AQUATIC BIOMES The biosphere is that portion of Earth inhabited by life and represents the sum of all communities and ecosystems. A biome is a broad, regional type of ecosystem characterized by distinctive climate and soil conditions and a distinctive kind of biological community adapted to those conditions.
Aquatic Biomes account for the largest part of the biosphere in terms of area, and all types are found in the globe. Ecologists distinguish between freshwater biomes and marine biomes on the basis of their physical and chemical differences.
Marine biomes generally have salt concentrations that average 3%, whereas freshwater biomes only have less than 1%.
Many aquatic biomes are physically and chemically stratified for both a lake and marine environment. Vertical Stratification based on physical and chemical variables, such as light temperature
is absorbed by organisms and the water intensity decreases rapidly with dept
light-penetrated layer warmed by heat energy from sunlight2 deep waters beyond penetration of light are uniformly cold
The surface waters are warmer and the deeper ocean is colder. Between them is the thermocline which is a thin zone where temperature decreases rapidly with depth.
PRIMARY PRODUCTIVITY In Marine Ecosystems is limited by: Light is first variable to control primary production in oceans since solar radiation can only penetrate to a certain depth (photic zone) more than 50% of solar radiation is absorbed in first meter of water even in "clear" water, only 5-10% of radiation reaches depth of 20m Nutrients nitrogen and phosphorus most often limit marine production are examples of limiting nutrients (nutrients that must be added for production to increase) concentrations are low in photic zone where photosynthesis could occur often more available in deep waters where its too dark for photosynthesis
PRIMARY PRODUCTIVITY In Freshwater Ecosystems is limited by: Solar radiation and Temperature Nutrient limitations also common phosphorus is usually limiting nutrient (rather than nitrogen as in oceans), hence, shift in late 1970’s to phosphate-free detergents Cultural eutrophication Eutrophication of lakes as a result of input of nutrients from sewage and fertilizer pollution
THE FRESHWATER BIOMES 1. Standing (Lentic) Bodies of Water Lakes and Ponds Wetlands 2. Moving (Lotic) Bodies of Water Rivers and Streams
THE MARINE BIOMES Marine biomes include three categories: 1) Oceans 2) Coral reefs3) Estuaries