Norm Nelson, Dave Siegel

Institute for Computational Earth System Science, UCSB

Bermuda Bio-Optics ProjectBermuda Bio-Optics ProjectDecade-Plus Perspective on Ocean ColorDecade-Plus Perspective on Ocean Color

OverviewOverview

Science GoalsScience GoalsData StreamsData StreamsAccomplishmentsAccomplishments

A Look at the Time SeriesA Look at the Time Series

Bermuda Bio-Optics ProjectBermuda Bio-Optics Project

Understand processes controlling Understand processes controlling underwater light environment in the underwater light environment in the Sargasso SeaSargasso Sea

Algorithm developmentAlgorithm development(With Stéphane Maritorena)(With Stéphane Maritorena)

Calibration and validation of ocean Calibration and validation of ocean color sensorscolor sensors

Bermuda Bio-Optics ProjectBermuda Bio-Optics ProjectOverview - Main Science GoalsOverview - Main Science Goals

Light, primary productivity, and Light, primary productivity, and photosynthetic quantum yield photosynthetic quantum yield

Distribution and dynamics of CDOMDistribution and dynamics of CDOM(Sargasso Sea and global)(Sargasso Sea and global)

Photochemistry and DMS cyclingPhotochemistry and DMS cycling

Bermuda Bio-Optics ProjectBermuda Bio-Optics ProjectOverview - Main Science AchievementsOverview - Main Science Achievements

Bermuda Bio-Optics ProjectBermuda Bio-Optics ProjectOverview - Data StreamsOverview - Data Streams

Time-series co-located with BATSTime-series co-located with BATS(32N 64W), starting in 1991(32N 64W), starting in 1991Also - Also - ffrequent regional studiesrequent regional studies

Core MeasurementsCore Measurements::EEdd, , EEss, , LLuu (7-14(7-14 , , BSI & Satlantic radiometersBSI & Satlantic radiometers))

[[chl achl a] ] (fluorometric)(fluorometric)

Since 1994Since 1994::

aapp,,aadd (QFT)(QFT)

aacdomcdom (conventional UV-Vis spectroscopy)(conventional UV-Vis spectroscopy)

Concurrent data from the BATS ProjectConcurrent data from the BATS ProjectHydrographyHydrographyCarbon (inorganic, organic)Carbon (inorganic, organic)NutrientsNutrientsPrimary ProductionPrimary ProductionC and N flux (sediment traps)C and N flux (sediment traps)Phytoplankton pigments (HPLC)Phytoplankton pigments (HPLC)

Other BBOP dataOther BBOP data (not full time-series) (not full time-series)AC-9 absorption coefficient profilesAC-9 absorption coefficient profilesLLww(0+), ASD FieldSpec radiometer(0+), ASD FieldSpec radiometerLLsunsun, Microtops sunphotometer, Microtops sunphotometer

Bermuda Bio-Optics ProjectBermuda Bio-Optics ProjectOverview - Data StreamsOverview - Data Streams

Radiometer calibrationRadiometer calibration: in house, : in house, using NIST-traceable standards, using NIST-traceable standards, participated in SeaWiFS and SIMBIOS participated in SeaWiFS and SIMBIOS intercomparisons: Same engineer for intercomparisons: Same engineer for entire project (Dave Menzies)entire project (Dave Menzies)

Bermuda Bio-Optics ProjectBermuda Bio-Optics ProjectOverview - Data StreamsOverview - Data Streams

0

0.002

0.004

0.006

0.008

0.01

0.012

0.014

0.016

0.018

0.02

1992 1994 1996 1998 2000 2002 2004 2006

Rrs

(sr

^-1

)

Bermuda Bio-Optics ProjectBermuda Bio-Optics ProjectRadiometry – 14 year time seriesRadiometry – 14 year time series

441 nm (MER)441 nm (MER)

443 nm (SPMR)

Absorption Coefficient ComponentsAbsorption Coefficient ComponentsCDOMCDOMPhytoplanktonPhytoplanktonDetritusDetritusPhytoplankton absorption ratios Phytoplankton absorption ratios (440/674nm)(440/674nm)

Are there interannual or longer term Are there interannual or longer term trends in addition to already-documented trends in addition to already-documented seasonal patterns?seasonal patterns?

Bermuda Bio-Optics ProjectBermuda Bio-Optics ProjectAbsorption Coefficient – 10 Year Time SeriesAbsorption Coefficient – 10 Year Time Series

0.05 0.1 0.15 0.2-500

-450

-400

-350

-300

-250

-200

-150

-100

-50

0

acdom

(325 nm, m-1)

Dep

th (

m)

STMWBATS CDOM ProfileBATS CDOM Profile

STMW (18° Water)

Surface Bleached Layer

Main Thermocline

1994 1996 1998 2000 2002 2004 20060

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

a cd

om (

m-1

)

Surface CDOM at BATS

324 nm400 nm

1994 1996 1998 2000 2002 2004 20060

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

a cd

om (

m-1

)

Surface CDOM at BATS

324 nm400 nm

1994 1996 1998 2000 2002 2004 20060

0.05

0.1

0.15

0.2

0.25

0.3

0.35a cd

om

(m

-1)

160 m CDOM at BATS

324 nm400 nm

1994 1996 1998 2000 2002 2004 20060

0.05

0.1

0.15

0.2

0.25

0.3

0.35a cd

om

(m

-1)

160 m CDOM at BATS

324 nm400 nm

1994 1996 1998 2000 2002 2004 20060

0.05

0.1

0.15

0.2

0.25

0.3

0.35a cd

om

(m

-1)

250 m CDOM at BATS

324 nm400 nm

1994 1996 1998 2000 2002 2004 20060

0.05

0.1

0.15

0.2

0.25

0.3

0.35a cd

om

(m

-1)

250 m CDOM at BATS

324 nm400 nm

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

a cdom

(m

-1)

Surface CDOM at BATS

324 nm400 nm

1994 1996 1998 2000 2002 2004 2006

-2

-1

0

1

2

NA

O In

de

x (S

.D.)

CDOM exhibits CDOM exhibits seasonal and seasonal and interannual interannual variabilityvariability

Possible Possible teleconnection teleconnection to climate to climate oscillators oscillators (NAO shown)(NAO shown)

Control of CDOM at BATSControl of CDOM at BATS

Annual: Balance between local Annual: Balance between local production and solar bleachingproduction and solar bleaching

Interannual: Multi-year accumulation Interannual: Multi-year accumulation at depth and ‘resetting’ by deeper at depth and ‘resetting’ by deeper winter mixing (similar to DOC winter mixing (similar to DOC patterns)patterns)

Absorption by PhytoplanktonAbsorption by Phytoplankton Phytoplankton pigments dominate Phytoplankton pigments dominate

absorption (detrital contribution small, absorption (detrital contribution small, correlated with phytoplankton)correlated with phytoplankton)

Strong seasonal cycle related to spring Strong seasonal cycle related to spring bloombloom

Seasonal change in absorption properties Seasonal change in absorption properties related to photoadaptation and seasonal related to photoadaptation and seasonal succession of phytoplankton speciessuccession of phytoplankton species

Primary production variability has been Primary production variability has been linked to climate oscillators such as ENSOlinked to climate oscillators such as ENSO

1994 1996 1998 2000 2002 2004 20060

0.005

0.01

0.015

0.02

0.025

a p,d

(44

0 nm

, m-1

)

Surface Particulate Absorption at BATS

ap

ad

Particle AbsorptionParticle Absorption

1994 1996 1998 2000 2002 2004 20060

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0.045

0.05a p

,d (

440

nm, m

-1)

80 m Particulate Absorption at BATS

ap

ad

1994 1996 1998 2000 2002 2004 20061

1.5

2

2.5

3

3.5

4

4.5

5

5.5

6a p

h (44

0 nm

/ 67

4 nm

)

Surface Phytoplankton Absorption Ratio at BATS

Blue-Red Absorption Ratio

1994 1996 1998 2000 2002 2004 20061

1.5

2

2.5

3

3.5

4

4.5

5

5.5

6a p

h (44

0 nm

/ 67

4 nm

)

80 m Phytoplankton Absorption Ratio at BATS

Blue-Red Absorption Ratio

Trends in Absorbing Components Trends in Absorbing Components at BATSat BATS

CDOM abundance governed in part CDOM abundance governed in part by physical processes possibly by physical processes possibly teleconnected to climate oscillatorsteleconnected to climate oscillators

Phytoplankton abundance and Phytoplankton abundance and species succession has not varied species succession has not varied along the same time scalesalong the same time scales

Conclusions (so far)Conclusions (so far)

The BBOP time series is enabling us to The BBOP time series is enabling us to observe and diagnose ocean color observe and diagnose ocean color variations occurring on climate-oscillator variations occurring on climate-oscillator time scales.time scales.

CDOM abundance apparently responds on CDOM abundance apparently responds on these time scalesthese time scales

So far we are not seeing this in a dramatic So far we are not seeing this in a dramatic way with the phytoplankton community way with the phytoplankton community

AcknowledgmentsAcknowledgments

Ocean Biology and Biogeochemistry Ocean Biology and Biogeochemistry Program, NASAProgram, NASA

Collaborators I’ve not mentioned (there Collaborators I’ve not mentioned (there are many, thank you)are many, thank you)

BBOP and BATS Project technicians, BBOP and BATS Project technicians, engineers, and students over the years (I engineers, and students over the years (I could fill several slides)could fill several slides)