Use of regularly migrating non-biological Use of regularly migrating non-biological platforms as vehicles for spatio-temporal platforms as vehicles for spatio-temporal

sampling of Southern Ocean systemssampling of Southern Ocean systems

Simon Wright, Brian Griffiths, Bronte Tilbrook,Simon Wright, Brian Griffiths, Bronte Tilbrook,Steve Rintoul, Alain Poisson Steve Rintoul, Alain Poisson

25 Jan 2003 10 Feb 2003 26 Feb 2003

How to model microbial populations?

Recognize different types of communities

Key species and associations

When and where do they occur?

Time of season

Oceanographic conditions

MLD, nutrients, ice, etc

Parameterize the community properties

Primary production, respiration

Aggregation

Sedimentation

Size distribution

What would a Southern Ocean Observing System look like?

Regularly Migrating Non-Biological Platforms

Seagoing Hydro-Investigative Platforms

(SHIPs)

(RMNBPs)

Aurora Australis

L’Astrolabe

Programmable

Ecological

Observing

Package

(Live Elements)

(PEOPLE)

Three pronged approach

Monitoring on repeat transects l’Astrolabe

Intensive oceanographic surveys Aurora Australis

Process studies in minicosms

Coupled with laboratory experiments

Aurora Australis

-65.6 -65.4 -65.2 -65.0 -64.8 -64.6 -64.4 -64.2 -64.0 -63.8 -63.6 -63.4 -63.2 -63.0

Latitude

Total Chlorophyll a 112E

-200

-180

-160

-140

-120

-100

-80

-60

-40

-20

0

Dep

th (

m)

0.1

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2.4

2.6

2.8

3.0

3.2

3.4

ice

ASF

Tmin

Pycnocline

-65.6 -65.4 -65.2 -65.0 -64.8 -64.6 -64.4 -64.2 -64.0 -63.8 -63.6 -63.4 -63.2 -63.0

Latitude

Prasinophytes 112E

-200

-180

-160

-140

-120

-100

-80

-60

-40

-20

0

Dep

th (

m)

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0.10

0.11

0.12

0.13

0.14

ice

ASF

Tmin

Pycnocline

Disadvantage of Aurora Australis

erratic migratory route

Three pronged approach

Monitoring on repeat transects l’Astrolabe

Intensive oceanographic surveys Aurora Australis

Process studies in minicosms

Coupled with laboratory experiments

Sokolov & Rintoul 2002

Regular monitoring of Hobart - Dumont d’Urville

3 – 4 repeat transects per season

Astrolabe lab in hold

Astrolabe lab interior

l’Astrolabe repeat transects

– Oceanography: • XBT sections, nutrients: Steve Rintoul, CSIRO • alkalinity

– Alain Poisson IPEV, Paris

– Phytoplankton: • Chlorophyll fluorometry , FRRF

– Brian Griffiths, CSIRO• HPLC pigments, Species ID and counts (whole

and net), coccolithophorid counts

– Australian Antarctic Division – Carbon dioxide: pCO2

• Bronte Tilbrook, CSIRO

CO2 drawdown

Chlorophyll a

Astrolabe2002/03

CO2 drawdown

Chlorophyll a

Astrolabe2002/03

2 0 4 0 6 0 8 0 1 0 0 1 2 0 1 4 0 1 6 0

D a y s s i n c e 1 O c t 2 0 0 2

- 6 5

- 6 0

- 5 5

- 5 0

- 4 5

Lat

itu

de

0

0 . 2

0 . 4

0 . 6

0 . 8

1

1 . 2

1 . 4

1 . 6

1 . 8

2

2 . 2

A s t r o l a b e 2 0 0 2 - 0 3 T o t a l C h l a ( u g / L )

Oct | Nov | Dec | Jan | Feb | Mar

Date of bloom at mid latitude (53- 60ºS)

Season Bloom peak

1997-98 3 Dec

1998-99 19 Dec

1999-00 01 Jan

2000-01 09 Jan

2001-02 25 Jan

2002-03 10 Feb

2003-04 10 Jan

2004-05 15 Dec

3 0 5 0 7 0 9 0 1 1 0 1 3 0 1 5 0

D a y s s i n c e 0 1 O c t 2 0 0 3

- 6 5

- 6 0

- 5 5

- 5 0

- 4 5

Lat

itu

de

0

0 . 2

0 . 4

0 . 6

0 . 8

1

1 . 2

1 . 4

1 . 6

1 . 8

A s t r o l a b e 2 0 0 3 - 0 4 T o t a l C h l a ( u g / L )

Oct | Nov | Dec | Jan | Feb | Mar

20 30 40 50 60 70 80 90 100 110 120 130 140 150-66

-64

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-48

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-44

00.10.20.30.40.50.60.70.80.911.11.21.3

Astrolabe 2004 -05 Total Chl a (ug/L)

Days since 01 Oct 2004

Lat

itu

de

Oct | Nov | Dec | Jan | Feb | Mar

Bloom dynamics at mid latitude (53- 60ºS)

2002 - 2003• Bloom in Feb• about 1 ug Chl a/ L• Dominant species

– F. kerguelensis, Phaeocystis, Trichotoxon, Thalassiothrix, Pseudonitzschia

2003 – 2004, 2004 – 2005 (Typical)• Bloom in Dec - Jan• about 0.8 - 1 ug Chl a/ L• Dominant species

• F. kerguelensis, Pseudonitzschia, Trichotoxon, Chaetoceros dichaeta

2 0 4 0 6 0 8 0 1 0 0 1 2 0 1 4 0

D a y s s i n c e 1 O c t

- 6 6

- 6 4

- 6 2

- 6 0

- 5 8

- 5 6

- 5 4

- 5 2

- 5 0

- 4 8

- 4 6

- 4 4L

atit

ud

e (S

)

- 2

0

2

4

6

8

1 0

1 2

1 4

1 6

S u r f a c e T e m p . 2 0 0 3 - 0 4

2 0 4 0 6 0 8 0 1 0 0 1 2 0 1 4 0

D a y s s i n c e 0 1 O c t

- 6 6

- 6 4

- 6 2

- 6 0

- 5 8

- 5 6

- 5 4

- 5 2

- 5 0

- 4 8

- 4 6

- 4 4

Lat

itu

de

(S)

- 2

0

2

4

6

8

1 0

1 2

1 4

1 6

S u r f a c e T e m p . 2 0 0 4 - 2 0 0 5

Oct | Nov | Dec | Jan | Feb | Mar Oct | Nov | Dec | Jan | Feb | Mar

2 0 4 0 6 0 8 0 1 0 0 1 2 0 1 4 0

D a y s s i n c e 0 1 O c t

- 6 6

- 6 4

- 6 2

- 6 0

- 5 8

- 5 6

- 5 4

- 5 2

- 5 0

- 4 8

- 4 6

- 4 4

Lat

itu

de

(S)

- 2

0

2

4

6

8

1 0

1 2

1 4

1 6

S u r f a c e T e m p . 2 0 0 2 - 2 0 0 3

2 0 4 0 6 0 8 0 1 0 0 1 2 0 1 4 0

D a y s s i n c e 1 O c t

- 6 6

- 6 4

- 6 2

- 6 0

- 5 8

- 5 6

- 5 4

- 5 2

- 5 0

- 4 8

- 4 6

- 4 4

Lat

itu

de

(S)

- 2

0

2

4

6

8

1 0

1 2

1 4

1 6

S u r f a c e T e m p . 2 0 0 3 - 0 4

Oct | Nov | Dec | Jan | Feb | MarOct | Nov | Dec | Jan | Feb | Mar

33.633.733.833.93434.234.334.434.634.83535.235.435.5

Salinity 2003-04

1 2 3 4 5 6

Transect No.

-62

-61

-60

-59

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-53

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-50

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-47

-46

-45

-44

La

titu

de

(S

)

33.633.733.833.93434.234.334.434.634.83535.235.435.5

Salinity 2004-05

1 2 3 4 5 6

Transect No.

-62

-61

-60

-59

-58

-57

-56

-55

-54

-53

-52

-51

-50

-49

-48

-47

-46

-45

-44

Lat

itu

de

(S)

33.633.733.833.93434.234.334.434.634.83535.235.435.5

Salinity 2003-04

1 2 3 4 5 6

Transect No.

-62

-61

-60

-59

-58

-57

-56

-55

-54

-53

-52

-51

-50

-49

-48

-47

-46

-45

-44

La

titu

de

(S

)

1 2 3 4 5 6

Transect No.

-62

-61

-60

-59

-58

-57

-56

-55

-54

-53

-52

-51

-50

-49

-48

-47

-46

-45

-44

Lat

itu

de

(S)

33.633.733.833.93434.234.334.434.634.83535.235.435.5

Salinity 2002-2003

2003-04 Silicate

0

10

20

30

40

50

60

70

80

43 47 51 55 59 63 67

Latitude

R0_S

R0_N

R1_S

R1_N

R3_S

R3_N

2002-03 Silicate

0

10

20

30

40

50

60

70

80

43 47 51 55 59 63 67

Latitude

R0_S

R0_N

R2_S

R2_S

R4_S

R4_N

Bloom dynamics at mid latitude (53- 60ºS)

The late bloom in 2002-2003 was associated with relatively warm, very low salinity water

This water had low nutrient concentrations.

A bloom developed only after nutrient concentrations

increased

Conclusions

Regular sampling of Southern Ocean from l’Astrolabe identified seasonal patterns in microbial populations

–relationship to carbon dioxide uptake

–Relationship to nutrient drawdown

Substantial interannual differences in bloom dynamics appeared to be driven by seawater chemistry

An anomalous late bloom developed only after nutrient concentrations increased in a large area of warm low salinity water.

A small subset of total data: made possible by repeated sampling of many parameters in a collaborative program

l’Astrolabe repeat transects

– Organization: – Alain Poisson IPEV, Paris– Bronte Tilbrook, CSIRO

– Acknowledgements– Captain and crew S.V. l’Astrolabe– Many volunteer samplers

What should a SOOS look like?

– Regular transects along the same transect

What should a SOOS look like?– Oceanography:

• Thermosalinograph

• XBT sections, nutrients• Alkalinity• Carbon dioxide: pCO2

– Atmospheric• Carbon dioxide, oxygen, DMS• Dust

– Environment• Temperature, radiation, wind speed, wave height, ice

– Plankton: • Chlorophyll fluorometry, FRRF • HPLC pigments, Species ID and counts (whole

and net)• Continuous plankton recorder