The Deep Ocean The deep oceans are divided into various regions based on light, plankton, and oxygen availability… each of these regions supports specific (and very different) types of organisms… Epipelagic Mesopelagic Bathypelagic Abyssopelagic Hadopelagic

The Deep Ocean Many of the characteristics of deep ocean waters are a function of distance from surface; however, remember that polar regions are a major source for these waters too…

The Deep Ocean The movement of the colder polar waters to great depths is a part of a global pattern of circulation known as the great ocean conveyor. This circulation plays a central role in regulating the earth’s climate, and it replenishes the deep seas with oxygen…

Organisms of the Deep Ocean The Mesopelagic The mesopelagic contains large numbers of zooplankton (primarily krill, copepods, and ostracods). There are also a number of deep water worms, squids, and of course, fishes. A major characteristic associated with many of these organisms is bioluminescence. Most squids in these areas have photophores that contain bioluminescent symbiotic bacteria and can help the animals give off light…

Organisms of the Deep Ocean The Mesopelagic This bioluminescence allows for counter-illumination which helps with predator (or prey) avoidance.

Organisms of the Deep Ocean The Mesopelagic Furthermore, many of the fish, squid, and arthropods have the ability to regulate the amount of light given off by their photophores…

Organisms of the Deep Ocean The Mesopelagic Combination of life under very low light levels, as well as conditions where bioluminescence is a major player, has evolutionarily selected for tubular eyes with large retinal regions for many of the deep ocean organisms…

Organisms of the Deep Ocean The Mesopelagic In addition to photophores, the different mesopelagic organisms will have varying adaptations based on their ecology and “lifestyle”… Consider mesopelagic fishes that may or may display daily vertical migration… What would be possible advantages and disadvantages of each of these lifestyles?

Organisms of the Deep Ocean The Mesopelagic Remember that the mesoplelagic is also the zone of the oxygen minimum layer. The effect of this change in the oxygen level is evident in the morphology of the different fishes…

Organisms of the Deep Ocean The Bathypelagic The fishes of the bathypelagic look somewhat different…

Organisms of the Deep Ocean The Bathypelagic Most deep ocean fishes will have large mouths… why do you think this is?

Organisms of the Deep Ocean The Bathypelagic

Organisms of the Deep Ocean The deep sea bottom fishes In addition to being elongated, deep-sea bottom fish tend to be larger… this is part of a general pattern referred to as deep-sea gigantism.

Organisms of the Deep Ocean Review of the Fishes

Organisms of the Deep Ocean sex in the deep? Many deep ocean organisms are hermaphroditic… Others have separate sexes, but will use pheromones to attract mates… Yet others will use patterns of bioluminescence for attraction of mates… But stranger techniques do exist… consider the angler fish:

Organisms of the Deep Ocean Sources of food?… the surface?

Organisms of the Deep Ocean Sources of food?… hydrothermal vents? Many hydrothermal vents in the deep ocean give off hydrogen sulfide. Certain bacteria can use this chemical as a source of energy instead of the sun… Entire communities are established based on direct or indirect feeding on the products made by the chemoautotrophic bacteria…

Organisms of the Deep Ocean Sources of food?… hydrothermal vents? The tube worm Riftia has symbiotic bacteria that allow it to survive near hydorthermal vents in the deep ocean…