and help up by water. Suspension occurs in moderate currents transporting silts or strong transporting sand. Grains transported as wash leads are always in suspension consisting of clay and dissolved material. Deposition is governed by sediment size and shape and may flocculate

Answer 46

The coastal or littoral cell system examines coastal processes and patterns. It ranges from a single bay to regional. Each littoral cell is self contained where inputs and outputs are balanced. Dynamic equilibrium states that the littoral cell is the result of the inputs and processes operating in it. Change to 1 input has a knock on effect on processes and a change in landform. The balance changes so dynamic equilibrium

Answer 47

Leads to sediment moving gradually along the shore. The swash moves sediment up the beach in direction of prevailing wind while backwash moves straight down the beach in direction of steepest gradient. Net movement is downdrift

Answer 48

As a wave front approaches the shore, speed falls. Due to the interaction between onshore wind and direction and trend of coast wave fronts approach obliquely. This causes wavefront to bend and swing to break parallel to the shore. The speed and distortion change of the wavefront is wave refraction. If completed the fronts break parallel to the shore. Due to coastline shapes, refraction is not always totally achieved causing longshore drift which is a major transport of material. Refraction also distributes energy along a coast. Along a complex transverse coast with alternating headlands and bays, wave refraction concentrates wave energy and so erosional activity on headlands while energy is dispersed in bays as deposition. If refraction isn't complete, longshore drift occurs

Answer 49

Begins with the erosion of weak points in coastal cliffs often at the base where the sea exerts the most force. Marine erosion involves hydraulic action, abrasion and corrosion. Over time these processes enlarge cracks into small cavities. As erosion continues the cavities grow into substantial recesses or caves. The initial formation if heavily influenced by rock type and structure. Sedimentary rocks with bedding planes and joints are especially susceptible to cave formation

Answer 50

As caves deepened they can penetrate through a headland. Happens when the sea erodes both sides of a headland where waves developed. Continuous wave action and sub aerial processes like weathering contribute to the enlargement and eventual meeting of opposite caves. Arches are further sculpted by marine and sub aerial erosion. The top of the arch is subjected to weathering like freeze-thaw and biological. This weakens the rock above the arch so is more susceptible to collapse

Answer 51

When the arch is too unstable to support its weight it collapses leaving an isolated pillar of rock. Characterised by vertical form, standing alone due to the seas erosive power. Erosion continues on the stack particularly at its base where most wave energy is concentrated. Abrasion and hydraulic action are key eroding the base. This leads to further weakening and collapse of the stack into a smaller more stable form

Answer 52

As the base of a stack is undercut by wave action the structure becomes unstable and collapses. The remaining base of the eroded stack only just visible at high tide is a stump. Stumps are the last remnants of the original cliff and are often submerged in high tide

Answer 53

Loose material removed by waves. Energetic waves and microtidal range

Answer 54

Rock surfaces scoured by waves induced flow with water and sediment. Soft rocks, energetic waves and microtidal range

Answer 55

Wave induced pressure variations in the rock cause and widen cracks. Weak rocks, energetic waves and microtidal range

Answer 56

Frost action and cycles of wetting and drying cause and widen cracks. Sedimentary rocks in cool regions

Answer 57

Volumetric growth of crystals widens cracks. Sedimentary rocks in hot and dry regions

Answer 58

Removal of rock material through hydrolysis, oxidation, hydration and solution. Sedimentary rocks in hot and wet regions

Answer 59

Physical, salt and chemical work along the edges of rock pools. Sedimentary rocks in areas with high evaporation

Answer 60

Chemical weathering by metabolism products. Limestone in tropical regions

Answer 61

Physical rock removal by animals grazing or boring. Limestone in tropical regions

Answer 62

Rocks fall straight down cliff face. Well jointed rocks, undercutting by waves

Answer 63

Deep-seated failures. Deeply weathered rock, undercutting by rock

Answer 64

Flow of loose material down slope. Unconsolidated material, undercutting by waves

Answer 65

Sloping shore platforms smoothly transition to seabed. Sub-horizontal shore platforms have larger drop offs with more potholes and pools. Plunging cliffs have no ramp of shore platform and drops straight into the sea. The dip of the bedding will create varying cliff profiles. If the bed dips vertically a sheer cliff face is formed. If the neds dip steeply seaward then steep, shelving cliffs with landslips form. Also takes into account weathering processes

Answer 66

Composite cliffs are made of more than one type of rock. Shape is determined by relative strength and structure of each rock, relative hardness and types of waves involved. Tidal range can also be significant

Answer 67

Granite: <0.001m/year Limestone: 0.01-0.1m/year Shale: 0.01-0.1m/year Chalk: 0.1-1m/year Glacial till: 0.1-10m/year Volcanic ash: >10m/year

Answer 68

A sea cliff whose upper part has been trimmed to a relatively low angle by quaternary periglacial processes while the lower part is still steep as a result of recent marine activity

Answer 69

1. Vertical cliff was formed due to marine processes in the last interglacial period when sea levels were higher than now 2. During the glacial phase sea levels dropped and periglacial processes like solifluctuation and freeze-thaw affected the former sea cliff forming a bevelled edge 3. When sea levels rose again during the interglacial there was renewed wave erosion which removes the debris and steepends the base leaving the upper part at a lower angle

Answer 70

Strong rock of uniform resistance: Cliff retreat is determined by rock strength. Slow for granite. Fast for glacial till Weaker rock strength and faster cliff retreat: Form of cliff depends on relative position of weaker rock. If at the base, undercutting and collapse may occur. If near the top, subject to sub-aerial processes and wave undercutting

Answer 71

Strata dipping to inland: Sliding unlikely as movement is landwards Strata dipping to sea: Movement is seawards and large potential for sliding. Seaward dipping rocks pose greater management challenges Impermeable over permeable: Limited percolation and more stable cliff Permeable over impermeable: Water may soak into cliff and slope failure is more likely where water builds up at the junction of 2 rock types

Answer 72

The tallest cliffs are often in temperate regions. This is due to the rapid removal of material at the base by high energy waves while the processes of undercutting actively develops new cliffs. In the tropics there is lower wave energy and the high rates of chemical weathering lends itself to more gentle slopes. In high latitudes there is a dominance of mechanical weathering resulting in a lot of material falling to the base of a cliff

Answer 73

Traditionally called wave-cut or abrasion platforms. Now called coastal platforms because of role of other agents of weathering and erosion which is as significant as the wave

Answer 74

Some marine geomorphologists believe coastal platforms are relict or ancient features. They argue they were created hundreds of thousands of years ago during periods when sea levels were more constant. Sea levels have risen and fallen but are now similar to the period when they were created so are visible during low tide

Answer 75

Frost action: Could speed up weathering in high latitudes creating wider coastal platforms. Salt crystallisation: SOlution weathering could support wave action especially in tidal and splash zones

Answer 76

Marine organisms can accelerate weathering during low tide at the point just above HWM. At night these organisms release more CO2 due to the lack of photosynthesis. The CO2 then combines with cold sea water to create an acidic environment and so increased chemical weathering. Some other organisms can also secrete acids that slowly rot the rock near HWM. Polychaetes and annelids, molluscs and sea urchins bore into the rock especially on chalk and limestone

Answer 77

An area of sand or small stones near the sea or another area of water. A beach is the accumulation of material deposited between LWM fro the lowest spring tides and the highest point storm waves reach during high tide

Answer 78

A cliff or marked by a line of dunes. Above and at HWM there may be a berm or shingle ridge. This is coarse material pushed up the beach by spring tides and arises by storm waves that fling material above wave level. The seaward edge of the berm is scalloped and irregular due to beach cusps. These could be due to the edge of the swash which is often scalloped or due to the action of 2 sets of wavefront approaching the shore obliquely from opposite directions. Cusps are self perpetuating: swash is broken up by cusp projection concentrating energy onto it which removes material. Develop best in areas of high tidal range where waves approach at 90. Spacing is related to wave height and swash strength

Answer 79

Exposed at low tide. Beach material may be undercutting due to ridges (fulls) parallel to water line, pushed up by constructive waves at the height of tides. Separated by troughs (swales). Stretches of sand may compromise the foreshore. In complex coasts sand beaches may only be exposed as small bay head beaches in bays

Answer 80

The first material is deposited. Waves touch the seabed so material is disturbed being pushed up as offshore bars when the offshore gradient is shallow

Answer 81

God beach development is on a lowland coast with a sheltered aspect or trend made of soft rocks which are a good supply of material or where longshore drift supplies material. the closest area of water is nearshore

Answer 82

The larger/coarser material fallen from cliffs in the backshore

Answer 83

Finer material worn down by attrition usually in offshore

Answer 84

Beach form is affected by the size, shape and composition of materials, tidal range and wave characteristics. As storm waves are more frequent in winter and swell waves in summer, beaches differ in winter and summer profiles. Constructive waves in summer may build up the beach but destructive waves in winter may change its size and shape. Steep destructive waves reduce beach angle whereas gentle constructive waves increase it. A low gradient produces shallow water which increases wave steepness. Plunging waves are on gentle beaches and surging waves on steeper beaches

Answer 85

Affects through percolation rate. Pebbles allow rapid infiltration and percolation so swash and backwash impact is reduced. The reduced backwash does not impede the next swash. If swash is stronger, deposition may occur. Sand produces a lower angle and less percolation. Backwash is greater on a gravel beach. Sediment size varies up a beach. The largest particles (cliff recession) are at the rear. Large, round material on upper beach is supplied during the highest spring tide only. On lower beach, wave action is more frequent, attrition is common and particle size is smaller

Answer 86

These are beaches and coasts that are oriented parallel to the crests of the prevailing wind. They are closed systems. There is very little longshore drift transportation. The net littoral drift rates are 0. There is little movement of the coarser material found in the backshore. Sediment moves up and down the beach with little lateral transfer

Answer 87

Coastlines and beaches that are oriented at an angle to the crest of the prevailing waves. Longshore drift is strong and are open systems. They result in the creation of spits, bars, tombolos and cuspate forelands. Sediment is transferred along the coast by longshore drift

Answer 88

Abundant material is available especially shingle and sand The coastline is irregular Deposition is increasing by vegetation There are estuaries and major rivers

Answer 89

Common along indented coast where wave energy is reduced. The long narrow ridges of sand and shingle are joined at one end to the mainland. They become curved as waves undergo refraction. Cross-currents or storm waves may assist the hooked formation. If the curved end is pronounced it is a recurved spit. They grow in the direction of longshore drift and only exist through the continued supply of sediment. Within the curve, water is shallow and an area of mudflat and saltmarsh is exposed at low water. These grow as mud is trapped by marsh vegetation. The saltmarsh is intersected by channels or creeks which contain water even at low tide

Answer 90

A compound recurved spit has a narrow proximal end and a wide recurved distal end that can enclose a lagoon. The wide end usually consists of dune or beach ridges associated with older shorelines, demonstrating seaward migration

Answer 91

A bar is a ridge of material connected at both ends to the mainland. Above sea level. If a spit continues to grow lengthwise, it may link two headlands to form a bay bar. These can be composed of shingle or of sand. May also be formed by the onshore movement of material. Bay bars form across estuaries, blocking rivers formed from offshore material driven in by waves

Answer 92

If a ridge of material links an island with mainland the ridge is a tombolo. May also form in the shadow of wave refraction caused by an offshore island

Answer 93

Consist of ridges deposited in a triangular shape and are the result of two spits joining or the combined effects of two sets of regular storm waves. Some are stabilised by vegetation while others migrate down the shoreline downdrift

Answer 94

Usually composed of coarse sand or shingle. Develop as bars offshore on a gently shelving seabed. Waves feel bottom far offshore. This causes disturbance in the water which leads to deposition forming and offshore bar below sea level. Between the bar and shore, lagoons or sands develop. If the water in the lagoon is calm and fed by rivers, marshes and mudflats can develop. Bars can be moved onshore by storm winds and waves

Answer 95

Natural sandy breakwaters that form parallel to a flat coastline. They form only under certain conditions. A gently sloping and low-lying coast unprotected by cliffs faces an ocean. Over the land 15000 years the sea level has risen by 120m as glaciers and ice caps have melted. Wind and waves have formed sand dunes at the edge of a continental shelf. As the rising sea breaks over the dunes this forms lagoons behind the sandridge which divides into islands. Currents parallel to the coast scour sand form barrier beaches and deposit it further up or down the coast to form new islands

Answer 96

Coastal sand dunes are any accumulation of sand grains shaped into a mound of ridge by the wind under the influence of gravity near the sea

Answer 97

Coastal sand dunes form where a beach is big enough to allow the sand to completely dry out between high tides and where there are onshore winds to blow the dry sand landwards. The sand is then trapped by dune grasses which grow through the accumulating layers of hard, inorganic sand

Answer 98

Sand accumulates on the beach from longshore drift At low tide, the sand dries out allowing the prevailing winds to move the loose sand up the beach If there is a large tidal range there is more time for the sand to dry out

Answer 99

Sand needs and obstruction to accumulate around Seaweed, dead seabirds, driftwood and other detritus may save this purpose

Answer 100

The first plants to colonise the foredunes are lyme grass, sea couch grass and marram grass

Answer 101

Being to show a greater diversity of plants as conditions become more favourable. As plants die and decay, a humus layer builds up and this traps water and nutrients

Answer 102

The most mature dunes are several hundred metres from the shore. Left undisturbed these develop a soil which can support shrubs and trees

Answer 103

pH decreases at surface of soil Colour changes yellow to yellow and grey to grey to brown soil colour Percentage of humus increases from <1% to >40% Percentage of calcium carbonate decreases from 10% to <0.1% Age of landform increases to 250+ years old

Answer 104

Coastal wetlands that are flooded and drained by the tides. They are boggy and marshy as their soils are composed to deep mud and peat. They are areas of low, flat, poorly drained ground that is subject to daily or occasionally flooding by salt water, covered by a thick layer of grass

Answer 105

Low energy coastlines Behind spits and barrier islands In estuaries and harbours Silt accumulates and on reaching sea level, forms mudbanks. In the tropics and subtropics, saltmarshes are replaced by mangroves

Answer 106

A thin layer of mud forms over sand which is covered at each tide. Algae is the only plant growing on the mud More mud is deposited and the first plants appear. The plants trap more mud and silt. The marsh is covered at each high tide and channels are cut as the water recedes More plants appear higher up the marsh which accelerates mud accretion. Channels deepen as the marsh surface rises More plants move into the higher zones and the mud deepend. High tides still flood the marsh but low tides are confined to the creeks which are further eroded as the water runs off

Answer 107

Marshes in S England dominated by cordgrass. The first plants like green algase colonise the bare mudflat. Algae traps sediment and provides the conditions for the seeds of marsh samphire and eelgrass Also provide nurseries for fish, mammals and birds. Glassworts and cordgrass are useful as they increase sediment deposition, provide food for fish and slow the movement of water. They are important for resident and migratory birds like egrets and spoonbills. These use the higher grasses as cover

Answer 108

Acts as carbon sinks and can be very efficient at storing carbon. Carbon is brought in on the tide. When buried in the wet mud, decomposition is slows and the carbon is locked in. When plants die, rather than decomposing, the plants become buried instead of releasing carbon. As sea levels rise, more layers get buried and more blue carob gets locked beneath the surface Protect shorelines and the people that live there from flooding. During heavy storms they provide a buffer. They reduce the strength of incoming water and preventing the worst of the storm from hitting populated areas further inland They absorb and clean run off from farms. This filters herbicides, pesticides and heavy metals as well as excess sediment and nutrients

Answer 109

The need for productive farmland has seen them being reclaimed and drained. Also drained to expand cities and build new airports. Rising sea levels and frequent storms put them under pressure. Other human threats include contamination from sewers and runoff, overfishing, pollution and erosion. The interaction of saline water with a saltmarsh also causes the decay of some plants within them

Answer 110

They are trees or shrubs that can survive in harsh conditions such as low oxygen, high salinity, poor nutrients, high winds, wave action and unstable sediment. Mangroves have many essential adaptations that allow them to survive in the conditions they are in

Answer 111

The first trees grow with large pneumatophores are they are completely submerged underwater. The vertical roots begin to trap sediment and organic material from the water. There are more nutrients allowing the trees to grow bigger and they grow buttress roots to allow for more stability in the loose sediment. The larger root system traps more sediment allowing other plants to begin to grow as the sediment is above the HWM. Other coastal species will grow as a climate community behind the mangroves

Answer 112

Birds such as herons, egrets, kingfishers. Many shrimp, molluscs, rabs, worms and bivalves. Juvenile and adult fish species including mudskippers and baby sharks. Mammals like bats, primates, fishing cats and more

Answer 113

Major carbon stores, traps decaying material and the carbon dioxide it releases as it decays. Provides habitat for juvenile fish as well as many birds, insects and mammals. Act as coastal protection reducing coastal erosion. Protects coral reefs and seagrass from being smothered by sediment from rivers.

Answer 114

Pollution of coastal areas. Coastal development and over exploitation. Rising sea levels and climate change

Answer 115

Act as tidal forests between land and sea. Plants are so close to the shoreline that they are submerged in salt water when tides come in. Make up around 75% of tropical coastline. Temperature must be above 24C in the warmest month. Rainfall much be over 1250mm

Answer 116

Where one or more freshwater rivers or streams meet the salty ocean. The combination of this seawater and freshwater forms bracksing water. It is a partly enclosed protected coastal body of water. They are indentations in the coastline, often funnel shaped that are infilled with sediment

Answer 117

Sea level rise at rapid pace, drowning river valleys and filling glacial troughs. They became traps for sediment due to the lack of strong waves. When the sea retreats, there is a lower volume of water so the river deposits silt to create mudflats. The intertidal zone undergoes environmental changes in salinity, tides and sediment composition.

Answer 118

Yellowfin bream, sand whiting and various mullets. Crabs, shellfish and migratory birds are also found. Large numbers of wading birds are often attracted to estuaries due to the colonies of worms, molluscs and crustaceans.

Answer 119

Provides nursing grounds for over 75% of the USAs commercial fish catch and 90% of its recreational fishing. 22/32 largest cities in the world are located on estuaries. Water draining carries sediment, nutrients and pollutants which is filtered out creating cleaner water. Estuarine plants help prevent erosion, floods and stabilise the shoreline

Answer 120

Urban coastal development, introduction of invasive species, recreation, structures, erosion and sediment build up, increased input from construction sites and dredging. Winds, tidal currents, waves and ice but many of the natural factors are also influenced by global warming

Answer 121

Coastal plain Bar-built Complex Ria Tectonic Fjord

Answer 122

Found at the mouths of freshwater rivers as this is where the freshwater can mix with the saltwater of the ocean. Shallow bays and inlets also form estuaries or in river delta systems. Common in temperate and tropical regions but not found far inland

Answer 123

Global scale sea level change caused by a change in the volume of water in the ocean store

Answer 124

Local scale sea level change caused by a change in the level of the land relative to the level of the sea

Answer 125

The impact of a relative fall in sea level (marine regression)

Answer 126

The impact of a rise in relative sea level (marine transgression)

Answer 127

Climate gets colder Precipitation falls as snow Turns to ice Hydrological cycle slows Water doesn't return to sea Global sea level fall Eustatic sea level change

Answer 128

Ice grows Weight causes land to sink Affects some coastlines Isostatic sea level change

Answer 129

Climate gets warmer Ice begins to melt Begins to replenish oceans Sea level rise Produces submergent features

Answer 130

Land areas adjusting to ice removing and melting Isostatic change If isostatic is greater than eustatic, emergent features form

Answer 131

Drowned river valley

Answer 132

Created by the drowning of U shaped glacial valleys by the rising sea and/or sinking land

Answer 133

A fjard is a large open space of water between groups of islands or mainland in archipelagos. Fjards can be found along sea coasts in freshwater lakes or in rivers

Answer 134

Fjords are characterised by steep high relief cliffs carved by glacial activity and often have split or branching channels Fjards are glacial depressions or valleys that have much lower reliefs. They fill with eroded local materials which assist in filling along with rising sea levels since the ice age also contributing. Other low relief landforms like mudflats, saltmarshes and floodplains are only associated with fjards which further characterises the difference

Answer 135

Initially sea level rise was faster than isostatic uplift. This led to the formation of marine erosion features and beaches which have been exposed by gradual uplift

Answer 136

Exposed marine platforms are erosional Fossil cliffs are erosional Raised beaches are depositional

Answer 137

High rock platforms Older raised beaches 10m raised beach Post glacial shorelines

Answer 138

The land is relatively flat and gently sloping, ideal for building The sites are close to the sea for fishing They allow good communication via coastal roads Raised shore lines and higher platforms are valuable for farming

Answer 139

Calcium carbonate structures made up of reef building stony corals. It is limited to the depth of light penetration so occur in shallow water to depths of 60m. They are also only found where the surrounding waters contain little suspended material. Reef building corals live only in tropical seas where theres temperature, salinity and less turbid water. Reefs occupy <0.25% of marine environments but shelter over 25% of marine life. There are 800 types of rock forming corals. Reefs have up to 2 million species

Answer 140

All reefs begin as polyps which attach to a hard surface in shallow seas where there is enough light for growth. As they grow they exude calcium carbonate forming their skeleton. Then as they die they create reefs. Polyps have zooxanthellae, small algae inside them. There is a symbiotic relationship. The algae get shelter and food and the polyp gets food via photosynthesis

Answer 141

Tropical reefs grow at <2.5-60cm per year making them the largest and oldest systems on earth

Answer 142

None develop where mean annual temperature is <20C. Optimal conditions are 23-25C

Answer 143

Most grow in <25m of water so are found on margins of continents

Answer 144

The photosynthesis algae need light so live in shallow water and supply the coral with 98% of their food

Answer 145

Intolerant of water with salinity <32 psu but can tolerate >42 psu

Answer 146

Clogs feeding structures and cleansing systems and reduces available light

Answer 147

Prefer strong wave action which ensures oxygenated water, removes trapped sediment and supplies plankton. In storm conditions, waves may be too destructive

Answer 148

Die is exposed for too long so found below low tide mark

Answer 149

Fringe the coastline of a landmass. Usually characterised by an outer reef edge capped by an agal ridge, a broad reef flat and a sand floored boat channel close to the shore. Many grow along shores protected by barrier reefs and so are characterised by organisms that are best adapted to low wave energy conditions

Answer 150

Occur at greater distances from the shore and are separated from the shore by a wide, deep lagoon. Tend to be broader, wider and more continuous than fringing reefs

Answer 151

Rise from submerged volcanic foundations and often support small islands of wave borne detritus. They are indistinguishable in form and species composition from barrier reefs except they are only on submerged oceanic islands

Answer 152

Small, circular or irregular reefs that rise from the sea floor of lagoons behind barrier reefs or within atolls

Answer 153

Simply grow seaward from the land. Barrier reefs and atolls rise from a greater depth far below which coral can grow and many atolls are isolated in deep water. The lagoons between them and the coast are usually 45-100m deep and many km wide

Answer 154

In 1842 he explained the growth of barrier reefs and atolls as a gradual process due to subsidence. He outlines the way coral reefs could grow upwards from submerging fountains. This made it clear that fringing reefs might be succeeded by barrier and then atoll reefs. A fringing reef grows around an island and as the island subsides the coral continues to grow, keeping pace with the subsidence. Coral growth is more vigorous on the outer side of the reef so forms a higher rim whereas the inner part forms a wide and deep lagoon. The inner island becomes submerged. forming a ring of coral that is the atoll

Answer 155

In 1872 he suggested that the base of the reef consisted of a submarine hill or plateau rising from the ocean floor. These reached within 60m of the sea surface and consisted of subsurface volcanic peaks to wave worn stumps. As a fringing reef grows, pounded by breaking waves, masses of coral fragments accumulate on the seaward side, washed there by waves and are cemented into a solid bank

Answer 156

Suggested that a rise in sea level may be responsible. A rise occurred in post glacial times due to melting ice sheets. He discovered traces of glaciation in Hawaii. It was much colder and lower in glacial times. All coral would have died and any surfaces would have been eroded. Once conditions warmed up and the sea levels rise, the previous reefs provided a base for the upward growth of coral. This accounts for the narrow, steep sided reefs that comprise most atolls, some with 75 degree slopes

Answer 157

Darwin still receives considerable support. Daly was correct in principle but it is now believed that the erosion of old reefs was less rapid then he believed and the time in the glacial stages as not long enough for the formation of platforms. The erosional modification is now believed to be due to sub aerial limestone processes

Answer 158

Have 4000 species of fish and 800 species of reef building corals. They support rich communities through recycling processes and have high specie diversity rates Seafood: 1/4 of fish catch in LICs providing foor for 1 billion in Asia. Can yield 15 tonnes of seafood/km^2 per year Medicine: Use array of chemicals Recreation:Major draw for tourism Protection: Buffer adjacent shorelines through wave action

Answer 159

Global warming, sea level rise, overfishing, destruction of coasts and pollution endanger coral reefs. 58% are at high or medium risk of degradation

Answer 160

Reef building corals need warm, clear water. Pollution, sedimentation, climate change and other factors pressure this, halting photosynthesis resulting in the death of the living part of the reef. Zooxanthellae live in the tissue and carry out photosynthesis, providing energy. They give the coral its colour. When conditions are stressful it may leave, leaving the coral in an energy deficit without colour. If recolonised in a certain time ir may recover but if not it will die. Coral bleaching can be caused by 1-2C rises. The shallower the water the greater the potential for bleaching

Answer 161

1/5 of reefs are beyond repair. The percentage of recovering reefs has risen but 70% are still threatened. The destruction is cause for economic and ecological concern especially for the communities that depend on their fish and revenue from tourism. The main causes are climate change, poor land management practices and coastal development

Answer 162

Coral reefs were the first ecosystem to show damage from climate change. Climate change will cause irreversible damage due to Increasing sea temperatures causing more bleaching. Some species may become extint Bleaching will become a more frequent event Increased acidification will reduce calcification causing slower growth, weaker skeletons and dissolution Increase in storms will result in the destruction of reefs and erosion of coastline. 19% have already been lost and 35% are seriously threatened

Answer 163

60% were under threat from local sources When thermal stress was added this rose to 75% By 2050 over 90% will be affected by local and global threats

Answer 164

500 million depend on reefs for food, protection, materials and income. They provide 30 million with their livelihoods. Human will being will be reduced if corals are destroyed. 50% of the population lived on coasts in 2015 putting pressure on coastal resources

Answer 165

First large scale bleaching was in 1983. The hottest years were 1997, 1998, 2003, 2004 and 2005. Any recovery was reversed by other human pressures Temperatures have risen in all oceans in the last 40 years

Answer 166

Reduce greenhouse gas emissions and develop plants to sequester CO2 Limit damaging human activities to allow coral to recover Provide assistance to LICs Develop alternative livelihoods Introduce local coastal management practices Improve the management, monitoring and enforcement of regulations Designate more reefs as marine protected areas to act as reservoirs of biodiversity

Answer 167

Will become extinct if CO2 levels are above 450ppm Low lying coastal communities will become more vulnerable

Answer 168

Human pressure on the fragile coastal environment requires careful management. The management could be short term or long term and sustainable or unsustainable. Any management plan requires a detailed knowledge of coastal processes including sea level prediction, currents, tides and storm frequency. Many coasts are coming under increased human pressure due to population growth and urban development

Answer 169

SMPs are designed to develop sustainable coastal defence schemes. Sections of the coast are divided into littoral cells and plans are drawn up for the use and protection of each zone

Answer 170

Do nothing Maintain existing levels of coastal defences Improve the coastal defence Allow the retreat of the coast in selected areas

Answer 171

Planning Coastal protection Cliff stabilisation and ground movement Coastal infrastructure Cost of beaches and public safety Recreational activities and sport Beach cleaning Pollution and oil spills Offshore dredging Management of coastal land and property

Answer 172

Hard engineering Soft engineering Managed natural retreat

Answer 173

When structures are built to either stop flooding, reduce erosion or both. These are expensive so are only used where the land is deemed economically valuable

Answer 174

Does not involve building artificial structures but takes a more sustainable and natural approach. Less expensive and more long term, attractive and sustainable as they work with natural process

Answer 175

Allows nature to take its course but still have some control. They allow the sea to break through sea defences and flood the land behind but the way this happens is managed

Answer 176

Cost of building Maintenance/repair Increased erosion downdrift due to beach starvation or reduced longshore drift Reduced access to beach during works Reduced recreational value Reduced accessibility Smaller beach due to scour Disruption of ecosystems Visually unattractive Works disrupt natural processes

Answer 177

Protected buildings, roads and infrastructure Land prices rise Peach of mind for residents Employment on works

Answer 178

Land use and habitat destruction Water pollution Increased vulnerability to climate change

Answer 179

Port development and habitat loss Ship pollution Coastal erosion

Answer 180

Runoff and eutrophication Wetland drainage Conflicts over water use

Answer 181

Coastal development Overcrowding and pollution Conflicts with local communities

Answer 182

Overfishing Bycatch and species loss Conflicts with conservation efforts

Answer 183

Habitat destruction Water pollution Genetic pollution

Answer 184

Coastal pollution Habitat degradation Social conflicts

Answer 185

Oil spills and marine pollution Visual and noise pollution Tourism and fishing conflict

Answer 186

Large scale concrete curved walls designed to reflect wave energy

Answer 187

Porous designed to absorb wave energy

Answer 188

Rocks held in wire cages, absorb wave energy

Answer 189

To prevent longshore drift

Answer 190

Large rocks at base of cliff to absorb wave energy

Answer 191

Reduce wave power offshore

Answer 192

To reduce longshore drift

Answer 193

Removal of water from rocks in the cliff

Answer 194

Lowering of slope angle to make cliff safer

Answer 195

Waste materials to reduce speed of incoming wave

Answer 196

Sand pumped from seabed to replace eroded sand

Answer 197

Coastline allowed to retreat in certain places

Answer 198

Accept that nature will win

Answer 199

Planning permission withdrawn. New line of defences set back from existing coastline

Answer 200

Easily made Good in areas of high density Expensive Lifespan about 30-40 years Foundations may be undermined

Answer 201

Easily made Cheaper than seawalls Lifespan limited

Answer 202

Cheaper than seawalls and revetments Small scale

Answer 203

Relatively low cost Easily repaired Cause erosion on downdrift side Interrupt sediment flow

Answer 204

Cheap Unattractive Small scale May be removed in heavy storms

Answer 205

Cheap to build Disrupt local ecology

Answer 206

Relatively low cost Easily repaired Disrupt longshore drift Erosion downdrift

Answer 207

Cost effective Drains may become new lines of weakness Dry cliffs may produce rockfalls

Answer 208

Useful on clay Uses large amounts of land Impractical in heavily populated areas

Answer 209

Low technology and relatively cost effective Long term impacts unknown

Answer 210

Looks natural Expensive Short term solution

Answer 211

Cost effective Maintains a natural coastline Unpopular Political implications

Answer 212

Cost effective Unpopular Political implications

Answer 213

Cost effective Unpopular Political implications

Unit 7: Coastal Environments Flashcards

what even is this bro (238 cards)