Plankton & Re Flashcards
What is plankton?
Small organisms that live suspended in the water column, neither attached to the bottom (benthos) not able to effectively swim against the currents (nekton)
Why is plankton important?
Food source Produce oxygen Cause toxic blooms Dispersal of organisms Global carbon cycle
What is a holoplankton?
Plankton for their whole life
Live in water column
What is a meroplankton?
Only plankton for a part of their lives
Usually larval forms of benthic and nektonic adults
More abundant in coastal areas
High Re
Inertia dominates
Turbulent flow
Large, fast organisms
Low Re
Viscous dominates
Laminar flow
Small, slow organisms
What is Re
Reletionship between inertia and viscosity
Wake left behind from organism
What does Re predict
- Types of drag effects that are most influential
2. What happens to water or air as an animal is moving
Copepods
Holoplankton
Small crustaceans
Larval stages of copepods
1st larval stage = nauplius
2nd larval stage = copepodites
5-6 stages before adult
Copepods in FW
cladocerans (water fleas)
Jellyfish
holoplankton
but some are meroplankton - pelagic life stage + benthic as polyps (sea anemones)
Meroplankton reproduction
70% release eggs into the water - then hatch into planktonic larvae
Plankton challenges - locomotion
cillia
jointed appendages
whole-body contractions
Plankton challenges - defense
transparent spines detection of pressure waves toxicity swimming bioluminescence
