John Dower Lecture Flashcards
3 Types of Distributions
Uniform
Random
Patchy
What causes patchiness
Physical and biological processes
What drives phytoplankton patchniess
Driven by physical traits, water movement, nutreints etc
What drives zooplankton patchiness
Driven by biological processes
Mainly behaviour of zooplankton
What is the importance of selective transport
This is the movement of water in specific directions at different depths and areas
This can affect how zooplankton get moved based on where they are in the water collumn
What is windrow, and its importance?
Counter-rotating eddies caused by wind
If the eddies are converging they will concentrate plankton
If the eddies are diverging they will make plankton more disperese
Frontal zones and their importance
Abrupt boundary between water masses
Phytoplankton get concentrated here
This causes zooplankton and fish to aggregate here
Problems with zooplankton nets
Don’t catch everything
Large zooplankton tend to avoid it
Patchy areas that you may tow it through
Clogging
Copepod food chain importance?
Copepods are highly abundant (~80%)
Most major fish species, have their juvenile forms feeding on copepods
Copepod species diversity
~13 000 species
Relatively few species compared to insects.
Due to lack of niche differentiation in open ocean and connectivity between habitats
Propulsion at low Re
Producing a reciprocal swimming motion at low Re will result in net zero movement
Need to use non-reciprocal movements
How to copepods catch prey at low Re
Need to use complicated movements of appendages, that are out of sync and have non-reciprocal movements
Copepod escape response
Can jump 400-500 mm s-1 in a few milliseconds
The stimulus must be a few body lengths away
Uses a second set of appendages exclusively for escape, like having a two-gear engine
The force output is the highest of any animal
