1

Quality Control of Phycoerythrin Data from The

Columbia River EstuaryDevelopment of a Correction for

Turbidity Artifacts.

Observation ● Prediction ● Analysis ● Collaboration

www.stccmop.org

Sarah Riseman

Acknowldegements:

Antonio BaptistaCharles Seaton

Needoba/Peterson LabLydie Herfort

CMOP Field TeamCMOP Staff

2Background: phycoerythrin

• Chemotaxonomic pigment– Synechococcus spp.– Cryptophytes– Myrionecta rubra**

• Measured using Fluoromtry– Autofluorescent: fluorometers designed with filter sets to

specifically measure the presence of phycoerythrin

– Turbidity & temperature are two sources of bias of in situ fluorometric measurements

3Background: Basics of a Filter Fluorometer

Adapted from:http://www.turnerdesigns.com/t2/doc/appnotes/998_0050/0050_c3.html

4Chlorophyll & Phycoerythrin Spectral Properties

Chlorophyll a

Phycoerythrin

460

523

620 - 715

578

5SATURN-03 Data from 2m (July 2010 – March 2011)

Turbidity

Chlorophyll

Raw Phycoerythrin

6Combined Turbidity Correction

Turbidity

Chlorophyll

Corrected Phycoerythrin

7Preliminary Turbidity Correction

AugustJuly September

*NovemberOctober

Monthly Phycoerythrin vs. Turbidity, Colored by Chlorophyll Saturn03 - 2m

Turbidity

Ph

yco

eryt

hri

n

8Preliminary Turbidity Correction

combined remainder of data into single data set

time period not usedin regression(8/15 – 10/10)

Time

9Preliminary Turbidity Correction – Linear Fits

Low (< 225ntu)

high(225-500ntu)

All Data

10Preliminary Turbidity Correction

11Preliminary Turbidity Correction

back

Turbidity

Corrected Phycoerythrin

Chlorophyll

12Combined Turbidity Correction

Turbidity

Chlorophyll

Raw Phycoerythrin

13New Turbidity Correction

14Details of Correction Determination

Simple Exonent: 3Pf = y0+a*(1-b^x)

r2 = 0.9984

Turbidity0 200 400 600

Ph

yco

eryt

hri

n

0.0

2.0e+4

4.0e+4

6.0e+4

8.0e+4

1.0e+5

1.2e+5

1.4e+5

1.6e+5

1. Data Selection: - winter only- all 3 depths- chlorophyll < 2 ug/L- turbidity < 625 NTU

2. Data Binned & Averaged- 1 NTU turbidity bins - data within mean +/- 3 s.d. averaged

3. Curve Fitted- several evaluated- simplest selected: - Exponential rise to maximum:

Single 3 parameter Exponent

15New Turbidity Correction

Corrected Phycoerythrin

Turbidity

Chlorophyll

16Comparison of Turbidity Corrections

17Conclusions

• The turbidity corrections need to be periodically evaluated for changes and updated accordingly

• With correction, the phycoerythrin data display a clear pattern corresponding to Chlorophyll

• These data clearly identified the onset of the 2010 M. rubra bloom

• With field samples a calibration to cell abundance should be possible

18Discussion Topics: where do we go from here?

• Are the corrected data useful?

- Can they be used to monitor the onset & development of M. rubra blooms in the CRE?

• How do we validate these signals?

- field sampling sampling

- monitoring sensor drift

19

• EXTRA SLIDES FOLLOW

20

21Phycoerythrin/Turbidity Relationship Over Time

RE-PLAY

JULYAUGUSTSEPTEMBEROCTOBERNOVEMBERDECEMBERJANUARYFEBRUARYMARCHJULY 2010 – MARCH 2011

22Processing of SATURN-03 Data

23Preliminary Correction

24Turbidity

Chlorophyll

Phycoerythrin - raw

25Turbidity

Chlorophyll

Phycoerythrin - corrected

26Phycoerythrin - corrected

Salinity

27Saturn01 Turbidity Correction based compiled data from 3 depths (2m,8m,13m) where chl < 1.5 ug/L during Aug 4 – Aug 22, 2010)

Saturn01 Turbidity FactorBased on Bin/Avg Regression:

TF = 1178.4*turb + 1334.1

Corrected PE = PE – TF(+2850 to raise to raw data baseline)

28Sat01 -2m PE Correction