SHORT AND LONG TERM

DYNAMICS OF OXYGEN IN THE

SOUTHERN BALTIC OFF POLAND

Janusz Pempkowiak

Instytut Oceanologii PAN

Sopot

•G-P Symposium, Sopot, 13-14.10. 2014•Coastal anoxia, Turku,2007

Respiration

C6H12O6 + 6O2 + ADP + H3PO4 → 6CO2 + 7H2O + ATP

A man uses 0.3 gO2/min

Oxygen is a biogenic element

Tlen, Sauerstoff (oxygen)- 8/16 O; O2

Discovered; 1773/1774- Sheele/Prestley

1603- Sędziwój

Properties:

•Tm- -220 C

•Tb- -180 C (Olszewski)

•Dissolution- 8,5 mg/l

•Reactive

Distribution•20,95 % - atmospheric air

•46,5% - earth crust

Significance

C6H12O6 (aq) + 6 O2 (g) → 6 CO2 (g) + 6 H2O (l)

∆G = -2880 kJ per mole of C6H12O6

6H2O + 6CO2 ���� C6H12O6+ 6O2

Ozone layer�

respiration/photosynthesis

Outline:

1.Introduction

2.Solubility of Oxygen in sea water

3. Oxygen in the Southern Baltic

4. Conclusions

2. Solubility in seawater

A(g) A(aq)

K = [A(aq)] / [A(g)]

Oxygen solubility

p (atmosphere)

c (water)

( )RT

P A A

g =

KH - Henry’s constant

A(aq) - [mol/litr]

( ) ( )

( )

( ) AHaq

Aaq

gaq

PK C

P RT

K C

A K A

⋅=

⋅=

⋅=

O2

A(g)

A(aq)

Factors influencing o-gen s-ty_1

C(aq) = KH·PA [mol/l]

= KH·22,400·PA [ml/l]

αA – Bunsen sol.coeff.

Bunsen solubility coefficient- ααααA

C(aq) units• cm3/dm3 (v/v)• mg/dm3 (m/v)

���� m/v ~ 1.6 (v/v)• mol/m3

���� m/32Cactual

Cequilibri= SI (saturation index- %)

T (°C)252015105

20

40

60

80

αml/l·atm

N2

O2

=

T

1 f α

Solubility of oxygen in water depends on temperature

T1=5oC ceq=9ml/l

cmeas=9ml/l � SI1 = 100% T2=20oC ceq=5ml/l

cmeas=5ml/l� SI2 = 100%

http://pl.wikipedia.org/w/index.php?title=Plik:Land_ocean_ice_2048.jpg&filetimestamp=20060901114718

Saturation index

Concentration of oxygen in seawater

gas

molecule

% in

atmosphere

% in

surface

seawater

ml/litre

sea water

mg/kg

(ppm)

in sea

water

molecular

weight

mmol/

kg

Nitrogen

N278% 47.5% 10 12.5 28.014 0.446

Oxygen

O221% 36.0% 5 7 31.998 0.219

Carbon

dioxide

CO2

0.03% 15.1% 1.5 90 * 44.009 2.142

Argon 1% 1.4% . 0.4 39.948 0.01

Solubility of gases in sea water

2.1. Factors influencing concentraion o foxygen in seawater.

Does oxygen concentration depend on river run-off ?

Odra River run-off Vistula

~17 km3/year ~40km3/year

Org.matter~1,400,000 ton/year

18° 19°54°

55°18° 19°

2-6 VI 2005Drgas, 2009

Vistula

SIizolines(%)

No, it does not.

(Pempkowiak, 1994)

CO2 + H2O CH2O + O2

CO2 + H2O CH2O + O2

hνννν

N,P

CO2

O2

Depositionto sediments

Assimilation

Mineralization

bacteria

Factors controlling oxygen concentration-2

1. CO2 assimilation/OM mineralization

2. Oxygen saturation disequilibrium•Temperature oscilations

•Supersaturation

O2conc.

O2

0m

Depthz

CO2 + H2O CH2O + O2hνννν

N,P

CO2 + H2O CH2O + O2

CO2 mg/l0m

20m

40m

60m

mineralization

diffusionsedimentation

Fluffy sediment layer

assimilation

turb.

mix.

Temporal and spatial decoupling of oxygen and OM production/consumption-the reason for oxygen deficit in near bottom water in shellow areas

CO2 + H2O CH2O + O2

CO2 + H2O CH2O +

H2S + CO2 + H2O CH2O + SO42-

CO2 + CH4 CH2O

N2

Fe2+

Mn2+

+NO3

-

Fe3+

Mn4+

oxic

unoxic

-150 400mV

reducing

oxic

unoxic

0cm

20cm

40cm

Eh

CO2 O2

Fluffy layer

Zawiesina naddena

CH2O + O2 ���� CO2 + H2O

- OM sedimentation

rapid flux

- O2 diffusionslow flux

water

sediments

Bay of Gdańsk, 37m depth (Garnelia pospolita)

June, 2007

Fluffy layer organic matter

O2Sat.

%

100T CO2+O2�CH2O+O2

cO2 T,

cO2

CO2+O2CH2O+O2

January M May S N month

Oxygen saturation disequilibria

1. Temperature fluctuations)

2. PP oversaturation

Surface

Sub-surface

Sub-halocline

Vertical distribution of salinity (parts

per thousand) in the Bothnian Bay, Bothnian Sea and Baltic proper

http://www.balticuniv.uu.se/environmentalscience/ch5/chapter5_g.htm

Vertical profiles for

temperature (broken line), salinity and oxygen (solid

lines) in the Gotland deep in 1998

Oxygen in the Baltic

Oxygen concentrations – offshore (Pastuszak,2012)

)

Głębia Gdańska - P1

100

80

60

40

20

0

m

I II III IV V VI VII VIII IX X XI XII

0

2

4

6

8

10

12

2H S

100

80

60

40

20

0

m

I II III IV V VI VII VIII IX X XI XII

0

50

100

a) stężenie tlenu

b) nasycenie tlenem

2H S

•2011

CO2 + H2O � CH2O + O2

CO2 + H2O

Gdańsk Deep, P1 station

a) concentration (ml/l)

b) saturation index (%)

I V IX I V IX I V IX I V IX I V IX I V IX I V IX I V IX I V IX I V IX I V IX I V IX I V IX I V IX I V IX I V IX I V IX I V IXI V IX

0 2 4 6 8 10 122H S [cm dm ]3 -3

1990 1992 1994 1996 1998 2000 2002 2004 2006

20

40

60

80

100[m]

[lata]

0

•1992-2010

S

7%o0m

40m

80m

120m

Zasięg stref beztlenowych w Morzu Bałtyckim

Areas with low oxygen content (red) or no

oxygen content (black) in the Baltic Sea in

1906 (A), 1955 (B) and 2012 (C),

respectively

http://www.balticuniv.uu.se/environmentals

cience/ch5_g.htm

Oxygen in coastal areas of the Baltic sea

Number of profiles over time

for the entire Baltic Sea and

frequency of hypoxia

calculated as the number of

profiles with recorded hypoxia

(<2 mg L–1) relative to the total

number of profiles.

Hypoxia Is Increasing in the Coastal Zone of the Baltic SeaEnviron Sci Technol. 2011; 45(16): 6777–

6783

Conley DJ

VISTULA LAGOON

VISTULA

ODRA

SZCZECIN LAGOON

SZCZECIN LAGOON

POMERANIAN BAY

BAY OF PUCK

PuckLagoon

BAY OF GDAŃSK

VISTULA LAGOON

COASTAL- LENGTH [km] 241 28 102

-AREA [km²] 687 5911 364 101 4940 838

AVERAGE DEPTH [m] 3,8 15 12,5 2.1 59 3,6

0

20

40

60

80

100

0 20 40 60

[nM]

[m

]

0

20

40

60

80

100

0 20 40 60

[nM]

[m

]

0

20

40

60

80

100

0 20 40 60

[nM] [

m]

POMERANIAN BAY

PUCK Lagoon

BAY OF PUCK

BAY OF

GDAŃSK

5 10 O2ml/l

1.5

3.0

m

8.9s

5.0Puck LagoonAugust,2011

5 10 O2ml/l

1.5

3.0

m

7,9s

5.8 Vistula LagoonAugust, 2011

5 10 O2ml/l

2.0

4.0

m

7.7s

3.2Szczecin LagoonAugust, 2011

5 10 O2ml/l

15

30

m

9.2s

3.9bGdańsk BayAugust, 2011

Oxygen concentrations – coastal (Pastuszak,2012

•surface(0-2m) vs bottom (2-0.5m above bottom)

P1

5 10 O2ml/l

15

30

m

9.5s

6.6b Middle coastAugust, 2011

Nasycenie tlenem [%]

60

70

80

90

100

110

120

130

140

1 2 3 4 5 6 7 8 9 10 11 12

Nasycenie tlenem [%]

85

95

105

115

125

135

1 2 3 4 5 6 7 8 9 10 11 12

Nasycenie tlenem [%]

90

100

110

120

130

140

150

160

1 2 3 4 5 6 7 8 9 10 11 12

Nasycenie tlenem [%]

70

90

110

130

150

170

1 2 3 4 5 6 7 8 9 10 11 12

Monthly oxygen concentrations (%saturation)- surface (Pastuszak, in prep.)

- 1990-2005 averages

Long term- conclusions•surface- ~ (!)

•bottom - (?)

Jan. June Dec.

Jan. June Dec.

Jan. June Dec.

Jan. June Dec.

1990-1998

(Poleszczuk,2002)

s

b

(Pastuszak,2006)

Conclusions and Outlook

Oxygen depletion consequences

1. Denitrification (O2 conc. < 2mg/dm3)- still oxic

NO3- + CH2O N2 + H2O + CO2

2. Reduction of Fe (III) and Mn (IV) (O2 conc. ~0mg/dm3)- unoxic

Fe3+ + CH2O Fe2+ + H2O + CO2

- phosphates release

- mobilization of heavy metals

- mobilization of POPs bioavailability, toxicity

- number of organisms/species (?)

3. Methylation of Hg (II) (O2 conc. <0 mg/dm3)- reducing

- Hg mobility/bioavailability

4. H2S generation (O2 conc. < 0mg/dm3)- reducing

- all biota extinguished

- reducing bacteria

� Biota !!!

Guesstimations

Future trends

Organic matter supply related � organic matter loads? � nutrients

•increase nutrients loads , river run-off climate,, agriculture trends, politics I, politics II•Decrease politics II (BAP, Targrev, consensus)

Water layerts•< 40m temperature stratification, salinity decrease , stormness climate•> 70m organic matter, water inflows surface freshening, temper. climate

Eco- enginireeng (????)

Layer Org.mat

increas

Climate

s.l.fresh

Climate

temp.

Climate

storms

Climate

inflows

surface ~ ~

Subsurf. ~

Subhalo. ~ ~

Guesstimations

Large scale ecological engineering

•Pumping oxygen

•Stoping inflows

Nutrients and climate

Good

Bed

Neutral~

Hipoxia

CO2 + H2O CH2O + O2

CO2 + H2O CH2O + O2

hνννν

N,P

CO2

O2

Depositionto sediments

Assimilation

Mineralization

bacteria

Factors controlling oxygen concentration

1. CO2 assimilation/OM mineralization

O2conc.

O2

0m

Depthz

3.Tlen w wodzie Morza Bałtyckiego

Areas with low oxygen content (red) or no oxygen content (black) in the Baltic

Sea in 1906 (A), 1955 (B) and 2012 (C), respectively

(York et al., 1999)

Temporal and spatial decoupling

- experimental evidence

3.Tlen w wodzie Morza Bałtyckiego

CO2 + H2O CH2O + O2

CO2 + H2O CH2O + O2