These are thick orange microbial mats ( thick ) with patches of yellow biofilms extending from the aphotic deep cave orifice.
12.
The deep sea starts at the aphotic zone, the point where sunlight loses most of its energy in the water.
13.
The aphotic zone is further divided into additional zones : the bathyal zone, the abyssal zone, and the hadal zone.
14.
Extending from the bottom of the photic zone down to the seabed is the aphotic zone, a region of perpetual darkness.
15.
Changes in primary production in the photic zone are expected to alter the standing stocks in the food-limited aphotic zone.
16.
At equilibrium, the export flux of organic material sinking into the aphotic zone is balanced by the upward flux of nitrate.
17.
Hydrothermal vents are the primary source of energy in what is known as the aphotic zone ( depths exceeding 200 m ).
18.
In the ocean, this leads to a vertical separation of nitrification from primary production, and confines it to the aphotic zone.
19.
In general, the deep sea is considered to start at the aphotic zone, the point where sunlight loses its power of transference through the water.
20.
This leads to the situation whereby any nitrate in the water column must be from the aphotic zone, and must have originated from organic material transported there by sinking.
