FUNCTIONS OF THE MARINE ECOSYSTEM

• The fitting together and interaction between all the parts –living and non-living– Movement of materials or biogeochemical cycles– Movement of energy or food web

• Responding to changes both natural and man made

MOVEMENT OF MATERIALS

• Cycles- One way abiotic and biotic factors interact– Occur due to biological and chemical reactions– Recycle materials needed by living things to build

DNA , proteins, lipids etc..

Hydrologic Cycle

• Movement of water from the ground to the atmosphere and back again

http://www.srh.noaa.gov/jetstream/atmos/hydro.htm

•evaporation•transpiration•condensation•precipitation•runoff

N, P, Fe and C

Nitrogen Cycle

• Most biologically limiting • N2 must be “fixed” before it is biologically

available• When too much N is available (fertilizer or

sewage carried via land runoff) there is often a negative effect called eutrophication

bloom of aquatic algae…algae use up N and die…decomposition consumes all the dissolved oxygen in all or part of the water column and leads to an animal die-off..

MOVEMENT OF ENERGY

• Trophic level… position or feeding level• Producers…base of the food web and create

sugars from sun’s energy or chemical energy• Consumers…eat other living things• Food webs are the connection between many

food chains in an ecosystem

OTHER FOOD ROLES

• Decomposers… break down food and nutrients left over from predation or in dead orgs or waste– Microbial loop…bacteria consmueeven smaller

nutrients called DOM (dissolved organic matter) that would otherwise be lost

• Omnivores…feed on consumers and producers

Marine Food Chain

Phytoplankton…single celled plant like orgs (diatoms)

Zooplankton…tiny animal life that drift thru the water and graze on plankton (copepod)

Secondary consumers…filter feed out zoo and phytoplankton (silverside or clam)

Tertiary consumers…predators that feed on smaller fish in level below (bluefish)

Apex predators…efficient hunters, opportunistic feeding habits (eat what is available) (tuna, sharks, billfish)

Higher level consumers…predators that feed on smaller fish in level below (bluefish or flounder)

10% Rule

• Higher trophic level orgs…larger in size and fewer in number than those at lower levels.

• each trophic level transfers 10% of its energy• each level supports a smaller total biomass to

compensate loss of food value. • 90% loss is used for heat, growth, reproduction,

repair etc…

What Does 10% Rule Mean?

• 100,000 lbs of phytoplankton feed 10,000 lbs of copepods,

• 10,000 lbs copepods feed 1,000 lbs of silversides• 1,000 lbs silversides feed 100 lbs of mackerel• 100 lbs of mackerel feed 10 lbs of bluefin tuna• tuna nourishes only one pound of apex predator