The euphotic depth is the depth at which light intensity falls to 1 % of the value at the surface.
12.
Maximum numbers of bacteria generally occur at the pycnocline, where phytodetritus accumulates by sinking from the overlying euphotic zone.
13.
The supply of nutrients, primarily nitrates, to the euphotic zone is thought to impact levels of dissolved oxygen.
14.
The biological pump is the conversion of particulate organic matter in the euphotic zone and transference to the deeper ocean.
15.
This restricts the symbiotic organism to euphotic habitats and requires consistent exposure to high levels of ultraviolet radiation ( UVR ).
16.
At the euphotic depth, plants ( such as phytoplankton ) have no net energy gain from photosynthesis and thus cannot grow.
17.
Yet during winter convective mixing, nutrients penetrate the euphotic zone, causing a short-lived phytoplankton bloom in the spring.
18.
Typical euphotic depths vary from only a few centimetres in highly turbid eutrophic lakes, to around 200 meters in the open ocean.
19.
Positive values indicate regions where oxygen has been consumed to concentrations below its euphotic waters by primary production and the resulting oxygen evolution.
20.
Ammonium and nitrite show a maximum concentration at 50 80 m ( lower end of the euphotic zone ) with decreasing concentration below that depth.
