Question

In aquatic systems, which abiotic and biotic characteristics are most directly affected by depth? Which are the least affected?

This is for an ecology class. Please elaborate. Thanks!

Answer 1

Abiotic characters -

1) light - only blue light is able to penetrate to 500 m and little more after that in benthic zone no light is able to penetrate. Thus , light penetration changes with depth.

2) pressure- as the depth increase, pressure due to water and the atmosphere above it increases several times that of surface.

3) temperature- it decreases with increase in depth.

4) dissolved O2 - decreaes with increased depth.

Biotic factors-

1) algae- only red algae are present at depths , in middle portion the brown algae and green mostly on surface.

2) fishes- the fishes are highly adapted to high pressure gradient , due to physiological changes, like change in plasma membrane fluidity. Fishes with antifreeze proteins.

3) presence of benthons that is decomposers at depths.

4) presence of archae bacteria at high depths in high pressures.