Identify the limiting factors that play important roles for various communities
ID: 289894 • Letter: I
Question
Identify the limiting factors that play important roles for various communities of marine organisms (deep sea to intertidal zone and from the tropics to the polar regions) and for various communities of nonmarine organisms (from lowland equatorial regions to mountains to polar regions). How do the compositions of various communities reflect the presence of the limiting factors? Identify the limiting factors that play important roles for various communities of marine organisms (deep sea to intertidal zone and from the tropics to the polar regions) and for various communities of nonmarine organisms (from lowland equatorial regions to mountains to polar regions). How do the compositions of various communities reflect the presence of the limiting factors?Explanation / Answer
Limiting factors are defined by those resources which, if disturbed from their normal quantities, can restrict the growth of life in an ecosystem.
Nutrients such as nitrogen, phosphorus, and silicon are the main limiting factors in a shallow marine ecosystem. The scarcity of such elements can limit the growth of organisms in shallow waters as the microscopic plants, viz. phytoplankton form the base of the food chain. Polar regions, however, receive insufficient sunlight, so light also becomes a factor in shallow, cold ecosystems.
In deeper levels of oceans, where the intensity of sunlight, temperature and salinity change with depth, the nutrients also increase due to the sinking of dead organisms from shallow waters. So the temperature, salinity, nutrients in intermediate waters limit the growth of organisms such as corals and fishes. Deep-sea organisms thrive in high pressure, cold conditions and depend on dissolved oxygen and nutrients, so the factors that limit their distribution underwater are pressure, temperature, oxygen, and nutrients.
The lowland equatorial regions or savannahs are limited by various density-dependent factors such as predators and parasitic infestations. In addition, density-independent factors such as droughts, wildfires, and heat waves can also limit life in such ecosystems.
The deserts are characterized by abundant sunlight and nutrients but the scarcity of water limits the growth of vegetation in such regions. So, rainfall is a limiting factor in deserts. In mid-latitude and polar regions, however, sunlight is less, so it becomes a limiting factor in those latitudes.
Tropical rainforests receive plenty of rainfall, but the amount of sunlight and nutrients in soil tend to restrict their growth. Temperate and tundra ecosystems, in general, receive less sunlight, so it becomes a major limiting factor there as well.
Mountainous fauna heavily depends on food (plants, animals) and water, so any shift in such parameters is considered a limiting factor. Mammals and amphibians in temperate and polar regions thrive in cold climates but depend on other animals for food, so the fishes and other marine creatures become a limiting factor in high latitude ecosystems.
The composition of a community is an indication of the level of tolerance or the extent up to which it can survive within the safe boundaries of limiting factors. Any deviation from the normal limits can change the characteristic composition of a community. Thus, each community exists safely due to an optimum presence of limiting factors, but the endangered nature or non-existence of a community means that such factors are not present in their safe, operating space.