Aquatic BiomesA BIOME is a major ecosystem spread over a wide geographic area, and characterized by

certain types of flora and fauna.

Life originated in the oceans, and stayed there for nearly 3 billion years. The oceans

are the most influential of all terrestrial features affecting climate and biomes.

Major Aquatic Biomes - These occupy most of the biosphere

marine (average salinity 3%) freshwater (average salinity 1% or less) brackish (mixture of salt/fresh)

Aquatic biomes may be

Lakes/ponds River systems

Freshwater biomes may be:

Estuaries Marshes and wetlands

Freshwater or Brackish systems may be:

intertidal regions coral reefs oceanic pelagic zones abyssal zones

Marine

Light is absorbed by water and by living aquatic organisms...

· photic zone - light sufficient for photosynthesis

· aphotic zone - light insufficient for photosynthesis

Stratification of Aquatic Biomes

littoral zone - inshore, shallow, high light levels limnetic zone – center of lake, high light levels,

upper regions of water column (pelagic zone for the ocean!)

profundal zone – aphotic benthic zone – bottom substrate; often rich in detritus

Zonation in freshwater biomes

oligotrophic - deep, nutrient poor, water very clear

eutrophic - shallower, nutrient rich, murky with phytoplankton

mesotrophic - in between the above two classifications

Classification of Freshwater Biomes by Productivity