Seasonal to Interannual Variability in Phytoplankton Biomass and Diversity

on the New England Shelf

Heidi M. Sosik Hui Feng

In Situ Time Series for Validation and Exploration of Remote Sensing Algorithms

Woods Hole Oceanographic Institution

University of New Hampshire

Project Overview

Goal: Use unique time series to evaluate algorithms that extend MODIS ocean color data beyond chlorophyll to functional type or size-class-dependent phytoplankton retrievals

Approach: End-to-end time series observations, with step-by-step algorithm evaluation and error analysissingle cells phytoplankton community bulk water optical properties sea surface optical properties (air and water) MODIS optical properties

Martha’s Vineyard Coastal Observatory

Tower mountedAERONET-OC

MODIS productsSubmersible Imaging

Flow Cytometry

Approach

Phytoplankton ObservationsSingle cells to communitiesBiomass, size- and taxon-resolved

Phytoplankton AlgorithmsAbsorption spectral shape size structure

Diagnostic pigments size structure

Diagnostic pigments taxonomic structure400 500 600 7000

0.5

1

1.5

2

2.5

3

3.5

03-Jul-2007 20:00:00Fraction micro = 0.40

Rel

ativ

e ph

ytop

lank

ton

abso

rptio

n

Wavelength (nm)

pico

micro

MeasuredCiotti fit

400 500 600 7000

0.5

1

1.5

2

2.5

3

3.5

09-Dec-2007 21:15:00Fraction micro = 0.78

Wavelength (nm)

pico

micro

MeasuredCiotti fit

m m m m

m

m m m m

m

Variability in community structure

2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 20130

20

40

60

Car

bon

( mg

mL-1

)

SynechococcusGuinardia delicatula

.

Jan Apr Jul Oct Jan0

10

20

30

40

Dia

tom

s (m

gC m

-3)Diatoms

Cyano-bacteria

Jan Apr Jul Oct Jan0

2

4

6

8

10

12

Cya

noba

cter

ia (m

gC m

-3)

Pigment-based retrieval of taxonomic groups

10-2

10-1

100

10110

-1

100

101

102

Chl a (mg m -3)

Car

bon

(mg

m -3

)

y = 11.86x0.80

r = 0.604

Diatoms

Diatoms

“CHEMTAX” Mackey et al. 1996In situ FCM

Total Chl a = diatom Chl a + dinoflagellate Chl a + cyanobacteria Chl a + …

with partitioning according to accessory pigment ratios

10-3

10-1

10110

-1

100

101

102

Chl a (mg m -3)

Car

bon

(mg

m -3

)

y = 23.79x0.67

r = 0.390

Dinoflagellates

Pigment-based retrieval of taxonomic groups

10-2

10-1

100

10110

-1

100

101

102

Chl a (mg m -3)

Car

bon

(mg

m -3

)

y = 11.86x0.80

r = 0.604

Diatoms

Diatoms Dinoflagellates Cyanobacteria

10-6

10-4

10-2

100

10-2

100

102

Chl a (mg m -3)

Car

bon

(mg

m -3

)

y = 130.57x0.78

r = 0.34

Cyanobacteria

~1 mm cells

10 mm

Diagnostic pigment retrieval from RrsPan et al. 2010 band ratio algorithms

AERONET-OCSeaPRISM, Rrs(l)

Discrete samplesHPLC pigment analysis

0 2 4 60

2

4

6

In situ Chl (mg m -3)

SeaP

RIS

M C

hl, (

mg

m -3

) (%) = -20.37||(%) = 27.78

-0.4 -0.2 0 0.2 0.4-1.5

-1

-0.5

0

0.5

1

1.5

2

log10(Rrs488 / Rrs551)

log 10

(Chl

, mg

m -3

)

Chl a algIn situ data

Chl a

0 1 2 3 40

1

2

3

4

In situ Fucox (mg m -3)

SeaP

RIS

M F

ucox

(mg

m -3

) (%) = -8.27||(%) = 40.66

-0.4 -0.2 0 0.2 0.4-2

-1.5

-1

-0.5

0

0.5

1

1.5

log10(Rrs488 / Rrs547)

log 10

(Fuc

oxan

thin

, mg

m -3

)

Fucoxanthin algIn situ data

Diagnostic pigment retrieval from Rrs

0 2 4 60

2

4

6

In situ Chl (mg m -3)

SeaP

RIS

M C

hl, (

mg

m -3

) (%) = -20.37||(%) = 27.78

Chl a Fucoxanthin Zeaxanthin

-0.4 -0.2 0 0.2 0.4-1.5

-1

-0.5

0

0.5

1

1.5

2

log10(Rrs488 / Rrs551)

log 10

(Chl

, mg

m -3

)

Chl a algIn situ data

0 0.05 0.1 0.15 0.20

0.05

0.1

0.15

0.2

0.25

In situ Zeaxan (mg m -3)

SeaP

RIS

M Z

eaxa

n (m

g m

-3) (%) = -3.68

||(%) = 60.99

-2.5 -2 -1.5 -1 -0.5-2.5

-2

-1.5

-1

-0.5

0

0.5

log10(Rrs488 / Rrs547)-1.5log10(Tw)

log 10

(Zea

xant

hin,

mg

m -3

)

Zeaxanthin algIn situ data

Pan et al. 2010 band ratio algorithms

Seasonality – pigment retrievals

Jan Apr Jul Oct Jan0

2

4

6

Chl

(mg

m -3

)

MVCO in situMVCO MODIS

Jan Apr Jul Oct Jan0

0.5

1

1.5

2

Fuco

xant

hin

(mg

m -3

)

MVCO in situMVCO MODIS

Jan Apr Jul Oct Jan0

0.05

0.1

Zeax

anth

in (m

g m

-3)

MVCO in situMVCO MODIS

Diatom indicator pigment

Cyanobacteriaindicator pigment

Jan Apr Jul Oct Jan0

10

20

30

40

Dia

tom

s (m

gC m

-3)Diatoms

Cyano-bacteria

Jan Apr Jul Oct Jan0

2

4

6

8

10

12

Cya

noba

cter

ia (m

gC m

-3)

Ecosystem characterization

-4 -2 0 2 4-4

-2

0

2

4

r2 = 0.42

Temperature anomaly (relative)

Taxo

n an

omal

y (re

lativ

e)

Syn

-4 -2 0 2 4

-5

0

5

January

r2 = 0.59

Ditylum

-4 -2 0 2 4

-5

0

5

r2 = 0.39

Corethron

Taxa with positive response to warmer winters

Taxa with negative response to warmer winters

Interannual variability – taxon specific

Seasonally adjusted Biomass anomalies vs Temperature anomalies

Cyanobacterium Diatoms

Ecosystem characterization

Local detail Trends and patterns of change

Regional to basin scales

2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013

-1

0

1

Syn

echo

cocc

us

log(

mL-1

), an

om

2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013

102

104

106

Syn

echo

cocc

us, m

L-1

Decadal increase in pico-cyanobacteria at MVCO

http://ifcb-data.whoi.edu/

Open data access

Standard formats

Processing pipelines

End-to-end provenance