Crowded Coasts Topics to be covered Competition For

Crowded Coasts Topics to be covered: Competition For Coasts Coping With The Pressure Increasing Risk Coastal Management Fieldwork & Research – Zakynthos

COMPETITION FOR COASTS AIMS • To understand that physical factors create a variety of different coastal environments • To consider how humans use different coastal environments and how they can also threaten them

Starter Key Question to consider: Why do coasts vary so much?

Mangrove Coastline

Tropical Coastline

Salt Marsh coasts

Mudflats

Polar Coastline

Sand Dunes

Reef Coastline

Desert Coastline

The British Beach

What is a coast? A coast is ‘that part of the land most affected by its proximity to the sea and that part of the ocean most affected by its proximity to the land’. It is called the ‘Zone of Transition’. The coastline is the frontier between the sea and the land. The coast is on either side of the coastline in 2 zones. .

Coastal zones Onshore zone – it extends up to 60 km inland COASTLINE Offshore zone – reaches as far out as the Economic Exclusion Zone (EEZ) which is 370. 4 km out to sea. The coastal state has the rights all over the natural resources of the water and the sea bed

Knowledge check! What is the difference between the coastline and the coastal zone?

The Coastal Zone

The coastal system

Dynamic equilibrium The coast is an open system with inputs, transfers and outputs When all the inputs and outputs are equal it is said to be in DYNAMIC EQUILIBRIUM If one element changes then all the internal equilibrium is disturbed Human activity does this a lot on the coast Global warming also increases storms and rising sea levels increase coastal erosion and flooding

Coastal Diversity – the land, sea, atmosphere and humans cause a great diversity at the coast

Photo analysis Look at the set of photos in front of you…. a) Physical features shown? Think about: Topography – shape of the coast Geology – rock type Relief – height or slope of the land b)The human activities going on there and why this location has been chosen.

High Value coastal environments Exercise : Identify the features, opportunities, value and pressures for each of the following: Reefs Mangroves Salt Marshes

Mangrove swamp coastline p 165 -166 Pearson p 223 Philip Allan Low trees and shrubs with dense roots that grow in the marginal tidal zones between TROPICAL and SUBTROPICAL seas and land. Roots exposed at low tide and they trap silt and create new land. Adapted to area due to thick waxy leaves which conserve water by reducing transpiration during low tide. Salt tolerant ‘halophytes’. Protects against storm surges and tsunamis. Also provides fuel, timber for building. Cleared for shrimp aquaculture and tourist resorts.

UNEP Image: Shrimp farm expansion in the Gulf of Fonseca (Honduras/Nicaragua); below - 1987; above 1999. http: //mangroveactionproject. org/issues/mangr ove-loss

We have already lost over half of the world's original mangrove forest area, estimated at 32 million hectares (app. 80 million acres). In 2007, less than 15 million hectares (37 million acres) of mangroves remained. About half of mangrove loss has occurred in the last 50 years, mostly in the last two decades, due to: shrimp farming tourism urbanisation agriculture expansion roadways Marinas and other intrusive developments. The current rate of mangrove loss is approximately 1% per annum (according to the Food and Agriculture Organization - FAO), or roughly 150, 000 hectares (370, 050 acres) of mangrove wetlands lost each year.

Reef Coastline p 165 -166 +172 Pearson p 222 Philip Allan Coral are living organism called polyps, are tiny animals that resemble a miniature sea anemone, that secrete a limestone (Calcium Carbonate) base 3 types of reef: Fringe, barrier reefs and atolls. Charles Darwin first found these three and realised they were different stages of a sequence

Great Barrier Reef in Australia is the world’s largest coral reef at 1500 km long and comprises of 2900 different reefs Helps dissipate wave energy Fragile and open to exploitation

Conditions necessary for reef growth Coral reefs are found largely between the tropics of Capricorn and Cancer where: water temperatures are warm. Corals are unable to thrive in water that is much below 16 C and grow best with a range of 18 -30 C. In the tropics there is little annual variation in sea temperature. (But coral reefs are either restricted or absent from along the west coast of the Americas, as well as the west coast of Africa. This is due primarily to upwelling and strong cold coastal currents that reduce water temperatures in these areas. ) salinity is at favourable level. Freshwater kills coral and this is clearly seen where rivers flow out into coastal reef areas. Corals are restricted from off the coastline of South Asia from Pakistan to Bangladesh. They are also restricted along the coast around north-eastern South America and Bangladesh due to the release of vast quantities of freshwater from the Amazon and Ganges Rivers respectively.

clear water prevails. Silt that discharges at a river mouth will blanket the coral and affect the feeding mechanism of the corals and animals on the reef. For example at the mouth of the Amazon coral reef is absent due to the huge quantities of silt that are released. brightly lit waters that are fully penetrated by the sun’s rays. So corals are restricted to depths rarely exceeding 37 metres. Beyond this limit too little light is absorbed and the algae that feed the corals cannot be supported

Threats to coral See worksheet on the blog and text books

Mudflats/Salt Marshes p 165 Pearson p 224 Philip Allan Occur in estuaries where fresh water and sea waters mix. Defined as the vegetation that occurs on muddy shores where boggy ground is either flooded by sea water daily or less often. Form on the shore due to a lack of wave action and the tide. Incoming tide moves across the sheltered shore bringing sediment and detritus, the lack of wave action results in this material settling out at slack water. Accretion takes place; sediment builds up forming soil and can even raise the level of mud.

Abiotic Factors: (Non Living) Saline Mud/Soil: Seawater deposits salts (solutes) in the sediment. Causing problems for plants growing. Waterlogged Soil: The air spaces within the soil are filled with water rather than air. Roots need oxygen for respiration as much as other parts of the plant. Long-term waterlogging creates an anaerobic condition of black mud, which is toxic to plants. Drag and Scour: The tidal movement across the surface causes a sideways drag on the plant. With two tides a day this will possibly uproot the plants. The water contains sediment like sand mud particles and this will scour the plants like being buffed with sandpaper.

Biotic (living) Salt tolerant plants grow - Halophytes. May even be submerged for part of the day. See Pearson p 165 Valuable ecosystems as reduce tidal energy and provide a vital habitat to many wading birds. Threats Reclamation eg for farming Industrial pollution Agricultural pollution causes eutrophication Shipping and bating causes wash which leads to die back in vegetation Marinas and recreation adds pressure Global warming – high impact storms, changing temperature and rainfall affects the plants and sea level change.