Abiotic Components of the Marine Ecosystem

Question 1

List some examples of how marine ecosystems are influenced or limited by abiotic factors

Answer 1

• Light availability- The deeper the water depth, the less light availability
• Depth and density- fish tend to stay at depths where the density is equal to theirs
• Water viscosity- The structure of marine organisms are different to those of terrestrial, for example while land animals have hollow bones to reduce weight, marine animals have solid bones as the water has an upthrust which counteracts their weight.
• Stratification- Due to factors such as salinity, temperature, light and dissolved oxygen the marine environment is separated into groups
• temperature- Depth and temperature go hand in hand
• Waves and wind- creates areas of high and low energy
• Currents- carry reproductive material, bring nutrients, carry freshwater
• Tides- expose organisms to predators, habitats to sun and increased temperatures, flood habitats with sea water
• Sediment type- Turbidity and covering of sea floor organisms
• Nutrient availability

Question 2

Why are limiting factors important in population distribution?

Answer 2

Limiting factors determine the number of species that can survive in a certain area. For example, limits such as space and food availability determine how much of a species can survive in an area.

Question 3

Why are tolerance limits important in population distributions?

Answer 3

Tolerance limits determine the areas in which species can live. For example, there are the lower littoral, littoral and upper littoral zones. Depending on a species tolerance to abiotic factors such as salinity, temperature, need for water etc, it determines where they can survive best at and so where they are most concentrated in population.

Question 4

What is the zonation of the ocean?

Answer 4

Intertidal, pelagic, benthic and abyss.