EARLY DIAGENESIS AND BENTHIC FLUXES IN ADRIATIC AND IONIAN SEAS

Federico Spagnoli1; Gabriella Batholini1, Patrizia Giordano2

1Istituto Scienze Marine, CNR, Ancona, Italy 2Istituto Scienze Marine, CNR, Bologna, Italy

Early diagenesis processes and benthic fluxes in the Adriatic and Ionian sea as resulting from various research projects

carried out from 80s to present

• Early projects of the Institute of Marine Geology of Bologna (Italy), (1980-1989) Giordani P., Hammond D., Frascari F.;

• MAST, (1995-1997) Giordani et al.; • EUROMARGE, (1997-2000) Giordani et al.; • PRISMA1, (1993-1996) Frascari F., Spagnoli F., Bergamini M.C.,

Marcaccio M.;• PITAGEM, (2001-2004) Spagnoli F., Bartholini G., Giordano P.; • VECTOR, (2006-2009) Spagnoli F., Giordano P., Ravaioli M.

Sampling sites of previous researches

12.0°E 12.5°E 13 .0°E 13.5°E 14 .0°E 14.5°E 15.0°E

42.5

°N43

.0°N

43.5

°N44

.0°N

44.5

°N4

5.0°

N45

.5°N

0Km 20Km 40Km 60Km 80Km 100Km

Stazioni di campionamento Indagini processi diagenetici e flussi bentici

PRISMA1

12.0°E 12.5°E 13.0°E 13.5°E 14.0°E43.5°N

44.0°N

44.5°N

45.0°N

45.5°N

0Km 20Km 40K m 60K m 80K m 100Km

ISTITUTO DI GE OLOGIA MA RINA

C

B

A

Old IGM-CNR projects VECTORPITAGEMMAST, EUROMARGE

Methods• Early diagenesis

– Pore water and solid phase analyses in sediment cores;

• Dissolved benthic fluxes

– Benthic chamber deployments;

– Core incubations on deck;

– Pore water profile modelization.

ISMAR-CNRbenthic chamber

( )2

2 1 0z zC C CDs w K R It z z

δ δ δδ δ δ

= − + + + =

( ) 01 bz bzC C e C e−∞= − +2

0 1 2C C a z a z= + +

EE RRzz = = exponentialexponentialEE RRzz = = constantconstant EE RRzz = = quadraticquadratic

ISMAR-CNRon deck laboratory

Map of the main Adriatic diagenetic environments

Trieste

Venezia

Chioggia

Ravenna

Cervia

Rimini

Pesaro

Senigallia

Ancona

Civitanova

S.Benedetto

Giulianova

Pescara

Ortona

2300000 2350000 2400000 2450000 2500000

4700

000

4750

000

4800

000

4850

000

4900

000

4950

000

5000

000

5050

000

-10

-20

-40

-50

-60

-40

-60

-80

-100

-120

-120

-140

-140

-160-180

-200-220

-240-250

AA1

47

52

39

40

AA5

4

AA7

13 (S2)

10 (S3)

28

18 (S1)

17

0Km 25Km 50Km 75Km 100Km

Scale 1:1500000

Type B diagenesis

Type C diagenesis

Type D diagenesis

Type D' diagenesis

Type A diagenesis

Type E diagenesis

L E G E N D

D D' mixed type diagenesis

?

??

?

?

?

?

? More data needed

A

B

C

D

E

A

F1

F2

1

D2

?

? ?

?

?

?

Various diagenetic environments resulted from Various diagenetic environments resulted from different:different:

-- particulate and dissolved continental inputs;particulate and dissolved continental inputs;

-- distances from main sediment sources distances from main sediment sources (mainly the Po River);(mainly the Po River);

-- bottom sediment composition (bottom sediment composition (carbonaticcarbonatic or or silicoclasticsilicoclastic););

-- organic matter (fresh marine and old organic matter (fresh marine and old continental organic matter);continental organic matter);

-- depths (more or less depths (more or less resuspensionresuspension events, events, increasing pressure with depth);increasing pressure with depth);

-- oxygenation of water column.oxygenation of water column.

-10

AA7

28

18

17PO RIVER B

-120-100-80-60-40-20

00 10 20 30

Alkalinity (meq/l)

-120-100-80-60-40-20

00 25 50 75 100

Phosphate (uM)

-120-100-80-60-40-20

00 500 1000 1500

Ammonia (uM)

St. 17

-120-100

-80-60

-40-20

00 50 100 150

Mn (uM)

-120-100

-80-60-40-20

00 3 6 9 12

Nitrate (uM)

-120-100

-80-60

-40-20

00 100 200

Fe (uM)

-120-100

-80-60-40-20

00 20 40

Sulphate (mM)Oxygen (mg/l)

-20

-10

0

10

20

30

0 2 4 6

mm

Silicoclastic sediments, high sedimentation rates, high reactive and degraded organic matter contents, high Fe-oxy-hydroxide contents, very high benthic fluxes (NH4, PO4, DIC) for degradation of high organic matter contents, anoxic-non sulfidic-methanic environments

Early diagenesis Process: type B

Rimini

-10-20

AA7

28

18

PO RIVER

C

-120-100-80-60-40-20

00 10 20

Alkalinity (meq/l)

-120-100-80-60-40-20

00 10 20 30 40 50

Phosphate (uM)

-120-100

-80-60-40-20

00 500 1000 1500

Ammonia (uM)

St. 18

-140-120-100-80-60-40-20

00 50 100 150

Mn (uM)

-140-120-100-80-60-40-20

00 3 6 9 12

Nitrate (uM)

-140-120-100-80-60-40-20

00 100 200

Fe (uM)

-140-120-100-80-60-40-20

00 20 40

Sulphate (mM)Oxygen (mg/l)

-3

-2

-1

0

1

2

0 2 4 6

mm

Early diagenesis Process: type CSilicoclastic sediments, autochthonous organic matter, high Fe-oxi-hydroxides, medium sedimentation rates, medium benthic flues (NH4, DIC, Si(OH)4) for degradation of reactive organic matter in anoxic conditions, anoxic-non sulfidic-partially post oxic environments, high phosphate fluxes for Fe oxy-hydroxide dissolution.

Pesaro

Ancona

S.Benedetto

-20

-40

-50

-60

-60

47

3940

AA5

D

-120-100-80-60-40-20

00 10 20

Alkalinity (meq/l)

-120-100-80-60-40-20

00 10 20 30 40 50

Phosphate (uM)

-120-100-80-60-40-20

00 500 1000 1500

Ammonia (uM)

St. 39St. 47

-120-100-80-60-40-20

00 50 100 150

Mn (uM)

-120-100-80-60-40-20

00 3 6 9 12

Nitrate (uM)

-120-100-80-60-40-20

00 100 200

Fe (uM)

-120-100-80-60-40-20

00 20 40

Sulphate (mM)

Early diagenesis Process: type DMixed silicoclastic sediments, weak sedimentation rates, weak reactive organic matter for repeated reworking and low primary production, higher oxygenation of water column:

•D1) weak benthic fluxes for low reactive organic matter, anoxic-non sulfidic-post oxic environments;

•D2) medium benthic fluxes for local higher organic matter inputs, anoxic-non sulfidic-partially post oxic environments.

D1

D2

Pescara

-120

-140

-160-180

-200-220

-240-250

52

E

-120-100

-80-60-40-20

00 10 20

Alkalinity (meq/l)

-120-100-80-60-40-20

00 10 20 30 40 50

Phosphate (uM)

-120-100-80-60

-40-20

00 50 100 150

Mn (uM)

-120-100-80-60-40-20

00 3 6 9 12

Nitrate (uM)

-120-100-80-60

-40-20

00 100 200

Fe (uM)

-120-100-80-60-40-20

00 20 40

Sulphate (mM)

-120-100

-80-60-40-20

00 500 1000 1500

Ammonia (uM)

St. 52

Oxygen (mg/l)

-20

-10

0

10

20

30

40

0 2 4 6

mm

Early diagenesis Process: type EBasin area, greater depths and far away from main continental inputs, low sedimentation rate, fine sediment highly reworked, low reactive organic matter contents, main degradation at sediment-water interface, oxicenvironments up to 10 cm, very weak diagenetic processes and benthic fluxes, Fe and Mn oxy-hydroxides precipitation on first centimetres.

South Adriatic and Ionian SeaVery low organic Matter degradation product concentrations for low reactive

organic matter inputs

- low concentration layer in first cms (oxic layer, nitrification processes):

- thinner in Adriatic stations (higher organic matter inputs and sedimentation rates) ;- thinner in Ionian basin stations respect to slope stations;

- Deeper layers characterized by NH4 increase, stronger in Adriatic Sea (higher reactive Organic Matter and sedimentation rates).

Ammonia

Dissolved Inorganic Carbon

Adriatic Sea:Higher concentrations respect to Ionian Sea Station;

- DIC concentrations increase about linearly with depth;

- slow degradation processes, low reactive OM.

Ionian Sea:

-DIC concentrations decrease below sediment-water interface, and increase beyond 5-10 cm (CaCO3 precipitation in the uppermost cms);- lower values respect to Adriatic stations;- very slow OM degradation processes

DIC

Adriatic

Adriatic

IonianIonian

Electron final acceptors: dissolved Mn pore water profilesoxic and anoxic non-sulfidic post oxic environments

Oxic layer increases southward from Adriatic to Ionian stations.

Different thickness for different organic matter inputs and sedimentation rate (basin area in Ionian Sea).

South Adriatic and Ionian Sea

Adriatic

Ionian

Oxygen Benthic fluxes

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

4 13 10 17 18 AA7

28 AA5

40 39 47 52 S1_2002

S1_2003

S2_2002

S2_2003

St. P1

St. A1

St. O2

St. I2b

St. S3

St. M3

St. M5

Stations

mm

ol/m

2*d

Benthic chambers

Pore w aters

Nitrate Benthic fluxes

-1,5

-1

-0,5

0

0,5

1

4 13 10 17 18 AA7

28 AA5

40 39 47 52 S1_2002

S1_2003

S2_2002

S2_2003

St. P1

St. A1

St. O2

St. I2b

St. S3

St. M3

St. M5

Stations

mm

ol/m

2*d

Ammonia Benthic fluxes

-1

0

123

4

56

4 13 10 17 18 AA7

28 AA5

40 39 47 52 S1_2002

S1_2003

S2_2002

S2_2003

St. P1

St. A1

St. O2

St. I2b

St. S3

St. M3

St. M5

Stations

mm

ol/m

2*d

Phosphate Benthic fluxes

-0,050

0,050,1

0,150,2

0,250,3

0,35

4 13 10 17 18 AA7

28 AA5

40 39 47 52 S1_2002

S1_2003

S2_2002

S2_2003

St. P1

St. A1

St. O2

St. I2b

St. S3

St. M3

St. M5

Stations

mm

ol/m

2*d

DIC Benthic fluxes

-80

-60

-40

-20

0

20

40

60

80

4 13 10 17 18 AA7

28 AA5

40 39 47 52 S1_2002

S1_2003

S2_2002

S2_2003

St. P1

St. A1

St. O2

St. I2b

St. S3

St. M3

St. M5

Stations

mm

ol/m

2*d

Silica Benthic fluxes

01234567

4 13 10 17 18 AA7

28 AA5

40 39 47 52 S1_2002

S1_2003

S2_2002

S2_2003

St. P1

St. A1

St. O2

St. I2b

St. S3

St. M3

St. M5

Stations

mm

ol/m

2*d

Fe Benthic fluxes

-0,10

0,10,20,30,40,50,60,7

4 13 10 17 18 AA7

28 AA5

40 39 47 52 S1_2002

S1_2003

S2_2002

S2_2003

St. P1

St. A1

St. O2

St. I2b

St. S3

St. M3

St. M5

Stations

mm

ol/m

2*d

Mn Benthic fluxes

00,20,40,60,8

11,21,4

4 13 10 17 18 AA7

28 AA5

40 39 47 52 S1_2002

S1_2003

S2_2002

S2_2003

St. P1

St. A1

St. O2

St. I2b

St. S3

St. M3

St. M5

Stations

mm

ol/m

2*d

Adriatic and IonianBenthic fluxes

Electron acceptorsElectron acceptors O.M. degradation productsO.M. degradation products SilicaSilica

••Benthic fluxes generally decrease Benthic fluxes generally decrease leaving from Po River mouths leaving from Po River mouths (increasing distances from main (increasing distances from main sediment and nutrient sources, sediment and nutrient sources, continuous reworking, lower primary continuous reworking, lower primary production, less reactive organic production, less reactive organic matter)matter)

••Minimal fluxes in Ionian sediments Minimal fluxes in Ionian sediments

••Negative DIC fluxes in central Negative DIC fluxes in central Adriatic and Ionian slopes (DIC Adriatic and Ionian slopes (DIC sediment trap?)sediment trap?)

Early diagenesis and benthic fluxes in the GEOTRACES Programme

Information on the isotopic alteration in sediments during early diagenesis will enhance the ability to use stable isotope abundances from sedimentary records as proxy indicators

for past changes of environmental conditions.

• Trace element stable isotopes affected by early diagenesis:– d98/95Mo (McManus et al. 2002),

• Early diagenesis reactions fractionate Mo isotopes: lighter ratio in oxic pore water environment (2.1‰ pw, 2.3‰ sw) produced by Mn-oxide dissolution, heavier ratio in reducing sediments (3.5 ‰), net sink of isotopically light dissolved Mo) that explains the heavier sea water (2.3‰) ;

• Low temperature hydrothermal systems are sources of light Mo in the ocean (0.8‰);– d56Fe,

• Decreasing values in pw by Fe-oxide dissolution, increasing with depth in pw for sulfide precipitation;– d74Ge (Rouxel et al. 2006),

• Which is the segregation of Germanium isotopes in early diagenesis (opal dissolution and Ge precipitation)? Sea water >3‰, BSE ~1.3‰, authigenic marine sediments 3‰, mesozoic deep sea chert 0.7-2‰. How does the d74Ge change with climatic change in sea water (both with Ge/si and Si isotopes)?

• other stable element isotopes:– d13C (Lehmann et al. 2002), decreasing value in O.M. during oxic and anoxic early diagenesis (1.6‰), decreasing

values in pw (from -1 to -20‰) for degradation of O.M. or increasing value for CH4 production (Nissenbaum et al. 1972;

– d15N, decreasing value in O.M. during anoxic early diagenesis (3‰), no distinguishable trend in oxic degradation – d34S, increasing in pw by consuming of SO4 and producing of S.

• Early diagenesis and benthic fluxes are poorly investigated in the Mediterranean (Golfe du Lion et des Baléares, Rouibah & Cauwet, 1993; Picon & Buscail , 2000; Denis, Grenz, 2003; Local Iberian seas, Vidal & Morgui, 1998; Gómez-Parra and Forja; Ortega, Ponce, Forja and Gómez-Parra, 2002; Aegean Sea, Ozkan, Kocatas and Buyukisik, 2008

• Studies related to early diagenesis isotope fractionation are not many in the Mediterranean (some early data of δ13C and δ15N from Langone et al. 2009) so that investigation in this field could be very interesting.

ISMAR-CNR vessel facilities for GEOTRACES

RV UraniaOperator: CNR - National Research Council

Country: ItalyVessel Type: Multipurpose Research Vessel

Vessel Class: RegionalOperational Area: Mediterranean Sea

Endurance: 45 daysScientist berths: 20

Length: 61.3m

Website: http://www.cnr.it/sitocnr/UPO/gestione/infoce/navi/UPOnavi.html

M/N DalllaportaOperator: CNR - National Research Council

Country: ItalyVessel Type: Off shore research activity vessel

Operational Area: Mediterranean SeaLength: 33.30 m

Width: 7.65 mSpeed: 14 knots

Crew: 6Scientists 11

Available for GEOTRACES programme by scientific agreement with ISMAR-CNR scientists:

-2011: in alredy scheduled cruises (Adriatic Sea, Ionian Sea, Sicily Strait);

- 2012: by application of scientific proposals.