RealReal--time in situ measurements time in situ measurements of nitrate in marine and inland of nitrate in marine and inland

waterswaters

10 September 2003

Nitrate Sensor Development• ISUS (In Situ Ultraviolet Spectrometer)• Developed by Dr. Ken Johnson, MBARI• Testing/validation in open ocean• Tech transfer to Satlantic• Commercialized, product launch Oct 2002• Extensive test/validation plan estuarine/inland

waters

THE TECHNOLOGY

Why UV?

• Many inorganic compounds absorb light at wavelengths less than 300nm – nitrate, nitrite, bisulfide and

bromide• Direct determination of nitrate

based on measurement of its UV absorption

Wavelength (nm)

200 220 240 260 280

Abso

rban

ce B

r-

0.0

0.5

1.0

1.5

2.0

2.5

Abso

rban

ce ex

cept

Br-

0.0

0.2

0.4

0.6

840 µM Br-

50 µM HS-30 µMNO3

-

50 µM I-

a.

H2S

50 µMS2O3

2-

THE TECHNOLOGY

• ISUS design is based on the absorption characteristics of inorganic compounds in the UV portion of the spectrum

• ISUS illuminates the water sample with UV light into a UV spectrometer

• Absorption spectra ismeasured and comparedto the predicted spectra toderive nitrate

200 210 220 230 240 250 260 270 280 290 3000

0.05

0.1

0.15

0.2

0.25

Wavelength (nm)

Abso

rban

ce

ISUS Nitrate Computation20µM NO336.2psu SalMeasured SpectrumFitted SpectrumResidual X10Baseline

THE TECHNOLOGY• ISUS illuminates the open sample volume with UV light

source measures the path absorbance with a UV spectrometer

Measurement Cell

Titanium Retroprobe

Light from UV source

Light to UV spectrograph

Quartz Window

MirrorBifurcated fiber optics

APPLICATIONS

• Water quality• Phytoplankton blooms• Nutrient dynamics• Eutrophication• Monitoring run-off • Detection of environmental change

INSTRUMENT SPECIFICATIONSOpticalPath length: 1 cmUV spectrum: 200-400nm

3.3nm resolutionPhysicalDepth rating: 1000mSize: 510mm x 114mmWeight: 7.5kg (air)/2.1kg (water)Operating temperature: 0 to 35 CMaterial: Marine grade, hard anodized aluminum

PerformanceNitrate sensitivity (lab): ± 0.2 µM (3σ) (0.003mg/l)Nitrate accuracy (field): ± 2 µM (σ) (0.03mg/l)Sample frequency: 0.5 Hz

Probe Anti-Biofouling Cover

Computer System

UV Light Source

UV Spectrograph

User Interfaces

Retro-Probe Optics

DEPLOYMENT OPTIONS

• Water column profilers• Towed vehicles• Long-term moorings• Flow-through systems

Water Column Profiler• Profiling system

– Continuous nitrate measurements (2 sec)

– Easily mounted to CTD packages, lowering frames, or other profiling devices

– Internally logs nitrate 40h capacity with 128MB card

– Supplies analog signal to external loggers

– Digital output – Battery packs (20h lithium, 3h gel cell rechargeable)

© MBARI

Towed Vehicles & ROVs

• Analog signal to externalloggers

• Digital output on cable lengths of 1000 meters

• Internally logging nitrate– Spectra and Nitrate

• Used as ‘sniffer’ for hydrothermal vents using bisulfide

© MBARI

© MBARI

Moorings and Drifters

• Deployment time range 4 months- dependent on schedule and battery pack

• Antifouling cell• Memory capacity 128MB

- 256day capacity - 300 MB card available if required

• External battery pack - 41Ah Lithium – 4m- 6.8Ah Gel Cell – 2w moored © MBARI

Flow-through Systems• Great for mapping, gradient detection, location of point sources• Integrated with other sensors, externally pumped

- GPS- CDOM, DO, pH, CTD, Chl Fluor

• On deck transect mode- easy to use- quickly deploy as profiler

• In-lab flow cell mode- convenient for small samples- Bench top operation

Field ExperimentsOpen Ocean:

Equatorial PacificEquatorial AtlanticMonterey Bay

Estuarine:Halifax HarbourBedford Basin Florida Bay/Everglades NPElkhorn SloughChesapeake BayYaquina Bay

Fresh Waters:Bedford Basin WatershedKentville Water supplyAgCanada Research stationAnnapolis RiverCornwalis RiverLumsden LakeDairy farm water supplyVarious private wells

Open Ocean – Equatorial Pacific

Preliminary and Proprietary InformationData courtesy of Dalhousie University, the Japan Marine Science and Technology Center (JAMSTEC), and Satlantic under their long-term collaborative research program in the Western Equatorial Pacific

ISUS001 nitrates from 4400km transect in EqPac on R/V Mirai MR02K06 – Feb 200318 profiles to 300m, 10,000 real time nitrate measurements

Open Ocean – Equatorial Pacific

Nitr

ate

(µM

)

0

2

4

6

8

UV

Salin

ity35

36

37

38

11/00 12/00 1/01 2/01 3/01 4/01 5/01

Tem

pera

ture

(°C

)

24

26

28

Reg

ress

ion

Erro

r (A

bsor

b.)

0.00

0.01

0.02

A

B

C

Temp.

Error

EP2 - 170°W, 2°S

• Nitrate on the EP2 mooring in the TAO array Nov 2000 to May 2001. *Data provided by Dr. Ken Johnson, MBARI

Open Ocean – Equatorial Atlantic

ISUS001 nitrates from 110,000km2 in Gambia Plain – April 200350 profiles to 1000m, 100,000 real time nitrate measurementsInterfaced to SeaBird 911 profiler with Aanderaa Optode

Open Ocean – Equatorial Atlantic

ISUS001 nitrates from Gambia Plain – April 2003Single transect visualization

Open Ocean – Monterey Bay

10

11

12

13

14

Oce

anD

ata

Vie

w

0 20 40 60 80

50

40

30

20

10

0TEMPERATURE [°C]

Distance [km]

DE

PTH

[m]

TEMPERATURE [°C]

Distance [km]

DE

PTH

[m]

0

5

10

15

Oce

anD

ata

Vie

w

0 20 40 60 80

50

40

30

20

10

0NITRATE [µmol/kg]

Distance [km]D

EP

TH[m

]

NITRATE [µmol/kg]

Distance [km]D

EP

TH[m

]

Towed System Measurements of Nitrate

*Data provided by Dr. Ken Johnson, MBARI

Open Ocean – Monterey Bay

158

M2 Buoy Measurements of Nitrate

Real time data from M2: http://www.mbari.org/~johnson/isus_m2.htm

*Data provided by Dr. Ken Johnson, MBARI

Estuarine – Halifax Harbour

Halifax Harbour, Nova Scotia, Canada, Oct 2002

Estuarine – Halifax Harbour

ISUS001 Nitrate Profile with measured bottle samples (Station 2)

Estuarine – Bedford Basin

x

x

Bedford Wastewater

Bedford Basin Profiles

Estuarine – Bedford Basin

ISUS and CTD towed through sewage plume in Bedford Basin

Estuarine – Bedford Basin

Test System (WQM) in Bedford Basin

Estuarine – Florida Bay

Florida Bay / Everglades NP – High CDOM swamp

Estuarine – Florida Bay

Taylor Creek – Mangrove Swamp (very high CDOM)CDOM 10-100QSU, 4-28psu, 0.1-10NTU

Estuarine – Elkhorn Slough

Elkhorn Slough – Agricultural run-off

Estuarine – Elkhorn Slough

ISUS Harbor Nitrate

0

100

200

300

400

500

600

700

800

900

1/27/200312:00

1/28/2003 0:00 1/28/200312:00

1/29/2003 0:00 1/29/200312:00

1/30/2003 0:00 1/30/200312:00

1/31/2003 0:00 1/31/200312:00

Nitra

te (u

M)

-2

-1

0

1

2

3

4

5

6

7

Tide

Hei

ght (

ft)

NO3NutsSeries4Tide

Water samples 90cm

Water samples 30cm

ISUS at 60cm

Highly stratifiedSalinity: 10-30psuTurbidity: 10-60NTUNitrate: 100-600uM

(1.4-8.4mg/l)Data provided by Dr. Ken Johnson, MBARI

Elkhorn Slough – Agricultural run-off

Estuarine – Chesapeake Bay

15000 nitrate measurements

Nitrate 3-120uMCDOM 2-120+ QSUTurbidity 1-25 NTUSalinity 0.2-15psu

Estuarine – Chesapeake Bay

Validation Samples from UMD HPLwithin 1.8uM over full range of conditions

Estuarine – Yaquina Bay

Validation samples from EPA PCEB test site time series

EPA Dock

Inland Waters – Bedford Basin Watershed

xx

x Sackville River

Kearney Lake

Black Duck Brook

Bedford Basin Watershed – Residential/Urban run-off

Inland Waters – Bedford Basin Watershed

Black Duck Brook:Residential/Swamp drainageNitrate: 4.4uM

(0.06mg/l)Turbidity:1.4CDOM: 50QSU

Kearney Lake A: Industrial/Swamp

drainageNitrate: 16.4uM

(0.23mg/l)Turbidity:1.7CDOM: 60QSU

Kearney Lake Site

Inland Waters – Bedford Basin Watershed

Wastewater Plumes

Kearney Lake Discharge

Sackville River: Urban/Swamp drainageNitrate: 7.9uM

(0.11mg/l) Turbidity:4.7CDOM: 20QSU

Sackville River site

Inland Waters – Annapolis Valley, NS

Annapolis Valley

Cornwallis RiverCornwallis River

Annapolis RiverAnnapolis River

Lumsden Lumsden LakeLake

Agriculture Canada Agriculture Canada research stationresearch station

Halifax

Inland Waters – Annapolis Valley

Watershed area surrounded by intense agricultural operations

Cornwallis River

Nitrate = 130 uM (1.82mg/l)CDOM = 123 QSUTurbidity = 7.9 NTU Fluorescence = 3.1 ug/l

Inland Waters – Annapollis Valley

Watershed catchmentarea includes substantial municipal development

Annapolis River

Nitrate = 54 uM (0.76 mg/l)CDOM = 122 QSUTurbidity = 5.1 NTU Fluorescence = 3.7

Inland Waters – Annapollis ValleyLumsden Lake

Lake formed from Hydro-electric Dam

Nitrate = 19.7 uM (0.28mg/l)CDOM = 114 QSUTurbidity = 1.1 NTUFluorescence = 1.9 ug/l

Inland Waters – Annapollis ValleyAgriculture Canada Research Station

Experimental apple orchards

Sampled from orchard tile drainage system after experimental fertilization

with liquid manure

Nitrate = 470 uM (6.6mg/l)CDOM = 5.5 QSUTurbidity = 25 NTUFluorescence = 2.5 ug/l

Inland Waters – Sacramento River, CAPan Creek

Heavy industry surrounds watershed

Waste water discharge into creeks as point source

Inland Waters – Sacramento River, CAPan Creek Nitrate

Several heavy industry complexes

Industrial wastewater

Point source

Sacramento River

Pan Creek

Inland Waters – Sacramento River, CAPan Creek CDOM

Sacramento River

Pan CreekPoint source

Inland Waters – Sacramento River, CA

Nitrate ranges from 10 to 36 uM

CDOM ranges from 67 to 40 QSU

Brown’s Island

Scale = 2 kms

Junction with inlet

Inland Waters – Northern Alberta Lakes

Touchwood Lake profile

Lac La Biche transect

Golf Course

Inland Waters – Northern Alberta Lakes

Inland Waters – Northern Alberta LakesTouchwood Lake profile

ISUS demonstrated clear stratification and identified the nitracline at 25m.

Inland Waters – Agricultural Runoff

Samples from the wells of both dairy and grain farms

Grain and potato farms suffer from severe erosion -fertilizers end up in ground

water as a result

Inland Waters – Private well-water samples

Also sampled from private wells from across the

province.

ISUS data is validated against autoanalyzer results determined at Dalhousie University

SYSTEM ADVANTAGES• No chemistry for nitrate (ease of use)• Real-time output (µM nitrate, physical units all sensors)• Stand alone or fully integrated as WQM for total

water quality monitoring solution• Access to full UV absorption spectrum• Fast (2sec sampling)• Compact size (510mm x 114mm)• Endurance (4-6m)• Rapid deployment• High data precision and accuracy

SYSTEM ADVANTAGES cont.• Ease of integration (digital, analog outputs)

– Log internally, SatView, SeaSave

• Automatically adapts to wide range of environmental conditions

• Diverse applications (no conversion required)– profilers, towed vehicles, and moorings– marine, estuarine and inland waters