Biol. 317 - Lecture Notes - Ch. 4

Sunlight
* blue light penetrates further
* red is absorbed
* light scattering - blue oceans
* euphotic zone < 50 m
* decreased by low angle of sun, clouds, chop, silt, plankton
* animals can see in dysphotic zone (< 1000 m)
* "photosynthesizers" capture red/blue light: chlorophyll
* red and brown algae use accessory pigments
* reds capture yellow/green
* browns capture blue/green
* reds usually the deepest

Animals use light
* small eyes - light detectors
* large eyes - vision
* chromatophores (fish, squids) affect appearance
* pigmentory colors ("chromes")
examples: carotenoids, quinones, indoles, indigoids, melanins, ommochromes, porphyrins, bilins, flavins, purines, pterins
* rare structural colors (pearls)
whites, blue-scattering, interference
* combination colors
* countershading important

Bioluminescence
* adaptive value sometimes obscure
* luciferase/luciferin + oxygen + salt = light
* energy/oxygen required
* some animals use bacteria
(sepiolid squids/fish)
* countershading vs. spotlights

Diurnal and seasonal light use
* diurnal migrations common
* Photoperiodism in a marine organism only recently first demonstrated (Pearse & Eernisse) but is likely widespread
Reading:
How do animals detect and use underwater sound?
How do animals control buoyancy?
What animals live in a world controlled by turbulence?
What is streamlining?
How does S/V ratio affect animals?
What animals live in a world controlled by viscosity?
How does pressure affect marine animals?