BIODEEP WP 2 Chemical characterization of seawater/brine/ sediments and related fluxes.
A. A. watercolumn/brinewatercolumn/brine analyses (UU) analyses (UU) B. B. susp.mat.susp.mat. major/minor elements; C,N (UU) major/minor elements; C,N (UU) key trace elements (Pb,Co,Zn,Cu,Cd) (UP)key trace elements (Pb,Co,Zn,Cu,Cd) (UP) C. C. sed.trapssed.traps major/minor elements; C,N (UU) major/minor elements; C,N (UU) microfossils / biogenic components (UM)microfossils / biogenic components (UM) radiotracers (radiotracers (210210Pb, Pb, 230230Th) (SOC)Th) (SOC) D. D. sedimentssediments (major/minor elements; C,N) (SOC/UU) (major/minor elements; C,N) (SOC/UU) key trace elements (Pb,Co,Cu,Zn,Cd) (UP)key trace elements (Pb,Co,Cu,Zn,Cd) (UP) E. E. pore waterpore water extraction/analysis (UU) extraction/analysis (UU)
WP2.1 CRETE-
yr2
Aspects related to brine redox chemistry
o N-speciesN-specieso S-speciesS-specieso MnMn2+2+ - MnO - MnO22 cycling cycling
o FeFe2+2+ - Fe - Fe22OO33 - Fe,S cycling - Fe,S cycling
o SOSO4 4 22 -- - HS - HS-- cycling cycling
N-species
0 1000 2000 3000 4000NH 4
+ (uM)
3600
3400
3200
3000
Dep
th (d
bar
)
- 2 0 2 4 6
NO 3- (uM)
Bannock Brine
I
II
At interface seawater/brine: nitrate jumps from 5 to 0 uM, whereas ammonia goes from ~ 0.2 to 3600 uM
In oxic seawater: org.mat. + O2 106 HCO3- + 16 NO3
- HPO42-
In anoxic brine: org.mat. + SO42- 106 HCO3- + 16 NH4+ HPO4
2- + 53 HS-
S-species: examplified by the most extreme case: URANIA Brine
0 4 8 12 16HS- (m M )
3650
3600
3550
3500
3450
3400
De
pth
(d
bar)
2 0 4 0 6 0 8 0 1 0 0 1 2 0
SO 42- (m M)
Urania Brine East
I
II
CHCH44 + SO + SO442-2- - - HCO HCO33
-- + HS + HS-- + H + H22OO
Likely dominant reaction in Urania :
BD 10C T
0 1000 2000 3000 4000
D IC (uM )
0 4 8 12 16phosphate (uM )
Atalante Basin phosphate and DIC data (BD10CT); seawater/brine interface oyxgen en sulphide data (UM08CT)
ATALANTE Basin
0 500 1000 1500 2000 2500
HS (M )
-100
0
100
200
relative Dep
th (cm
)
0 40 80 120 160 200
O 2 (M )
WP2-CTD1
1 4 1 4 . 4 1 4 . 8
Tem perature (oC)
4000
3000
2000
1000
0
De
pth
(d
ba
r)
1 2 1 6 2 0 2 4 2 8Temperature
3700
3600
3500
3400
I
II
Bannock Brine
13.6 14 14.4 14.8 15.2Tem perature (oC)
3800
3600
3400
3200
Dep
th (dba
r) I
II
Bannock.B.
Density vs depth
3400
3450
3500
3550
3600
3650
3700
3750
1.204 1.206 1.208 1.210
dens ity [g/cm3]
Bannock brines I/II (BD34CT): density and alkalinity
Alkalinity vs depth
3400
3450
3500
3550
3600
3650
3700
3750
3.8 4.0 4.2 4.4
Alk mM
Note rapid increase in alkalinity at seawater/brine I interface, and the rapid decrease at the brine I/II transition
4 0 8 0 1 2 0 1 6 0 2 0 0
Conductivity
3560
3520
3480
Dep
th (
db
ar)
I
IIAtalante B .
Orca/AB interface comparison
ATALANTE Basin
0 500 1000 1500 2000 2500
HS (M )
-100
0
100
200
relative Dep
th (cm
)
0 40 80 120 160 200
O2 (M )
2060
2120
2180
2240
2300
2360
2420
Orca/AB-2
Orca/Med.brines
Major difference in interface thickness Major difference in interface thickness
(~ 100 m vs ~ 100 cm)(~ 100 m vs ~ 100 cm)
Major difference in redox-chemistry Major difference in redox-chemistry
(Fe, S a.o.; see below)(Fe, S a.o.; see below)
Orca relative to Mediterranean brine basins:
Manganese cycling:
observations in other redox-dominated environment :
o Tyro Basin
TB
Tyro basin, eastern Mediterranean
Manganese cycling at seawater/brine Interface : (replotting data De Lange et al.)
6000
4000
2000
0
Cl (
mM
)
0 2 4 6
Mn2+ (uM)
Bannock Brineseawater interface
VV
solid 'MnO2'
dissolved 'M n2+'
Ox/Anox boundary
0 1 2 3
HS- (mmole/kg)
4000
3600
3200
2800
De
pth
(d
bar)
0 2 4 6 8 10
Mn2+ (umole/kg)
Bannock Brine
I
II
At interface seawater/brine, Mn2+ concentration jumps from ~ 0.005 to 5 umole/kg,
whereas HS- goes from 0.03 to 1800 umole/l
BB-Mn/HS
Bannock and Orca brines dissolved Fe2+, HS- (UU, Saager et al.; after Trefry et al.; Wiesenburg et al.)
0 1 2 3HS- (um ole/kg)
2400
2300
2200
2100
2000
Dep
th (
dba
r)
0 10 20 30 40
Fe2+ (um ole/kg)
Orca Brine
0 1 2 3HS- (mm ole/kg)
4000
3600
3200
2800
De
pth
(d
bar)
0 40 80 120
Fe 2+ (nm ole/kg)
Bannock Brine
I
II
(note different scales !
20020044MnMn2+2+ (uM) (uM)
0.30.33.0003.000HSHS-- (uM) (uM)
30.00030.0002020FeFe2+2+ (nM) (nM)
Bannock Orca
BBvsOB Fe,S
Major importance of: S > Mn > Fe
Brine Density Cl Na K Mg Ca SO4 B Sr Li BrAvg. m m m m m m m u u mTB 1,21 4425 4410 16 59 30 44 0,8 275 75 1BB 1,21 4430 3500 105 537 14 113 3,8 141 280 8AB 1,23 4300 3800 300 333 5,9 323 4 34 76 4DB 1,35 7030 50 15 3700 1,9 71 19 2 320 75Ube 1,13 3300 3100 108 280 28 95 9,5 410 420 8Ubw 1,13 3000 2800 90 220 34 90 9 470 440 9NB 1,2 4458 4469 4 6 15 32 4 0,3
Red S 1,2 4350 4040 56 34 120 8 0,8 550 38 2Orca 1,19 4219 3983 16 43 27 40 1Med 1,03 590 500 10 58 10 28 0,4 80 25 1
Brines average major elements
2 5
2 0
1 5
1 0
5
0
rel.
dep
th
1 000 2000 3000C l (m m ole /kg )
2 5
2 0
1 5
1 0
5
0
rel.
de
pth
1 000 2000 3000C l (m m ole /kg )
BB U B
Interface
Brine basin interfaces
450 500 550 600 650 700
Ca (ppm)
0
20000
40000
60000
80000
Na
(pp
m)
0 1000 2000 3000 4000
K (ppm )
Interface
• Conservative behaviour of Ca, Sr, K
• Diss. Mn and HS- may only be done if sampled and stored properly
Bannock basin interface
Suspended matter
• How much material in suspension
• Composition of material: major and trace elements as well as C and N concentrations
Major analytical problems because of very little sample material, and also because of extremely high salt contents of samples, …. Salt corretions are only very rough, so the results are high in error. Samples should be washed just after filtreation to remove the salt, this is vital for a reliable analysis
0.0
5.0
10.0
15.0
20.0
25.0
30.0
Atalante Uraniaeast
Discovery Bannock
susp
end
ed m
atte
r (m
g/l
)
Suspended matter
Average suspended material in different basins
Suspended matter
1062049143611506210B B
774472 33628D B
502650542556112858U B
192976444108170211A B
ppmppmppmppm mg/l
SrSKCa susp. matter
Average total mass and composition
Mass and concentrations are corrected for salt influence
Suspended matter
0
10000
20000
30000
40000
50000
A B U B D B B BK
(p
pm
)
0
2000
4000
6000
8000
10000
12000
A B U B D B B B
Ca
(p
pm
)
bdl
Sediment traps
3500ST3
2500ST2
1500ST1
Depth (m)Station BD03
Bannock basin
Sediment traps
3500ST3
2500ST2
1500ST1
Depth (m)Station BD03
Bannock basin
Sediment traps
3500ST3
2500ST2
1500ST1
Depth (m)Station BD03
Bannock basin
3500ST4
2800ST3
1500ST2
460ST1
Depth (m)Station PS 027
Urania basin
Sediment traps
3500ST3
2500ST2
1500ST1
Depth (m)Station BD03
Bannock basin
3500ST4
2800ST3
1500ST2
460ST1
Depth (m)Station PS 027
Urania basin
Methodology:
• Total destruction of samples for ICP-OES and ICP-MS analysis
• Subsampling during total destruction for Si analysis with photospectrometer
• C-total, C-organic and N contents with CNS- analyser
0
1000
2000
BB oxic BB anoxic UB oxic UB anoxic
mg
/m2
/d
Total mass flux
(average september-may)
0
40
80
120
ma
teri
al f
lux
(mg
/m2 /
d)
J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D
1999 2000 2001 2002
U ran ia basin ox ic 2500 m
B annock basinox ic 2500 m
0
20
40
60
80
ext
ra S
i in
sam
ple
(%
)
J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D
1999 2000 2001 2002
U ran ia basin ox ic 2500 m
Bannock basinoxic 2500 m
Additional Si input in sediment: evidence for dust input
Urania Urania basin oxicbasin oxic
Bannock Bannock basin oxicbasin oxic
14,714,73,93,9average mass average mass flux (mg/m2/d)flux (mg/m2/d)
154.4353.71000.936.6134.8 anoxic
1.2 23.90.53.1 oxic
Urania basin
24.71.073.03.218.9 anoxic
0.8 3.80.31.0 oxic
(mg/m2/d)(mg/m2/d)(µg/m2/d)(mg/m2/d)(mg/m2/d) Bannock basin
SiSMnFeCa
Average elemental fluxes
Average chemical characterization of sediment
56,1Terr.
2,2OM
8,7SiO2 extra
33,0CaCO3
Wt%Comp.
WP2.1
Bannock anoxic
Bannock anoxic 2001/2002
2000
22002400
2600
28003000
3200
3400
36003800
4000
0 5 10 15 20
NH4+ in sediment trap bottles
Average Si-flux
autumn14%
winter11%
spring22%
summer53%
Bannock anoxic
autumn16%
winter12%
spring20%
summer52%
Average S-fluxBannock anoxic
autumn19%
winter14%
spring17%
summer50%
Average Mn-fluxBannock anoxic
Average CaCO3-fluxBannock anoxic
summer49%winter
13%
spring20%
autumn18%
Average Corg-fluxBannock anoxic
autumn15%
winter14%
spring17% summer
54%
Average N-fluxBannock anoxic
autumn13%
summer56%
winter12%
spring19%
WP2-2
Chemical characterization of Chemical characterization of sediments & pore waterssediments & pore waters
WP2.1d
Boxcore Sampling site
BW sample Winckler bottles
PW extr.
Glove-box
water% samples
BD19MC DB x X YES #1
BD21MC UB.e x X YES #1
BD26BC AB x X YES #1
BD27BC normal x x
BD31BC normal x x
BD42BC BB x x YES #1
BIODEEP 2002 pore/water sampling
Chemical characterization of sediments
Sediment preparation methods Sediment preparation methods (+/- salt removal, prior to analysis; intercalibration,..)(+/- salt removal, prior to analysis; intercalibration,..)
Intercalibration Intercalibration (methods, Labs,…) (methods, Labs,…) (see Thomson)(see Thomson)
Sediment composition Sediment composition
0
5
10
15
20
25
30
0 5000 10000
DIC [umol/l]
de
pth
[cm
]
0
5
10
15
20
25
30
0 5 10
Alk [umol/l]de
pth
[cm
]
BD26BC(AB)
0
2
4
6
8
10
12
0 2 4
Dep
th (
cm)
BD26BC(AB)
Mg/Al Na/Al
0
2
4
6
8
10
12
0 20 40
Dep
th (
cm)
BD26BC(AB)
0
2
4
6
8
10
12
0 2 4
Dep
th (
cm)
Ca/Al Mn/Al
0
2
4
6
8
10
12
0 0,01 0,02
Dep
th (
cm)
0
5
10
15
20
25
30
35
0 1000 2000
HS- umol/l]
BD41BC(BB)
0
5
10
15
20
25
30
35
0 5
Alk meq/l]
0
2
4
6
8
10
12
0 2 4
Dep
th (
cm)
BD41BC(BB)
Ca/Al Mn/Al
0
2
4
6
8
10
12
0 0,02 0,04
Dep
th (
cm)
UBcores
W
E
BD07BC
BD21MC
Major differences occur between the core in E and W
basin
0
10
20
30
40
50
60
0 500
Si [umol/l]de
pth
[dba
r]
0
10
20
30
40
50
60
0 20 40
PO4 [umol/l]
dept
h [d
bar]
BD21MC(UB east)
BD21MC (UB-east)
porewater results
0 20 40 60 80 100SO 4= (m m ole/kg)
6 0
4 0
2 0
0
Dep
th (
cm)
1 2 1 6 2 0 2 4
C a (mm ole/kg)
400 440 480 520 560 600M g (mm ole/kg)
6 0
4 0
2 0
0
Dep
th (
cm)
2000 2400 2800 3200
Sr (um ole/kg)
Brine ?!
Precip. ?!
BD21MC (UB-east)
solid phase results
0 4 8 12 16 20 24
CaCO3 (wt.%)
5 0
4 0
3 0
2 0
1 0
0
Dep
ht (
cm)
0 20 40 60 80
S (wt.%)
BD07BC (UB-west) sediment results
0 2 4 6% C.tot
1 0
8
6
4
2
0
Dep
th (
cm)
0.02 0.04 0.06 0.08 0.1 0.12 0.14
% N .tot
0 4000 8000 12000 16000 20000S .tot (ppm )
1 0
8
6
4
2
0
De
pth
(cm
)
40000 80000 120000 160000 200000
N a (ppm )
3 0 4 0 5 0 6 0 7 0 8 0
Water %
Clearly for some elements the total sediment is salt-Clearly for some elements the total sediment is salt-dominateddominated
Corrections can be done from intercalibration resultsCorrections can be done from intercalibration results
UR2001 sed.
0.1 0.2 0.3 0 .4 0 .5 0.6
% C.org
6 0
5 0
4 0
3 0
2 0
1 0
0
Dep
th (
cm)
0 10 20 30% CaC O 3
0.02 0.04 0.06 0.08Ntot
0 1 2 3 4Sto t%
Sediment composition(DB)
0.1 0.2 0.3 0 .4 0 .5 0.6
% C.org
6 0
5 0
4 0
3 0
2 0
1 0
0
Dep
th (
cm)
0 10 20 30% CaC O 3
0.28 0.3 0.32 0.34K/Al
0.1 0.2 0.3Na/Al
Sediment composition(DB)
BD19MC-Cl
0
10
20
30
40
50
60
0 5000 10000
Cl [mmol/l]
0
10
20
30
40
50
60
9000 9500 10000
Cl [mmol/l]
BD19MC(DB)
WP2.1e
BD19MC
0
10
20
30
40
50
60
0 20 40
Si [umol/l]
0
10
20
30
40
50
60
0 100 200
PO4 [umol/l]
BWBW
DB-sediment
0 1000 2000 3000 4000 5000M g (m m ole /kg)
6 0
4 0
2 0
0
Dep
th (
cm)
0 0.4 0 .8 1 .2 1 .6
C a (m m ole /kg)
0 20 40 60 80S O 4= (m m ole /kg)
0 2000 4000 6000
Sr/C a (m m ole/kg)
BD19MC porewater results
4 0 6 0 8 0 1 0 0 1 2 0 1 4 0P O 4= (um ole/l)
6 0
4 0
2 0
0
Dep
th (
cm)
2 0 2 2 2 4 2 6
A lk (m eq/l)
BD19MC
DBalls
DBalls
Prelim. Composition: Ca6Mg20(SO4)6Cl13(CO32-)x. y H2O
Future Perspectives
Suspended matter (esp. at interfaces)Suspended matter (esp. at interfaces) Gas content of brines (pressure sampling!)Gas content of brines (pressure sampling!) Sediment trapsSediment traps Sediment work (Discovery basin)Sediment work (Discovery basin)