Live (Rose Bengal stained) and dead benthic foraminifera from the ...

Marine Micropaleontology 62 (2007) 45–73 

www.elsevier.com/locate/marmicro 

Live (Rose Bengal stained) and dead benthic foraminifera 

from the oxygen minimum zone of the Pakistan 

continental margin (Arabian Sea) 

Stefanie Schumacher a, ⁎ , Frans J. Jorissen a , Delphine Dissard a,1 , 

Kate E. Larkin b , Andrew J. Gooday b 

a Laboratory of Recent and Fossil Bio-Indicators (BIAF), Angers University, 2 Bd Lavoisier, 49045 Angers Cedex 01, 

France, and Laboratory of Marine Bio-Indicators (LEBIM), Ile d'Yeu, Ker Chalon, France 

b National Oceanography Centre, Southampton, DEEPSEAS Benthic Biology Group, University of Southampton 

Waterfront Campus, European Way, Southampton SO14 3ZH, United Kingdom 

Received 29 July 2005; received in revised form 10 July 2006; accepted 12 July 2006 

Abstract 

Live (Rose Bengal stained) and dead benthic foraminiferal communities (hard-shelled species only) from the Pakistan 

continental margin oxygen minimum zone (OMZ) have been studied in order to determine the relation between faunal composition 

and the oxygenation of bottom waters. Samples were taken from 136 m to 1870 m water depth during the intermonsoon season of 

2003 (March–April). Live foraminiferal densities show a clear maximum in the first half centimetre of the sediment only few 

specimens are found down to 4 cm depth. The faunas exhibit a clear zonation across the Pakistan margin OMZ. Down to 500 m 

water depth, Uvigerina ex gr. U. semiornata and Bolivina aff. B. dilatata dominate the assemblages. These taxa are largely 

restricted to the upper cm of the sediment. They are adapted to the very low bottom-water oxygen values (≈ 0.1 ml/l in the OMZ 

core) and the extremely high input of organic carbon on the upper continental slope. The lower part of the OMZ is characterised by 

cosmopolitan faunas, containing also some taxa that in other areas have been described in deep infaunal microhabitats. The contrast 

between faunas typical for the upper part of the OMZ, and cosmopolitan faunas in the lower part of the OMZ, may be explained by 

a difference in the stability of dysoxic conditions over geological time periods. The core of the OMZ has been characterised by 

prolonged periods of stable, strongly dysoxic conditions. The lower part of the OMZ, on the contrary, has been much more variable 

over time-scales of 1000s and 10,000 years because of changes in surface productivity and a fluctuating intensity of NADW 

circulation. We suggest that, as a consequence, well-adapted, shallow infaunal taxa occupy the upper part of the OMZ, whereas in 

the lower part of the OMZ, cosmopolitan deep infaunal taxa have repeatedly colonised these more intermittent low oxygen 

environments. 

© 2006 Elsevier B.V. All rights reserved. 

Keywords: live (Rose Bengal stained); dead benthic foraminifera; oxygen minimum zone; Arabian Sea 

⁎ Corresponding author. Present address: Alfred Wegener Institute for Polar and Marine Research, Alter Hafen 26, 27568 Bremerhaven, Germany. 

Fax: +49 471 4831 1923. 

E-mail addresses: sschumacher@awi-bremerhaven.de (S. Schumacher), frans.jorissen@univ-angers.fr (F.J. Jorissen), 

ddissard@awi-bremerhaven.de (D. Dissard), kel1@noc.soton.ac.uk (K.E. Larkin), ang@noc.soton.ac.uk (A.J. Gooday). 

1 Now at Alfred Wegener Institute Wegener Institute for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany. 

0377-8398/$ - see front matter © 2006 Elsevier B.V. All rights reserved. 

doi:10.1016/j.marmicro.2006.07.004

46 S. Schumacher et al. / Marine Micropaleontology 62 (2007) 45–73

S. Schumacher et al. / Marine Micropaleontology 62 (2007) 45–73 

47 

1. Introduction 

The surface circulation of the Arabian Sea is driven 

by southwest and northeast monsoonal winds, which 

cause a strong seasonality (Wyrtki, 1973; Burkill et al., 

1993). During the SW monsoon (May to September), an 

anticyclonic surface circulation (Fig. 1, black arrows) 

causes an intense coastal upwelling off Somalia and 

Oman, and off the southwestern part of India. During the 

more gentle NE monsoon (November through March) a 

cyclonic surface circulation prevails (Fig. 1, gray arrows), 

and most of the upwelling phenomena disappear. 

Only off Pakistan, local and sporadical upwelling events 

are described during the NE monsoon (Wyrtki, 1973). 

The upwelling of nutrient-rich surface water leads to a 

high biological production during the SW monsoon 

(Ryther and Menzel, 1965; Qasim, 1977). A second 

maximum in biological productivity occurs during the 

NE monsoon (e.g. Caron and Dennett, 1999; Rixen 

et al., 2000). This second maximum is caused by convective 

mixing due to winter cooling and the injection of 

nutrients into the euphotic zone (Banse and McClain, 

1986; Madhupratap et al., 1996). In contrast to the 

western Arabian Sea, where the organic matter fluxes 

are much higher during the SW monsoon than during the 

NE monsoon, the fluxes in the central and eastern 

Arabian Sea are nearly the same during both monsoon 

seasons (Rixen et al., 2000). According to satellite observations 

by Antoine et al. (1996), annual primary 

productivity in the NE Arabian Sea is very high, and 

amounts to 400 gC m − 2 a − 1 . 

In the Arabian Sea, the combination of high primary 

productivity and a pronounced thermohaline stratification 

leads to a stable and expanded mid-water (150– 

1400 m) oxygen minimum zone (OMZ) (You and 

Tomczak, 1993; Olson et al., 1993; Wyrtki, 1973; Helly 

and Levin, 2004), defined as the zone with oxygen 

concentrations below 0.5 ml/l (Levin, 2003a). The OMZ 

results from different factors including oxygen consumption 

by organic matter decay, supply of oxygendepleted 

intermediate water-masses from the south and 

west (Swallow, 1984; Olson et al., 1993) and the semienclosed 

nature of the northern Arabian Sea (Wyrtki, 

1973; Shetye et al., 1994). 

Benthic foraminifera provide a valuable tool for 

reconstructing paleoceanographic parameters (Gooday, 

Table 1 

Locations, water depth and approximated bottom water oxygen values 

from CTD profiles for the stations studied here 

Station Water depth (m) Latitude (N) Longitude (E) Oxygen (ml/l) 

55901#11 136 23°16.61' 66°42.30' 1.4 

55808#3 150 23°16.57' 66°39.41' 0.5 

55803#5 306 23°12.53' 66°34.07' 0.1 

55818#4 512 23°08.24' 66°30.12' 0.105 

55916#1 598 23°01.69' 66°42.07' 0.11 

55922#2 738 22°57.57' 66°41.63' 0.12 

55921#1 844 22°57.61' 66°37.66' 0.13 

55918#7 944 22°53.58' 66°36.65' 0.175 

55907#1 1000 22°54.73' 66°34.93' 0.18 

55802#4 1201 22°59.99' 66°24.44' 0.4 

55830#3 1870 22°51.32' 66°00.01' 1.7 

2003), including paleo-oxygenation (Kaiho, 1994; 

Bernhard et al., 1997; Jorissen, 1999; Den Dulk et al., 

2000; Gooday, 2003; Schmiedl et al., 2003) as well as 

paleoproductivity conditions (Herguera and Berger, 

1991; Loubere, 1999; Loubere et al., 2003). The input 

of organic matter and the oxygenation of bottom- and 

sediment pore-water regulates faunal density, composition 

and vertical distribution in the sediment (Jorissen 

et al., 1995, Fontanier et al., 2002). High densities of 

benthic foraminifera in oxygen-deficient environments 

have been described by several authors (Phleger and 

Soutar, 1973; Bernhard, 1993; Sen Gupta and Machain- 

Castillo, 1993; Alve, 1994, 1995; Bernhard et al., 1997; 

Bernhard and Sen Gupta, 1999; Gooday et al., 2000). 

More particularly, high abundances of deep infaunal 

taxa such as Bolivina with a high length/width ratio, 

Chilostomella and Globobulimina are typical for most 

of these low oxygen settings (Mackensen and Douglas, 

1989; Alve, 1994, 1995; Bernhard et al., 1997; Jorissen 

et al., 1998; Fontanier et al., 2002). However, shallow 

infaunal species also may be common (Hermelin and 

Shimmield, 1990; Jannink et al., 1998; Maas, 2000). In 

order to better constrain the correlation between faunal 

density and composition, and bottom water oxygenation 

in these dysoxic environments, more systematical investigations 

are necessary. 

The composition of the benthic foraminiferal faunas 

of the Arabian Sea and Indian Ocean OMZ is still poorly 

known. Only few publications describe living (Rose 

Bengal stained) foraminiferal faunas from the OMZ. 

Gooday et al. (2000) and Hermelin and Shimmield 

Fig. 1. Surface hydrography in the Arabian Sea with the investigated area (Square) and previous studies on Recent benthic foraminifera (stars). 

During the SW monsoon (May through September), a strong anticyclonic surface circulation (black arrows), following the Findlater Jet (FJ) (after 

Rixen et al., 2000), dominates the surface circulation. The NE monsoon (November through March) causes a cyclonic circulation (light gray arrows), 

which is weaker than the SW monsoonal circulation. Site locations, investigated during April and May 2003, are given in the lower map. Bathymetry 

of the sampling area after Bett (2004a).

48 S. Schumacher et al. / Marine Micropaleontology 62 (2007) 45–73 

(1990) described the faunal distribution at stations from 

the Northwest Arabian Sea from water depths below 

400 m. In the Northeast Arabian Sea, Jannink et al. 

(1998) described two transects from 500 to 3000 m 

water depth. Until now, only one site in the upper part of 

the OMZ (233 m water depth) has been described in the 

Northeast Arabian Sea (Maas, 2000). Kurbjeweit et al. 

(2000) and Heinz and Hemleben (2003) provide an 

account of foraminiferal assemblages at greater water 

depths (N1900 m) in more central regions of the Arabian 

Sea. 

In this study we describe the hard-shelled foraminiferal 

assemblages sampled during the intermonsoon 

period (spring 2003) along a composite sampling profile 

(based on two transects) from 136 to 1870 m water 

depth. Our main aims are to improve knowledge of: (1) 

the faunal composition of live (Rose Bengal stained) 

and dead foraminiferal faunas, their bathymetrical 

distribution and microhabitats, (2) the relation between 

low oxygen environments and foraminiferal distribution 

and diversity indices and (3) the long-term adaptations 

that allow specific foraminiferal communities to survive 

in low oxygen environments. Preliminary observations 

on benthic foraminifera at the same sampling sites, 

based on ship-board sorting and including both hardand 

soft-shelled taxa, were reported by Larkin et al. 

(2003). 

2. Material and methods 

During R.R.S. Charles Darwin Cruises 145 and 146 

(12 March to 28 May 2003), 11 multicores were taken on 

the continental margin off Karachi, Pakistan (Fig. 1, 

Table 1). Two transects were sampled, constituting a 

composite bathymetric profile from 136 m (above the 

OMZ in spring 2003) down to 1870 m water depth 

(Fig. 2). Cores (surface area 25.5 cm 2 ) were processed as 

follows: for stations situated above, and in the upper part 

Fig. 2. Profiles over the Pakistan continental margin with locations of sampling sites and oxygen content in the water column (Bett, 2004a).


49 

of the OMZ, sediment slices were taken for the 0–0.5 and 

0.5–1 cm intervals, and then in 1 cm intervals down to 

10 cm. For the lower part of the OMZ, the second 

centimetre was also sliced in half-centimetre intervals. 

Each sample was stored in 10% borax-buffered formalin 

for further processing. Onshore, the samples were wet 

sieved over 63 μm, 150 μm and 300 μm sieves and the 

residues were stained for one week in ethanol with Rose 

Bengal (Walton, 1952). After staining, the residue was 

washed again. The stained faunas were picked wet in 

three granulometric fractions (63–150 μm, 150–300 μm 

and N300 μm), down to 10 cm depth. To gain more 

insight into the population dynamics (compare Jorissen 

and Wittling, 1999), we investigated the dead (unstained) 

foraminifera in the 2–3 cm level for the fractions 

150–300 μm and N300 μm. At this sediment depth we 

expected a strong decrease of taxa with rapidly 

decomposing tests (especially some arenaceous taxa), 

and also a more correct representation of deeper living 

infaunal species, that may be under-represented in 

superficial dead faunas (Loubere, 1989). The smaller 

fraction of the dead fauna has not been studied, since it 

may be seriously affected by post-mortem transport 

(Murray, 1991). When possible, a minimum of 200–300 

specimens was collected; if necessary samples were 

splitted with an Otto microsplitter. To enable a 

comparison of the sites, the 1–2 cm interval is treated 

as a single unit, even when it was sampled in halfcentimetre 

slices. The fractions N300 μm and 150– 

300 μm show nearly the same faunal distribution and 

therefore the results are presented here for both fractions 

combined (i.e. the N150 μm fraction). Data are available 

on doi:10.1594/PANGAEA.475995. The recognition of 

stained foraminifera may be somewhat subjective; for 

problems and discussion about the use of Rose Bengal 

see Bernhard (1988). We applied our staining criteria 

very strictly and only specimens with all chambers except 

the last one stained bright pink were counted as 

stained. Species determinations are based on the taxonomic 

references given in the Appendix. For our quantitative 

analysis we used all individuals of the total fauna 

with the exception of fragments of tubular foraminifera 

(e.g. Hyperammina, Rhizammina and Rhabdammina). 

In order to obtain a “potential fossil” fauna (Mackensen 

et al., 1990) we considered separately the “calcareous 

fauna”, containing only calcareous-perforate and porcellaneous 

taxa, for living as well as dead faunas. The 

numbers of fossilizable arenaceous taxa were negligible. 

Fig. 3. Faunal densities (counts/core 25.5 cm 2 ) of live (stained) foraminifera against water depth and oxygen content in the water column.


For the description of the vertical distribution, we use the 

Average Living Depth (ALD x , Jorissen et al., 1995). 

ALD x ¼ X i¼0;xðn i D i Þ=N 

x 

n i 

D i 

N 

lower boundary of the deepest sample 

number of individuals in interval i 

midpoint of sample interval i 

total number of individuals for all levels 

For all stations, ALD 10 was calculated for the entire 

hard-shelled (calcareous +arenaceous) live fauna and for 

the calcareous component of the fauna. We also present 

the species numbers and the diversities, expressed by the 

Shannon–Wiener Index (H(S ln )) (Shannon, 1948) and 

by the Fisher Alpha Index (Fisher et al., 1943). Calculations 

were based on the entire hard-shelled fauna as 

well as on calcareous taxa alone. 

Oxygen profiles of bottom water were obtained with a 

CTD (Fig. 2) at all sites and oxygen concentrations in 

Fig. 4. Vertical distribution of live (stained) foraminifera in the sediment for each core.


51 

core–top water were determined by Winkler titration 

(Cowie, 2003; Bett, 2004a). Down to about 150 m water 

depth, bottom waters were well oxygenated during 

March/April 2003. Oxygen values dropped to around 

0.1 ml/l between 150 and 500 m. Between 500 and 

1000 m they increased gradually and reach values of about 

0.2 ml/l. This is followed by a strong increase of oxygen in 

the lowest part of the OMZ and oxygen values N0.5 ml/ 

l below 1300 m water depth. CTD profiles obtained later 

in the year (September/October 2003) showed an upward 

shift of the upper OMZ boundary (0.5 ml/l oxygen level) 

from c. 180 m to c. 80 m (Bett, 2004b). 

Sediments are well bioturbated at 136 m water depth, 

in the lowest part of the OMZ (1000–1300 m) and below 

the OMZ (Levin, 2003b). The sediments within the core 

of the OMZ are laminated; the laminations are irregular at 

the 300-m site but are more regularly formed between 500 

and 700 m. The laminations are overprinted by vertical 

burrows at the 850-m and 950-m sites (Levin, 2003b). 

3. Results 

3.1. Foraminiferal densities 

Total abundances of live (Rose Bengal stained) foraminifera 

are shown for each core in Fig. 3. Faunal densities 

in the N150 μm fraction clearly decreased with increasing 

water depth. At 136 m, there were N620 individuals/core 

(25.5 cm 2 surface area), compared with only 13 per core at 

1000 m and 50 per core below the OMZ. The densities of 

calcareous taxa showed the same trend with a strong 

decrease below 600 m water depth. Densities in the 

smaller size fraction showed rather constant values in the 

upper 600 m, a sudden maximum at the 738-m site 

followed by a decrease at deeper sites. Total densities in 

the 63–150 μm fraction varied from 50 to about 2000 

individuals/core. Densities of calcareous taxa reached a 

maximum at 150 m water depth with a second maximum 

at 598 to 944 m. Densities in the two size fractions (N150 

and 63–150 μm) were very similar, except between 512 

and 844 m water depth, where the density in the smaller 

size fractions could be 10 times higher than in the larger 

size fraction. The overall (N63 μm) abundance of live 

foraminifera was highest from 138 to 306 m and 598 to 

844 m, with very low values below 944 m depth. 

3.2. Vertical distribution 

Live foraminifera were found at a maximum sediment 

depth of 2 cm in the OMZ and down to 3 cm and 4 cm 

depth above and below the OMZ, respectively. Most 

stations showed a clear maximum faunal density in the 

first half centimetre with an abrupt decrease in deeper 

layers (Fig. 4). At most stations more than 75% of the 

fauna occurred in the first half centimetre for both size 

fractions. This superficial life position was confirmed by 

Fig. 5. Average Living Depth for the entire hard-shelled fauna and calcareous fauna against water depth and oxygen content in the water column.


Fig. 6. Species number, Shannon–Wiener Index (H(S ln )) and Fisher Alpha Index for the living fauna N150 μm, 63–150 μm and N63 μm/core against 

water depth.


53 

Fig. 6 (continued). 

the fact that Average Living Depth of the entire hardshelled 

faunas (ALD 10 ) was mostly b0.4 cm for the 

N150 μm fraction (Fig. 5). Values were slightly higher 

below 700 m and a maximum value of about 1.4 cm was 

found at the deepest (1850-m) site. For the smaller size 

fraction, the ALD 10 was comparable to those derived 

from the N150 μm fraction. Between 512 and 844 m 

water depth the ALD 10 was minimal. 

In the N150 μm fraction, the ALD 10 for calcareous 

taxa was similar to the ALD 10 for the entire hard-shelled 

fauna down to 598 m water depth, whereas at deeper 

sites, the ALD 10 of calcareous taxa was systematically 

higher than the ALD 10 of the entire hard-shelled fauna. 

This pattern showed that more non-fossilizing arenaceous 

taxa lived in very superficial niches, whereas 

some calcareous taxa may have lived slightly deeper in 

the sediment. For the smaller size fraction, the ALD 10 of 

calcareous taxa was always comparable to that of the 

entire hard-shelled fauna (Fig. 5). 

3.3. Diversity 

3.3.1. Living faunas 

Between 8 and 17 species were observed in the 

N150 μm size fraction, between 13 and 33 species in 

the 63–150 μm size fraction, and between 17 and 37 

species in the N63 μm fraction (Fig. 6). The species 

number in the larger fraction did not vary significantly 

with water depth, whereas the species number in the 

small fraction was fairly well correlated with the faunal 

densities and showed maximum values at 138 to 150 m 

and at 737 m. The number of calcareous species in the 

larger size fraction decreased with increasing water 

depth, but there was no clear trend in the case of the 

smaller size fraction. In the larger size fraction, the 

Shannon–Wiener index (H(S ln )) showed a trend towards 

higher values at greater water depth. The Fisher 

Alpha index showed a similar tendency but it was 

weaker and started deeper. Both indices were positively 

correlated with bottom-water oxygen concentration in 

the 63–150 μm fraction. Shannon–Wiener and the 

Fischer Alpha values for the calcareous part of the fauna 

(large size fraction) were highly variable and followed 

the diversity of the entire hard-shelled fauna but with 

lower values. The difference between entire hard-shelled 

and calcareous values increased with increasing water 

depth, due to the higher proportion of arenaceous 

foraminifera at deeper sites. In the smaller size fraction, 

diversity indices for the calcareous taxa followed the 

same pattern with water depth as the entire hard-shelled


Fig. 7. Species number, Shannon–Wiener Index (H(S ln )) and Fisher Alpha Index for the dead fauna N150 μm in2–3 cm depth against water depth. 

fauna, but with slightly lower values. Diversity trends 

for the N63 μm fraction were similar to those for the 63– 

150 μm fraction. 

3.3.2. Dead fauna 

Between 13 to 49 species were encountered (Fig. 7) 

The species number showed a clear positive correlation 

with bottom-water oxygen values, with minimum numbers 

in the OMZ. The two diversity indices also showed a 

good correlation with oxygen. For the calcareous fauna, 

species numbers were lower, but showed the same trend 

as the entire hard-shelled fauna. Similar observations 

could be made for the two diversity indices. 

3.4. Faunal composition 

The live and dead faunas were mainly represented by 

calcareous-perforate and arenaceous foraminifera. Miliolids 

were very rare. The percentage of arenaceous 

foraminifers in the living fauna increased with increasing 

water depth. At the 136 and 306 m sites, the percentage 

of arenaceous foraminifera was about 20% in 

both size fractions. In deeper water, the proportion of 

arenaceous foraminifera in the N150 μm fraction rose to 

90% at 1200 m and 100% at 1850 m. In the 63–150 μm 

fraction, a maximum of 72% arenaceous taxa at 738 m 

water depth coincided with a strong abundance maximum 

(Fig. 3). In the other OMZ samples, arenaceous 

taxa accounted for 12 to 63% of the fauna. Most foraminifera 

lived in the first half centimetre of the sediment. 

There was no clear microhabitat differentiation; 

there were no species restricted to the uppermost level, 

nor infaunal taxa showing subsurface density maxima. 

The dead fauna was dominated by calcareous foraminifera 

(60–100%), with the exception of a maximum 

(N60%) of arenaceous foraminifera at the 598- and 

738-m sites. The latter were mainly represented by two 

species of Ammodiscus (see Appendix) and various 

species of Reophax and the Trochamminacea. The tests 

of all these taxa normally are strongly affected by early 

diagenesis and are not preserved in fossil faunas (Mackensen 

et al., 1990, 1993). Because we want to use our 

description of faunal patterns in the OMZ as a basis for 

paleoceanographic methods, we will now chiefly focus 

on the calcareous part of the fauna, which was usually 

dominated by the group of bi- and triserial species. For 

the live fauna N150 μm, this group reached a maximum 

density between 136 and 598 m water depth (more than


55 

Fig. 8. Counts of bi- and triserial species and their relative abundance in the entire calcareous fauna for the living fauna N150 μm and 63–150 μm, and 

for the dead fauna N150 μm against water depth. 

100 specimens/25.5 cm 2 core) (Fig. 8). In this depth 

interval, bi- and triserial taxa always accounted for more 

than 85% of the calcareous fauna. At deeper sites, these 

became much less abundant, although relative abundances 

remained elevated (50–100%). In the smaller 

size fractions, this group also strongly dominated the 

faunas (N75%) down to 844 m water depth. Among the 

dead faunas, all sites within the OMZ were strongly 

dominated (48–100%) by biserial and triserial taxa. 

Planoconvex species were infrequent in the 

N150 μm fraction and occurred in the live as well as 

in the dead fauna mainly above 306 m and below 800 m 

water depth (Fig. 9). Among live assemblages, absolute 

numbers were highest between 136 and 306 m water 

depth for the larger fraction and between 136 and 150 m 

and below 844 m for the smaller fraction. Planoconvex 

taxa were absent from the live assemblages N150 μm 

below 1000 m depth, although they persisted in the 

dead fauna. 

We could also recognise a third group containing 

species that were concentrated in the topmost sediment 

in our study area but have been described elsewhere as 

deep infaunal (e.g. Jorissen et al., 1998; Fontanier et al., 

2002; Licari et al., 2003). This group includes Bulimina 

exilis, Fursenkoina spp. Globobulimina spp. Chilostomella 

spp. and Praeglobobulimina spp. All these taxa, 

except Chilostomella, are also included in the group of 

bi- and triserial taxa. Significant numbers of these “deep 

infaunal” taxa occurred mainly in the lower part of the 

OMZ (Fig. 10) and especially in the dead fauna. For the 

smaller size fraction, a clear maximum (63–72%) could 

be observed from 306 to 738 m water depth, coinciding 

with the area of lowest oxygen concentrations. 

3.5. Single species distribution 

A limited number of dominant species characterised 

the fauna. In the upper part of the OMZ these were 

Uvigerina ex gr. U. semiornata, Bolivina aff. B. dilatata 

and Cassidulina laevigata in the N150 μm fraction and 

Bolivina aff. B. dilatata, B. exilis, Bolivina dilatata and 

Alliatina primitiva in the smaller fraction. Cancris auriculus 

also made a significant contribution to the dead 

assemblages at the shallowest stations. In the lower part 

of the OMZ, Uvigerina peregrina replaced Uvigerina 

ex gr. U. semiornata and other widely distributed species 

such as Pullenia bulloides, P. quinqueloba, and 

Bulimina aculeata also occurred. Among the arenaceous 

foraminifera, Ammodiscus spp. and several species of 

Reophax were common.


Fig. 9. Counts of planoconvex species and their relative abundance in the entire calcareous fauna for the living fauna N150 μm and 63–150 μm, and 

for the dead fauna N150 μm against water depth. 

Uvigerina ex gr. U. semiornata (see Appendix) was 

common in the OMZ core and between 136 and 306 m 

water depth, where it represented up to 90% of the 

calcareous assemblage N150 μm. With increasing water 

depth, the density of Uvigerina ex gr. U. semiornata 

decreased down to 512 m, where it was replaced by 

U. peregrina which was present down to 1000 m water 

depth and represented up to 89% of the live and dead 

calcareous fauna. In the smaller living fraction, Uvigerina 

ex gr. U. semiornata was less numerous, whereas 

U. peregrina sometimes still represented more than 60% 

of calcareous foraminifera (Figs. 11 and 12). In the dead 

fauna, Uvigerina ex gr. U. semiornata was again common 

down to 512 m water depth, where U. peregrina 

occurred for the first time. The latter species was common 

down to 1000 m water depth (Fig. 13). The absence 

of Uvigerina ex gr. U. semiornata and U. peregrina in 

the dead fauna of deeper stations was consistent with the 

absence of these species in the living fauna N150 μm. 

Bolivina aff. B. dilatata (see Appendix) was a dominant 

species in the larger size fraction at the shallower 

stations, while in the smaller fraction B. dilatata was 

also common. In the living fauna N150 μm an absolute 

density maximum of Bolivina aff. B. dilatata was present 

at 306 m water depth (229 individuals/core, 45%), 

while the highest percentage (88%) was found at the 

598 m site. For the dead fraction, Bolivina aff. B. dilatata 

reached a maximum relative abundance at 306 m 

(58%), correlating with the absolute density maximum 

observed in the living fauna. In the smaller size fraction, 

Bolivina aff. B. dilatata occurred between 136 and 

598 m water depth, while B. dilatata occurred in significant 

numbers only between 136 and 306 m. Where the 

two species occurred together, B. dilatata was more 

abundant than Bolivina aff. B. dilatata. The total dominance 

of these taxa seen in the larger size fraction was 

not observed in the finer fractions, where their relative 

abundance was b60%. 

The above-mentioned Uvigerina and Bolivina species 

strongly dominated the living and dead faunas in 

the N150 μm assemblages in the upper part of the OMZ. 

Low numbers of C. laevigata, C. auriculus, and other 

planoconvex species occurred here as well (Figs. 8 and 

11). In the smaller size fraction, B. exilis and A. primitiva 

also occurred in significant numbers in the live 

fauna. B. exilis occurred from 150 to 944 m water depth, 

with its maximum abundance between 306 and 738 m, 

where it made up N60% of the assemblage. This species


57 

Fig. 10. Counts of “deep-infaunal” species and their relative abundance in the entire calcareous fauna for the living fauna N150 μm and 63–150 μm, 

and for the dead fauna N150 μm against water depth. 

seemed to replace Bolivina aff. B. dilatata and B. dilatata, 

the dominant species in the upper region of the 

OMZ (150–306 m). B. exilis was nearly absent in the 

larger live and dead fraction except at the 600 m site 

where it accounted for 10% of the dead assemblage. 

A. primitiva was only represented in the smaller living 

fraction and occurred between 136 and 944 m water 

depth. Maximum values were found between 512 and 

738 m (Fig. 12). Some planoconvex species such as 

Gyroidina orbicularis and G. altiformis were a minor 

faunal element in the upper part of the OMZ (Abb. 8). 

The lower part of the OMZ had a more diverse fauna 

(compare Figs. 6 and 7) and contained more cosmopolitan 

species. Members of the Globobulimina group 

(G. cf. G. pyrula, Globobulimina sp. 3, Praeglobobulimina 

sp. 1 and Praeglobobulimina pupoides) were 

represented over the total OMZ with low numbers in 

the living fraction N 150 μm, except at the 512 m site 

where they accounted for more than 40% of the fauna. 

These species were virtually absent in the smaller size 

fraction. These were well represented in the dead fraction, 

with a maximum relative abundance of 21% at 

598 m water depth (Figs. 11 and 13). It appears that 

G. cf. G. pyrula was present across the OMZ, while 

Praeglobobulimina sp. 1 was more common below 

512 m. A significant difference could be observed in 

the relative abundances of this group between the living 

and dead faunas, with generally higher percentages in 

the dead faunas. 

Between 512 and 1201 m water depth, Reophax spp. 

and Ammodiscus spp. accounted for more than 20% of 

the entire hard-shelled fauna. This area was below the 

main occurrence of Uvigerina ex gr. U. semiornata, 

Bolivina aff. B. dilatata, and B. dilatata. Down to 738 m, 

the small sized B. exilis and A. primitiva occurred together 

with significant numbers of Reophax spp. and 

Ammodiscus spp. (Fig. 14). 

4. Discussion 

The assemblages described above present a clear 

zonation across the Pakistan margin OMZ in samples 

collected during March/April 2003 (Fig. 15). The main 

features of this pattern are as follows. 

1. At 136 m, above the OMZ, where the bottom water 

was relatively well oxygenated (N1.5 ml/l) during 

March/May 2003 (although not later in the year


Fig. 11. Single species distribution over the OMZ for the calcareous live faunaN150 μm. 

during the monsoonal season when this site becomes 

dysoxic), living foraminifera are present down to 

3 cm depth in the sediment. Faunal densities and 

diversities are high, especially for the smaller (63– 

150 μm) living and larger (N150 μm) dead fractions. 

The dominant species in the living and dead faunas of 

the larger size fraction are Uvigerina ex gr. U. semiornata 

and Bolivina aff. B. dilatata; in the 63– 

150 μm fraction B. dilatata is a major element and 

Uvigerina ex gr. U. semiornata less frequent.


59 

Fig. 12. Single species distribution over the OMZ for the calcareous live fauna 63–150 μm. 

2. At the upper boundary of the OMZ (150 m, oxygen 

0.5 ml/l during March/May 2003) and in the core of the 

OMZ (below 150 to about 500 m water depth), where 

bottom water oxygenation is very low (≈ 0.1 ml/l), 

living foraminifera are only found in the upper 2 cm of 

the sediment. High faunal densities contrast 

with relatively low diversity values. Uvigerina ex gr. 

U. semiornata and Bolivina aff. B. dilatata dominate 

the larger size fraction of the live as well as dead 

faunas, whereas B. dilatata and B. exilis are the


Fig. 13. Single species distribution over the OMZ for the calcareous dead fauna N150 μm. 

dominant taxa in the 63–150 μm fraction, where 

Uvigerina ex gr. U. semiornata is less frequent. 

3. In the lower part of the OMZ (about 600 to 1200 m 

depth) bottom water oxygenation shows a slight increase 

(values of 0.1 to 0.2 ml/l), and live foraminifera 

are found down to 1 or 2 cm depth in the sediment. In 

the larger fraction (N150 μm) faunal densities decrease 

significantly with increasing water depth. In the 

smaller size fraction (63–150 μm) a density maximum 

is observed at 738 m water depth. The dominant taxa 

are U. peregrina, Bolivina aff. B. dilatata (only at 

598 m), B. exilis, Reophax spp. and Ammodiscus spp.


61 

Fig. 14. Relative abundance of Ammodiscus sp. 1 and Reophax spp. in the entire hard-shelled living faunaN150 μm and 63–150 μm. 

Fig. 15. Scheme of species zonation across the OMZ. Given are the oxygen profile, the sediment depth until which stained foraminifera are found (0– 

4 cm), the densities and diversity (L=low, H=high), dominant taxa for the large size fraction (dead as well as live fauna) and for the 63–150 μm (live 

fauna). The hatched field indicates deep infaunal taxa, that are more prominent in the dead, than in the live faunas.

62 S. Schumacher et al. / Marine Micropaleontology 62 (2007) 45–73


63 

4. Below the OMZ (1870 m water depth, bottom water 

oxygen concentration≈1.75 ml/l), living foraminifera 

are found down to 4 cm in the sediment, faunal 

diversities are high and the fauna constitutes a typical, 

cosmopolitan deep-sea assemblage. 

4.1. Identification of dominant taxa 

Many of the dominant taxa found in the upper part of 

the OMZ (above 500 m) were difficult to identify. Earlier 

authors (Jannink et al., 1998; Maas, 2000) working with 

Indian Ocean faunas either incorrectly attributed these 

abundant species to morphologically very different 

cosmopolitan taxa, or placed them in the open 

nomenclature. 

4.1.1. Uvigerina ex gr. U. semiornata 

The test is normally triserial, rounded in outline and 

with a relatively low length/width ratio. Chambers are 

strongly inflated and overlapping. The short neck is 

positioned in a prominent depression, a tooth is present 

in the aperture. Except on the last chamber, where they 

may be absent, the test is ornamented with costae which 

can cross the sutures. Large pores are situated between 

the costae. Some specimens are more elongated and in 

adults the last chambers may become biserial. The position 

of the neck, the length/width ratio of the test and 

the inflated chambers, strongly overlapping the older 

chambers, clearly shows that this species belongs in the 

U. semiornata/U. mediterranea (Van der Zwaan et al., 

1986) group and is very different from U. peregrina, 

which is also present in our material. Uvigerina ex gr. 

U. semiornata differs from U. peregrina by the position 

of the short neck in a depression. U. mediterranea has 

more closely spaced costae, lacks a tendency towards 

biserial or uniserial chamber arrangement in later 

ontogentic stages, and does never become very 

elongated. We refrain from putting our material in the 

synonymy of U. semiornata because this taxon has 

mainly been described from Miocene and older 

deposits. 

Uvigerina ex gr. U. semiornata was reported previously 

on the Indo-Pakistan Continental Margin by 

Maas (2000). He described abundant populations of this 

species at 233 m water depth, where U. peregrina is 

absent. In two transects off Karachi, Jannink et al. (1998) 

reported Uvigerina phlegeri (=Rectuvigerina phlegeri 

Le Calvez, 1995) occurring together with U. peregrina 

at the shallowest station (500 m). We strongly suspect 

that U. phlegeri of Jannink et al. (1998) is identical to 

Uvigerina ex gr. U. semiornata of the present study 

and of Maas (2000). Adult specimens are sometimes 

very elongated, and have, like the much smaller U. 

phlegeri, a tendency to become biserial or even uniserial 

in the later stages, leading to a confusion between the two 

species. However, our assemblages always contain many 

specimens that are triserial throughout. Gooday (2003) 

misidentified this species from the Oman margin of the 

Arabian Sea as Rectuvigerina cylindrica. 

4.1.2. Bolivina dilatata Reuss, 1850 

Our morphotype correspond very well to the typical 

forms, originally described by Reuss (1850), and later 

figured by Von Daniels (1970) and Barmawidjaja et al. 

(1992). They have an elongated, slowly tapering test with 

the axis sometimes slightly twisted. Only the outer parts of 

the test are slightly compressed. The periphery is rounded. 

There are 16 to 20 chambers in adult specimens. The later 

chambers become strongly inflated, and are often 

imperforate in their upper parts. The sutures are not 

limbate, and are strongly curved downwards towards the 

center of the test. 

Plate I. Scale bar=100 μm. 

1–6. Uvigerina ex gr. U. semiornata. 1. 55901#11, 0–0.5 cm, 150–300 μm; 2. 55901#11, 0–0.5 cm, 150–300 μm; 3. 55901#11, 0–0.5 cm, 150– 

300 μm; 4. 55818#4, 0–0.5 cm, 150–300 μm; 5. 55808#3, 0–0.5 cm. 63–150 μm; 6. 55901#11, 0–0.5 cm, 63–150 μm. 

7. Uvigerina peregrina Cushman 55922#2, 0–0.5 cm, 150–300 μm. 

8–12. Bolivina aff. B. dilatata. 8. 55818#4, 0–0.5 cm, 150–300 μm; 9. 55901#11, 0–0.5 cm, 150–300 μm; 10. 55803#5, 0–0.5 cm, 150–300 μm; 

11. 55818#4, 0–0.5 cm, 150–300 μm; 12. 55901#11, 0–0.5 cm, 63–150 μm. 

13–14. Bolivina dilatata Reuss. 13. 55901#11, 0–0.5 cm, 63–150 μm; 14. 55901#11, 0–0.5 cm, 63–150 μm. 

15. Bulimina exilis, Brady. 5818#4, 0–0.5 cm, 63–150 μm. 

16. Alliatina primitiva (Cushmann and McCulloch). 55803#5, 0–0.5 cm, 63–150 μm. 

17. Praeglobobulimina sp. 1. 55922#2, 0–0.5 cm, 150–300 μm. 

18. Praeglobobulimina pupoides (d'Orbigny). 55922#2, 0–0.5 cm, 150–300 μm. 

19. Globobulimina sp. 3. 55922#2, 0–0.5 cm, N300 μm. 

20. Globobulimia cf. G. pyrula. 55921#1, 2–3 cm, N300 μm. 

21. Ammodiscus sp. 1 (Brady). 55916#1, 0–0.5 cm, 150–300 μm. 

22. Reophax bilocularis Flint. 55921#1, 0–0.5 cm, 150–300 μm. 

23. Reophax scorpiurus Montfort. 55921#1, 0–0.5 cm, 150–300 μm.


4.1.3. Bolivina aff. B. dilatata 

The test of Bolivina aff. B. dilatata is strongly tapering, 

strongly flattened, with large pores. The periphery 

is more or less rounded, without a keel, very often 

provided with a striate ornamentation. Adult specimens 

consist of about 10 chambers, rectangular in shape, 

making an angle of about 45° with the periphery. The 

sutures are limbate, straight until the very center of the 

test where they may be strongly inflated. Megalospheric 

forms have a very large and inflated first chamber (see 

Plate 1, fig. 12). Sometimes, a faint striate ornamentation 

on the earlier part of the test can be observed. This 

species was determined as B. dilatata by Maas (2000) 

and Jannink et al. (1998) but we are convinced that it is a 

different species. It is slightly resembles Longinelli's 

(1956) rather unclear figure of B. dilatata Reuss var. 

abbreviata, and correspond to his description. Unfortunately 

no type material is available for this taxon, so that 

a relationship between our species, which is very frequent 

in modern Indian Ocean faunas, and Longinelli's 

Miocene–Pleistocene variety, cannot be confirmed. 

Faunas dominated by morphotypes resembling Bolivina 

aff. B. dilatata have been documented from the 

Northeastern Arabian Sea at 230 m (Maas, 2000, as 

B. dilatata) and 550 m water depth (Jannink et al., 1998, 

as B. dilatata). This species was identified as Bolivina 

seminuda by Gooday et al. (2000), at 412 m on the 

Oman margin, where was the dominant taxon. 

4.2. Comparison with previous studies in the Indian 

Ocean 

Because we had a larger number of sampling points, 

we were able to determine the distribution of foraminiferal 

species in relation to water depth and bottomwater 

oxygen concentrations on the Indo-Pakistan Continental 

Margin in greater detail than in the study of Maas 

(2000). He described assemblages from 233, 658 and 

902 m water depth in an area where the bottom water 

oxygenation (∼ 0.2 ml/l at 230 and 650 m) was slightly 

higher than in the upper part of the OMZ in our study 

area. As in the present study, the faunas described by 

Maas (2000) at 233 m were dominated by B. dilatata 

(our Bolivina aff. B. dilatata), Uvigerina ex. gr. U. 

semiornata and C. auriculus, whereas arenaceous taxa 

were most abundant at 902 m depth. However, the 

assemblages described by Maas (2002) generally contained 

more “deep-infaunal” species (Globobulimina), 

especially at 650 m where Globobulimina affinis (our P. 

pupoides) were dominant. 

The work of Jannink et al. (1998) was based on two 

transects from 500 to 2000 m water depth off Karachi. 

As in our study area, the faunas described by Jannink 

et al. (1998) from 500 m were dominated by B. dilatata 

(our Bolivina aff. B. dilatata), C. laevigata and Ammodiscus 

sp., and, in the 63–150 μm size fraction, by 

B. exilis. From 1000 to 1254 m water depth, U. peregrina, 

Rotaliatinopsis semiinvoluta and Ammodiscus sp. were 

frequent, while below the OMZ B. aculeata and Lagenammina 

sp. were abundant. Although these taxa are not 

exactly the same as those found in our study, the decrease 

in faunal density and the increase in diversity and ALD 10 

with increasing water depth is very similar. 

Hermelin and Shimmield (1990) described faunas 

from the northwestern Arabian Sea (Oman margin). The 

upper bathyal (440–640 m) assemblages were characterised 

by high abundances of various Bulimina and 

Bolivina species, whereas below 530 m U. peregrina 

is present in low numbers. The authors consider these 

faunas to reflect the high organic carbon content of the 

sediment. In our samples, Uvigerina ex gr. U. semiornata 

is always a conspicuous faunal element in the 

upper part of the OMZ, between 136 and 500 m, although 

it decreases significantly with water depth. 

Hermelin and Shimmield (1990) do not mention this 

species. However, it is very abundant in samples from 

100 m water depth on the Oman margin analysed by 

Aranda da Silva (pers. comm. 2005). A specimen of 

Uvigerina ex gr. U. semiornata from this site was 

illustrated by Gooday (2003, Fig. 3F) as R. cylindrica (a 

misidentification). In the deeper part of the northwestern 

Arabian Sea (600–1000), oxygen depletion is slightly 

less severe, as in our study area. Here, Hermelin and 

Shimmield (1990) described a fauna dominated by 

U. peregrina, Ehrenbergina trigona, Hyalinea balthica 

and Tritaxis sp. 1. Although not all these species are 

found in our study area, the increase in diversity towards 

deeper sites is very similar in both areas. 

4.3. Comparison with other oxygen-depleted areas 

There are differences between the taxonomic composition 

of faunas from the Arabian Sea OMZ and those 

reported from other oxygen-depleted areas. In the 

dysoxic Santa Catalina Basin (bottom-water oxygen 

0.2 to 0.5 ml/l) faunas are dominated by Bolivina spissa 

and Globobulmina pacifica, while in the Santa Monica 

Basin (oxygen b 0.2 ml/l) the fauna is more diverse and 

includes Cancris inaequalis, Globobulimina pacifica, 

Rosalina columbiensis and Planulina ariminensis 

(Mackensen and Douglas, 1989). In the Santa Barbara 

Basin (oxygen 0.02–0.5 ml/l), B. seminuda, B. argentea, 

Bulimina tenuata, Chilostomella ovoidea and Nonionella 

stella are common taxa (Bernhard et al., 1997).


65 

Small, thin-shelled forms of Bolivina and Bolivina-like 

species are also abundant within the southern East 

Pacific margin OMZ (Sen Gupta and Machain-Castillo, 

1993). However, species of Uvigerina are almost absent 

in most previously described low-oxygen faunas, 

whereas this genus is a dominant faunal element in the 

Arabian Sea OMZ. All Bolivina species encountered in 

other low-oxygen areas tend to be very elongated, with a 

high length/width ratio, whereas our dominant taxon, 

Bolivina aff. B. dilatata, is strongly tapering and has a 

low length/width ratio. Low-oxygen faunas from 

Mediterranean sapropels exhibit very low diversity and 

are mainly dominated by deep infaunal taxa, e.g. Chilostomella 

spp. and Globobulimina spp. (Jorissen, 1999; 

Schmiedl et al., 2003). B. dilatata has been described as 

part of the repopulating faunas found in the upper parts of 

some sapropels (Schmiedl et al., 2003). 

4.4. Distribution of species across the OMZ 

In this section, we discuss species distributions on the 

Pakistan margin, using water depth as a proxy for bottom-water 

oxygenation. There is a major break at about 

500 m water depth in our study area. At this depth a live 

fauna dominated by Uvigerina ex gr. U. semiornata, 

Bolivina aff. B. dilatata, and in the 63–150 μm fraction 

also by B. dilatata and B. exilis, is replaced by a fauna 

with abundant U. peregrina, Reophax spp. and Ammodiscus 

spp., with B. exilis again present in the smaller 

fraction. The dead fauna below 500 m also includes 

Globobulimina spp., B. aculeata and H. balthica. 

Most species found below 600 m depth are well 

known in the literature and can be considered as cosmopolitan. 

U. peregrina is described in all ocean basins, 

including the North Atlantic (Lutze, 1986; Loubere 

et al., 1995; Jorissen et al., 1998; Fontanier et al., 2002, 

2003), South Atlantic (Mackensen et al., 1995; Licari 

et al., 2003), Pacific Ocean (Loubere, 1994; Kitazato 

et al., 2000), Indian Ocean below the OMZ (Hermelin 

and Shimmield, 1990; Jannink et al., 1998) and Mediterranean 

Sea (De Rijk et al., 2000). This species is also 

common in slightly oxygen depleted areas, e.g. off California 

(Bernhard, 1992), in the Angola Basin (Van 

Leeuwen, 1989) and is found associated with cold methane 

seeps (Rathburn et al., 2000). In the Arabian Sea 

OMZ, U. peregrina is described below 500 m water 

depth by several authors, in the northwestern (Hermelin 

and Shimmield, 1990), as well as in the northeastern part 

(Jannink et al., 1998; Maas, 2000). 

In our study area, the dominant Reophax species are 

R. dentaliniformis, R. bilocularis (with a varying test 

morphology), and morphotypes close to R. scorpiurus. 

These taxa have been described in many other ocean 

basins, for example, the North Atlantic (Schröder, 1986; 

Wollenburg and Mackensen, 1998; Gooday and Hughes, 

2002), South Atlantic (Mackensen et al., 1990, 1993; 

Licari et al., 2003), Pacific Ocean (Jonasson et al., 1995) 

and the Indian Ocean below the OMZ (Gooday et al., 

2000). In the northwestern Arabian Sea, Hermelin and 

Shimmield (1990) described Reophax species around the 

lower boundary of the OMZ (at 1048 m depth), whereas 

Gooday et al. (2000) described high abundances at 

3500 m, well below the OMZ. In the northeastern 

Arabian Sea, Reophax species occur with moderate 

abundances below 600 m water depth (Maas, 2000). 

The high densities of Ammodiscus spp. found in our 

study area between 300 m and 850 m are more unusual. 

The most abundant of these species, Ammodiscus sp. 1 

(see Appendix), was described as A. cretaceus from 

233 m and at 902 m water depth by Maas (2000). 

Jannink et al. (1998) described it as Ammodiscus sp., 

with occurrences between 500 and 2000 m depth on 

both her transects off Karachi. Similar species have been 

described on the Antarctic Shelf by Igarashi et al. (2001, 

as Ammodiscus sp.) and in the North Atlantic (Schröder, 

1986 as Ammodiscus incertus). 

We found B. exilis mainly in the 63–150 μm fraction 

between 150 and 944 m water depth. This usually very 

fusiform buliminid is known from upwelling and lowoxygen 

environments and is common between 700 and 

2000 m water depth in sediments off Cape Blanc (Caralp, 

1984, 1989), off Northwest Portugal (Caralp, 

1984), and on the continental slope off Southwestern 

Africa, (Schmiedl et al., 1997). In the Arabian Sea it 

commonly has a shorter, less fusiform test, with a lower 

length/width ratio. Maas (2000) described its main 

occurrence (as Buliminella exilis) at 658 and 902 m 

water depth. In the profiles off Karachi, Jannink et al. 

(1998) described our shorter morphotype between 500 

and 1555 m water depth, with highest abundances in the 

63–150 μm fraction between 500 and 1000 m. 

4.5. Low-oxygen tolerance of Arabian Sea OMZ species 

As indicated in Section 4.1, there are no reports of 

Uvigerina ex gr. U. semiornata and Bolivina aff. B. 

dilatata, the dominant species in the upper part of the 

Arabian Sea OMZ, in other oceans. They are largely 

restricted to the upper cm of the sediment, similar to the 

usual shallow infaunal microhabitat occupied by related 

species, such as U. mediterranea (De Stigter et al., 1998; 

Fontanier et al., 2002, 2003; Schmield et al., 2004), and 

B. dilatata/spathulata (Barmawidjaja et al., 1992; De 

Stigter et al., 1998). Apparently, in the Indian Ocean, these


shallow infaunal taxa are extremely tolerant of the persistent 

low-oxygen conditions encountered at the sediment–water 

interface within the upper OMZ. The faunas 

of the lower part of the OMZ, on the contrary, contain 

various elements known from deep infaunal microhabitats 

in other, better oxygenated areas. They include Globobulimina 

spp. (Jorissen et al., 1998; Kitazato, 1994; 

Rathburn et al., 2000; Fontanier et al., 2002; Licari et al., 

2003), Praeglobobulimina sp., Chilostomella (Corliss 

and Emmerson, 1990; Kitazato, 1994; Fontanier et al., 

2002; Licari et al., 2003), Fursenkoina (Jorissen et al., 

1998; Licari et al., 2003) andB. exilis (Caralp, 1989; 

Jannink et al., 1998; Maas, 2000). These taxa, which 

occupy deep infaunal niches elsewhere, are found in 

superficial sediments in the lower part of the OMZ of our 

study area. This observation are consistent with the TROX 

model of Jorissen et al. (1995) that predicts a migration of 

deep infaunal taxa to the sediment surface under very low 

oxygen conditions. In Late Quaternary Mediterranean 

sapropels, the same deep infaunal taxa, that are well 

adapted to low oxygen conditions, dominated the benthic 

foraminiferal faunas immediately before the onset of 

sapropel formation (Jorissen, 1999; Casford et al., 2003; 

Schmiedl et al., 2003). 

An interesting question is why these deep infaunal 

taxa, that are very resistant to low oxygen conditions (as 

is shown by their usual microhabitat around the zero 

oxygen boundary), are poorly represented in the superficial 

low oxygen environments in the upper part of the 

OMZ. In other words, why did a rather specific fauna, 

with species that we do not find in other oceans, dominate 

in the upper part of the OMZ, but not the lower 

part? We suggest that this important difference between 

upper and lower OMZ faunas may be explained by a 

difference in the stability of dysoxia over geological 

time. 

Various geochemical and micropaleontological studies 

describe variations in Arabian Sea OMZ intensity 

during the Late Quaternary (Reichart et al., 1997, 1998, 

2002; Schulte et al., 1999; Von Rad et al., 1999; Den 

Dulk et al., 2000). Changes in OMZ intensity are 

mainly inferred from reconstructed primary production 

rates (e.g. Reichart et al., 1997; Schulte et al., 1999; 

Agnihotri et al., 2003), that are correlated with 

millennium-scale orbital forcing and have been linked 

to climate at high latitudes in the northern hemisphere 

(Leuschner and Sirocko, 2000, 2003; Reichart et al., 

2002). Increased primary production has been associated 

with maximum summer monsoon intensity in 

glacial periods, whereas interglacial periods are supposed 

to have been characterised by lower productivity 

(Reichart et al., 1998; Schulte et al., 1999; Von Rad et 

al., 1999; Agnihotri et al., 2003). High glacial surfacewater 

productivity probably caused higher organic 

carbon flux rates, a vertical expansion of the OMZ, and 

lower O 2 levels over the whole OMZ. In interglacial 

periods, on the contrary, reduced productivity should 

cause a weakened, shallower, and more instable OMZ 

(Von Rad et al., 1999; Den Dulk et al., 2000). 

Bottom water circulation is a second factor influencing 

the lower boundary of the OMZ (Schulte et al., 

1999; Den Dulk, 2000; Schmiedl and Leuschner, 2005). 

Today, the OMZ is positioned below the Arabian Sea 

High Salinity Water, formed during winter monsoons in 

the Northern Arabian Sea. The waters residing in the 

OMZ are formed by a mixture of intermediate water 

masses, the Red Sea and the Persian Sea Outflow Water, 

and the North Indian Intermediate Water formed in the 

southern Indian Ocean. The very low (northward) transport 

rates of this water mass amplify its oxygen-depleted 

character (Prasanna Kumar and Prasa, 1999; Schott and 

McCreary, 2001). Below the OMZ, the Arabian Sea is 

bathed by well-oxygenated North Indian Deep Water 

(NIDW), which is formed mainly by North Atlantic 

Deep Water (NADW) and Circumpolar Deep Water 

(CDW) (Schott and McCreary, 2001; Van Aken et al., 

2004). 

According to Reichart et al. (2002), in the Late 

Quaternary, the upper part of the OMZ was only 

ventilated during the coldest phases of the Dansgaard– 

Oeschger cycles, the so-called Heinrich events, as a 

consequence of local intermediate water formation. 

Both during glacial periods, and during normal interglacial 

conditions, the upper part of the OMZ was 

always oxygen depleted. The lower part of the OMZ, 

on the contrary, has probably been much more 

sensitive to short-term changes in primary production 

(and resulting export production), and will probably 

have shifted up and down over time (Den Dulk, 2000; 

Schmiedl and Leuschner, 2005). The result is that the 

core region of the OMZ has been stable over periods 

of 1000s to 10,000s of years, despite evidence for 

seasonal fluctuations of the upper boundary (Bett, 

2004b). Such prolonged periods of severe dysoxia will 

have enabled faunal elements living in the OMZ core 

to acquire the evolutionary adaptations needed to 

invade these low oxygen environments (Rogers, 2000), 

that are attractive because of their extremely high food 

availability. In the lower part of the OMZ, on the 

contrary, conditions have probably been much more 

variable over geological time, because of changes in 

surface productivity and the intensity of the influence 

of NADW (Den Dulk, 2000; Schmiedl and Leuschner, 

2005). As a consequence, the cosmopolitan, deep-


67 

infaunal taxa were most successful in colonizing these 

environments that fluctuated between oxic and dysoxic 

conditions. The fact that the same or similar deep 

infaunal taxa also dominate the Mediterranean presapropel 

faunas for very short periods of time (50– 

100 years) when the system shifts from welloxygenated 

(N4 ml/l) to anoxic conditions (Jorissen, 

1999; Schmiedl et al., 2003), further illustrates the 

need for prolonged periods of time for the adaptation 

of taxa to severe low-oxygen conditions. As in the 

case of the onset of sapropels in the Late Quaternary 

Mediterranean, the lower part of the OMZ in the 

Indian Ocean apparently has not been sufficiently 

stable over geological time scales to allow the 

adaptation of a highly specialized, shallow infaunal 

fauna. 

5. Conclusion 

There is a clear zonation of benthic foraminiferal 

faunas in the Northeast Arabian Sea OMZ. Our composite 

profile from 136 to 1870 m water depth shows 

major faunal breaks at 300, 500 and 1000 m water depth. 

In the core of the OMZ and above the OMZ (136– 

500 m) a very specific fauna, unknown in other oceans, 

is found, dominated by shallow infaunal taxa such 

as Uvigerina ex gr. U. semiornata and Bolivina aff. 

B. dilatata; deep infaunal taxa are poorly represented. In 

the lower part of the OMZ (below 500 m), the fauna has a 

more cosmopolitan character. It includes various taxa, 

such as Globobulimina spp. Praeglobobulimina sp. B. 

exilis, which occupy deep infaunal niches in better oxygenated 

areas but are found in superficial sediment in our 

Pakistan margin samples. 

The contrasting nature of the faunas found in the 

core region and the lower part of the OMZ may be 

explained by a difference in the stability of dysoxia 

over geological time. During glacial and interglacial 

periods, the core of the OMZ was always oxygen 

depleted, except during the coldest phases, the Heinrich 

events, when it was ventilated as a consequence of local 

intermediate water formation. The core region has 

therefore been stable over long time periods. This 

enabled the adaptation of shallow infaunal taxa to 

extremely low oxygen conditions with a very high food 

availability. The lower part of the OMZ, on the 

contrary, has been much more unstable over time, 

reflecting a higher sensitivity to short-term changes in 

primary productivity and the intensity of NADW flow. 

As a consequence, cosmopolitan deep infaunal taxa 

were most successful in colonizing the temporarily 

available low oxygen environments. 

Acknowledgements 

We thank Greg Cowie for the chance to work on 

Arabian Sea material and for providing the opportunity 

for two of us (KEL and AJG) to sample on the Pakistan 

margin. We have special and kind thoughts for the crews 

and captains of the RRS Charles Darwin. We are grateful 

to members of the scientific parties on RRS Charles 

Darwin Cruises 145 and 146, particularly Rachel Jeffreys, 

Lisa Levin, Matt Schwartz, Christine Whitcraft and Clare 

Woulds, who helped in numerous ways. We are very 

grateful to Barun Sen Gupta and an anonymous reviewer 

for their valuable comments. SSch was supported by the 

Conseil Général of the Vendée, France. KEL and AJG 

were supported by the Natural Environment Research 

Council grant number NER/A/S/2000/01383. 

Appendix A 

Species of benthic foraminifera of the Pakistan Continental 

margin, with reference to plates and figures in 

the literature. 

Perforate species 

Alliatina primitiva 

(Cushmann and 

MaCulloch, 

1939) Plate 1, 

fig. 16 

Amphicoryna scalaris 

(Batsch, 1791) 

Amphicoryna sublineata 

(Brady, 1884) 

Anomalinoides 

globulosus Chapman 

and Parr, 1937 

Astrononion echolsi 

Kennett, 1967 

Astrononion sp. 1 

Bolivina alata 

(Seguenza, 1862) 

Bolivina dilatata Reuss, 

1850 Plate 1, 

figs. 13–14 

Bolivina pacifica 

Cushmann and 

MaCulloch, 1942 

Bolivina seminuda 

Cushman, 1911 

Bolivina spathulata 

(Williamson, 1858) 

Bolivina aff. B. dilatata 

Plate 1, figs. 8–12 

References 

Schiebel (1992), pl. 5, 

fig. 11 

Jones (1994), pl. 63, 

figs. 19–22 

Jones (1994), pl. 63, 

figs. 28–31 

Jones (1994) Cibicidoides 

globulosus, pl. 94, figs. 4–5 

Corliss (1979), pl. 3, 

figs. 16–17 

It differs from A. echolsi Kennett, 

1967, by a less significant 

ornamentation. 

Jones (1994) Brizalina alata, 

pl. 53, figs. 2–4 


fig. 4a 


figs. 6b,c 

Den Dulk (2001), pl. 1, 

fig. 4 

Jones (1994) Brizalina 

spathulata, pl. 52, figs. 20–21 

Test strongly tapering, strongly 

flattened, with large pores. 

(continued on next page)


Appendix A (continued) 



References 


References 

Bolivina aff. B. dilatata 

Plate 1, figs. 8–12 

Bolivina sp. 2 

Bolivina subspinescens 

Chusman, 1922 

Bulimina aculeata 

d'Orbigny, 1826 

Bulimina alazanensis 

Cushman, 1972 

Bulimina exilis Brady, 

1884 Plate 1, fig. 15 

Bulimina marginata 


Cancris auriculus (Fichtel 

and Moll, 1798) 

Cancris oblongus 


Cassidulina laevigata var. 

carinata Silvestri 1896 

Cassidulina laevigata 


Cassidulina obtusa 

Williamson, 1858 

Cassidulinoides bradyi 

(Norman, 1881) 

Chilostomella oolina 

Schwager, 1878 

Chilostomella ovoidea 

Reuss, 1850 

Cibicides lobatulus 

(Walker and Jacob, 

1798) 

Periphery more or less rounded, 

without a keel, very often 

provided with a striate 

ornamentation. Adult specimens 

with about 10 chambers, 

rectangular in shape, making an 

angle of about 45° with the 

periphery. Sutures limbate, 

straight until the very centre of 

the test where their end may be 

strongly inflated. Megalospheric 

forms with a very large and 

inflated first chamber. 

Sometimes with a faint striate 

ornamentation on the earlier 

part of the test. 

Maas (2000) Bolivina dilatata, 

pl. 2, fig. 5 

Jannink et al. (1998) 

Bolivina dilatata, pl. 1, fig. 1 

A biserial species with a Bolivina 

shape. The chambers are inflated 

and may be spinose at their lower 

end. 

Jones (1994) Brizalina 

subspinescens, pl. 52, figs. 24–25 

Jones (1994), pl. 51, figs. 7–9 

Schmiedl (1995), pl. 2, fig. 7 

Jannink et al. (1998), pl. 1, fig. 3. 

Our specimens are close to these 

relatively short specimens. 

Van Morkhoven et al. (1986), 

pl. 4, figs. 1−2. This figure shows 

the typical, more elongated 

morphotype. 

Jones (1994), pl. 51, figs. 5–6 

Jones (1994), pl. 106, fig. 4 

Jones (1994), pl. 106, fig. 5 

Jones (1994), pl. 54, figs. 2–3 

Den Dulk (2000), pl. 3, fig. 7 

Jones (1994), pl. 54, fig. 5 

Jones (1994), pl. 54, figs. 6–9 

Jones (1994), pl. 55, figs. 12–14, 

figs. 17–18 

Jones (1994), pl. 55, figs. 15–16, 

figs. 19–23 

Jones (1994), pl. 92, fig. 10, 

pl. 115, figs. 4 and 5 

Cibicidoides bradyi 

(Trauth, 1981) 

Cibicidoides kullenbergi 

(Parker, 1953) 

Cibicidoides 

robertsonianus 

(Brady, 1881) 

Cibicidoides spp. 

Cibicidoides wuellerstorfi 

(Schwager, 1866) 

Dentalina filiformis 

(d'Orbigny, 1826) 

Dentalina spp. 

Ehrenbergina spp. 

Epistominella exigua 

(Brady, 1884) 

Eponides pusillus Parr, 1950 

Fissurina spp. 

Fursenkoina mexicana 

(Cushman, 1922) 

Fursenkoina rotundata 

(Parr, 1950) 

Gavelinopsis lobatulus 

(Parr, 1950) 

Globobulimina cf. G. 

pyrula (d'Orbigny, 

1846) Plate 1, fig. 20 

Globobulimina sp. 3 

Plate 1, fig. 19 

Globocassidulina 

subglobosa 

(Brady, 1881) 

Gyroidina altiformis (R.E. 

and K.C. Stewart, 1930) 

Gyroidina orbicularis 


Gyroidinoides polius 

(Phleger and Parker, 

1951) 

Gyroidioides soldanii 


Hanzawaia boueana 


Hyalinea balthica 

(Schroeter, 1783) 

Ioanella tumidula 

(Brady, 1884) 

Lagena spp. 

Laticarinina spp. 

Lenticulina calcar 

(Linné, 1767) 

Lenticulina spp. 

Marginulina obesa 

(Chushman, 1923) 

Den Dulk (2000), pl. 6, fig. 2 

Den Dulk (2000), pl. 6, fig. 4 

Jones (1994), pl. 95, fig. 4 

Jones (1994), pl. 98, figs. 8–9 

Jones (1994), pl. 63, figs. 3–5 

Schmiedl et al. (1997), 

pl. 2, figs. 7–9 

Van Leeuwen (1989) Nuttallides 

pusillus pusillus, pl. 14, 

figs. 10–14 

Schmiedl (1995), pl. 2, 

figs. 14–15 

Jones (1994), pl. 52, figs. 10–11 

Den Dulk (2000), pl. 4, fig. 6 

Fontanier (2003), pl. 1, 

fig. A–E (p. 245), 

Maas (2000), G. turgida 

(Bailey, 1851), pl. 2, fig. 7 

This species shows more whirls, 

than Globobulimina cf. G. pyrula 

Jones (1994), pl. 54, fig. 17 

Fontanier (2003), pl. 7, 

figs. I, J, K 

Den Dulk (2000), pl. 8, fig. 1 

Van Leeuwen (1989), pl. 12, 

figs. 10–12 

Den Dulk (2000), pl. 8, fig. 2 

Abu-Zied (2001), pl. 11, figs. 3–4 

Jones (1994), pl. 112, figs. 1–2 

Jones (1994), pl. 95, figs. 6–7 

Jones (1994), pl. 70, figs. 8–12 

Maas (2000), L. articulata 

(Terquem, 1862), pl. 2, fig. 10 

Jones (1994), pl. 65, figs. 5–6


69 



Melonis pompilioides 

(Fichtel and Moll, 1798) 

Melonis zaandamae 

(Van Voorthuysen, 1952) 

Neolenticulina variabilis 

(Reuss, 1850) 

Nonion fabum 

(Fichtel and Moll, 1798) 

Oridorsalis umbonatus 

(Reuss, 1851) 

Osangularia culter 

(Parker and Jones, 1865) 

Planodiscorbis sp. 

Praeglobobulimina 

pupoides (d'Orbigny) 


Praeglobobulimina sp. 1 


Pullenia bulloides 


Pullenia quinqueloba 

(Reuss, 1851) 

Reussella spinulosa 

(Reuss, 1850) 

Robertina chapmani 

(Heron-Allen and 

Earland, 1922) 

Rosalina vilardeboana 


Rotaliatinopsis 

semiinvoluta 

(Germeraad, 1946) 

Saracenaria latifrons 

(Brady, 1884) 

Sphaeroidina bulloides 

(Deshayes, 1832) 

Spirilina vivipara 

(Ehrenberg, 1843) 

Uvigerina ex gr. U. 

semiornata Plate 1, figs. 

1−6 

References 

Jones (1994), pl. 109, figs. 10–12 

Schmiedl et al. (1997), pl. 2, 

figs. 12–13 

Jones (1994), pl. 68, figs. 11–16 

Jones (1994), pl. 109, figs. 12–13 

Jones (1994), pl. 95, fig. 11 

Schmiedl et al. (1997), pl. 2, 

figs. 4–6 

Jones (1994), pl. 50, figs. 14–15 

Den Dulk (2000), Globobulimina 

affinis (d'Orbigny, 1846), pl. 1, 

fig. 11 

Maas (2000), Protoglobobulimina 

pupoides (d'Orbigny, 1846), 

pl. 3, fig. 12 

Jones (1994), pl. 84, figs. 12–13 

Den Dulk (2000), pl. 4, figs. 2–3 

Jones (1994), pl. 47, figs. 1–3 

Wiesner (1931), pl. 50, fig. 18 

Jones (1994), pl. 86, fig. 9 

Loeblich and Tappan (1988), 

pl. 714, figs. 7 and 11 

Jones (1994), pl. 113, fig. 11 

Jones (1994), pl. 85, Figs. 1–5 

Jones (1994), pl. 85, figs. 1–4 

Test normally triserial, rounded in 

outline and with a relatively low 

length/width ratio. Chambers 

strongly inflated and overlapping. 

The short neck is positioned in a 

prominent depression, a tooth is 

present in the aperture. Test is 

ornamented with costae, which 

can cross the sutures. On the last 

chambers, the costae can miss. Large 

pores between the costae. Some 

specimens become more elongated 

and in adult specimens the last 

chambers may become biserial. 

Maas (2000), U. ex, 

gr. U. semiornata, pl. 2, figs. 1–3 

Appendix A (continued ) 


Uvigerina peregrina 

Cushman, 1923 Plate 1,fig.7 

Uvigerina probiscidea 

Schwager, 1866 

Valvulineria araucana 


Valvulineria minuta 

(Schubert, 1904) 

Porcellaneous species 

Pyrgo spp. 

Sigmoilopsis schlumbergeri 

(Silvestri, 1904) 

Spiroloculina communis 

Cushman and Todd, 1944 

Spiroloculina rotunda 


Spirosigmoilina tenuis 

(Czjzek 1848) 

Triloculina spp. 

References 


pl. 3, fig. 3 

Van Morkhoven et al. 

(1986), pl. 6 

Phleger et al. (1953), pl. 8, 

figs. 29, 30 

Jones (1994), pl. 91, fig. 4 

Jones (1994), pl. 8, figs. 1–4 

Jones (1994), pl. 9, figs. 5–6 

Jones (1994), pl. 5, figs. 15–16 

Jones (1994), pl. 10, figs. 7,8,11 

Arenaceous species 

Adercotryma glomerata Jones (1994), pl. 34, figs. 15–18 

(Brady, 1878) 

Ammobaculites filiformis Jones (1994), pl. 32, 

(Earland, 1934) 

Figs. 21?, 22–23 

Ammodiscus sp. 1 (Brady, Maas (2000) A. cretaceus 

1881) Plate 1, fig. 21 (Reuss, 1845), pl. 1, fig. 2 

Jannink et al. (1998) 

Ammodiscus sp., pl. 1, fig. 2 

Ammodiscus sp. 2 

A single-celled species with 

vaulted, coiled, test. 

Ammomarginulina foliacea Jones (1994) Eratidus foliaceus, 

(Brady, 1881) 

pl. 33, figs. 20–25 

Cribrostomoides jeffreysii Jones (1994) Veleroninoides 


jeffreysii, pl. 35, figs. 1–2 

Maas (2000) Labrospira sp. A1, 

pl. 1, fig. 1 

Cribrostomoides cf. C. 

Hess (1998), pl. 7, fig. 9 

nitidum (Goes, 1896) 

Cribrostomoides scitulus Jones (1994) Veleroninoides 

(Brady, 1881) 

scitulus, pl. 34, figs. 11–13 

Cribrostomoides subglobosus Jones (1994), pl. 34, figs. 8–10 


Cribrostomoides wiesneri Jones (1994) Veleroninoides 

(Parr, 1950) 

wiesneri, pl. 40, figs. 14–15 

Cyclammina cancellata Jones (1994), pl. 37, figs. 8–16 

(Brady, 1879) 

Deuterammina grahami Wollenburg and Mackensen 

Brönnimann and 

(1998), pl. 2, figs. 6–8 

Whittaker, 1988 

Deuterammina spp. 

Egerella bradyi (Cushman, 1911) Jones (1994), pl. 47, figs. 4–7 

Eggerella sp. 1 

A triserial test, with a high length/ 

width ratio. Chambers are less 

inflated than by E. bradyi. The 

test material is coarse grained. 

(continued on next page)




Eggerelloides scabra 


Globotextularia anceps 

(Bradyi, 1884) 

Glomospira charoides 

(Jones and Parker, 1860) 

Glomospira gordialis 

(Jones and Parker, 1860) 

Haplophragmoides 

sphaeriloculus 


Karrerulina conversa 

(Grzybowski, 1901) 

Karrerulina sp. 1 

Lagenammina apulacea 

(Brady, 1881) 

Lagenammina difflugiformis 

(Brady, 1879) 

Martinotiella communis 


Paratrochammina challengeri 



Portatrochammina bipolaris 



Recurvoides contortus 

Earland, 1934 

Recurvoides turbinatus 

(Brady, 1881) 

Reophax bilocularis Flint, 

1899 Plate 1, fig. 22 

Reophax dentaliniformis 

Brady, 1881 

Reophax fusiformis 


Reophax gracilis 

(Kiaer, 1900) 

Reophax guttifera Brady, 1881 

Reophax micaceus Earland, 

1934 

Reophax mortenseni 

Hogker, 1972 

Reophax pilulifera 

Brady, 1884 

Reophax scorpiurus 

Montfort, 1808 


Reophax spp. 

Saccammina sphaerica 

Brady, 1871 

Siphotextularia spp. 

Textularia spp. 

Trochammina globulosa 

Cushman, 1920 

References 

Jones (1994) pl. 47, figs. 15–17 

Jones (1994) pl. 35, figs. 12–15 

Jones (1994) Usbekistania 

charoides, pl. 38, figs. 10–16 

Jones (1994), pl. 38, figs. 7–8 

Schröder (1986), pl. 18, figs. 5–7 

Jones (1994), pl. 46, figs. 17–19 

Jones (1994), pl. 30, fig. 6 

Mackensen et al. (1990), pl. 6, 

fig. 9 

Jones (1994), pl. 48, 

figs. 1–2, 4–8, 3? 

Brönnimann and Whittaker (1988), 

pl. 16, figs. h–k 

Brönnimann and Whittaker (1988), 

pl. 20–31 

Loeblich and Tappan (1988), 

pl. 68, figs. 7–14 

Jones (1994), pl. 35, fig. 9 


pl. 1, figs. 3–4 

Jones (1994) pl. 30, figs. 21–22 

Jones (1994), pl. 30, figs. 7–10 

Maas (2000) Nouria 

polymorphoides Heron-Allen and 

Earland, 1914, pl. 1, fig. 3 

Hess (1998), pl. 3, fig. 12 

Jones (1994) Hormosinella 

guttifera, pl. 31, figs. 10–15 

Timm (1992), pl. 2, fig. 6 

Jones (1994), pl. 31, figs. 3–4 

Jones (1994) Hormosina 

pilulifera, pl. 30, figs. 18–20 

Schröder (1986), pl. 14, 

figs. 1–5, pl. 23 

Jones (1994), pl. 18, 

figs. 11–15, ?17 

Schröder (1986), pl. 19, 

figs. 9–11 



Trochammina spp. 

Verneuilinulla propinqua 

(Brady, 1848) 

References 

References 

Jones (1994), pl. 47, figs. 8–12 

Abu-Zied, 2001. High resolution LGM—present paleoceanography of 

the NE Mediterranean: a benthic perspective. PhD Thesis, University 

of Southampton, 195 pp. 

Agnihotri, R., Sarin, M.M., Somayalulu, B.L.K., Jull, A.J.T., Burr, 

G.S., 2003. Late-Quaternary biogenic productivity and organic 

carbon deposition in the eastern Arabian Sea. Palaeogeography, 

Palaeoclimatology, Palaeoecology 197, 43–60. 

Antoine, D., André, J.-M., Morel, André, 1996. Oceanic primary production. 

2. Estimation at global scale from satellite (Coastal Zone 

Color Scanner) chlorophyll. Global Biogeochemical Cycles 10, 

57–69. 

Alve, E., 1994. Opportunistic features of the foraminifera Stainforthia 

fusiformis (Williamson): evidence from Frierfjord, Norway. Journal 

of Micropaleontology 13, 24. 

Alve, E., 1995. Benthic foraminiferal distribution and recolonization 

of formerly anoxic environments in Drammensfjord, southern 

Norway. Marine Geology 25, 169–286. 

Barmawidjaja, D.M., Jorissen, F.J., Piskaric, S., Van der Zwaan, G.J., 

1992. Microhabitat selection by benthic foraminifera in the northern 

Adriatic Sea. Journal of Foraminiferal Research 22, 297–317. 

Banse, K., McClain, C.R., 1986. Winter blooms of phytoplankton in 

the Arabian Sea as observed by the Coastal Zone Colour Scanner. 

Marine Ecology Progress Series 34, 201–211. 

Bernhard, J.M., 1988. Postmortem vital staining in benthic foraminifera: 

duration and importance in population and distributional studies. 

Journal of Foraminiferal Research 18, 143–146. 

Bernhard, J.M., 1992. Benthic foraminiferal distribution and biomass 

related to porewater oxygen content: central California continental 

slope and rise. Deep-Sea Research 39, 585–605. 

Bernhard, J.M., 1993. Experimental and field evidence of Antarctic 

foraminiferal tolerance to anoxia and hydrogen sulfide. Marine 

Micropaleontology 20, 203–213. 

Bernhard, J.M., Sen Gupta, B.K., 1999. Foraminifera of oxygendepleted 

environments. In: Sen Gupta, B.K. (Ed.), Modern Foraminifera. 

Kluwer Academic Publisher, Dordrecht, pp. 201–216. 

Bernhard, J.M., Sen Gupta, B.K., Borne, P.F., 1997. Benthic foraminiferal 

proxy to estimate dysoxic bottom-water oxygen concentrations: 

Santa Barbara basin, U.S. Pacific continental margin. 

Journal of Foraminiferal Research 27, 301–310. 

Bett, B.J., 2004a. RRS Charles Darwin Cruise 145 12 Mar–09 Apr 

2003. Benthic ecology and biogeochemistry of the Pakistan margin. 

Southampton Oceanography Centre Cruise report, No. 50, 161 pp. 

Bett, B.J., 2004b. RRS Charles Darwin Cruise 150, 22 Aug–15 Sept 

2003. Benthic ecology and biogeochemistry of the Pakistan margin. 

Southampton Oceanography Centre Cruise report, No. 51, 

143 pp. 

Brönnimann, P., Whittaker, J.E., 1988. The Trochamminacea of the 

Discovery Reports. British Museum (Natural History), London. 

152 pp. 

Burkill, P.H., Mantoura, R.F.C., Owens, N.J.P., 1993. Biogeochemical 

cycling in the northwestern Indian Ocean: a brief overview. Deep- 

Sea Research II 40, 643–649.


71 

Caralp, M.H., 1984. Impact de la matière organique dans des zones de 

forte productivité sur certains foraminifères benthiques. Oceanologica 

Acta 7, 509–515. 

Caralp, M.H., 1989. Abundance of Bulimina exilis and Melonis barleeanum: 

relationship to the quality of marine organic matter. Geomarine 

Letters 9, 37–43. 

Caron, D.A., Dennett, M.R., 1999. Phytoplankton growth and mortality 

during the 1995 northeast monsoon and spring intermonsoon 

in the Arabian Sea. Deep-Sea Research II 46, 1665–1690. 

Casford, J.S.L., Rohling, E.J., Abu-Zied, R.H., Fontanier, C., Jorissen, 

F.J., Leng, M.J., Schmiedl, G., Thomson, J., 2003. A dynamic 

concept for the eastern Mediterranean circulation and oxygenation 

during sapropel formation. Palaeogeography, Palaeoclimatology, 

Palaeoecology 190, 103–119. 

Corliss, B.H., 1979. Taxonomy of recent deep-sea benthonic foraminifera 

from the southeast Indian Ocean. Micropaleontology 25, 

1–19. 

Corliss, B.H., Emmerson, S., 1990. Distribution of Rose Bengal stained 

deep-sea benthic foraminifera from the Nova Scotian continental 

margin and Gulf of Maine. Deep-Sea Research 37, 381–400. 

Cowie, G., 2003. RRS “Charles Darwin” Cruise RRS Charles Darwin 

Cruise 145 12 Mar–09 Apr 2003. Arabian Sea benthic processes 

study. University of Edinburgh, Cruise report, 133 pp. 

Den Dulk, M., 2000. Benthic foraminiferal response to Late Quaternary 

variations in surface water productivity and oxygenation in the 

northern Arabian Sea. Geologica Ultraiectina 188, 1–205. 

Den Dulk, M., Reichart, G.J., Van Heyst, S., Zachariasse, W.J., Van 

der Zwaan, G.J., 2000. Benthic foraminifera as proxies of organic 

matter flux and bottom water oxygenation? A case history from 

the northern Arabian Sea. Palaeogeography, Palaeoclimatology, 


De Rijk, S., Jorissen, F.J., Rohling, E.J., Troelstra, S.R., 2000. Organic 

flux control on bathymetric zonation of Mediterranean benthic 

foraminifera. Marine Micropaleontology 40, 151–166. 

De Stigter, H.C., Jorissen, F.J., Van der Zwaan, G.J., 1998. Bathymetric 

distribution and microhabitat partitioning of live (Rose 

Bengal stained) benthic foraminifera along a shelf to bathyal 

transect in the southern Adriatic Sea. Journal of Foraminiferal 

Research 28, 40–65. 

Fisher, R.A., Corbet, A.S., Williams, C.B., 1943. The relation between 

the number of species and the number of individuals in a random 

sample of an animal population. Journal of Animal Ecology 12, 

4258. 

Fontanier, C., 2003. Écologie des foraminifères benthiques du Golf 

de Gascogne: Études de la variabilité spatiale et temporelle des 

faunes de foraminifères benthiques et de la composition isotopique 

(δ 18 O, δ 13 C) de leurs tests. PhD Thesis, University 

Bordeaux, 471 pp. 

Fontanier, C., Jorissen, F.J., Chaillou, G., David, C., Anschutz, P., 

Lafon, V., 2003. Seasonal and interannual variability of benthic 

foraminiferal faunas at 550 m depth in the Bay of Biscay. Deep-Sea 

Research I 50, 457–494. 

Fontanier, C., Jorissen, F.J., Licari, L., Alexandre, A., Anschutz, P., 

Carbonel, P., 2002. Live benthic foraminiferal faunas from the Bay 

of Biscay: faunal density, composition, and microhabitats. Deep- 

Sea Research II 49, 751–785. 

Gooday, A.J., 2003. Benthic foraminifera (Protista) as tools in 

deep-water palaeoceanography: a review of environmental 

influences on faunal characteristics. Advances in Marine 

Biology 46, 1–90. 

Gooday, A.J., Hughes, J.A., 2002. Foraminifera associated with 

phytodetritus deposits at a bathyal site in the northern Rockall 

Trough (NE Atlantic): seasonal contrasts and a comparison of stained 

and dead assemblages. Marine Micropaleontology 46, 83–110. 

Gooday, A.J., Bernhard, J.M., Levin, L.A., Suhr, S.B., 2000. Foraminifera 

in the Arabian Sea oxygen minimum zone and other oxygendeficient 

settings: taxonomic composition, diversity, and relation 

to metazoan faunas. Deep-Sea Research II 47, 24–54. 

Heinz, P., Hemleben, C., 2003. Regional and seasonal variations of 

recent benthic deep-sea foraminifera in the Arabian Sea. Deep-Sea 

Research I 50, 435–447. 

Helly, J., Levin, L.A., 2004. Global distribution of naturally occurring 

marine hypoxia on continental margins. Deep Sea Research I 51, 

1159–1168. 

Herguera, J.C., Berger, W.H., 1991. Paleoproductivity from benthic 

foraminifera abundance: glacial to postglacial change in the westequatorial 

Pacific. Geology 19, 1173–1176. 

Hermelin, J.O.R., Shimmield, G.B., 1990. The importance of the 

oxygen minimum zone and sediment geochemistry in the distribution 

of Recent benthic foraminifera in the northwest Indian 

Ocean. Marine Geology 91, 1–29. 

Hess, S., 1998. Verbreitungsmuster rezenter benthischer Foraminiferen im 

Südchinesischen Meer. (Distribution patterns of recent benthic foraminifera 

in the Southern China Sea). Berichte — Reports. Geologisches 

und Paläontologisches Institut der Universität Kiel 59, 1–173. 

Igarashi, A., Numanami, H., Tsuchiya, Y., Fukuchi, M., 2001. Bathymetric 

distribution of fossil foraminifera within marine sediment 

cores from the eastern part of Lützow–Holm Bay, East Antarctica, 

and its paleoceanographic implications. Marine Micropaleontology 

42, 125–162. 

Jannink, N.T., Zachariasse, W.J., Van der Zwaan, G.J., 1998. Living 

(Rose Bengal stained) benthic foraminifera from the Pakistan 

continental margin (North Arabian Sea). Deep-Sea Research I 45, 

1283–1513. 

Jonasson, K.E., Schröder-Adams, C.J., Patterson, R.T., 1995. Benthic 

foraminiferal distribution at Middle Valley, Juan de Fuca Ridge, a 

northeast Pacific hydrothermal venting site. Marine Micropaleontology 

25, 151–167. 

Jones, R.W., 1994. The Challenger Foraminifera. Oxford University 

Press, Oxford, New York. Tokyo, 149 pp. 

Jorissen, F.J., 1999. Benthic foraminiferal succession across Late Quaternary 

Mediterranean sapropels. Marine Geology 153, 91–101. 

Jorissen, F.J., Wittling, I., 1999. Ecological evidence from live-dead 

comparison of benthic foraminiferal faunas off Cape Blanc (Northwest 

Africa). Palaeogeography, Palaeoclimatology, Palaeoecology 

149, 151–170. 

Jorissen, F.J., De Stigter, H.C., Widmark, J.G.V., 1995. A conceptual 

model explaining benthic foraminiferal microhabitats. Marine 


Jorissen, F.J., Wittling, I., Peypouquet, J.P., Raboulle, C., Relexans, 

J.C., 1998. Live benthic foraminiferal faunas off Cape Blance, 

NW-Africa: community structure and microhabitates. Deep-Sea 

Research I 45, 2157–2188. 

Kaiho, K., 1994. Benthic foraminiferal dissolved-oxygen index and 

dissolved-oxygen levels in the modern ocean. Geology 22, 

719–722. 

Kitazato, H., 1994. Foraminiferal microhabitats in four marine environments 

around Japan. Marine Micropaleontology 24, 29–41. 

Kitazato, H., Shirayama, Y., Nakatsuka, T., Jujiwara, S., Shimanaga, 

M., Kato, Y., Okada, Y., Kanda, J., Yamaoka, A., Masuzawa, T., 

Suzuki, K., 2000. Seasonal phytodetritus deposition and responses 

of bathyal benthic foraminiferal populations in Sagami Bay, Japan: 

preliminary results from “Project Sagami 1996–1999”. Marine 

Micropaleontology 40, 135–149.


Kurbjeweit, F., Schmiedl, G., Schiebel, R., Hemleben, Ch., Pfannkuche, 

O., Wallmann, K., Schäfer, P., 2000. Distribution, biomass and 

diversity of benthic foraminifera in relation to sediment geochemistry 

in the Arabian Sea. Deep-Sea Research II 47, 2913–2955. 

Larkin, K.E., Gooday, A.J., Levin, L.A., 2003. Metazoan and protozoan 

assemblages. In: Cowie, G. (Ed.), RRS “Charles Darwin” 

Cruise 146: 12 April–30 May 2003. Benthic Ecology and Biogeochemistry 

of the Pakistan Margin. University of Edinburgh, 

Cruise report, pp. 64–71. 

Le Calvez, Y., 1995. Recent Travaux de l'Institut des Peches Maritimes, 

vol. 23, 263 pp. 

Levin, L.A., 2003a. Oxygen minimum zone benthos: adaptation and 

community response to hypoxia. Oceanography and Marine Biology: 

an Annual Review 2003 41, 1–45. 

Levin, L.A., 2003b. Sediments — visual observations, photography, X- 

radiography. In: Cowie, G. (Ed.), RRS “Charles Darwin” Cruise 146: 

12 April–30 May 2003. Benthic Ecology and Biogeochemistry of the 

Pakistan Margin. University of Edinburgh, Cruise report, pp. 53–59. 

Leuschner, D.C., Sirocko, F., 2000. The low-latitude monsoon climate 

during Dansgaard–Oeschger cycles and Heinrich events. Quaternary 

Science Reviews 19, 243–254. 

Leuschner, D.C., Sirocko, F., 2003. Orbital insolation forcing of the 

Indian Monsoon — a motor for global climate changes? Palaeogeography, 


Licari, L.N., Schumacher, S., Wenzhöfer, F., Zabel, M., Mackensen, A., 

2003. Communities and microhabitats of living benthic foraminifera 

from the tropical east Atlantic: impact of different productivity 

regimes. Journal of Foraminiferal Research 33, 10–31. 

Loeblich Jr., A.R., Tappan, H., 1988. Foraminiferal Genera and Their 

Classification. Van Nostrand Rheinhold Company, New York. 970 pp. 

Longinelli, A., 1956. Foraminiferi del Calabriano e Piacebziano di 

Rosignano Marittimo e della Val di Cecina. Paleontographica 

Italica 49, 1–159. 

Loubere, P., 1989. Bioturbation and sedimentation rate control of 

benthic microfossil taxon abundances in surface sediments: a 

theoretical approach to the analysis of species microhabitats. Marine 


Loubere, P., 1994. Quantitative estimation of surface ocean productivity 

and bottom water oxygen concentration using benthic foraminifera. 

Paleoceanography 9, 723–737. 

Loubere, P., 1999. A multiproxy reconstruction of biological productivity 

and oceanography in the eastern equatorial Pacific for the 

past 30,000 years. Marine Micropaleontology 37, 173–198. 

Loubere, P., Fariduddin, M., Murray, R.W., 2003. Patterns of export 

production in the eastern equatorial Pacific over the past 

130,000 years. Paleoceanography 18, 6-1–6-21. 

Loubere, P., Meyers, P., Gary, A., 1995. Benthic foraminiferal microhabitat 

selection, carbon isotope values, and association with larger 

animals: a test with Uvigerina peregrina. Journal of Foraminiferal 

Research 25, 83–95. 

Lutze, G.F., 1986. Uvigerina species of the eastern North Atlantic. In: 

Van der Zwaan, G.J., Jorissen, F.J., Verhalten, P.J.J.M., von Daniels, 

C.H. (Eds.), Atlantic–European Oligocene to Recent Uvigerina. 

Utrecht Micropaleontological Bulletins, vol. 35, pp. 21–46. 

Maas, M., 2000. Verbreitung lebendgefärbter benthischer Foraminiferen 

in einer intensivierten Sauerstoffminimumzone, Indo-Pakistanischer 

Kontinentalrand, nördliches Arabisches Meer (Distribution 

of Rose Bengal stained benthic foraminifera within an intensified 

oxygen minimum zone, Indo-Pakistan Continental Margin, Northwest 

Arabian Sea). Meyniana 52, 101–128. 

Mackensen, A., Douglas, R.G., 1989. Down-core distribution of live 

and dead deep-water benthic foraminifera in box cores from the 

Weddell Sea and the California continental borderland. Deep-Sea 

Research 36, 879–900. 

Mackensen, A., Fütterer, D.K., Grobe, H., Schmiedl, G., 1993. Benthic 

foraminiferal assemblages from the eastern South Atlantic Polar 

Front region between 35° and 57°S: distribution, ecology and 

fossilization potential. Marine Micropaleontology 22, 33–69. 

Mackensen, A., Grobe, H., Kuhn, G., Fütterer, D.K., 1990. Benthic 

foraminiferal assemblages from the eastern Weddell Sea between 

68° and 73°S: distribution, ecology and fossilization potential. 

Marine Micropaleontology 16, 241–283. 

Mackensen, A., Schmiedl, G., Harloff, J., Giese, M., 1995. Deep-sea 

foraminifera in the Southern Atlantic Ocean: ecology and assemblage 

generation. Micropaleontology 41, 342–358. 

Madhupratap, M., Prasanna Kumar, S., Bhattahiri, P.M.A., Dileep 

Kumar, M., Raghukumar, S., Nair, K.K.C., Ramaiah, N., 1996. 

Mechanisms of the biological response to winter cooling in the 

northeastern Arabian Sea. Nature 483, 549–552. 

Murray, J., 1991. Ecology and Paleoecology of Benthic Foraminifera. 

Longmann. 398 pp. 

Olson, D.B., Hitchcock, G.L., Fine, R.A., Warren, B.A., 1993. Maintenance 

of the low-oxygen layer in the central Arabian Sea. Deep- 

Sea Research II 40, 673–685. 

Phleger, F.B., Soutar, A., 1973. Production of benthic foraminifera 

in three east Pacific oxygen minima. Micropaleontology 19, 

110–115. 

Phleger, F.B., Parker, F.L., Peirson, J.F., 1953. North Atlantic foraminifera. 

Reports of the Swedish Deep-Sea Expedition 7, sediment 

cores from the North Atlantic Ocean 1. 

Prasanna Kumar, S., Prasa, T.G., 1999. Formation and spreading of 

Arabian Sea high salinity water mass. Journal of Geophysical 

Research 104, 1255–1464. 

Qasim, S.Z., 1977. Biological productivity of the Indian Ocean. Indian 

Journal of Marine Science 6, 12–137. 

Rathburn, A.E., Levin, L.A., Held, Z., Lohmann, K.C., 2000. Benthic 

foraminifera associated with cold methane seeps on the northern 

California margin: ecology and stable isotopic composition. Marine 


Reichart, G.J., Den Dulk, M., Visser, H.J., Van der Weiden, C.H., 

Zachariasse, W.J., 1997. A 225 kyr record of dust supply, paleoproductivity 

and the oxygen minimum zone from Murray Ridge 

(northern Arabian Sea). Palaeogeography, Palaeoclimatology, 


Reichart, G.J., Lourens, L.J., Zachariasse, W.J., 1998. Temporal variability 

in the northern Arabian Sea oxygen minimum zone (OMZ) 

during the last 225,000 years. Paleoceanography 13, 607–621. 

Reichart, G.J., Schenau, S.J., de Lange, G.J., Zachariasse, W.J., 2002. 

Synchroneity of oxygen minimum zone intensity on the Oman and 

Pakistan Margins at sub-Milankovitch time scales. Marine 

Geology 185, 403–415. 

Reuss, A.E., 1850. Neue Foraminiferen aus den Schichten des 

Österreischischen Tertiärbeckens. K. Akad. Wiss. Wien, Math.- 

Nat. Cl., Denkschr., 18, Bd. 1. 

Rixen, T., Ittekkot, V., Haake-Gaye, B., Schäfer, P., 2000. The influence 

of the SW monsoon on the deep-sea organic carbon cycle 

in the Holocene. Deep-Sea Research II 47, 2629–2651. 

Rogers, A.D., 2000. The role of oxygen minima in generating biodiversity 

in the deep sea. Deep-Sea Research II 47, 119–148. 

Ryther, J.H., Menzel, D.W., 1965. On the production, composition and 

distribution of organic matter in the western Arabian Sea. Deep- 

Sea Research I 12, 199–209. 

Schiebel, R., 1992. Rezente benthische Foraminiferen in Sedimenten 

des Schelfes und oberen Kontinentalhanges im Golf von Guinea


73 

(Westafika) (Recent benthic foraminifera in sediments of the shelf 

and upper continental slope from the Gulf of Guinea (West 

Afrika)). Berichte — Reports Geologisches und Paläontologisches 

Institut der Universität Kiel, vol. 59, pp. 1–179. 

Schmiedl, G., 1995. Rekonstruktion der spätquartären Tiefenwasserzirkulation 

und Produktivität im östlichen Südatlantik anhand 

benthischer Foraminiferen (Late Quarternary benthic foraminiferal 

assemblages from the eastern South Atlantic Ocean: reconstruction 

of deep water circulation and productivity changes). Berichte zur 

Polarforschung 160, 1–207. 

Schmiedl, G., Leuschner, D.C., 2005. Oxygenation changes in the 

deep western Arabian Sea during the last 190,000 years: productivity 

versus deepwater circulation. Paleoceanography 20, 

doi:10.1029/2004PA001044 PA2008. 

Schmiedl, G., Mackensen, A., Müller, P.J., 1997. Recent benthic 

foraminifera from the eastern South Atlantic Ocean: dependence 

on food supply and water masses. Marine Micropaleontology 32, 

249–287. 

Schmiedl, G., Mitschele, A., Beck, S., Emeis, K.-C., Hemleben, C., 

Schulz, H., Sperling, M., Weldeab, S., 2003. Benthic foraminiferal 

record of ecosystem variability in the eastern Mediterranean Sea 

during times of sapropel S5 and S6 deposition. Palaeogeography, 


Schmield, G., Pfeilstricker, M., Hemleben, C., Mackensen, A., 2004. 

Environmental and biological effects on the stable isotope composition 

of recent deep-sea benthic foraminifera from the western 

Mediterranean Sea. Marine Micropaleontology 51, 129–152. 

Schott, F.A., McCreary Jr., J.P., 2001. The monsoon circulation of the 

Indian Ocean. Progress in Oceanography 51, 1–123. 

Schröder, C.J., 1986. Deep-water arenaceous foraminifera in the 

northwest Atlantic Ocean. Canadian Technical Report of Hydrography 

and Ocean Sciences 71, 1–188. 

Schulte, S., Rostek, F., Bard, E., Rullköter, J., Marchal, O., 1999. Variations 

of oxygen-minimum and primary productivity record in sediments of 

the Arabian Sea. Earth and Planetary Science Letters 173, 205–221. 

Sen Gupta, B.K., Machain-Castillo, M.L., 1993. Benthic foraminifera 

in oxygen-poor habitats. Marine Micropaleontology 20, 18–201. 

Shannon, C.E., 1948. A mathematical theory of communication. Bell 

System Technical Journal 27, 379–423. 

Shetye, S.R., Gouveia, A.D., Shenoi, S.S.C., 1994. Circulation and 

water masses of the Arabian Sea. In: Lal, D. (Ed.), Biogeochemistry 

of the Arabian Sea. Indian Academy of Sciences, Bangalore, 

pp. 9–25. 560 080, India. 

Swallow, J.C., 1984. Some aspects of the physical oceanography of the 

Indian Ocean. Deep-Sea Research 31, 639–650. 

Timm, S., 1992. Rezente Tiefsee-Benthosforaminiferen aus Oberflächensedimenten 

des Golfes von Guinea (Westafrika) — Taxonomie, 

Verbreitung, Ökologie und Korngrößenfraktion. Berichte — 

Reports, Geologisches und Paläontologisches Institut der Universität 

Kiel 59, 1–192. 

Van Aken, H.M., Ridderinkhof, H., de Ruijter, W.P.M., 2004. North 

Atlantic deep water in the south-western Indian Ocean. Deep-Sea 

Research. Part 1. Oceanographic Research Papers 51, 755–776. 

Van Leeuwen, R.J.W., 1989. Sea-floor distribution and Late Quarternary 

faunal patterns of planktonic and benthic foraminifers in the 

Angola Basin. Utrecht Micropleontological Bulletins 38, 1–288. 

Van der Zwaan, G.J., Jorissen, F.J., Verhallen, P.J.J.M., von Daniels, 

C.H., 1986. Uvigerina from the Eastern Atlantic, North Sea 

Basin, Paratethys and Mediterranean. In: Van der Zwaan, G.J., 

Jorissen, F.J., Verhallen, P.J.J.M., von Daniels, C.H. (Eds.), Atlantic–European 

Oligocene to Recent Uvigerina. Utrecht Micropleontological 

Bulletins, vol. 35, pp. 7–19. 

Van Morkhoven, F.P.C.M., Berggren, W.A., Edwards, A.S., 1986. 

Cenozoic cosmopolitan deep-water benthic foraminifera. Bulletin 

des Centres de Recherches Exploration–Production Elf-Aquitain 

11 421 pp. 

Von Daniels, C.H., 1970. Quantitative ökologiosche Analyse der 

zeitlichen und räumlichen Verbreitung rezenter Foraminiferen im 

Limskikanal bei Rovinj (nördliche Adria). Göttinger Arbeiten zur 

Geologie und Paläontologie 8, 1–190. 

Von Rad, U., Schaaf, M., Michels, K.H., Schulz, H.D., Berger, W.H., 

Sirocko, F., 1999. A 5000-yr record of climate change in varved 

sediments from the oxygen minimum zone off Pakistan, northeastern 

Arabian Sea. Quarternary Research 51, 39–53. 

Walton, W.R., 1952. Techniques for recognition of living foraminifera. 

Contribution Cushman Foundation of Foraminiferal Research 3, 

56–60. 

Wiesner, H., 1931. Die Foraminiferen der Deutschen Südpolar-Expedition 

1901–1903. In: Drygalski, E.v. (ed.): Deutsche Südpolar- 

Expedition 1901–1903, Vol. 20, Zoologie 10, 49–169. 

Wollenburg, J.E., Mackensen, A., 1998. Living benthic foraminifers 

from the central Arctic Ocean. Faunal composition, standing stock 

and diversity. Marine Micropaleontology 34, 153–185. 

Wyrtki, K., 1973. Physical oceanography of the Indian Ocean. In: 

Zeitschel, B. (Ed.), The Biology of the Indian Ocean. Springer, 

Berlin, pp. 18–36. 

You, Y., Tomczak, M., 1993. Thermocline circulation and ventilation 

in the Indian Ocean derived from water mass analysis. Deep-Sea 

Research I 40, 13–56.

Live (Rose Bengal stained) and dead benthic foraminifera from the ...

Create successful ePaper yourself

Delete template?

Save as template?