EUMELI    STATION

Operation Label

Latitude

Longitude

Water Depth (m)

Gear

Date

Eu-KGS02

21¡02.94'N

31¡12.17'W

-4629

USNEL Box Core

15/01/91

Eu-KGS06

21¡02.87'N

31¡10.51'W

-4569

USNEL Box Core

17/01/91

Eu-KGS07

21¡03.16'N

31¡11.38'W

-4580

USNEL Box Core

17/01/91

Eu-KTB02

21¡03.17'N

31¡09.36'W

-4512

Multicorer

18/01/91

Eu-KTB10

21¡02.57'N

31¡11.50'W

-4597

Multicorer

17/02/91

EU-KTB13

21¡03.44'N

31¡10.48'W

-4584

Multicorer

25/05/92

Eu-KGS11

18¡31.57'N

20¡59.72'W

-3125

USNEL Box Core

22/01/91

Eu-KGS21

18¡30.42'N

21¡02.94'W

-3118

USNEL Box Core

25/01/91

Eu-KGS30

18¡35.28'N

20¡59.68'W

-3137

USNEL Box Core

27/01/91

Eu-KTB05

18o 33.62'N

21¡01.07'W

-3137

Multicorer

23/01/91

Eu-KTB07

18¡30.21'N

21¡03.67'W

-3114

Multicorer

26/01/91

Eu-KTB14

18¡27.92N

21¡03.31W

-3104

Multicorer

1/06/92

Eu-KGS67

18¡28.00N

21¡02.01W

-3112

USNEL Box Core

2/06/92

EU-KGS37

20¡28.41'N

18¡04.59'W

-1069

USNEL Box Core

3/02/91

EU-KGS38

20¡36.03'N

18¡28.64'W

-1556

USNEL Box Core

4/02/91

EU-KTB09

20¡31.99'N

18¡35.88'W

-2030

Multicorer

6/02/91

Eu-KTB16

20¡31.98'N

18¡35.93W

-2042

Multicorer

5/06/92

Eu-KTB17

20¡32.00N

18¡19.99W

-1259

Multicorer

7/06/92

Eu-KGS71

20¡31.96'N

18¡36.05W

-2046

USNEL Box Core

6/06/92

EU-KTB06

18¡31.99N

21¡03.08W

-3121

Multicorer

23/01/91

EU-KTB03

21¡00.61N

31¡13.75W

-4569

Multicorer

18/01/91

SEDORQUA  STATION

Operation Label

Latitude

Longitude

Water Depth (m)

Gear

Date

SDQ-S1

19¡28Õ23

17¡03'99

-507

Multicorer

11/03/94

SDQ-S2

19¡29Õ41

17¡16Õ87

-1403

Multicorer

11/03/94

SDQ-S7

21¡11Õ40

18¡51Õ50

-3010

Multicorer

17/03/94

SDQ-S8

21¡15Õ77

18¡27Õ49

-2530

Multicorer

17/03/94

SDQ-S9

21¡19Õ76

18¡15Õ10

-2005

Multicorer

17/03/94

SDQ-S10

21¡25Õ02

18¡04Õ70

-1525

Multicorer

16/03/94

SDQ-S11

21¡28Õ87

17¡57Õ35

-1195

Multicorer

16/03/94

SDQ-S17d

26¡53'23

14¡40'61

-2597

Multicorer

24/03/94

SDQ-S21

24¡53Õ00

16¡31Õ20

-750

Multicorer

19/03/94

SDQ-S24

26¡58Õ30

14¡01Õ30

-765

Multicorer

25/03/94

SDQ-S15

23¡43.60N

17¡15.60

-1000

Multicorer

18/03/94

__________________________________________________________________

         Sampling

EUMELI: Sediment samples were obtained using either a USNEL box corer (ref: KGS) or a multitube coring device (ref: KTB) (Barnett et al., 1984). The cores were retrieved upon arrival and immediately after transported to a cold room. The cold room was maintained at bottom water temperature (2-5oC) and the sediments were extruded as soon as possible. Sediments were packed into cleaned plastic tubes and centrifuged (Heraeus Model Omnifuge 200 refrigerated at 5oC) at a maximum of 9000 rpm for 5 to 10 minutes. The supernatant was subsequently transferred into plastic syringes and then filtered through Minisart Sartorius 0.45 mm filters. The pore waters samples were then stored into polypropylene Falcom tubes, acidified with ultra-pure H2SO4 (5N), and stored until chemical analysis.

SEDORQUA: Sediment samples were obtained using a multitube coring device (Barnett et al., 1984). The cores were retrieved upon arrival and immediately processed at 20°C. The sediments were quickly extruded and were packed into cleaned plastic tubes and centrifuged (Heraeus Model Omnifuge 200 refrigerated at 5oC) at a maximum of 6000 rpm for 10 minutes. The supernatant was subsequently transferred into plastic syringes and then filtered through Minisart Sartorius 0.45 microns filters. The porewaters samples were then stored into polypropylene Falcom tubes, acidified with ultra-pure HCl, and stored at 4°C until chemical analysis.

         Oxygen measurements

Two replicate profiles were achieved for each core. Briefly, a minielectrode of external diameter of 0.7 mm was inserted in the sediment using a micromanipulator which lowers the electrode by 0.5 mm at each movement. During this operation, the core was kept at bottom water temperature. The oxygen polarographic sensors is calibrated by Winkler titration of the overlying water and a zero oxygen on water in which Na2SO3 has been added. The electrode response is linearly proportional to the oxygen content of the porewater. The change of porosity near the sediment water interface may cause some artifact on the minielectrode. This was corrected using porosity measurements as described in De Wit et al (1997).

         Nitrate measurements

In the laboratory, nitrate determination was performed using colorimetric measurements on a RFA Alpkem 300 using a standard Cadmium reduction technique (Strickland and Parsons, 1972). The reproducibility of the measurement was 3% at this concentration level.

         Silicate measurement

In the laboratory, silicate determination was performed using colorimetric measurements on a RFA Alpkem 300 using a standard Molybdenum technique (Strickland and Parsons, 1972). The reproducibility of the measurement was 2%.

         Organic carbon measurements

EUMELI: Organic carbon measurements were carried out using a LECO WR12 analyser after decarbonation with HCl 2N (Khripounoff et al, 1998).

TABLE 1: Analytical procedures utilized for the chemical analysis of pore waters and sediments. METODS and INSTRUMENTATION: SFA = Segmented Flow Analysis: Alpkem RFA 300; CHN-EA = Elemental Analyzer: LECO CHN;. Reference list: (1) Revsbech et al. (1980); (2) Strickland and Parsons (1972); (3) LECOR techniques.

References:

De Wit, R., J.-C. Relexans, T. Bouvier, and D. Moriarty. 1997. Microbial respiration and diffusive oxygen uptake of deep-sea sediments in the Southern Ocean (Antares-1 cruise). Deep-sea Res., 44, 1053-1069.

Khripounoff, A., Vangrieshem, A. and Crassous, P., 1998. Vertical an temporal variations of particle fluxes in the deep tropical atlantic. Deep-Sea Res., 45: 193-216.

Relexans, J-C., J. Deeming, A. Dined, J-F. Gaillard, and Sibuet M. 1995. Sedimentary organic matter and micro-meiobenthos with relation to trophic conditions in the Northeast Tropical Atlantic. Deep-Sea Res., 43:1343-1368.

Revsbech N.P., Jorgensen B.B.& Blackburn T.H., 1980. Oxygen in the sea bottom measured with a microelectrode. Science, 207: 1355-1356.

Revsbech N.P.& Jorgensen B.B., 1986. Microelectrodes: their use in microbial ecology, in: Advances in Microbial Ecology, vol. 9. Plenum Press, New York. pp 293-352.

Strickland, J. D. H. and T. R. Parsons, 1972. A practical Handbook of Seawater Analysis. Bulletin 167, Fisheries Research Board of Canada, 310p.