“ECOSPHERE” (Biosphere)

 

*Interacts with atmosphere, hydrosphere & lithosphere at or near Earth’s surface.

*Key component of biogeochemical cycles of carbon, oxygen, nitrogen, sulfur, etc.

*Energy and mass flow.

 

        Biotic Components

                Prokaryotes, eukaryotes         

                Trophic Levels

                        (trophe=nourishment)      

                        ØProducers (autotrophs)

Organic matter produced from inorganic matter (energy from light)

                ØPrimary Consumers (heterotrophs)

                        Consume O.M. of autotrophs

                        Herbivores

                ØSecondary consumers (heterotrophs)

                        Consume O.M. of other heterotrophs

                        Carnivores

                ØDecomposers

                        Consume O.M. of dead plants & animals

       

        Food “chains” & food “webs”

       

        Biomassºliving mass of plants and animals at any or all trophic levels

~90% loss of energy from one trophic level to the next

        (µ biomass of level)

 

        Biotic Components

                Energy (sunlight); water; climate; nutrients

 

Biotic components + Abiotic components= biosystems (ecosystems)

Regional climates interact with regional biota to produce large, easily recognizable community units known as Biomes. The life form is uniform in a biome (eg, grass in the “grasslands” biome), but the actual species may vary from one part of the biome to another.

There are aquatic biomes in rivers, lakes and oceans (benthic organisms = bottom dwelling attached and free moving; pelagic organisms = floating or swimming)

Estuaries border terrestrial and ocean biomes, and are highly productive; many commercial fish/shellfish spend at least some portion of their life in estuaries. San Francisco Bay and Chesapeake Bay are estuaries.

 

                                                             

Biomass and Productivity

 

Biomass

Phytomass + zoomass = biomass    (units: mass/volume; mass/area)

        zoomass is very small  (£10%)

        \phytomass » biomass

          worldwide total  » 1250 bT dry matter

Of total biomass, ~603 bT C on land, ~3bT C in ocean.

(hence, potential importance of biomass burning)

Generally, biomass decreases from low latitudes to high latitudes

 

Productivity º rate of formation of plant matter by photosynthesis (usually per area)

        Gross primary productivity (GPP) º total productivity

        Net primary productivity (NPP) º GPP – respiration loss

                                            » ½ GPP

 

        Aquatic: 125g d.m./m2/y   to     2500g/m2/y

                   (open ocean)        (algal beds, reefs)

 

        Terrestrial: 10g d.m./m2/y    to      400g/m2/y

                         (desert)                   (tropical wet lands)

 

Total NPP on land » 2´ total NPP of oceans

    (125 bT d.m.)       (65 bT d.m.)

 

Terrestrial vs Marine Ecosystems

        Aquatic distribution of biomass & productivity

        Terrestrial distribution of biomass & productivity

        Terrestrial biomass very high (gravity consequences)

        Marine has rapid turnover

        Terrestrial (carbohydrates): marine (proteins)