Ecosystem Organization

Marine environment is divided by distance from land, depth and the type of organisms living there.

Food chains, the linkagebetween food webs, arefairly easy to determinewhen animals are specialists.

In this three step chain, whales arethe top predator existing ultimatelyon krill (which exist on phytoplankton).

Each step in the chain is known as a trophic level.

How many trophic levels are presenthere?

Multiple food chainsat multiple trophic levelsresult in a food web.

As you can observe, manyinteractions are possible.

Energy can be transferredfrom one level to the otherin amazing ways.

•Here is anotherway of looking at it.

•Killer whalesare the top predators.

•Each part of the trophiclevel could be viewed as a “factory” for convertingone thing to another!

•How many “factories”does it take to convertdiatoms intokiller whale??

Trophic Pyramids: Heat conversion

In a trophic pyramid plants and animals all are assigned a caloric value. As we travel “up” the trophic pyramid, heat is lost. By the time we reach the uppermost level many calories have been used, and much heat produced to make a pound of blue or right whale.

How much is being produced?

By measuring the ratesof p-synth. Ecologistsare often able to determine how much carbon is fixed by plants(gross primary productivity)

This is yet another methodto measure system productivity and its efficiency.

Units: gC/m2/day

Earth’s Primary Production

Ocean Production: Red = high, blue = lowLand Production: Green = high, yellow = low

Carbon Cycle

Nitrogen Cycle

Phosphorus Cycle