Water Chemistry Field Sampling
42
TABLE 2.3 PARAMETERS TO CONSIDER FOR POSSIBLE INCLUSION IN
STUDIES OF ATMOSPHERIC NUTRIENT N ENRICHMENT OF
FRESHWATERS
Parameter
Preferred Unit Importance
Rationale
Total N
μM
High
Reflects all forms of N in the
system
NO 3
−
μM
High
Biologically available form of N
NH 4
+
μM
High
Biologically available form of N
Dissolved
organic N
(DON)
μM
Moderate
Potentially available form of N
Total P
μM
High
Reflects all forms of P in the
system
Soluble reactive
P (SRP)
μM
High
Biologically available P
Chlorophyll a
μg/L
High
Reflects primary productivity
Fe
μM
Variable
May bind with P, influencing
its bioavailability and
transport
Total Al
μM
Variable
May bind with P, influencing
its bioavailability and
transport
Ca 2+
μM
Variable
May bind with P, influencing
its bioavailability and
transport
Si
μM
Variable
May be limiting to diatoms
under some conditions
Dissolved
oxygen (DO)
mg/L
Variable
May decrease to biologically
stressful levels under extreme
conditions of nutrient inputs
(under most conditions of
atmospheric nutrient
deposition, decreased DO is
not an important issue)
Total suspended
solids (TSS)
mg/L
Variable
May be an erosional source of
P to streams
Turbidity
Standard units
Variable
May be used to estimate TSS
Secchi depth
m
Variable
Can reflect algal abundance in
lakes