Biodiversity 4 - Marine Ecosystems Flashcards
Explain marine ecosystems
- Classified according to the depth at which they occur, their distance from shore, and sunlight penetration
- Divided into two major types:
- Coastal ecosystems ( Seashores )
- Open ocean ecosystems (Pelagic division; Benthic division )
Explain seashores
- Intertidal zones
- Areas where the land and sea meet
- Extend from low-tide to high-tide mark
- Alternately submerged and exposed by daily tide cycles
- Organisms need to be well adapted becuase enviro changes constantly
What do organisms in seashores need to cope with
- Large variations in the availability of seawater
- Variations in temperature
- Mechanical forces of wave action
Explain the sandy shores
- No attachment sites available as the sand is unstable and constantly shifting
- Nearly all permanent residents live in underground burrows
- Volitle and unstable environment
- Mobile animals
Explain oceans
- Play a significant role in all ecosystems
- Most of the planet’s rainfall is provided by evaporation of seawater
- World’s climate and wind patterns are affected by ocean temperatures
- Marine algae produce a large portion of the Earth’s oxygen and consume large amounts of carbon dioxide
Explain the rocky shore
- Sessile organisms
- Characterised by organisms that attach themselves to rocks
- Has a littoral zone which has 3 sub zones
- Not a lot of spae leading to a lot of competition ( limiting factor )
What are the 3 sub-zones of the littoral zone
- Upper littoral zone
- Mid littoral zone
- Lower littoral zone
Explain eachh of the sub-zones of the littoral zone
- Upper littoral zone – submerged only by the highest tides ( at top & more exposed to sunlight )
- Mid littoral zone – exposed at low tide and submerged at high tide
- Lower littoral zone – exposed only during the lowest tides ( at bottom & always covered by water )
What makes up pelagic division
- Neritic province
- Oceanic province :
2.1 - Epipelagic zone
2.2 - Mesopelagic zone
2.3 - Bathypelagic zone
2.4 - Abyssopelagic zone
What makes up Benthic division
- Continental shelf
- Continental slope
- Abyssal plain
Explain pelagic divison
- Open waters of any depth
Neritic province
Oceanic province
Explain the neritic province
- Extends from the intertidal zone, across the shallow regions, to the edge of the continental shelf
- High concentration of organisms due to high sunlight penetration and a constant supply of inorganic nutrients from river runoff
- Photosynthetic phytoplankton form the base of the food chain
not very deep & very productive zone
Explain coral reefs
- Found in the neritic province, bordering tropical coastlines
- Productivity and species diversity comparable to a tropical rain forest
- Shallow, warm waters allow much photosynthetic activity, which in turn supports a large animal biomass
- Structure of coral provides diverse habitats for animal species
Explain coral bleaching
- Corals very sensitive to climate change
- Small rise in temperature stresses corals; expel their zooxanthellae symbionts
- Leads to death of the coral
What zones make up the oceanic province
- Epipelagic
- Mesopelagic
- Bathypelagic
- Abyssopelagic
Explain the oceanic province
Conditions change from surface to bottom of ocean:
- Light diminishes
- Temperatures become colder
- Water pressure increases
- Oxygen diminishes
Explain the epipelagic zone
- Uppermost layer that extends from the water’s surface to the limit of sunlight penetration
- Majority of life in the open ocean is found here
- Well developed body of animals in zone to withstand waves
animals = fish; whales; sharks
Explain mesopelagic zone
- Not enough light for photosynthesis
- Animals are mostly carnivores
- Often migrate to surface at night to feed
eg ) squid; shrimp ; red fish ( disguise from predators )
Explain bathypelagic zone
- Almost entirely dark; there is some bioluminescence
(Bioluminescence is a form of chemi- luminescence where light energy is released by a chemical reaction)
- Dominated by carnivores and scavengers
- Use light source to communicate with others; attract prey; escape predators
- Lomg stomach and body; slow metabolism
Explain benthic
- Refers to the sea floor
Divided into:
- Continental shelf (sublittoral zone)
- Continental slope (bathyal zone)
- Abyssal plain (abyssal zone)
Explain abyssopelagic zone
- Bottom layer of ocean water
- Completely dark
- Organisms need to be able to withstand enormous pressures and extreme cold of the ocean depths
Explain ocean ccurrents
- Major ocean currents move heat from the equator to cooler parts of the biosphere
- Currents move in a circular path – clockwise in the
Northern hemisphere
and counterclockwise
in the Southern hemisphere
Explain hydrothermal vents briefly
- Vents support chemosynthetic bacteria which form the basis of unique ecosystems
Explain hydrothermal vents fully
- Abyssal plain interrupted by oceanic ridges – enormous underwater mountain chains
- Ocean crust splits apart along these ridges to form hydrothermal vents
- Seawater heats up to 350°C due to volcanic reactions
