Planktonic foraminifera from the southwest Atlantic ...
References Fuhrman, J . A., and Azam, F. 1980. Bacterioplankton secondary production estimates for coastal waters of British Columbia, Antarctica and California. Applied and Environmental Microbiology, 39, 1085-1095. Hagström, A., Larsson, U., Horstedt, P., and Normark, S. 1979. Frequency of dividing cells, a new approach to the determination of bacterial growth rates in aquatic environments. Applied and Environmental Microbiology, 37, 805-812. Hanson, R. B., and Lowery, H. K. 1981. Bacterial glucose uptake and production estimates in the Drake Passage, Antarctica. Abstracts. American Society for Microbiology, 81st Annual Meeting (Dallas, Texas, 1-6 March 1981), (N-21), 176.
Planktonic foraminifera from the southwest Atlantic, collected by Atlantis II (cruise 60) SILVIA WATANABE
Museo Argentino de Ciencias Naturales "B. Rivadavia" and Consejo Nacional de Investigaciones Cientificas y Tecnicas, Argentina
Hanson, R. B., Lowery, H. K., Shafer, D., Sorocco, R., and Pope, D. H. In preparation. Bacterioplankton productivity in the Drake Passage, Antarctica. McCartney, M. S. In preparation. Observation of the convective formation of the antarctic intermediate water of the south Pacific Ocean. Wiebe, W. J . , and Hendricks, C. W. 1972. Distribution of heterotrophic bacteria in a transect of the antarctic ocean. In R. R. Colwell and R. Y. Morita (Eds.), Effects of the ocean environment on microbial activities. Baltimore, Md.: University Park Press. Zimmerman, R., Iturriaga, R., and Becker-Berck,J. 1978. Simultaneous determination of the total number of aquatic bacteria and the number thereof involved in respiration. Applied and Environmental Microbiology, 36, 926-935.
noides (d'Orbigny); and (3) Cosmopolitan. Globigerinita glutinata (Egger). Three kinds of water masses in the sampling area were identified on the basis of species collected (figure): pure subtropical waters, pure subantarctic waters, and waters having different mixtures of subtropical and subantarctic waters. The three types of waters were distributed in patches; generally, subtropical waters predominated over subantarctic waters down to 39°30'S latitude. No direct contact was found between pure subtropical and pure subantarctic waters. The results
HAYDEE LENA
Department of Biological Sciences Florida Institute of Technology Melbourne, Florida 32901
Since 1959, Boltovskoy and co-workers have studied the surface hydrology of the southwest Atlantic using foraminifera as biological indicators. Boltovskoy published a detailed bibliography of those studies in 1970 and 1978. The present investigation augments what has already been done to determine the different water masses and hydrologic limits of the southwest Atlantic. The main objective of this investigation was to determine, by means of planktonic foraminifera, the structure and composition of the northwest region of the sub / tropical/subantarctic convergence zone. The material analyzed consisted of 29 planktonic samples, 16 collected in the surface layer by horizontal tows, and 13 collected in the epipelagic zone by vertical tows between 225 and 0 meters (figure). The fauna was found to be qualitatively and quantitatively poor. Sixteen species were found. They can be divided according to their temperature requirements into three well-defined groups: (1) Subtropical. Globigerina rubenscens Hofker, Globigerinella aequilateralis (Brady), Globigerinoides conglobatus (Brady), G. ruber (d'Orbigny), C. trilobus (Reuss), Globorotalia hirsuta (d'Orbigny), C. Menardii (d'Orbigny), and Orbulina universa (d'Orbigny); (2) Subantarctic. Globigerina bulloides (d'Orbigny), G. Quinqueloba Natland, Globigerinita uvula (Ehrenberg), Globoquadrina pachyderma (Ehrenberg), Globorotalia inflata (d'Orbigny), C. scitula (Brady), and G. truncatuli-
132
L__!5V / /5'O
/ / ,, •.: /
/
/
eo
/ ,
/
/
C
/ ' , / /
SUBTROPICAL/SUBANTARCTIC CONVERGENCE ZONE
40
F / - - AILANTIS II ) LEUISE 601 • Subtropical °- Subantarctic
0
Subtropical > Subantarctic
C
ISubtropical Subantarctic
-
Subtropical < Subantarctic
0 C
Sample without Foramin ilera 0
Different types of waters found during cruise 60 of the Atlantis II, Identified on the basis of occurrence of planktonic foraminifera. (Hydrologic scheme after Boltovskoy 1978.) ANTARCTIC JOURNAL
confirmed once again the existence of a wide convergence zone in the southwest Atlantic Ocean (Boltovskoy 1966, 1970, 1978).
References Boltovskoy, E. 1966. La zona de Convergencla SubtropicaliSubantártica en el Océano Atlántico (parte occidental) (Un estudio en base a
Calcareous dissolution of deep-sea benthonic foraminifera BRUCE H. CORLISS
and
SUSUMU
la investigación de ForaminIferos indicadores) (Publication H. 1015). Buenos Aires: Argentina Servicio de Hidrografia Naval. Boltovskoy, E. 1970. Masas de agua (caracterIstica, distribución, movimientos) en la superficie del Atlántico suboeste, segiIn indicadores biológicos—ForaminIferos (Publication H. 643). Buenos Aires: Argentina Servicio de Hidrografia Naval, Boltovskoy, E. 1978. Problema de los indicadores biológicos en OceanografIa. Anales de la Academia Nacional de Ciencias Exactas, FIsicas y Naturales, Buenos Aires, 30, 229-251.
Little attention has been given to the effect of carbonate dissolution on calcareous deep-sea benthonic foraminifera other than the observation by many workers that benthonic foraminifera are more resistant than planktonic foraminifera to carbonate dissolution. One of the complicating factors in studying calcareous deep-sea benthonic foraminifera in the southern ocean is the presence of highly corrosive Antarctic Bottom Water, which may influence the faunal distribution patterns by differentially removing solution-susceptible spe-
HoNjo
Woods Hole Oceanographic Institution Woods Hole, Massachusetts 02543
SALINITY (%) 3420 3430 3440 3450 3460 3470 3480 3490i SAMPLE NUMBER I and TEMPERATURE (°C) DEPTH(m_40 -30 250 300 400 0 0 5 0 10 0 15 0 200 NORTH ' PACIFIC CENTRAL WATER
cj
-20
I i3O6 2 378
.
Oh
% BROKEN BENTHONIC FORAMINIFERA -10 0 01 02 03 04 0 50 100 -
3 11978 NORTH PACIFIC INTERMEDIATE WATER
- 2000
Nt PACIFIC DEEP WATER
S(%0)
2778
3000
3978
4000
6 5000
4278
4878
9i,5582 10
Figure 1. Temperature, salinity, and 141 data from GEOSECS (Geochemical Ocean Sections Study) station 235, together with dissolution sample number and percentage of broken benthonic foraminiferal tests per sample vs. water depth (Corliss and Honjo In press). 141is an Index of undersaturation with respect to calcite. Note the different scales for 141 above and below zero. Negative values Indicate supersaturation of calcium carbonate (CaCO1), zero is saturation, and positive values indicate undersaturatlon of CaCO1. In this region, the upper 500 meters are supersaturated, with undersaturation increasing steadily below this level.
1981 REVIEW
133
Planktonic foraminifera from the southwest Atlantic, collected by Atlantis II (cruise 60) SILVIA WATANABE
Museo Argentino de Ciencias Naturales "B. Rivadavia" and Consejo Nacional de Investigaciones Cientificas y Tecnicas, Argentina
Hanson, R. B., Lowery, H. K., Shafer, D., Sorocco, R., and Pope, D. H. In preparation. Bacterioplankton productivity in the Drake Passage, Antarctica. McCartney, M. S. In preparation. Observation of the convective formation of the antarctic intermediate water of the south Pacific Ocean. Wiebe, W. J . , and Hendricks, C. W. 1972. Distribution of heterotrophic bacteria in a transect of the antarctic ocean. In R. R. Colwell and R. Y. Morita (Eds.), Effects of the ocean environment on microbial activities. Baltimore, Md.: University Park Press. Zimmerman, R., Iturriaga, R., and Becker-Berck,J. 1978. Simultaneous determination of the total number of aquatic bacteria and the number thereof involved in respiration. Applied and Environmental Microbiology, 36, 926-935.
noides (d'Orbigny); and (3) Cosmopolitan. Globigerinita glutinata (Egger). Three kinds of water masses in the sampling area were identified on the basis of species collected (figure): pure subtropical waters, pure subantarctic waters, and waters having different mixtures of subtropical and subantarctic waters. The three types of waters were distributed in patches; generally, subtropical waters predominated over subantarctic waters down to 39°30'S latitude. No direct contact was found between pure subtropical and pure subantarctic waters. The results
HAYDEE LENA
Department of Biological Sciences Florida Institute of Technology Melbourne, Florida 32901
Since 1959, Boltovskoy and co-workers have studied the surface hydrology of the southwest Atlantic using foraminifera as biological indicators. Boltovskoy published a detailed bibliography of those studies in 1970 and 1978. The present investigation augments what has already been done to determine the different water masses and hydrologic limits of the southwest Atlantic. The main objective of this investigation was to determine, by means of planktonic foraminifera, the structure and composition of the northwest region of the sub / tropical/subantarctic convergence zone. The material analyzed consisted of 29 planktonic samples, 16 collected in the surface layer by horizontal tows, and 13 collected in the epipelagic zone by vertical tows between 225 and 0 meters (figure). The fauna was found to be qualitatively and quantitatively poor. Sixteen species were found. They can be divided according to their temperature requirements into three well-defined groups: (1) Subtropical. Globigerina rubenscens Hofker, Globigerinella aequilateralis (Brady), Globigerinoides conglobatus (Brady), G. ruber (d'Orbigny), C. trilobus (Reuss), Globorotalia hirsuta (d'Orbigny), C. Menardii (d'Orbigny), and Orbulina universa (d'Orbigny); (2) Subantarctic. Globigerina bulloides (d'Orbigny), G. Quinqueloba Natland, Globigerinita uvula (Ehrenberg), Globoquadrina pachyderma (Ehrenberg), Globorotalia inflata (d'Orbigny), C. scitula (Brady), and G. truncatuli-
132
L__!5V / /5'O
/ / ,, •.: /
/
/
eo
/ ,
/
/
C
/ ' , / /
SUBTROPICAL/SUBANTARCTIC CONVERGENCE ZONE
40
F / - - AILANTIS II ) LEUISE 601 • Subtropical °- Subantarctic
0
Subtropical > Subantarctic
C
ISubtropical Subantarctic
-
Subtropical < Subantarctic
0 C
Sample without Foramin ilera 0
Different types of waters found during cruise 60 of the Atlantis II, Identified on the basis of occurrence of planktonic foraminifera. (Hydrologic scheme after Boltovskoy 1978.) ANTARCTIC JOURNAL
confirmed once again the existence of a wide convergence zone in the southwest Atlantic Ocean (Boltovskoy 1966, 1970, 1978).
References Boltovskoy, E. 1966. La zona de Convergencla SubtropicaliSubantártica en el Océano Atlántico (parte occidental) (Un estudio en base a
Calcareous dissolution of deep-sea benthonic foraminifera BRUCE H. CORLISS
and
SUSUMU
la investigación de ForaminIferos indicadores) (Publication H. 1015). Buenos Aires: Argentina Servicio de Hidrografia Naval. Boltovskoy, E. 1970. Masas de agua (caracterIstica, distribución, movimientos) en la superficie del Atlántico suboeste, segiIn indicadores biológicos—ForaminIferos (Publication H. 643). Buenos Aires: Argentina Servicio de Hidrografia Naval, Boltovskoy, E. 1978. Problema de los indicadores biológicos en OceanografIa. Anales de la Academia Nacional de Ciencias Exactas, FIsicas y Naturales, Buenos Aires, 30, 229-251.
Little attention has been given to the effect of carbonate dissolution on calcareous deep-sea benthonic foraminifera other than the observation by many workers that benthonic foraminifera are more resistant than planktonic foraminifera to carbonate dissolution. One of the complicating factors in studying calcareous deep-sea benthonic foraminifera in the southern ocean is the presence of highly corrosive Antarctic Bottom Water, which may influence the faunal distribution patterns by differentially removing solution-susceptible spe-
HoNjo
Woods Hole Oceanographic Institution Woods Hole, Massachusetts 02543
SALINITY (%) 3420 3430 3440 3450 3460 3470 3480 3490i SAMPLE NUMBER I and TEMPERATURE (°C) DEPTH(m_40 -30 250 300 400 0 0 5 0 10 0 15 0 200 NORTH ' PACIFIC CENTRAL WATER
cj
-20
I i3O6 2 378
.
Oh
% BROKEN BENTHONIC FORAMINIFERA -10 0 01 02 03 04 0 50 100 -
3 11978 NORTH PACIFIC INTERMEDIATE WATER
- 2000
Nt PACIFIC DEEP WATER
S(%0)
2778
3000
3978
4000
6 5000
4278
4878
9i,5582 10
Figure 1. Temperature, salinity, and 141 data from GEOSECS (Geochemical Ocean Sections Study) station 235, together with dissolution sample number and percentage of broken benthonic foraminiferal tests per sample vs. water depth (Corliss and Honjo In press). 141is an Index of undersaturation with respect to calcite. Note the different scales for 141 above and below zero. Negative values Indicate supersaturation of calcium carbonate (CaCO1), zero is saturation, and positive values indicate undersaturatlon of CaCO1. In this region, the upper 500 meters are supersaturated, with undersaturation increasing steadily below this level.
1981 REVIEW
133
