Life in the deep ocean is sparse due to lack of sunlight and nutrients. Organisms have adapted specialized features to survive in these conditions such as bioluminescence, transparent bodies, and downward-facing eyes. Nutrients cycle through the water column as plankton and organic matter sink from the surface. Some fish migrate vertically to feed in nutrient-rich surface waters at night, while non-migrators survive on the metabolisms and protein of migrators. Extreme pressures and darkness present challenges for reproduction which organisms overcome through bioluminescent signals, chemical cues, and hermaphroditism.

1. Chapter 16 The Ocean Depths Click here for introduction video!!

2. Life in the mesopelagic and deep sea is linked to plankton and light intensity in the water.

3. Amount of nutrients at different depths is controlled by photosynthesis, respiration, and the sinking of organic particles. Nutrients are recycled but sink!

4. Oxygen Minimum Layer

5. Deep water originates at the cold surface at the poles. Cold water sinks and spreads out along the bottom.

6. The deep currents are part of the great ocean conveyor. Small variations in the conveyor produce big changes in weather patterns around the world (El Nino). Large changes create ice ages.

7. Mesopelagic Crustaceans

8. Photophores Specialized light structures that make “living light” or bioluminescence.

9. Vampire Squid click here for video

10. Typical Mesopelagic Fish

11. Rectangular midwater trawls used to collect mesopelagic organisms. Net has remote control to open only at certain depths.

12. As more shallow fish are over fished other deeper fish like this black scabbord fish are being caught.

13. Adaptations of Vertical migrators like the Lanternfish on left and non-migrators like dragonfish on right. Well developed muscles and bones Swim bladder of air or fat Withstand extreme temperature changes

14. Viperfish Large hinged jaw that can accommodate large prey

15. Many non-migrators like this Rattrap Fish eat the more muscular migrators because they have more protein!

16. Special Eyes Tubular eyes like this midwater bristlemouth fish, with acute (great) upward vision.

18. Check out this video of a weird fish with tubular eyes

22. Coloration and Body Shape Midwater predators rely on sight. Midwater prey cannot afford energy for swimming fast, spines, or scales so they are… Camouflaged with countershading (dark on top, light bottom or sides) Transparent or see through Silhouetted (bioluminescence on bottom) With blue-green light they control! Cool!

23. Value of Photophores Photophores on lower or ventral surface makes the silhouettes hard to see when they are viewed through water.

24. Midwater shrimp experiment

26. Bioluminescence Living light is used for… Counterillumination to mask silhouette Escape from Predators with confusing light Attract or see prey Communication and Courtship

27. Typical Characteristics of deep-sea pelagic fish

28. Compare mid-water and deep-water fish - Which has the smaller muscles, fewer light organs, smaller brain and respiratory system and why?

29. Living under pressure Tremendous pressure of 1,000 atmospheres or 14,700 psi Tough to visit and bring fish back alive Metabolism affected by pressure Molecules are adapted to allow enzymes to work under extreme pressures.

31. Sex in the Deep Sea Finding mates is a problem in the dark So they use… Bioluminescence Chemical signals Hermaphroditism Male Parasitism

32. Benthic Fish

34. Reduced eyes or are completely blind (Live in complete darkness) Huge mouths to eat prey larger than themselves (Scarce food -less than 5% from higher waters) No vertical migrations to richer surface waters (Flabby muscles, weak skeletons, no scales, and poorly developed respiratory, circulatory, and nervous systems) Nature of Life in Deep-Sea Benthos

35. Nature of Life in Deep-Sea Benthos Slow Pace (Save Energy) Low Temp and High Pressure (slow pace) Live Long and Large (up to 100 years) Produce fewer larger eggs (a lot of food for larva) Dominated by Deposit Feeders (eat biological snow)

36. Hydrothermal Vent Tube Worms

37. Deep-sea Hydrothermal vents harbor rich communities. The primary production that supports these communities comes from microbial chemosynthesis, not photosynthesis. Tubeworms have symbiotic bacteria in them that take the hydrogen sulfide or methane from vents, or dead bodies and make energy rich molecules to feed the worms!

38. Summary

39. Inquiring minds want to know … . How Do Light Sticks Work? What is Bioluminescence? How does Bioluminescence work?

40. A light stick consists of a glass vial, containing one chemical solution, housed inside a larger plastic vial, containing another solution. When you bend the plastic vial, the glass vial breaks, the two solutions flow together, and the resulting chemical reaction causes a fluorescent dye to emit light.

41. Bioluminescence Lab Glowing Fishing Lures How Living Light Works Strike Bright Fishing Lures Video Strike Bright Lure Commercial