oil spills

offshore oil extractions

-Leakage from the rigs, Greater risk of spill on land
- have safety valves fitted, yet accidents are caused
-Enters marine and coastal ecosystems if the oil reaches seabed
-Can be spilled wile transferred to ships or through pipelines to shore
-Leaks can also be caused if the equipment is outdated or poorly manages
-Oil rigs are vulnerable to string winds (hurricanes)

oil pipeline

-Leakage in oil pipework
-Most common method of transporting oil to land
-Sometimes leak due to corrosion, metal fatigue and human error on construction
-Have been incidents where pipelines have been affected during wars, conflicts, leading to oil entering ecosystems

shipping

-Risk of collision or damage to oil tankers
-Not as common as poplins
-Maritime accidents in oceans
-Can be carried away by ocean currents
-Oil spill can wash up onto nearby shorelines

Marine Coastal ecosystems

-when floats on salt water, spreads out swiftly forming an oil slick
-eventually slick thins out, leaves a thin sheen of oil on the water
-oil itself is toxic to birds, mammals and fish, which encounter it on the surface and when it washes up, to beaches and reefs.
-clean-up operations are harmful to ecosystem, use detergents

phytoplankton

-oil floats on the surface of the water and blocks the sunlight from entering the water. Hence the phytoplankton can’t photosynthesise which in a result causes them to die.

fish

-choking, skin/eye irritation, species decline, chemical burns
-shortage + damage in food-coz reduction in phytoplankton
-inhale oil when breathing on surface
-oil floating on the surface prevents gas exchange.
+direct contact of the fish w oil affects their gills
+fish become short on oxygen hence die

birds

-suffer eye irritation and drowning
-shortage of food as fish and other creatures die-starvation
-may consume/swallow oil when eating the fish (toxic, poisoned)
-when hunting, feather gets covered in oil-inability to fly
-long term population decline

mammals

-food sources are depleted
-mammals may also swallow oil while feeding
-coating of oil will affect their skin
-destroys insulation of fur bearing mammals-leads to exposure

reefs

-areas may be covered in oil
-coral bleaching + build up in toxicity
-reduction in photosynthesis result in slow plant growth
-Oil mixed with detergent used for clean-up results in more damaging + devastation to the reef ecosystem

beaches

- oil absorbed into beach sediment
-tar balls form on the sand
-oil (washed by tides) coats the rocks
-organisms in shallow water and rock pools may die due to toxic effects of the oil
-clean up operations release detergents onto the beach
-animal food sources affected/poisoned - accumulation of toxins in clams, crabs, shellfish
-tourism are affected

MARPOL

-marine pollution
-international convention for the prevention of pollution from ships
-designed to eliminate marine pollution in the sea
-treaty has 6 sections, and section 1 relates to oil pollution and specifically bans ships from releasing oil waste from engines and tanks into the sea

regulations of the MARPOL

-Supervise the transport of oil at sea
-All tankers must be certified to show they have appropriate systems in use
-If not, it can result in heavy fine, or the ship may not be permitted to leave the port

tanker design

-Oil spills can be caused by damage to the hull (a hole in the hull of the boat causes it to leak)
-Inc number of compartments in the hull of the ship: if one of the compartments are damaged, the contents of the whole ship aren’t lost
-Double-hulled tankers: if the outer layer’s damaged, the contents are still secure by the inner plate. Though th double-hulled tankers cost more than the single-hulled tankers, the risks of oil spills are far less on an comparitive note.

minimising impacts of oil spill

-floating booms
-detergent sprays
-skimmers

floating booms

these are barriers used to surround the oil slick, preventing it from spreading. This process works well when the spill covers a relatively small area, and the sea is calm.

detergent sprays

detergent helps break down the oil slick into smaller droplets, that eventually degrade and the disperse it. They are only effective on smaller spills, but cause damage to the coral reefs themselves as they’re not tolerant to detergent.

skimmers

clean the water using material that oil easily catches to. The skimmers drag the oil off the seawater to the surface that is then scrapped of into a container. This is used when oil slick is contains within a boom and the sea is calm.