Fluid Environment Flashcards
pelagic
open water
benthic
on the bottom
neritic
near to shore
oceanic
out in the open water
photic
where light reaches
aphotic
dark
how are regions classified?
by physical parameters
- light
- oxygen
- temp
eurythermal
wide temp tolerances
- some plankton and mammals
stenothermal
narrow temp tolerances
- benthic animals like corals, sponges and clams
homeotherm
regulates body temp
- mammals
poikilotherm
conforms to temp
- all marine invertebrates
- most fishes
what is an example of a homeotherm?
sea otter
what is an example of a poikilotherm
feather duster worm
how does oxygen vary with depth?
- on the surface there is high O2
- low in mesopelagic
- high O2 in deep ocean
why does deep ocean have high oxygen levels?
decomposition of dead phyotplankton and marine snow
why does the surface water have high oxygen?
mixing
which ocean has minimum oxygen?
pacific
why does the Atlantic Ocean not have minimal oxygen?
the global conveyor belt causes the warm water to move toward the Artic and oxygen is brought down when cooled through Atlantic
how much light penetrates in coastal waters?
10s of a m
- more life and more turbidity
how much light penetrates in open ocean waters or tropics?
100m+ as there is less chaos
is seawater viscous?
yes
what do viscous fluids resist change in?
shape
what is viscosity dependent on?
organisms size and how fast it moves
what is Re?
relative importance of inertial and viscous forces
- dimensionless
- velocity and size determine Re
small and slow = ?
low Re
large and fast = ?
high Re
high Re = ?
turbulent
low Re = ?
laminar
what does viscosity lead to?
streamlines
laminar flow
streamlines are all parallel and flow is regular
turbulent flow
streamlines irregular to chaotic
when happens to laminar flow when Re increase?
changes to turbulent flow
what is the force exerted on an object by the liquid moving over it?
drag
what is a way to reduce drag?
shark skin is adapted to reduce drag by shape and type of scales
- dermal teeth (placoids) and placoid scales - reduce drag - break viscosity - by making turbulence
how do ships reduce drag?
use riblets to reduce on their hulls
- hydrophobic surfaces
how do whales reduce drag?
whales’ tropical migrations may be to shed their skin
- shed algal growth on skin removes draf
how is viscosity useful?
finding prey and avoiding predatorys
how to copepods hide or reveal themselves?
shape their fluid motion
- 1st antennae: flick for rapid escape
- 2nd antennae: thoracic limbs create gliding and feeding current
how do copepods organize fluid medium?
- copepod moves through water it creates fluid disturbance
- when it hovers it creates a laminar feeding current using fine setae on second antennae -> disturbance appears as lines of equal speed of fluid (isotachs)
- sensors on antennae detect changes in speed of isotachs in three directions -> detect water-borne signals in 3 dimensions (x,y,z and time)
how does viscosity change with temperature?
low temp = viscosity dominates
high temp = inertia dominates
what is more developed in tropical copepods?
mechanisms that stop sinking
what is more dense than water?
tissues
how do planktonic plants and animals keep afloat?
shape-> broad shape prevents skinking
projections -> long spines prevent sinking
composition of tissues -> less dense tissues prevent sinking
how to siphonophore float?
oil droplets
have a bell with float
- diatoms use same method
who uses gas chambers to float?
- physalia
- vellela vellela
- janthina
describe janthina
> raft of bubbles with mucus
-> floats on ocean whole life
-> eats physalia and ellela vellela
what is another method used to float?
mesoglea jelly -ECM
- made of hydrated collagen-like fibers
- neutrally buoyant due to density
- compressible and elastic for recoil when swimming
what is transparency?
- provides camo
- involves whole organism
- evolved multiple times
- in ocean, transparent tissues make animal invisible
- animals are in an arms race to find prey and avoid predators
sighting distance
max distance which prey animal is detected by an animal relying on visual cues
transparency
- allows prey with short sighting distance to not be seen by visually orienting predators
- ambush predators with short sighting distance to increase chances of entangling prey before being detected and avoided
- raptors to get within striking distance before being detected
what is polarization vision?
- light is polarized when entering water
- birefringent tissues seen in polarized light
what is an example of birefrigent tissues?
copepods muscle
describe the squid hatchlings use polarized vision
regular plastic beads and polarization active PA beads
-> hatchlings caught more beads that were PA than plain
uv vision
- animals can see in uv light
-> mantis shrimp: 12 colors, polarized light, uv light , 16 color receptors
