INTEGRATION OF NUTRIENT CYCLES

Types of Reactions
    A. Dissolved inorganic carbon/alkalinity
        1. PS/Resp. cause -/+ CO2 , +/- pH , +/- O2
    B. Redox Reactions
        1. +/- O2 cause change in Eh
    C. PO4  and Fe (solubility)
        1. +/- Eh changes Fe solubility and PO4 co-precipitation
patterns of temperature, oxygen, redox potential, iron, phosphate, DIC, pH and alkalinity in an oligotrophic lake after stratification

patterns of temperature, oxygen, redox, iron, phosphate, DIC, alkalinity, and pH after stratification in an oligotrophic lake
 

In an oligotrophic lake, the redox sequence of reactions occurs in the sediments

daytime patterns of temperature, oxygen, redox, iron, phosphate, DIC, alkalinity, and pH in a eutrophic lake

 DAYTIME PATTERNS
daytime patterns of temperature, oxygen, redox, iron, phosphate, DIC, alkalinity and pH in a eutrophic lake

In a eutrophic lake, the redox sequence of reactions occurs in the water column

                                      HYPOLIMNETIC VALUES DURING SUMMER STRATIFICATION

LAKE STATUS		  [O2]  Eh  Fe+2 H2S  PO43-

Oligotrophic 		 High (orthograde)  400-500 mV  Absent  Absent  Very low
Mesotrophic Much reduced (clinograde)  400-500 mV  Absent  Absent  Low
Eutrophic  Much reduced or absent (clinograde)  ~250 mV  High  Absent  High
Hypereutrophic Absent <100 mV  Decreasing (formation of FeS)  High  Very high

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