PLS 147 Lecture Notes - Lecture 5: Space Marine, Viscosity, Dune
Connor Dibble
2003 Wickson
Lab TA
Marine Plant Communities of California
The Aqueous Medium
●Properties of Seawater
○density 840x greater than air
■structural support
○heat capacity 4x greater than air (absorbs more energy to change same degree
temp)
■relatively stable temperatures
○viscosity
■(stickiness of a fluid)
■60x greater than air
■a lot of drag on marine plants
●growing too much surface area, can lose parts
■friction due to drag leads to boundary layer conditions
●like on land, dune plants
●plants are lower experience less wind/drag
■at some point, velocity is zero
○diffusivity 10000x less than air
■(movement of particle through a fluid)
■boundary layers are an issue because plants can't rely on diffusion to
exchange gases and nutrients
●trade off: between surface area for photosynthesis and increased drag
○drag increases turbulence, helps overcome boundary layer limits
○kelp polymorphism
■ripples on the fronds create turbulence for nutrient exchange
●Limiting Resources
○not water, roots not needed to absorb nutrients
○light and space
■marine plants live in an aqueous environment, but can't venture far from it
■light does not penetrate very far into the ocean
■eutrophic (high nutrient) vs oligotrophic (low)
●Life History
○sexual reproduction and dispersal is easier
■planktonic habitat (the dispersal highway) safer than many benthic habitats
(less predation)
Document Summary
Heat capacity 4x greater than air (cid:840)absorbs more energy to change same degree temp(cid:841) A lot of drag on marine plants. Growing too much surface area, can lose parts. Friction due to drag leads to boundary layer conditions. Boundary layers are an issue because plants can"t rely on diffusion to exchange gases and nutrients. Trade off: between surface area for photosynthesis and increased drag. Drag increases turbulence, helps overcome boundary layer limits. Ripples on the fronds create turbulence for nutrient exchange. Not water, roots not needed to absorb nutrients. Marine plants live in an aqueous environment, but can"t venture far from it. Light does not penetrate very far into the ocean. Planktonic habitat (cid:840)the dispersal highway(cid:841) safer than many benthic habitats (cid:840)less predation(cid:841) Don"t have to worry about drying out. Dispersal distances typically not far for attached plants Most of the ocean inhabitable for plants, risky to go far. Alternation of generations: distinct gametophyte and sporophyte phases are common.
