“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.
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)