HYPOX kickoff: Site introduction Introduction to the Koljö Fjord … · 2009. 7. 8. · Seaguard & RCM deployment 2, 17-23. Sep. 2008. Baltic Sea, Gotland Basin, Station GB-A, 50

Introduction to the Koljö Fjord SitePer Hall (UGOT)

....HYPOX kickoff: Site introduction

Koljö Fjord map (1)....HYPOX kickoff: introduction to Koljö Fjord



Hydrography....HYPOX kickoff: introduction to Koljö Fjord

Distribution of oxygen....HYPOX kickoff: introduction to Koljö Fjord

Koljö Fjord - Existing data (1)....HYPOX kickoff: introduction to Koljö Fjord

SMHI: Water column depth distributions of S, T, O2 , H2 S, nutrients, tot N, tot P, chlorophyll, Secchi depth, pH, alkalinity, etc. at the central deepest site. Most of these parameters (and certainly S, T and O2 ) have been measured:- on a monthly basis since 1986, - on a bimonthly or quarterly basis during 1958-1985, - (at least) annually during 1934-37. There are no measurements for the period 1938-57. The monitoring program in the Koljö Fjord is ongoing and presently run by SMHI.

Koljö Fjord - Existing data (2)....HYPOX kickoff: introduction to Koljö Fjord

Other data exist especially on sediments in the Koljö Fjord, e.g. on foraminifera, C and N, water content, etc. Used for paleo-climatological/oceanographic studies (Dept. of Earth Sciences, UGOT).These studies focused on e.g. previous oxygen conditions in the fjord on time-scales of up to hundreds of years.

Aim of the HYPOX work at the site and suggested key parameters to measure (1) (UGOT in cooperation with IFM-GEOMAR)

....HYPOX kickoff: introduction to Koljö Fjord

*Long term mooring in neighboring basin (Havstens Fjord) from where most water is imported - T, S, O2 at 4 levels in the top 15 m

*Long term mooring at exit of fjord (shallow Malö strömmar) - T, S, currents

*Weather station at Koljö Fjord - wind speed and direction, humidity, light

*Biweekly-monthly water column measurements in Koljö Fjord and Havstens Fjord - T, S, O2 , Nu, chlorophyll, … (by us and SMHI for at least a year)

Aim of the HYPOX work at the site and suggested key parameters to measure (2)


*Intensive measuring campaigns year 1 and 3: Weekly measurements in Koljö Fjord and 3 adjacent basins/fjords for 2 months of T, S, O2 , Nu (surface 20 m), DIC and N2 /Ar (also deep water), and of sea level

*Coupled 1-D process modeling (the 4 basins)

*Lander in-situ flux measurements on oxic and anoxic Koljö Fjord sediments - O2 , Nu, DIC, DOC, CH4 , N2 O, …

*2-D in-situ O2 imaging across SWI using autonomous planar optode

*Vertical O2 gradients and horizontal currents in water close to sea- floor

Description of the coupled 1-D process model:A 1-D process-based physical-biogeochemical model with high temporal (hours) and vertical (1 m) resolution will be used for Koljö Fjord. The barotropic and baroclinic exchange through the straits are computed using observations in Havstensfjord and Björnsund (boundary conditions). The model may produce budgets for S, T, O2, C, nutrients and N2 , and can be used to test various process formulations.

Planned HYPOX work at the site (cont.)....HYPOX kickoff: introduction to Koljö Fjord


Göteborg benthic lander

General configuration:1. Buoyancy2. Ballast3. Ballast release

system4. Experimental

modules5. Surface spotting

3.

4.

2.

1.

5 .


Göteborg benthic lander

RCM-LW Current Meter (Horizontal current speeds)

Seaguard Current Meter (Vertical current speeds)

OxygenOptodes

Ballast weight (rail)



Studies of dissolved oxygen dynamics

Seaguard & RCM deployment 2, 17-23. Sep. 2008. Baltic Sea, Gotland Basin, Station GB-A, 50 m.



Seaguard & RCM deployment 2, 17-23. Sep. 2008. Baltic Sea, Gotland Basin, Station GB-A, 50 m.



Seaguard & RCM deployment 2, 17-23. Sep. 2008. Short-term oscillations of O2 (recording every 10 s)


Studies of dissolved oxygen dynamics Mini Lander with planar optode

(1) sensing film (2) sensor window (3) excitation LEDs (4) diffuser (5) mirror (6) dichroic mirror, (7) excitation filter (8) lens (9) CCD camera, (10) electronics controlling excitation light (11) connectors (12) central housing


Planar optode side view

1)

Camera

Window

Mirror

2)

Sediment

[1] [2]

Mirror

Sediment

Window

Camera


Planar optode functioning


Gradients from planar optode images (1)





Oxygen Gradients at station GBA

200210220230240250260270280290300310320330

17-sep 18-sep 19-sep 20-sep 21-sep 22-sep

Time

Oxy

gen

(µM

) RCM9 (4.45m)

RCM9 (3.45m)

O2#23 (2.85m)

O2#39 (2.35m)

O2#40 (2.0m)

Plan Opt, high

Plan Opt, middle

Plan Opt, low




Planar optode time series example (1)

S1, May 5, 21:18S1, May 5, 21:18


Planar optode time series example (2)

S1, May 5, 21:18S1, May 5, 21:18


Expected outcome of the HYPOX work in Koljö Fjord (1)*An O2 budget for the Koljö Fjord based on the model:Import from and export to adjacent basins; sum effect of exchange with atmosphere, pelagic prim.prod and benthic prim. prod; consumption in water and sediment; and consumption in water as a function of depth.Similar budgets will be produced for nutrients, organic carbon and N2 .The model will be based on, and validated against, the weekly water column, benthic chamber, planar optode, and vertical BW O2 gradient measurements.


*Comparison of different in-situ methods to estimate benthic O2 uptake:Benthic chamber fluxes, bottom water and sediment µ-profiles obtained from planar optode, and computations based on “long- term” vertical O2 gradients and horizontal currents in bottom water.*Contribution from benthic prim. prod. to the O2 budget of the fjord (based on continuous combined oxygen and light measurements near bottom)*Organic C deposition, recycling and burial in sediment on a basin wide scale*Production of green-house gases (CH4 , N2 O) in this anoxic fjord

Expected outcome of the HYPOX work in Koljö Fjord (2)


S1, May 5, 21:18S1, May 5, 21:18

Oxygen & Photosynthetic photons

0

100

200

300

400

500

600

700

800

900

1000

1100

1200

1300

1400

1500

1600

1700

1800

08-05-01 08-05-06 08-05-11 08-05-16 08-05-21 08-05-26 08-05-31

Time

Pho

tons

[µM

/s/m

2]

1

2

3

4

5

6

7

8

9

10

O2

[ml/l

]

Photons

O2

http://www.smhi.se/cmp/jsp/polopoly.jsp?d=103&l=sv


S1, May 5, 21:18S1, May 5, 21:18

Oxygen & Photosynthetic photons

0

100

200

300

400

500

600

700

800

900

1000

1100

1200

1300

1400

1500

1600

1700

1800

08-05-01 08-05-06 08-05-11 08-05-16 08-05-21 08-05-26 08-05-31

Time

Pho

tons

[µM

/s/m

2]

1

2

3

4

5

6

7

8

9

10

O2

[ml/l

]

Photons

O2

Comments:During most spring/summer days with sunny weather there is benthic primary production.Average depth of Öresund around 15 m.Importance of benthic primary production compared to pelagic?

http://www.smhi.se/cmp/jsp/polopoly.jsp?d=103&l=sv

An ESONET test site observatory in Koljö Fjord? A possible opportunityAspirations:Cable to shore enabling internet accessAccess to data in real-timeSensors for O2 , T, S, fluorescence, turbidity, NO3 ?, …Long-term (6-30 months) observationsPartners:Uni-HB, UGOT, IFM-GEOMAR, IFREMER?, …Others?


Additional measurements in Koljö Fjord and Gotland Basin: Green-house gas production (methane and nitrous oxide)We plan to measure benthic in-situ fluxes, and water column distributions, of methane and nitrous oxide in the Koljö Fjord and the By Fjord (the latter fjord will be oxygenated by pumping).This work will be carried out in cooperation with Leif Klemedtsson‘s group at Dept. of Plant and Environmental Sciences, UGOT.We also plan to do these measurements in the eastern Gotland Basin.Other HYPOX partners who have similar plans there? IOW?Cooperation?


HYPOX kickoff: Site introduction Introduction to the Koljö Fjord … · 2009. 7. 8. · Seaguard & RCM deployment 2, 17-23. Sep. 2008. Baltic Sea, Gotland Basin, Station GB-A, 50

Documents