Oceanic Remote Chemical/optical Analyzer (ORCA)
description
Transcript of Oceanic Remote Chemical/optical Analyzer (ORCA)
Oceanic Remote Chemical/optical Analyzer (ORCA)
An autonomous profiler monitoring water quality in south Puget Sound
T,S, O2
NO3,
ORCA overall;Steven Emerson; Allan Devol
Jan Newton; Rick Reynolds
PRISM John Dunne; Wendi Ruef
General Support
Nutrient Analyzer
• Develop a robust remote chemical and biological monitoring system
• T, S, Light, Meteorology
• NO3, O2, Chl-a, turbidity
• NH4, Gas Exchange parameters
• Telemeter data back to UW
• Monitor the spectrum of time-scales
• Hourly (tides), Daily (solar), Weekly (plankton growth), Monthly (blooms), Annual (seasons, and inter-annual, e.g., El Nino)
• Describe natural variability and characterize and help evaluate potential human influence
• Validate PRISM physical and biological models
ORCA GOALS
WHAT DOES ORCA LOOK LIKE?
light
solar panel
radarreflector
superstructure
Platform and housing For Winch, electronics, etc
Atlas float(cut awayview)
ballast ring
anchoring(break inscale)
pack
age
weather station
ORCA Schematic View
4.2 m
solar panel
WHERE IS ORCA?
Seattle
Seattle
Tacoma
Tacoma
http://www.ocean.washington.edu/research/orca/
Nutrient Analysis
Spring Bloom Movie
Fall Bloom Movie
Growing Season Movie
Basic data shows varibility
July 12 - 28, 2000
enhancement
October 15-21, 2000Sept. 20- Oct. 2, 2000
no enhancement surface enhancement
Sigma-t
Chl ug/l
O2 mg/l
enhancement no enhancement surface enhancement
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12 Oct 0025 Sep 0010 Jul 00
dep
th (
m)
primary productivity (mg C m-3 d-1)
Effect of nutrient addition on phytoplankton productivity
blue = ambient production
red = spiked with NH4 and PO4
Carr Inlet, WA Ecology
What Causes varibility ?
Tidal Advection ?
What causes high frequency variability ?
What causes high frequency variability ?
Wind and destratification ?
Analysis by Kate Edwards
Photosynthesis (J)CO2 + H2O + nutrients CH2O + O2
O2 flux
C flux
5 mMixedDeep mixing
1. How frequently do we need to sample?
2. What is gross O2 production (GP)?
3. What is net community O2 production (NCP)?
How frequently do you need to sample?
Gas Exchange = G* (O2sat-O2obs)
Gas exchange (moles m-2 d-1)
2-hr 0.012 0.012 0.012
0.012 0.012 0.012 0.012 0.012
Daily 0.021 0.020 0.021
0.019 0.021 0.022 0.021 0.020
Weekly 0.028 0.014 0.018
0.029 0.024 0.021 0.023 0.010
Bi-Weekly
0.013 0.014 0.018
0.036 0.008 0.327 0.016 0.009
Monthly 0.007 0.019 0.021
0.048 0.012 0.019 0.018 0.009
G=f(average daily wind speed)(Liss and Merlivat, 1986)
Diurnal O2 Change Model
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850 900 950 1000
jDay
O2
mm
ole
s/m
3/d
1Apr. 10 Oct.
So, how do we get O2 production terms?
diurnal O2 change
150 day average
Time of Day (hr)
0 4 8 12 16 20 24
Ave
rag
e O
2 (
m m
ole
s m
-3d-1
)
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1) night-time respiration, R = 14 mmoles m-3 (d/2)-1
2) Assume R~ constant, thus, R =28 mmoles m-3 d-1*5 m = 140 mmoles m-2 d-1
3) Since dO2/dt = 0 over 24 h, R = j = 140 mmoles m-2 d-1
(j = O2 production required to balance R)
Amplitude ~ 14 mmoles m-3
Hourly Oxygen Averages
Box Model for net oxygen production
hh**dOdO22/dt/dt = G*O2 + Kz*dO2/dz + NCP
h h ** dO dO22/dt/dt = observed box depth & oxygen change with time
G * O2 = gas exchange: wind speed; oxygen gradient
across air-water interface
Kz * dO2/dz = vertical diffusion: diffusion coefficient &
observed vertical oxygen gradient
NCP = net biological oxygen production: determined from
model
G = f (average daily wind speed) (Liss and Merlivat, 1986)
Kz = f (buoyancy frequency) (Denman and Gargett, 1983)
Simple Box Model Results
• NCP = 0.011 moles m-2 d-1
(132 mg C m-2 d-1)
• G.E. = -0.012 moles m-2 d-1
• Vertical mixing = -0.0008
• h (dO2/dt) = -0.0021
Is This Reasonable ?
regression = 380-320 mmoles m-3
(380-320)/150 = 0.4 mmoles m-3d-1
h*(dO2/dt) = 2.1 mmoles m-2d-1
(2.1mmoles m-2d-1)/(5m)=0.4mmoles m-3d-1
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jDay
O2
mm
ole
s/m
2/d
O2
Linear (O2)
1Apr. 10 Oct.
NCP=0.011, G.E.=-0.012, mix=-0.0008, h*dO2/dt=-0.0021
Conclusion: NCP ~0.011 mmoles m-2d-1
GP = j + G.E.
= 140 + 12
= 152 mmoles m-2 d-1
(1824 mg C m-2 d-1)
What, then is GP?
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mg
C m
-2 d
-1 Carr Inlet
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mg
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Nisqually Reach
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-2 d
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mg
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-2 d
-1
Totten Inlet
Figure 15. Seasonal levels of ambient primary production integrated over the euphotic zone. Data shown are Apr. 99, Jul. 00, Sep. 99 and Dec. 99.
Newton and Reynolds, 2000
Integrated Chl * Daily Ed(PAR, 0+)
[ gChl m-2 * (mol m-2 d-1) ]
10-2 10-1 100 101 102
Inte
grat
ed P
rodu
ctio
n [
gC m
-2 d
-1 ]
10-2
10-1
100
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SPASM (N=34)Other Puget Sound (N=42)
Y = 1.22 X0.85
r 2 = 0.93
Chl Based Productivity Model*
*Rick Reynolds
Productivity Model Input Data
EdP
AR
(m
ole
m-2
d-1
)
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Date
1/1/02 3/1/02 5/1/02 7/1/02 9/1/02 11/1/02
Ch
l (m
g m
-2)
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Daily-IntegratedSurface Insolation
Daily depth-IntegratedChl
Date
1/1/02 3/1/02 5/1/02 7/1/02 9/1/02 11/1/02
Pri
mar
y P
rod
uct
ivit
y (g
C m
-2 d
-1)
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Modeled* Daily Production atThe Carr Inlet-ORCA Site
*Rick Reynolds model
Production Summary
mmoles m-2 d-1 mg C m-2 d-1
Mixed layer net
O2 production 10 120
Mixed layer Gross O2 production
150 1900
14C-based
Model production3400
• High frequency sampling reveals high frequency features
• Some of the high frequency signal is due to tidal effects
• Frequent sampling required to capture the true value of certain fluxes, e.g. gas exchange
• Bloom starts when water air temperature becomes equal to water temperature
• Frequent summer destratification driven by wind events
• Production can be derived from oxygen distribution
Wrap Up
Orca Home Page
Longer Term Goals
• Science
• Study Bloom Dynamics/gas exchange/nutirent/physics coupling
• Mixed layer
• Aphotic zone
• Add Sensors (PO4, Eddy Correlation, micro-gradient)
• Publish Orca Results
• Expand Network:
• South Sound, Main Basin, Hood Canal, Admiralty Inlet
• Continue and Expand Outreach/Education
Advection
Production
Goals for 2003
• Science Goals:
• MIXED experiment (April 2003)
• Nutrients; NO3 and NH4
• Move Orca for Brightwater
• Publish Orca Results
• Prism Goals:
• Use Orca to Validate ABC-POM
• Carr Inlet
• Brighwater site
• Outreach
• Maintain Orca Website
• Orca School
[O2] Box Model