4 biotic and 4 abiotic factors?

Question

What are 4 biotic and 4 abiotic factors in

a)freshwater ecosystem(lake)

b)terrestrial ecosystem(forest)

Answer 1

Ambient temperature, days of cloud cover versus days of sun for amount of sunlight and its influence that create patterns of rainfall when combined with geography factors of altitude & latitude plus landforms influence water qualities. Typical wind speed  and direction effects how soil erodes and is deposited as silt in the lake as well as rainfall. Winds cause waves that in turn mixes the water. Dissolved oxygen varies seasonally if the lake is deep enough to have a thermal gradient in hot weather so oxygen is depleted in denser stratified water. Middle depths with cooler, denser water can become anoxic (lacking O2) during the summer in a mesotrophic or eutrophic lake. While the dissolved oxygen is equal at all depths in cooler months.

http://www.rmbel.info/Reports/Static/Str...

http://aquanic.org/publicat/state/il-in/...

Forests are obviously equally effected by geography and weather but fire become a major factor. Soil qualities are very dependent of bedrock type eroding to produce its mineral composition.

Biotic factors are the living components that affect an organism. What it eats, what eats it. Activities like how it reproduces: things like gestation time and parental care are biotic factors. How the community members interact: social, herd forming, pair bonding, or primarily solitary. What diseases is it subject to and parasites. How mobile is it, what territory is able to cover. In a forest the type and density of trees impacts the size of animal and how freely it can move, find shelter and forage.

Biotic factors in a lake include algae species for oxygenation and the algal feeders to check its growth whether zooplankton or fish. Migrational visitors and year round species of aquatic birds. Some fish may leave to reproduce in running water while others remain in the lake. Shallow shores may support plentiful aquatic plants like reeds.