Mesopelagic Zone

200-1000 meters

depth of mesopelagic zone

halocline and thermocline

what two -clines are found in the mesopelagic zone

increase

does salinity increase or decrease through the mesopelagic zone?

decrease

does temperature increase or decrease through the mesopelagic zone?

pycnocline

what is also found in the mesopelagic due to the thermo and halocline (hint: density)

highly variable environment

results from changing temps/salinity/density in the mesopelagic zone (not stable)

lower biodiversity

what is a result of the mesopelagic zone being highly variable and requiring adaptations

bioluminescence

blue/green light given off by organism in defense or attratction

photophores/luminescent fluids/symbiotic bacteria

what 3 things can cause bioluminescence

acute vision/polarized lenses/yellow and green filter

three ways predators have adapted to their pray using bioluminesence

counterillumination

blends in with a darker background but turns on ventral biolum. in lighter places/around other of same species

cephalopods

squid/octopus that have a plankton stage as larvae and nekton stage as adult

webbing

adaptation cephalopods have that increases buoyancy/swimming force/stability (on tentacles)

Midwater

fish that stay in mesopelagic and don’t travel up much

larger eyes and mouths

two characteristics of midwater fish

cock-eyed squid

has a small right eye for biolum, and a large left eye for light detection

tubular eyes

eyes that have an extended retina that increases field of vision upward