Lec 19 and 20 Nutrient Pollution & Eutrophication

Young lakes

Low nutrient (oligotrophic), particulary nitrogen and phosphorus, concentrations and low plant productivity

Low DO impact on fish

Not enough oxygen for the fish to continue to survive with the microbrial growth demanding O2 also at night when there is no light

SOD (sediment oxygen demand)

Draws O2 from water to sediment

How are levels of eutrophication measured?

Counts (numbers/mL) of specific phytoplankton species

cell volume (micronmeter³/mL)

Chrolophyll a concentratons (microngram/L)

Chlorophyll a concentrations

Large # = lots of active algae in a bdy of water, essential for photosynthesis

More Phosphrus = greater eutrophication

Total P < 10 ug/L = oligotrophic

Total P > 20 ug/L = eutrophic

Limiting Nutrient

Nitrogen or phosphorus depending on N and P

N/P > 10: Phosphorus Limiting (remove P)

N/P < 10: Nitrogen Limiting (remove N)

Algae bloom

Only occurs during the day

Biological Decay of dead algae

Occurs 24/7/365

What is total inorganic nitrogen

Ammonia, nitrate and nitrite