Download - From NIMS-AQ to an Application Example
From NIMS-AQ toFrom NIMS-AQ to
an Application Examplean Application Example
CalculatingCalculating
River Metabolism:River Metabolism:
The case of a river confluenceThe case of a river confluence
River Metabolism:River Metabolism:
Primary Productivity and Community RespirationPrimary Productivity and Community Respiration
-Primary productivity (GPP): Rate of formation of organic matter from inorganic carbon by photosynthesizing organisms and represents the conversion of solar energy to reduced chemical energy.
-Respiration (R): Portion of that fixed energy is lost through autotrophic respiration
2 2 2 6 12 6 26 12 6 6CO H O photons O C H O H O
6 12 6 2 2 26 6 6C H O O CO H O energy
Then, photosynthesis stores energy, and respiration releases it for use in functions such as reproduction and basic maintenance.
Carbon dioxide (g) + water (l) + photons oxygen (g) + glucose (aq) + water (l)
Glucose + oxygen carbon dioxide + water + energy
-They help to determine ecosystem biomass (i.e. how much energy is available to support an ecosystem).
-They help to understand the trophic structure, thus to evaluate the potential for competition for food.
-They serve as indicators of river health when compared with undisturbed sites or when comparing over periods of time (e.g. changes in Net Primary Productivity can be symptomatic of stresses).
We calculate Primary Productivity and Respiration in lotic We calculate Primary Productivity and Respiration in lotic ecosystems because:ecosystems because:
Some Key terms:Some Key terms:
a hCR R R
aGPP NPP R
-While NPP is the net amount of primary production after the costs of plant respiration are included, Net Ecosystem Production (NEP), Net Community Production (NCP), or Net Daily Metabolism (NDM) is the amount of primary production after the costs of respiration by autotrophs and heterotrophs are all included.
NEP GPP CR
24NDM GPP CR
-Community Respiration is the sum of the autotrophic and heterotrophic respiration. We use it because so far it’s not possible to measure them separately.
Gross Primary Productivity, the total fixed energy, is the sum of the portion of energy stored in biomass (Net Primary Productivity) + the portion that is lost through autotrophic respiration (Ra).
(instantaneous)
(daily)
The open-system dissolved oxygen (DO) change methodThe open-system dissolved oxygen (DO) change method
3 1q p r d a M L T
2 1Q P R D A M L T
Rate of change of DO per area:
:
:
:
:
Q
P
R
D
A
Rate of GPP per area
Rate CR per area
Diffusion rate per area
GW accrual per area (usually assumed negligible)
Modified from Odum (1956)
Single-station Method:
Q or q: is the rate of DO change between two consecutive sampling times.
Metabolism
The open-system OThe open-system O22 change change
Observed diel (24 h) DO cycle
Light penetration
Rate of change of DO per hour
Community respiration
Diffusion in or out of the stream water according to water DO saturation
-Undersaturated: O2 in, -Supersaturated: O2 out,
- Gross primary productivity
River Lark (England). Source: Odum (1956)
3inq p r d a M L T
inq p r d outq p r d
inp q r d outp q r d
Calculation of river metabolism using NIMS dataCalculation of river metabolism using NIMS data
The confluence by the time of the experimentThe confluence by the time of the experiment
Calculation of river metabolism using NIMS dataCalculation of river metabolism using NIMS data
* Upstream view
Dissolved Oxygen(mg / L)
Temperature (C)
Merced River zone
Mixing zone
San Joaquin Riverzone
hour hour
Merced River Zone San Joaquin River Zone
Day 1
Day 2
Day 3
Units: gr/m2-min
Pink line: average community respiration (CR24)
Green line: Gross Primary Productivity (GPP)
Zone 1: Merced River zone
Zone 2: Mixing zone
Zone 3: San Joaquin River zone
Future Directions:Future Directions:
-Evaluation of the effects of irrigation returns at a river reach.
- Groundwater-surface water interactions and their effect on river biota.
-Association of those distributed physicochemical parameters to Ecosystem diversity?