Phytoplankton Biomass Feedbacks on in situ Heat Budget

8/2/2019 Phytoplankton Biomass Feedbacks on in situ Heat Budget

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Phytoplankton Biomass Feedbacks

on in situ Heat Budget

M.J. GarzioA, L.A. KahlB, T.N. MilesA, K.E. ColemanA, O.M. SchofieldA.

A. Institute of Marine and Coastal Sciences, Rutgers University.

B. AAAS Fellow, State Department Washington D.C.


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OUTLINE

What is Palmer Station Long Term Ecological

Research (PAL-LTER)

Additional sampling added to LTER in 2008

Current optical measurements within the LTER

Preliminary analysis of the optical properties and

phytoplankton feedbacks

Importance of biomass Importance phytoplankton composition


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What is the LTER?

Spatial- Season glider missions and a cruise every January on the historical grid

Temporal-Fixed sampling at Palmer Station coupled to seasonal annual sampling with partners conducting the

Rothera Antarctic Timeseries

1. To document and quantify the processes of climate and ecosystem change in the west Antarctic

Peninsula continental shelf via nearshore land-based, offshore shipboard, unattended mooring,

autonomous glider and satellite remote sensing observations;

2. To understand, through process measurements, manipulative experiments, comparative analysisagainst other marine ecosystems, data synthesis and modeling, the physical and ecological

mechanisms of climate and ecosystem change;

3. To predict/project the future course of ecosystem change in the west Antarctic Peninsula region.

Sampling Strategies


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Ecosystem changes in LTER

Temperature trends per yearTaken from Ducklow et al. (2012)

-Winter warming, 6rC in 50yrs (Skvarca et al. 1999, Vahghan et al. 2003)-Retreating glaciers (Cook et al. 2005)

-Ice season has shortened drastically (Stammerjohn et al. 2009)

-Summertime surface chl has decreased (Montes-Hugo et al. 2009)

-Communities shifting pole-ward (Montes-Hugo et al. 2009)


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AUVs, Teledyne Webb

Gliders

Optics

Todays focus will be

on the optical

additions to thePAL-LTER

W avelength (nm )

Depth

(m)

Quanta (W /m 2)

400 450 500 550 600 650 700

-30

-25

-20

-15

-10

-5

0

0

5

10

15

20

25

30

35

40

Quanta(W/m^2)

New tools added to LTER examining phytoplankton-light

interactions (since 2008)


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Optical Sampling Methods

Inherent Optical

Properties

(IOPs)

[a, b, c, bb]

Apparent Optical

Properties

(AOPs)

[Ed, Lu, Kd]

~250 casts at Palmer and close to

200 on the R/V L.M.Gould

Used AOP profiling instrument

every station we dropped IOP

Copyright 2008 by Curtis D. Mobley.

Radiative Transfer Equations

WetLabs Absorption-Attenuation

meter(ac-9) & Backscatter Pucks

Satlantic profiling

Hyperspectral Radiometer


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Palmer Station, St.

B.December 28, 2009

Palmer Station, St.

B.December 01, 2009

The optical properties vary

dramatically over the season.

Moderate to high chlorophyll and

low CDOM except near penguin

islands.

Nearshore there is also highly

scattering particles associated

with glacial flour.

IOPs from two casts 27

days apart


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We assess the accuracy of optical measurements by conducting closure

experiments to how well we can reconcile the IOP and AOP measurements.

12/01/09 St. B

0

5

10

15

20

25

30

35

40

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4

depth

(m)

Modeled Kd

Measured Kd

0.08

0.1

0.12

0.14

0.08 0.1 0.12 0.14

Modeled Kd

MeasuredKd

12/28/09 St. B

0

10

20

30

40

0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5

depth(m

Modeled Kd

Measured Kd

y = 0.9902x + 0.0009

0.08

0.12

0.16

0.2

0.24

0.08 0.13 0.18 0.23

Modeled Kd

MeasuredKd

We find that we have good agreement between measured AOPs (here the diffuse

attenuation coefficient) and the modeled AOPs from the IOPs. There is a close to one to

one relationship. This allows us to optimize ship sampling, by allowing the propagation of

light through the water column at any time of day given our measured IOPs

IOP

AOP

IOP

AOP


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What are the feedbacks of the phytoplankton on

the in situ optics in the WAP?

Biology/Ecology(Phytoplankton)

Biomass

Composition


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IOPs clearly show the presence or absence

of phytoplankton blooms

Tim e

Depth

(m

)

PA L0910 December St .B absorp t ion @488

11/29 12/06 12/13 12/20 12/27 01/03

-6 0

-5 0

-4 0

-3 0

-2 0

-1 0

0

0

0.02

0.04

0.06

0.08

0. 1

0.12

0.14

0.16

0.18

0. 2

Sampled 2 times a week and additional

days when weather permitted

Dec. 2009

Early 09-10 season bloom where wind forcing was low, stabilizing the water column


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Integrated Chlorophyll a at

Palmer Station

Chlorophyll (mg/m) for LTER

0

20

40

60

80

100

120

140

10/4/1990 6/ 30/1993 3/ 26/1996 12/21/1998 9/ 16/2001 6/ 12/2004 3/ 9/2007 12/3/2009 8/ 29/2012

Time

How variable is Biomass?

Chlorophyll a for cruise survey

grid

Timeseries

Spatial survey


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How variable is Biomass?

Rothera Time Series (RaTS) data from our colleagues at the British AntarcticSurvey (BAS). Thank you Hugh Venerable & Michael Meredith for all the

collaborative efforts between LTER/IMCS and BAS.

Chlorophyll values off Rothera Point, Adelaide Island


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We are interested on the relationship between high biomass and light because it

has been shown there are strong feedbacks of biomass on radiant heating in

temperate waters (Chang & Dickey 2004, Ohlmann et al 2000, Cahill et al 2008).

13m

Optical properties in high biomass blooms

Case Example Jan. 2011 bloom in Marguerite Bay, chlorophyll values ranged from 15-40mgC/m3

Modeled light profile in the bloom, note good agreement between modeled and measured AOPs


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Hydrographic models without acoupled ecological model often usePaluson & Simpson (1977) equationsto derive irradiance curves fromassumed Jerlov water types.

Jerlov III significantly overestimatesthe propagation of light in the watercolumn. 1% light value is at 35mwhere measurements show 1% light

value at 13m

Jerlov III curve

Feedbacks between high biomass and physics

Hydrolight Ed curve1%

1%


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50 Watt (J/s) difference betweenobserved and a ROMS type modeloutput.

4000 J will increase 1 L of water +1rC.(Millero et al., 1973; using algorithmsin Fofonoff and Millard, 1983).

Theoretically every 4min. +3rC to oneliter on a very bright sunny day with nomixing.

The potential errors will lead tosignificant errors in the modeled upper

water column heat budget

Especially important in high biomasswaters in the WAP

Feedbacks between high biomass and physics


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What are the feedbacks of the phytoplankton on

the in situ optics in the WAP?

Biology/Ecology(Phytoplankton)

Biomass

Composition

Community structure

Preliminaryfindings


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B) cryptophytes

D) prasinophytes

A) diatoms

C) mixed flagellates

100

50

0100

50

0

%c

hlorophyllaassociatedwi

thphytoplankton

taxa

01/01/95 01/01/05

Date (day/month/year)01/01/95 01/01/05

E) type-4 haptophytes

ChemTax software takes chlorophylla and accessory pigments using a

multilinear regression to produce a

percent of phytoplankton taxa

present in a sample.

Notice either diatoms or cryptophytes

are the major players.


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WatercolumnIntegratedAlloxanthin

Water column Integrated Fucoxanthin

WatercolumnIn

tegratedChloroph

ylla

>300

200

100

0

Diatoms and Cryptophytes are not found at the same time. A shift in

phytoplankton composition shows a shift in particle size distribution

10

m

100

m

McMinn &

Hodgson (1993)


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2005/2006

-Cryptophytes -Diatoms


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2005/2006-Cryptophytes -Diatoms


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Conclusions

Optical properties are effective tools for measuring theinteractions between phytoplankton and physical properties ofthe water column.

It will be difficult to model the radiant heat budget effectivelywithout accurately modeling the propagation of light through

higher biomass conditions frequently found along the WAP.

Additionally phytoplankton community and composition shiftswill result in distinct shifts in the particle size distribution whichin turn should have a strong affect on the in water opticalproperties.

Acknowledgments: We would like to extend a special thank you to the captain and crew of theR/V L.M. Gouldand to Raytheon Polar Services for the support in the field and statesideassistance. Also, we acknowledge the other technicians that have helped sample andcollect our data from field teams other than B-019. This work was done in cooperation withthe Palmer LTER project supported by NSF.


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Montes-Hugo et al 2009


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0

250

12/1/910

50

03/1/92

1991-1992

0

40

10/25/92

1992-1993

0

4

02/8/93

0

200

11/21/940

40

02/27/95

0

400

11/15/950

40

01/08/96

1994-1995

1995-1996

Date (month/day/year)

0

150

11/18/960

50

03/24/97

1996-1997

0

20

12/01/97 0

50

04/10/98

0

20

10/01/980

50

02/01/99

1997-1998

1998-1999

0

1000

11/01/990

10

04/01/00

0

200

11/01/020

40

04/01/03

2002-2003

0

400

11/01/05 0

200

05/01/06

2005-2006

0

400

10/01/050

25

04/01/06

2006-2007

0

20

11/01/080

80

04/01/09

2000-20012008-2009

Fucoxanthin (mg m-2) Alloxanthin (mg m-2)


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Phytoplankton Biomass Feedbacks on in situ Heat Budget

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