• An ecosystem is a community of interacting?biotic?and?abiotic?organisms
• All ecosystems, whether on land or in water function in the same way
• All survive by nutrient cycling around three stores:
  • Biomass
  • Litter
  • Sea Water

Nutrient Cycle of a Coastal Ecosystem?

Nutrient Cycle of Coastal Ecosystems

Overview of Coastal Nutrient Cycling

Biotic Components of a Coral Reef

• A coral reef is a well-organized food web comprising of:
  • Producers
  • Consumers
  • Scavengers
  • Decomposers
• Producers?in a coral reef include seaweed, seagrass, and?phytoplankton.?zooxanthellae?are also producers that provide the nutrients from photosynthesis to coral
• Consumers?are organisms that eat other organisms to gain energy. There are three main types of consumers in a food web:?primary,?secondary, and?tertiary
  • Primary consumers only eat producers - the green sea turtles graze on sea grass
  • Secondary consumers eat primary consumers - stingrays, octopuses, squid, and larger fish for example
  • Tertiary consumers, also called?apex predators,?are carnivores that do not prey upon themselves.? These consumers help maintain the balance of the ecosystem - ?sharks, dolphins, tuna and barracuda, etc.
• Scavengers?feed on dead and decaying plants and animals - crabs and lobsters scavenge for food
• Decomposers?bring nutrients back into the ecosystem to support another cycle - examples include?bacteria, sea cucumbers, and fungi

Abiotic Features of a Coral Reef

• Light: Corals need some sunlight to survive:
  • Too little, then the zooxanthellae will not be able to photosynthesize and produce food for corals.
  • Too much may cause corals to expel zooxanthellae, causing bleaching
• Depth: As corals need light, they are typically found at approximately 25 meters
• Water temperature:? Corals thrive in the warm waters of the tropics. They prefer a temperature range of 23-25°C, but will survive at lower and higher temperatures for short periods of time
• Salinity:?Corals need salty water
• Air: Can survive out of water for very short periods of time
• Water: Corals need clean, clear water

Biotic Components of a Mangrove

• Mangroves are the?producers?of their own ecosystem
  • Many organisms feed on the?detritus?created from falling leaves?
  • Phytoplankton can float on the surface of the water and algae grow on the mangroves' roots
• Primary consumers?are usually the decomposers (e.g. the mangrove tree crab). Small fish, crabs, clams, and shrimp feed off of the detritus. Very few consumers directly feed on the mangroves
• Secondary consumers?are the larger predatory fish, turtles, and crabs
• Tertiary consumers?include birds (e.g. herons and ospreys), eels, saltwater crocodiles, tigers, and humans
• Scavengers?include?shrimp, crabs mussels and mullet
• Decomposers?include worms, bacteria and fungi

Abiotic Features of Mangroves

• Temperature: Mangroves typically grow in areas where the temperature does not drop below 19°C
• Oxygen: Just like other plants, mangroves need oxygen to survive. Complex root systems allow the mangroves to receive the oxygen they need by sticking out of the water?
• Salinity:?Mangroves have adapted to live in salt water with some removing excess salt through their leaves
• Soil:?Mangroves can grow within the intertidal zone of a coast. The soils are made up of sand, silt, and mud?
• Wave Energy:?Mangrove vegetation cannot develop on exposed coast with a lot of wave energy or currents that move sediments which would stop seeds from colonising
• Ocean Currents:??These distribute mangrove seeds and help keep the areas full of trees?

Biotic Components of Sand Dunes

• Producers?that provide the initial beach fuel for dunes include:
  • phytoplankton, microscopic algae (green scum found on a beach), detached seaweeds such as kelp and seagrass and blown-in seeds.
  • These support the growth of pioneer species such as couch grass, and lyme grass. As succession continues, multiple species of vegetation begin to colonize - marram grass, gorse, sea buckthorn, heathers, red fescue, etc.
• Primary consumers:?beetles, butterflies, moths, bees, wasps, flies, rabbits, etc
• Secondary consumers:?sand lizards, snakes, spiders, frogs, bats, etc
• Tertiary consumers:?seagulls, waders, hawks, swans, bats, etc
• Scavengers:?crabs, beetles, flies, wasps, crows, rats, etc
• Decomposers:??flies, fungi, bacteria, weevils, etc

Abiotic Features of Sand Dunes

• Wind?- an onshore prevailing wind is needed to blow dried sand into ridges
• Tidal Range?- needs to be large to allow sand to dry
• Water?- a mix of fresh and saline to support pioneer spices
• Sand?- large quantities needed
• Beach?- needs to be wide
• Obstacles?- needed for sand to accumulate behind

Biotic Components of Salt Marshes

• Producers?- algae, seaweed, rushes, samphire, cord grass, salt marsh hay etc
• Primary consumers?- fish, insects, mussels, crabs, bees, oysters, shrimp etc
• Secondary consumers?- fish, mice, frogs, herons, lizards, sandpipers, bats etc
• Tertiary consumers?- harriers, sea eagles, gulls etc
• Scavengers?- snails, rats, crows, flies, crabs etc
• Decomposers -?fungi, bacteria, worms, etc

Abiotic Features of Salt Marshes

• Waves?- sheltered away from the open sea & destructive waves, usually behind a spit or in sheltered bays
• Water?- brackish (mix of fresh and salty)
• Tidal Range?- large tidal range with occasional flooding. Mud flats need to be exposed to colonise
• Mud?- sediment needed to build up mud flats
• Elevation?- needs variation in height to build up mud flats and stabilise marshes