- Email: [email protected]
The boundary region between the Weddell Sea and Drake Passage currents
Deep-SeaResearch1977,Vol.24, pp. 505to 510. PergamonPress. Printedin Great Britain.
The boundary region between the Weddell Sea and Drake Passage currents G. E. R. DEACON* and THEODORED. FOSTER'~ (Received 8 October 1976; accepted 11 November 1976) Abstract The boundary between the currents from the Weddell Sea and the Drake Passage has been investigated in the area between the South Shetland and South Orkney islands. New data confirm the existence of a sharp boundary over the Scotia Ridge and show that the warm deep layer in the northwestern Weddell Sea is cooled below 0°C when it reaches depths shallower than about 1000 m.
THE INTERNATIONALWeddell Sea Oceanographic Expedition (IWSOE) in 1975 on USCGC Glacier included a line of eight TSD observations between 60°S, 50°W and 62°S, 49°30'W, across the accepted boundary region between currents flowing east by north from the northern side of the Weddell Sea and the southern side of the Drake Passage (Fig. 1). The potential temperature and salinity sections, supported by Nansen-bottle sampling at Stas. 1, 4 and 8, are drawn in Figs. 2 and 3. Near Sta. 3 there is a narrow zone with deep temperatures less than 0°C, between warm water modified during passage round the Weddell Sea to the south, and appreciably warmer water, just reached by the section, that can only Come from the Drake l~ssage, to the north. There are lower deep-water salinities in the same narrow zone. The temperature and salinity sections are very similar to those shown by DEACONand MOOREY in their recent note in Deep-Sea Research (1975}, and agreeing with the earlier conclusions of WOST (1926), DEACON(1937), MODEL(1958) and GORDON(1971), confirm the special interest of the region. To assist further consideration we have plotted the geographical distribution of the maximum potential temperatures in the warm deep layer at most of the stations included in the NODC tape from 58 to 64°S in 44 to 64°W, adding those of IWSOE 1975 and 1976, and using the section drawn by Deacon and Moorey (Fig. 4). While trying to include all usable information we had to omit a few stations where it seemed likely that the sampling was not deep enough to reach the nucleus of the warm layer. The temperatures plotted in the cold shelf water regions near theAntarctic peninsula and near the South Orkney Islands are temperature maxima in water of about the same density as the warm deep water further offshore. Although the data are not sufficient for satisfactory geographical coverage there are enough to show that the warm deep layer has been cooled below 0°C when it reaches areas that are shallower than about 1000 m. The diagram indicates that the cold-deep-water area associated with the Antarctic peninsula extends eastwards across the ocean at least as far as 49°W, and that there is a similar area on the 500-m plateau south of the South Orkney Islands. There is another cold area in 42 to 43°W on the Scotia Ridge east of the Orkneys * Institute of Oceanographic Sciences, Wormley, Godalming, Surrey, GU8 5UB, England. t Scripps Institution of Oceanography, La Jolla, California 92093, U.S.A.
505
506 56°W I
o.E.R. DEACONand THEODORED. FOSTER
I
54"W I
52"W I
Av
/
50"W I
I
48°W I i
46" W
44°W 59"S
59"5
200
/
BO°S
60*S
SOUT~ t ,~ ORKNEY ZSLANDS
61"S
61"S
62°S
6Z'S
63"
63°S
JOINVILLE ZSLAND
__.•
64"
64°S
56~W
54°W
52°W
50*W
48°W
46°W
44°W
Fig. 1. Bathymetry in metres of northwestern Weddell Sea (after D. G. W^TT~S,Antarctic geology and geophysics, R. G. ADn~,editor, Osio University Press, 1972, pp. 33-38) and station location of section ~crou Scotia Ridge.
(Discovery Stas. 1036, 1866; Eitanin Sta. 102). The possibility of surface water sinking in such areas, either by total convection in winter, or by mechanical mixing processes between currents of water of somewhat different densities, and possibly with different velocities, was mentioned by the previous authors. The geographical distribution seems to suggest that in the large shallow areas convection may provide an adequate mechanism. The observations there were all made in summer when the near-surface water is warmed and diluted, but there can be little doubt that winter cooling, ice formation and advection from the neighboring Weddell Sea is sufficient to raise the salinity above 34.5%o and to lower the surface temperature to freezing point. For example, it would take about 1.1 m of sea ice formation at IWSOE 75 Sta. 2 to make the whole water column isohaline. Under such conditions convection and mixing could incorporate the surface, deep and bottom waters into a cold,
I
Fig. 2.
5000 t
0
I
2
0.25
3
4
~
5
8
~-I 5
SCALIE (kin) I I 50 ...... IO0__
7
POTENTIAL TEMPERATURE I
I 0 ....
6
Potential temperature section across Scotia Ridge near 50°W.
.
(GLACIER 1975) STATION NUMBER
e II I-/1'
I '/'~
Z
I
3
. ,~' \
/
I
4
Fig. 3.
5000
O0 -
5
..//
, 0
,.
6
, 50
SALINITY
SCALE ( km)
--...
' IO0
54.68"-
. . . . . . ~,,~ . . . . ---
............
I
7
Salinity section across Scotia Ridge near 50°W.
ooo - 1 / / \
~L
~
I
(GLACIER 1975) STATION NUMBER I
8
/
1
"l /
-t
/
&
,,,,,
0
?,
~r 0 :::1
-}
508
G . E . R . DEACON and THEOOOi~ D. FOSTER
56°W
5,4°W
52*W
1
'
590S
'
I
50DW
I
I
48"W
1
!
+1.44
+2.0~
DRAKE PASSAGE
•
"
"
_ _
d'"
~ELEP~4NT
t
t
,
]
~
---
_-"
.,ooo,--' _,t /~
-
/
t~mo & <
_,'...~
-o.,,
~op
U
t;
tO00
....
,, m1P.o.,, "48 ] +~ ~ •
x,
-~"
--.
/ . .~, /.-'"
~,,~I.i
"-~/
.--"
+0.45
---
~-v"
o o
mox
"~ ....
(~.6
~ L~'~
/
-o.s9
I{
/ u
I 560W
l
Fig. 4.
~'1/ 54°W
I
\
",
" ,
\
~
,,,
n m
-..
~
+o.4o
~
-v.,~,
..o.~
""
-o z~
-2X.10,/,~
o
62"S
-0" 17 "
~o~--'-'--" I,
+0
4-0 35
SEA !63°S
+0.~
~
~+0.43
X
X\
+0.3? I 52'=W
61°S
Omax
{.,,
+0.06 I^I
-0.33 , /
"Vm~_,ooO--
• -0.73
+0.40 ~"
-o~.o~ 64°~
"0 14
"
-'t.02
-urn,
'
WEDDELL
07 .. r~o,.', ",u ~
-o~o o..,,-;s,,,,o,
r,,
0 mox > OoC
-0.48 "( )
+~T3
"-u~.~._~
I
"~o.~
JOINVILLE XSLAND
60°S
P
. ~ / - o - -
,j i
+o.~
• ¢o.~m
~'~
.o.s.
(-'-V - - - ' ~ -~ - - ~ ~ /
o~,9~ ,
~,=+7C>+o-4~
-'~'~ ~0.0, ,-",a).19 x.-o:z~
"
~
+0.~
-~-(~.3~ +n~+o.~ +o2,7.....
/ ..... ,
--
~-"-,~----~."~'~
~-~o:s
+,.Te + 0 64
--
--
,,"~
+ , . , 3 ~
~ : , . o ~ j _ . ~ . -" -". . . . D ~
59"5
+,.6=
s
'12+L=1 fx'~°~+~.~°~-~-~ 0 Z ~ - ~7 , ~ 1/ ?~>-'rL') /
•t ( " ~ O . 2 ~ 3 ~ O " ~ f
63%
I
~...-..~E~T--.--+,.o.~
+1.68
.~
I
+1.57
/ + 0 . 2 4 1 + ~ . 4+20 544 1 1 0 1 ~ ' - O-
+131 +1.81... -,- 8+l 76 +,.e, +, 52
-"
620S
44°W
I
+ 1.93
Omo x > I.O°C
+1.92
60°'.
,
I
+l.z8
+,.~
61°~
46%V
I
+1.73 +1.62
~+0.5__._.._.../ /// Ornax>0.5°C
~ I
I 500W
I
1 4B°W
I
+0.6, 1 46°W
I
~4°S 1 44°W
Horizontal distribution of maximum potential temperatures in the warm deep layer. One thousand-metre depth contour is indicated by dashed line.
more or less, homogeneous layer reaching to the bottom in shelf areas and, except near the surface, sufficiently resistant to change to remain below 0°C throughout Summer as well as winter. The low temperatures and salinities in the narrow region between Stas. 1 and 3 in Figs. 2 and 3 may alternatively be due largely to motion and mixing brought about by dynamical processes between two currents. Figure 5 shows the lateral mixing paths calculated by moving parcels of water adiabatically from various depths at Sta. 1 towards Sta. 8 using the method described by FOSTER and CARMACK (1976). We see that warm, salty water north of the Scotia Ridge at Sta. 1 at a depth of 300 m could mix laterally with much colder, fresher water south of the ridge at Sta. 8 at a depth of 93 m. It is worth adding that cold, less saline, water in the boundary region also has a high oxygen content. There is some evidence of variability near the boundary. Discovery Sta. 638 in 61°01'S, 49°49'W showed a deep temperature o f - 0 . 1 9 ° C at 800 m with a salinity of 34.59%0, while
The boundary region between the Weddell Sea and Drake Passage currents
I I
2 I
3 I
( G L A C I E R 1975) STATION NUMBER 4 5 6 7 I I I I
509
8 I
J J
J IO00 -
2000
I w
3000
4000
SCALE (km) 1
0
I
50
I00
MIXING PATHS
Fig. 5.
5000 Lateral mixing paths from Sta. 1 to 8 across the South Ridge near 50°W.
IWSOE 75 Sta. 6 in 61°01'S, 49°46'W showed a temperature of 0.41°C and salinity of 34.69%0 at the same depth; there was, however, a time difference of 44 years between the two observations. It is a region whose study might well advance our understanding of convection and current boundaries, and it may be reasonably accessible in winter. The Swedish South Polar Expedition reported open water near the tip of the Antarctic peninsula in September 1902 and again when the Argentine ship Uruguay rescued them on 8 November 1903. There was also open water when the Chilean ship Yelcho rescued Shackleton's men from Elephant Island on 30 August 1916. Convection in this and adjoining areas may contribute to the formation of bottom water in the open ocean, as well as in the neighbouring deep sea basins. The bottom water in the deep basins of the Bransfield Strait may be partly formed here as well as on the western shelf of the peninsula. It has much lower temperatures and lower salinities than the Weddell Sea bottom water. The oxygen content of the deep basins is high. Eltanin Sta. 287 in 60°21'S, 47°40'W is particularly interesting: made in a deep basin with soundings greater than 5000 m it shows uniform well-oxygenated water at all depths below the sill at about 2000 m. The silicate values seem to be about what might be expected near the surface in winter. The current boundary is known to be a region of high biological productivity, influencing the distribution of krill on the former whaling grounds east of South Georgia. General support for the conclusion that the boundary region is one of increased vertical mixing can be obtained by contrasting its small temperature and salinity gradients with the sharper layering on both sides.
510
G.E.R. DEACONand THEODORED. FOSTER
Acknowledgements--This work was supported by the National Science Foundation under Grants GA-41578 and OPP75-14936. The authors would like to thank R. L. MICHEL,D. A. MUUS,J. P. COSTELLO,J. K. JAIN, H. R. KAYE and R. A. ROWE of Scripps Institution of Oceanography, and the officers and crew of the USCGC Glacier, particularly the Marine Science Division, for their assistance in making the observations at sea, and S. F. LOWEfor her assistance in the data processing. REFERENCES DEACON G. E. R. (1937) The hydrology of the Southern Ocean. 'Discovery" Reports, 15, p. 25 and p. 109. DEACONG. E. R. and J. A. MOOREY(1975) The boundary region between currents from the Weddell Sea and Drake Passage. Deep-Sea Research, 22, 265 268. FOSTER T. D. and E. C. CARMACK(1976) Frontal zone mixing and Antarctic Bottom Water formation in the southern Weddell Sea. Deep-Sea Research, 23, 301-317. GORDON A. L. (1971) Oceanography of Antarctic waters. In: Antarctic oceanology 1, American Geophysical Union, p. 173. MODEL F. (1958) Ein Beitrag zur regionalen Ozeanographie der Weddellsee. Deutsche Antarktische Expedition 1938/39. Wissenschaftliche und fliegerische Eroebnisse, Hamburg, p. 63. Wt3ST G. (1926) Zweiter Bericht tiber die ozeanographischen Untersuchungen der deutschen Atlantischen Expedition. Zeitschrift der Gesellschaft fur Erdkunde zu Berlin, No. 5/6, p. 243.
The boundary region between the Weddell Sea and Drake Passage currents G. E. R. DEACON* and THEODORED. FOSTER'~ (Received 8 October 1976; accepted 11 November 1976) Abstract The boundary between the currents from the Weddell Sea and the Drake Passage has been investigated in the area between the South Shetland and South Orkney islands. New data confirm the existence of a sharp boundary over the Scotia Ridge and show that the warm deep layer in the northwestern Weddell Sea is cooled below 0°C when it reaches depths shallower than about 1000 m.
THE INTERNATIONALWeddell Sea Oceanographic Expedition (IWSOE) in 1975 on USCGC Glacier included a line of eight TSD observations between 60°S, 50°W and 62°S, 49°30'W, across the accepted boundary region between currents flowing east by north from the northern side of the Weddell Sea and the southern side of the Drake Passage (Fig. 1). The potential temperature and salinity sections, supported by Nansen-bottle sampling at Stas. 1, 4 and 8, are drawn in Figs. 2 and 3. Near Sta. 3 there is a narrow zone with deep temperatures less than 0°C, between warm water modified during passage round the Weddell Sea to the south, and appreciably warmer water, just reached by the section, that can only Come from the Drake l~ssage, to the north. There are lower deep-water salinities in the same narrow zone. The temperature and salinity sections are very similar to those shown by DEACONand MOOREY in their recent note in Deep-Sea Research (1975}, and agreeing with the earlier conclusions of WOST (1926), DEACON(1937), MODEL(1958) and GORDON(1971), confirm the special interest of the region. To assist further consideration we have plotted the geographical distribution of the maximum potential temperatures in the warm deep layer at most of the stations included in the NODC tape from 58 to 64°S in 44 to 64°W, adding those of IWSOE 1975 and 1976, and using the section drawn by Deacon and Moorey (Fig. 4). While trying to include all usable information we had to omit a few stations where it seemed likely that the sampling was not deep enough to reach the nucleus of the warm layer. The temperatures plotted in the cold shelf water regions near theAntarctic peninsula and near the South Orkney Islands are temperature maxima in water of about the same density as the warm deep water further offshore. Although the data are not sufficient for satisfactory geographical coverage there are enough to show that the warm deep layer has been cooled below 0°C when it reaches areas that are shallower than about 1000 m. The diagram indicates that the cold-deep-water area associated with the Antarctic peninsula extends eastwards across the ocean at least as far as 49°W, and that there is a similar area on the 500-m plateau south of the South Orkney Islands. There is another cold area in 42 to 43°W on the Scotia Ridge east of the Orkneys * Institute of Oceanographic Sciences, Wormley, Godalming, Surrey, GU8 5UB, England. t Scripps Institution of Oceanography, La Jolla, California 92093, U.S.A.
505
506 56°W I
o.E.R. DEACONand THEODORED. FOSTER
I
54"W I
52"W I
Av
/
50"W I
I
48°W I i
46" W
44°W 59"S
59"5
200
/
BO°S
60*S
SOUT~ t ,~ ORKNEY ZSLANDS
61"S
61"S
62°S
6Z'S
63"
63°S
JOINVILLE ZSLAND
__.•
64"
64°S
56~W
54°W
52°W
50*W
48°W
46°W
44°W
Fig. 1. Bathymetry in metres of northwestern Weddell Sea (after D. G. W^TT~S,Antarctic geology and geophysics, R. G. ADn~,editor, Osio University Press, 1972, pp. 33-38) and station location of section ~crou Scotia Ridge.
(Discovery Stas. 1036, 1866; Eitanin Sta. 102). The possibility of surface water sinking in such areas, either by total convection in winter, or by mechanical mixing processes between currents of water of somewhat different densities, and possibly with different velocities, was mentioned by the previous authors. The geographical distribution seems to suggest that in the large shallow areas convection may provide an adequate mechanism. The observations there were all made in summer when the near-surface water is warmed and diluted, but there can be little doubt that winter cooling, ice formation and advection from the neighboring Weddell Sea is sufficient to raise the salinity above 34.5%o and to lower the surface temperature to freezing point. For example, it would take about 1.1 m of sea ice formation at IWSOE 75 Sta. 2 to make the whole water column isohaline. Under such conditions convection and mixing could incorporate the surface, deep and bottom waters into a cold,
I
Fig. 2.
5000 t
0
I
2
0.25
3
4
~
5
8
~-I 5
SCALIE (kin) I I 50 ...... IO0__
7
POTENTIAL TEMPERATURE I
I 0 ....
6
Potential temperature section across Scotia Ridge near 50°W.
.
(GLACIER 1975) STATION NUMBER
e II I-/1'
I '/'~
Z
I
3
. ,~' \
/
I
4
Fig. 3.
5000
O0 -
5
..//
, 0
,.
6
, 50
SALINITY
SCALE ( km)
--...
' IO0
54.68"-
. . . . . . ~,,~ . . . . ---
............
I
7
Salinity section across Scotia Ridge near 50°W.
ooo - 1 / / \
~L
~
I
(GLACIER 1975) STATION NUMBER I
8
/
1
"l /
-t
/
&
,,,,,
0
?,
~r 0 :::1
-}
508
G . E . R . DEACON and THEOOOi~ D. FOSTER
56°W
5,4°W
52*W
1
'
590S
'
I
50DW
I
I
48"W
1
!
+1.44
+2.0~
DRAKE PASSAGE
•
"
"
_ _
d'"
~ELEP~4NT
t
t
,
]
~
---
_-"
.,ooo,--' _,t /~
-
/
t~mo & <
_,'...~
-o.,,
~op
U
t;
tO00
....
,, m1P.o.,, "48 ] +~ ~ •
x,
-~"
--.
/ . .~, /.-'"
~,,~I.i
"-~/
.--"
+0.45
---
~-v"
o o
mox
"~ ....
(~.6
~ L~'~
/
-o.s9
I{
/ u
I 560W
l
Fig. 4.
~'1/ 54°W
I
\
",
" ,
\
~
,,,
n m
-..
~
+o.4o
~
-v.,~,
..o.~
""
-o z~
-2X.10,/,~
o
62"S
-0" 17 "
~o~--'-'--" I,
+0
4-0 35
SEA !63°S
+0.~
~
~+0.43
X
X\
+0.3? I 52'=W
61°S
Omax
{.,,
+0.06 I^I
-0.33 , /
"Vm~_,ooO--
• -0.73
+0.40 ~"
-o~.o~ 64°~
"0 14
"
-'t.02
-urn,
'
WEDDELL
07 .. r~o,.', ",u ~
-o~o o..,,-;s,,,,o,
r,,
0 mox > OoC
-0.48 "( )
+~T3
"-u~.~._~
I
"~o.~
JOINVILLE XSLAND
60°S
P
. ~ / - o - -
,j i
+o.~
• ¢o.~m
~'~
.o.s.
(-'-V - - - ' ~ -~ - - ~ ~ /
o~,9~ ,
~,=+7C>+o-4~
-'~'~ ~0.0, ,-",a).19 x.-o:z~
"
~
+0.~
-~-(~.3~ +n~+o.~ +o2,7.....
/ ..... ,
--
~-"-,~----~."~'~
~-~o:s
+,.Te + 0 64
--
--
,,"~
+ , . , 3 ~
~ : , . o ~ j _ . ~ . -" -". . . . D ~
59"5
+,.6=
s
'12+L=1 fx'~°~+~.~°~-~-~ 0 Z ~ - ~7 , ~ 1/ ?~>-'rL') /
•t ( " ~ O . 2 ~ 3 ~ O " ~ f
63%
I
~...-..~E~T--.--+,.o.~
+1.68
.~
I
+1.57
/ + 0 . 2 4 1 + ~ . 4+20 544 1 1 0 1 ~ ' - O-
+131 +1.81... -,- 8+l 76 +,.e, +, 52
-"
620S
44°W
I
+ 1.93
Omo x > I.O°C
+1.92
60°'.
,
I
+l.z8
+,.~
61°~
46%V
I
+1.73 +1.62
~+0.5__._.._.../ /// Ornax>0.5°C
~ I
I 500W
I
1 4B°W
I
+0.6, 1 46°W
I
~4°S 1 44°W
Horizontal distribution of maximum potential temperatures in the warm deep layer. One thousand-metre depth contour is indicated by dashed line.
more or less, homogeneous layer reaching to the bottom in shelf areas and, except near the surface, sufficiently resistant to change to remain below 0°C throughout Summer as well as winter. The low temperatures and salinities in the narrow region between Stas. 1 and 3 in Figs. 2 and 3 may alternatively be due largely to motion and mixing brought about by dynamical processes between two currents. Figure 5 shows the lateral mixing paths calculated by moving parcels of water adiabatically from various depths at Sta. 1 towards Sta. 8 using the method described by FOSTER and CARMACK (1976). We see that warm, salty water north of the Scotia Ridge at Sta. 1 at a depth of 300 m could mix laterally with much colder, fresher water south of the ridge at Sta. 8 at a depth of 93 m. It is worth adding that cold, less saline, water in the boundary region also has a high oxygen content. There is some evidence of variability near the boundary. Discovery Sta. 638 in 61°01'S, 49°49'W showed a deep temperature o f - 0 . 1 9 ° C at 800 m with a salinity of 34.59%0, while
The boundary region between the Weddell Sea and Drake Passage currents
I I
2 I
3 I
( G L A C I E R 1975) STATION NUMBER 4 5 6 7 I I I I
509
8 I
J J
J IO00 -
2000
I w
3000
4000
SCALE (km) 1
0
I
50
I00
MIXING PATHS
Fig. 5.
5000 Lateral mixing paths from Sta. 1 to 8 across the South Ridge near 50°W.
IWSOE 75 Sta. 6 in 61°01'S, 49°46'W showed a temperature of 0.41°C and salinity of 34.69%0 at the same depth; there was, however, a time difference of 44 years between the two observations. It is a region whose study might well advance our understanding of convection and current boundaries, and it may be reasonably accessible in winter. The Swedish South Polar Expedition reported open water near the tip of the Antarctic peninsula in September 1902 and again when the Argentine ship Uruguay rescued them on 8 November 1903. There was also open water when the Chilean ship Yelcho rescued Shackleton's men from Elephant Island on 30 August 1916. Convection in this and adjoining areas may contribute to the formation of bottom water in the open ocean, as well as in the neighbouring deep sea basins. The bottom water in the deep basins of the Bransfield Strait may be partly formed here as well as on the western shelf of the peninsula. It has much lower temperatures and lower salinities than the Weddell Sea bottom water. The oxygen content of the deep basins is high. Eltanin Sta. 287 in 60°21'S, 47°40'W is particularly interesting: made in a deep basin with soundings greater than 5000 m it shows uniform well-oxygenated water at all depths below the sill at about 2000 m. The silicate values seem to be about what might be expected near the surface in winter. The current boundary is known to be a region of high biological productivity, influencing the distribution of krill on the former whaling grounds east of South Georgia. General support for the conclusion that the boundary region is one of increased vertical mixing can be obtained by contrasting its small temperature and salinity gradients with the sharper layering on both sides.
510
G.E.R. DEACONand THEODORED. FOSTER
Acknowledgements--This work was supported by the National Science Foundation under Grants GA-41578 and OPP75-14936. The authors would like to thank R. L. MICHEL,D. A. MUUS,J. P. COSTELLO,J. K. JAIN, H. R. KAYE and R. A. ROWE of Scripps Institution of Oceanography, and the officers and crew of the USCGC Glacier, particularly the Marine Science Division, for their assistance in making the observations at sea, and S. F. LOWEfor her assistance in the data processing. REFERENCES DEACON G. E. R. (1937) The hydrology of the Southern Ocean. 'Discovery" Reports, 15, p. 25 and p. 109. DEACONG. E. R. and J. A. MOOREY(1975) The boundary region between currents from the Weddell Sea and Drake Passage. Deep-Sea Research, 22, 265 268. FOSTER T. D. and E. C. CARMACK(1976) Frontal zone mixing and Antarctic Bottom Water formation in the southern Weddell Sea. Deep-Sea Research, 23, 301-317. GORDON A. L. (1971) Oceanography of Antarctic waters. In: Antarctic oceanology 1, American Geophysical Union, p. 173. MODEL F. (1958) Ein Beitrag zur regionalen Ozeanographie der Weddellsee. Deutsche Antarktische Expedition 1938/39. Wissenschaftliche und fliegerische Eroebnisse, Hamburg, p. 63. Wt3ST G. (1926) Zweiter Bericht tiber die ozeanographischen Untersuchungen der deutschen Atlantischen Expedition. Zeitschrift der Gesellschaft fur Erdkunde zu Berlin, No. 5/6, p. 243.