Basics of Marine Biology

Is much of the ocean chronically nutrient limited? If yes, why?

Yes as there aren’t enough nutrients to supply the primary producers

What does primary production convert?

It converts inorganic nutrients into organic matter in the surface ocean

What removes nutrients?

Death and sinking

Describe what happens to phytoplankton (a primary producer)

It sits at the surface and is happy because it has nitrogen and phosphorous. Eventually N and P go so phytoplankton start feeling sick and will sink

What happens as organic matter sinks into the deep ocean?

It starts getting attacked by bacteria and decomposers so nitrogen and phosphorous will go back from organic form into inorganic form in the deep ocean (sinking organic matter decays in deep water)

What is there an exponential decrease in?

The amount of light in the ocean as you go deeper and deeper (Beers law)

Is there a pycnocline in the ocean? What is it?

Yes there is and this is a rapid change in density. There is low density water at the top because it is warmer and less salty and then high density at the bottom because it is colder and more salty.

Describe features of the surface water and deep water. What is required based on this?

Surface: lots of light but low nutrients

Deep: low light but lots of nutrients

Energy is required to mix dense water upward to supply more nutrients

What does stratification sequester?

Nutrients

What does particle sinking remove?

Nutrients from surface waters

What does stratification limit?

Upward mixing of nutrients back to surface ocean to supply another round of primary production

Compare marine and terrestrial realms in terms of primary production

Marine cover three times the area of terrestrial but average primary productivity is less than one third. However, marine and terrestrial total annual production of carbon is about equal.