1. Aphotic Ecosystems
A World Without Light

5. Plate Tectonics

8. Convergence Continental Mountain Ranges

9. Subduction Zones: Trenches Volcanic Mountain Ranges or Island Arcs form on the continental plate
Seafloor is made of dense basalt which “dives” under lighter continental granite

10. Island Arcs - when ocean plate collides with ocean plate
Aleutian Islands
Island Arcs - when ocean plate collides with ocean plate

11. Location of Plates

12. Hot Spots
Hot spots remain stationary, but above them, the Earth's crustal plates move slowly.
Imagine moving a sheet of paper horizontally a few inches above a burning candle.
Similar to the candle's flame, a hot spot leaves a scorched trail of volcanic islands on its overlying plate.

13. Zones review What are the open ocean zones? Which are photic?
Epipelagic
Mesopelagic
Bathypelagic
Abyssoplegic
Hadalpelagic
Every Mother Buys A Handbag
Which are photic?
Only the epipelagic (top 100m) lies in the photic zone
Photosynthesis
Which are aphotic?
All the rest
No photosynthesis

14. Oxygen in the Deep Sea Depend on the surface for Oxygen Oxygen Balance
Added
Mixing
Photosynthesis
Taken out
Respiration
Thermohaline Circulation
Ocean Conveyor Belt
Brings oxygen to deep sea
The map shows how oxygen is distributed in the global ocean. Regions of near-zero oxygen, are colored purple and are concentrated in the tropics.

15. Ocean Conveyor Belt provides Oxygen to the Deep Sea as Cold Dense Water Sinks

16. Epipelagic Photosynthesis Lots of oxygen & food Fish Fast swimming
Streamlined
Strong muscles
Countershading
Dark dorsal side
Light ventral side
Helps organisms hide

17. Mesopelagic Twilight Zone Some light but not enough for photosynthesis
200m-1000m
Main thermocline occurs here
Rapid temperature change
Density layer (invisible barrier)
Organisms that move through this layer must be adapted to deal with this temperature change

18. Zooplankton of the Mesopelagic: Midwater Organisms
Krill, shrimp & copepods
Ostracods
Carapace that makes them look like clams with legs
Usually 1/8 in long
Gigantocypris is ½ in
Amphipods
Arrow worms
Worm-like predators
Squid
Jellies & comb jellies
Photophores
Bioluminescent organs

19. Fish of the Mesopelagic: Midwater Organisms
Most fish are very small
Hatchetfish
Viperfish
Bristlemouths are most common
Cyclothone signata is the most abundant fish on earth
Photophores

20. Adaptations in Mesopelagic: Feeding
Lack of food
Small size (growing takes energy)
Live under productive oceans where there is more detritus
Large mouths to avoid gape limitation
Elastic stomach to eat organisms larger than themselves
Broad diets (eat anything they can find)
Some move to the surface at night to feed
Gulper Eel - Loosely hinged, huge mouth
Black swallower - elastic stomach

21. Adaptations in Mesopelagic: Vertical Migration
Migratory (up to feed at night & down to hide during day)
Layer of vertical migrators is called the Deep Scattering Layer
Tolerate wide range of temperatures as they cross the thermocline
Strong muscles & bones
Swim bladder (helps keep buoyancy when changing depth)
Can rapidly release gas
Many filled with fat instead

22. Adaptations in Mesopelagic: Vertical Migration
Non-migratory
Eat detritus-decaying organic matter from the epipelagic
Flabby muscles/weak bones makes them more buoyant
Don’t swim much so they aren’t very streamlined
No swim bladder (saves energy)
Eat the vertical migrating fish because they are more nutritious than non-migrators

23. Adaptations in Mesopelagic: Sense Organs
Large sensitive eyes
Some have tubular eyes
Like having 2 pairs of eyes
See well only in the direction they are aimed (usually upward)
Have a second retina to compensate & aid in lateral vision
Retinas are the light sensitive part of the eye located on the back
Second retina is on the side to aid seeing objects on the side

24. Adaptations in Mesopelagic: Coloration & Body Shape
Takes too much energy to swim fast or grow spines for predator avoidance
Camouflage is main source of protection
Transparency
More common in shallower mesopelagic
Silvery
Middle of mesopelagic
Red or Black
Deeper mesopelagic
Red light is the first light filtered out so red appears black in the depths
Black is a bit more visible because blue light is reflected
Countershading
Black back & silvery sides
Reduction of silhouette
long thin bodies that disappear from some angles

25. Adaptations of Mesoplegaic: Bioluminescence
Attract mates or Communication
Confuse Predators
Bioluminescent fluids
Squirt these fluids out to distract predators
Counterillumination (like countershading)
Photophores on the belly match blue-green sunlight above
Symbiotic bacteria or chemical in tissues
Can control intensity (brightness) of their photophores
Animals looking up at their prey can’t see the shadow that would be produced
Tests on bioluminescent shrimp show that this is controlled by eyesight
Shrimp with blinders produce no light
Eyes exposed to more light/ shrimps bodies produced brighter bioluminescence
Attract or see prey
Bioluminescent anglerfish lures
Or headlights used like flashlights (some are even red lights to see red fish)
Some predatory fish have special eyes that can tell the difference between photophores and the sun!

26. Adaptations of Mesopelagic: Oxygen Minimum Layer
500m Oxygen Minimum
Not in contact with atmosphere
Little or no photosynthesis
Lots of respiration
more detritus than deeper zones
Large gills
Inactive so they use less oxygen
Hemoglobin
Protein in blood
Transports oxygen to body tissues
Functions well in low oxygen environments

27. Deep Sea Pelagic Largest environment on earth 75% of the ocean
Area of the ocean that receives no light
No seafloor bottom
Relatively constant physical environment
Little change in temp (2C), light (none), salinity etc.
Includes:
Bathypelagic
Abyssopelagic
Hadopelagic (trenches)

28. Deep Sea Pelagic: Bioluminescence, camouflage & vision
Courtship, communication, attracting prey, confusing predators
Not for counter illumination
Less common than in mesopelagic
Most organisms are black or red
Small eyes or blindness

29. Deep Sea Pelagic: Lack of food
Only 5% of photic production makes it as detritus 20% in mesopelagic
Large mouths & stomachs
No vertical migration
Hardly move / wait for prey
Lure prey
Small, but larger than mesopelagic
Grow slowly but live longer than in mesopelagic
Reproduce later in life
Flabby muscles & weak bones
Poorly developed circulatory & nervous systems
No scales
No swim bladders
Can use energy that isn’t used in migration & reproduction

30. Deep Sea Pelagic: Reproduction
Mates are hide to find
Right species
Right gender
Low abundance
High diversity
Hermaphrodites
Can mate with anyone in the species
Both are fertilized
2 for the price of one
Attract mates
Pheromones-chemicals in the water
bioluminescence
Male parasitism
Males permanently attach to females

31. Deep Sea Pelagic: Extreme Pressure
Makes it hard to study the deep
Pressure resistant enzymes
Lack swim bladders
Too much energy to fill in the deep
Deepest fish
8,370 m
Invertebrates
Found in Mariana Trench
11,022m

32. Deep Sea Pelagic Fish Small, but larger than mesopelagic
No streamlining
Weak flabby muscles
Small eyes / no eyes
Black, red, or no color
Bioluminescence
Attract mates & prey

33. Benthic Deep Sea: Food Deep seafloor & detritus
Detritus from above sinks to the bottom
Marine snow
Most is eaten before it reaches the bottom
Food that is missed doesn't keep sinking
Food particles accumulate on benthos
Bacteria
Decompose detritus
Bacteria are eaten
Deposit feeders
Eat food that has settled on the bottom
Infauna-live in sediment
Epifauna-live on sediment
(all pictured)

34. Benthic Deep Sea Fish Large Elongated bodies Strong muscles Small eyes
Dark brown, white or black
Only some bioluminescense

35. Location of Seeps & Vents

36. Bacteria & Bologna Alvin sank with lunches on board
sub was recovered after ten months on the bottom
the seawater soaked lunches were in a remarkable state of preservation.
Bologna sandwiches were not spoiled and the meat was still pink.
The apples tasted salty, but were still quite fresh.
The lunches had just been sitting in an open leather satchel inside the sub, protected from all the little scavenging animals, but free for microbes to act.
Decomposition is slow & so is metabolism

37. Oasis: Cold Seeps Discovered 1984 in Gulf of Mexico
Methane & sulfur seep out of the ground
Methane hydrate is frozen, but not cold to the touch and will light on fire if you put a match to it “fire ice”
Slow & steady emisson
Chemosynthesizing bacteria
Slow growth rates
World oldest invertebrate
Lamellibrachia luymesi
Live 250 years

38. Oasis: Brine Pool extreme concentration of salinity
5x the salinity of the ocean
Kills organisms accidentally swimming into them
So salty that the submersibles (like Alvin) can hardly penetrate into them
just sit there, on top of the salt-"inversion" boundary.
rich sources of methane
Chemosynthesis
dense colonies of mussels form on the halocline
symbiotic relationship with methanogenic (methane-metabolizing) bacteria
Bacteria live in the gills

39. Oasis: Whale falls Discovered in 1987
Whale or other animal carcass that has fallen to the seafloor
Feeds scavengers for decades

40. Oasis: Hydrothermal Vents
Water seeps into seafloor fissures
heats up, reemerges loaded with minerals
Water jets out of vents in the seafloor
hits cold water,
minerals precipitate out &
leave mineral deposits that build up into chimneys or smokers (white or black)
H2S (hydrogen sulfide) is also released,
used by chemosynthetic bacteria
Biology:
High abundance
Low diversity
Tubeworms
Riftia feet long, Alvinella, Tevnia, Pompeii worm

41. Discovery of Vents Found in 1977 in the Galapagos Rift valley
Marine Geologists
Scientists thought that there was no life in the depths (no life without light)
Alvin submersible

42.                                                                                                                          
                                                                                              
                           
Location of vents
Vents are found on Ridges

43. Phylum: Annelida