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Distribution of Diatoms, Coccolithophores and Planktic Foraminifers Along a Trophic Gradient During SW Monsoon in the Arabian Sea

Distribution of Diatoms, Coccolithophores and Planktic Foraminifers Along a Trophic Gradient During SW Monsoon in the Arabian Sea

Marine Micropaleontology 51 (2004) 345–371 www.elsevier.com/locate/marmicro

Distribution of , and planktic foraminifers along a trophic gradient during SW monsoon in the Arabian Sea

Ralf Schiebela,*,1, Alexandra Zeltnerb, Ute F. Treppkea, Joanna J. Waniekc, Jo¨rg Bollmannd, Tim Rixene, Christoph Hemlebena

a Institute of Geosciences und Palaontologie, Tu¨bingen University, Sigwartstrasse 10, D-72076 Tu¨bingen, Germany b Wilonstrasse 19, 72072 Tu¨bingen, Germany c Southampton Oceanography Centre, SOC, European Way / Empress Dock, Southampton SO14 3ZH, UK d Department of Earth Sciences, Swiss Federal Institute of Technology, ETHZ, Sonneggstrasse 5, 8092 Zurich, Switzerland e Zentrum fu¨r Marine Tropeno¨kologie, Bremen University, ZMT, Fahrenheitstr. 6, 28359 Bremen, Germany Received 1 September 2003; received in revised form 19 January 2004; accepted 14 February 2004

Abstract

The distribution of diatoms, coccolithophores and planktic foraminifers mirrored the hydrographic and trophic conditions of the surface (0–100 m) across the upwelling area off the Oman coast to the central Arabian Sea during May/June 1997 and July/August 1995. The number of diatoms was increased in waters with local temperature minimum and enhanced nutrient concentration (nitrate, phosphate, silicate) caused by upwelling. Vegetative cells of dominated the assemblage in the coastal upwelling area. Towards the more nutrient depleted and stratified surface waters to the southeast, the number of diatoms decreased, and planktic foraminiferal numbers increased, and floral and faunal composition changed. In particular, the transition between the eutrophic upwelling region off Oman and the oligotrophic central Arabian Sea was marked by moderate nutrient concentration, and high coccolithophore and foraminifer numbers. Florisphaera profunda, previously often referred as a ‘lower-photic-zone-species’, was frequent in water depths as shallow as 20 m, and at high nutrient À 1 À 1 concentration up to 14 Amol NO3 l and 1.2 Amol PO4 l . To the oligotrophic southeast of the divergence, cell densities of coccolithophores declined and Umbellosphaera irregularis prevailed throughout the water column down to 100 m depth. In general, total coccolithophore numbers were limited by nutrient threshold concentration, with low numbers ( < 10 Â 103 cells À 1 3 À 1 l ) at high [NO3] and [PO4], and high numbers (>70 Â 10 cells l ) at low [NO3] and [PO4]. The components of the complex microplankton succession, diatoms, coccolithophores and planktic foraminifers (and possibly others), should ideally be used as a combined paleoceanographic proxy. Consequently, models on ecology should be resolved at least for the seasonality, to account for the bias of paleoceanographic transfer calculations. D 2004 Elsevier B.V. All rights reserved.

Keywords: coccoliths; diatom flora; ; nutrients; oceanography; paleoceanography

* Corresponding author. Tel.: +41-1-6323676; fax: +41-1-6321080. E-mail address: [email protected] (R. Schiebel). 1 Current address: Department of Earth Sciences, Swiss Federal Institute of Technology, ETHZ, Sonneggstrasse 5, 8092 Zu¨rich, Switzerland.

0377-8398/$ - see front matter D 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.marmicro.2004.02.001 346 R. Schiebel et al. / Marine Micropaleontology 51 (2004) 345–371

1. Introduction in coastal waters off India were studied for their standing crop, unfortunately without being discussed The Indian Ocean Dipole is one of the most for their ecology (Prasad and Nair, 1960; Durairat- prominent climate systems on Earth today, and is nam, 1964). Simonsen (1974) gave a broad and connected to other climatic patterns such as the North detailed overview of species in plankton samples from Atlantic Oscillation (NAO), El Nin˜o Southern Oscil- net hauls taken during the International Indian Ocean lation (ENSO) and the Indonesian to Australian region Expedition (IIOE) in 1964/1965, but only little infor- via tele-connections (e.g., Ashok et al., 2003). The mation on diatom ecology was presented. Diatoms of Indian Monsoon affects the precipitation on land as the Arabian Sea have not yet been investigated in a well as the hydrography and the biogeochemistry of temporal and spatial resolution that would allow an the Indian Ocean (e.g., Ittekkot and Nair, 1993; ecological interpretation. Fleitmann et al., 2003). Distribution and the standing The taxonomic composition of coccolithophore stock of marine planktic organisms, including dia- assemblages from the Arabian Sea and northern toms, coccolithophores and planktic foraminifers, is Indian Ocean was investigated by Norris (1965, related to the monsoonal oscillation, which varied 1971, 1983, 1984, 1985), Kleijne et al. (1989) and over the historic past and over geologic time scales Kleijne (1991, 1992, 1993). Bernard and Lecal (1960) (e.g., Gupta et al., 2003; Ivanova et al., 2003). reported the distribution of extant coccolithophores in The fossil remains of , for example a general study. Martini and Mu¨ller skeletons and alkenones, are used as paleoceano- (1972) and Guptha et al. (1995) analyzed the cocco- graphic tools although microplankton dynamics and lithophore assemblage along transect at 65jE during trophic conditions are not yet fully understood. In this the late SWM. Sediment trap studies from the north- study, we therefore focus on the effect of the south- eastern Arabian Sea (Andruleit et al., 2000), and from west monsoon (SWM) on the ecology of living the Somalia upwelling region (Broerse et al., 2000) diatoms, coccolithophores and planktic foraminifers, revealed a strong relationship between the monsoon and on the differential population dynamics among and the seasonal flux of coccolithophores. A first these three microplankton groups. comparison between monsoon induced changes of Different phytoplankton groups co-occur accord- the living coccolithophore assemblage in the north- ing to ecological demand on trophic (nutrients, food), western Arabian Sea, compared to Holocene and physical (e.g., light, mixing, temperature) or biolog- Quaternary assemblages, was carried out by Woellner ical factors (e.g., competition, predation) (cf. Smayda, et al. (1988). Holocene sediment assemblages in the 1986). In particular, we focus on the effect of Arabian Sea are dominated by Gephyrocapsa oce- hydrography on nutrient concentration in the upper anica (Martini and Mu¨ller, 1972; Guptha, 1985; 100 m of the water column and production of Houghton and Guptha, 1991; Andruleit and Rogalla, autotrophic organisms (diatoms and coccolitho- 2002). Potential environmental control of coccolitho- phores). This is pursued by quasi-synoptic investiga- phores in surface waters off Pakistan was investigated tions on the spatial and temporal succession of by Andruleit et al. (2003). diatoms, coccolithophores and planktic foraminifers Planktic foraminifers were investigated for their along a productivity gradient from the coastal general distribution, ecology and fossil record in the upwelling off Oman (eutrophic) to the stratified Indian Ocean by Be´ and Tolderlund (1971), Be´ and (oligotrophic) central Arabian Sea. Hutson (1977) and Guptha et al. (1994). Seasonal changes of the planktic foraminiferal fauna and stable 1.1. Previous studies on diatoms, coccolithophores isotope composition over the course of the monsoons and planktic foraminifers in the Arabian Sea are described by Kroon and Ganssen (1988) and Curry et al. (1992). Kroon (1988) and Ivanova et al. Diatoms of the Indian Ocean were studied by (1998) reported Globigerinita glutinata, Neoglobo- Cleve (1901), Karsten (1907), Taylor (1967), Sournia quadrina dutertrei and Globorotalia menardii as up- (1968), Hendey (1970), Thorrington-Smith (1970) welling indicators in the Arabian Sea. While and Mathur and Singh (1993). Certain diatom taxa Globigerina bulloides occurs mainly during the late R. Schiebel et al. / Marine Micropaleontology 51 (2004) 345–371 347

SWM (September, after Kroon and Ganssen, 1988), the method of Kleijne (1991). Coccolithophores were N. dutertrei is more frequent during the early SWM, filtered onto a 50-mm diameter, regenerated cellulose in June and July, along with decreased sea surface membrane filter with a pore size of 0.45 Am (SAR- temperatures, which is again indicative of upwelling. TORIUS) using a vacuum pump. The vacuum was adjusted to 200 mbar and the actual filtration area was 1249 mm2. All filters were air dried for 12 h, stored 2. Materials and methods in plastic petri dishes and were kept dry in closed boxes with silica gel. For the analysis on a scanning Water and microplankton was collected from the electron microscope (SEM), circular pieces (area of upper 100 m of the water column in the Arabian Sea. 133 mm2) were punched out of the center of the filter During R/V METEOR cruise 32/5 (M32/5), July 14 to membrane and mounted onto aluminium stubs using August 14, 1995, nine stations along a transect perpen- double-sided adhesive tape. Subsequently, samples dicular to the coast of Oman towards 14jN/65jE were coated with 20 nm of gold/palladium, and (Central Arabian Sea Station, CAST) and at 10jN/ colloidal silver suspension was put on the border of 65jE (Southern Arabian Sea Station, SAST) were the membrane to provide optimal conductivity of the sampled (Table 1, Fig. 1). During R/V SONNE cruise sample. The stubs were examined on a Cambridge 119 (SO119), May 12 to June 10, 1997, nine stations Stereoscan S250 SEM at 15–20 kV. were sampled along the coast of the Oman and at the Diatoms and coccolithophores were counted on Northern, Western, Central and Southern Arabian Sea the same microscope stub. Diatoms were counted Stations (NAST, WAST, CAST and SAST). from eight sites sampled during M32/5 and SO119 To obtain diatoms and coccolithophores, water (Table 1) at a magnification of 1000 Â . Diatom was sampled with 5-liters Niskin bottles at 10, 20, valves were counted in an area of 15–275 SEM 40, 60, 75 and 100 m water depth. The Niskin bottles screens, randomly distributed on the filter. In general, were attached to and synchronized with an opening– diatoms were preserved as single valves and complete closing-net. Water samples were treated according to cells. Counting units were defined according to

Table 1 List of sampling locations Cruise Date Sta. #a Lat. (jN)a Long. (jE)a MN #a Sample depth (m) Db Coccob plFb SO119 16.05.97 NAST-3 19j56.9V 65j49.5V 1272 – 20/60/100 20.05.97 CAST-5 14j27.5V 64j35.1V 1278 – 20/60/100 0–100 22.05.97 SAST-6 10j00.7V 64j59.9V 1281 – 20/60/100 0–100 24.05.97 WAST-7 16j12.1V 60j18.5V 1284 – 20/60/100 0–100 26.05.97 12 17j14.5V 58j31.3V 1288 – 60/100 – 31.05.97 28 17j18.6V 58j23.6V 1295 – 20/60/100 0–100 01.06.97 31 17j45.9V 59j04.2V 1298 – 20/60 – 02.06.97 36 19j02.1V 58j48.9V 1301 20 20/60/100 – 03.06.97 37 20j33.9V 60j03.1V 1303 – 20/60/100 0–100 M32/5 24.07.95 404 09j58.8V 65j01.1V 971 – 20/60/100 – 27.07.95 414 14j26.8V 65j00.9V 974 – 20/60/100 0–100 30.07.95 423 16j01.9V 62j00.8V 977 60 20/60/100 – 01.08.95 430 17j06.8V 60j00.8V 979 10 60/100 0–100 04.08.95 438 18j31.8V 57j20.5V 981 10 40/75 – 04.08.95 440 18j36.7V 57j28.5V 982 20 10/40/75 – 06.08.95 444 18j13.7V 58j13.2V 986 20 60/100 – 07.08.95 446 17j41.2V 58j53.2V 988 20 20/60/100 – 10.08.95 460 16j13.5V 61j28.3V 990 – 20/60/100 À a Sta. = station, Lat. = latitude, Long. = longitude, MN = multinet number. b D = diatoms, Cocco = coccolithophores, plF = planktic foraminifers. 348 R. Schiebel et al. / Marine Micropaleontology 51 (2004) 345–371

Fig. 1. Location of sampling sites during R/V Sonne cruise 119 and R/V Meteor cruise 32/5. (after Antoine et al., 1996, gCmÀ2 yearÀ 1) is given in italic numbers (dashed lines). Coastal upwelling off Oman causes highest primary production. Lowest biological productivity occurs in oligotrophic waters at the southeast of the study area. The Findlater Jet Axis is indicated by the arrow (cf. Rixen et al., 2000).

Schrader and Gersonde (1978). The abundance of solution buffered with hexamin at pH8.2.Inthe diatoms is given as valves per liter and the relative laboratory, planktic foraminiferal tests were picked, amount of taxa was calculated (see Appendix A). dried, sieved into size classes of >100–125–150– Coccolithophores were counted on 500 randomly 200–250–315 and >315 Am then counted on a chosen fields (49.50Â38.25 Am = 1893.38 Am2)at species level. Cytoplasm bearing tests (‘living speci- 2000 Â magnification along transects over the mens’) were counted separately from empty tests complete circular sub-sample of the membrane filter. (‘dead specimens’). The taxonomy of planktic fora- If possible, at least 200 individuals (complete cocco- minifers used here follows Hemleben et al. (1989).On spheres) per sample were analyzed. Unequivocally average, more than 90 % of specimens are classified collapsed coccospheres were considered complete. as ‘living’ (up to 99.25%). Therefore, in the following The number of coccolithophores is given in cells we refer to the total numbers of specimens (sum of per liter (Appendices B and C). Morphometric mea- ‘living’ and ‘dead’). surement of gephyrocapsids was carried out according During cruise M32/5, temperature and salinity to Bollmann (1997), by analyzing 50 specimens per were measured with a Neil Brown Mark III CTD with sample on the SEM. fluorometer and oxygen sensor, and during cruise Planktic foraminifers were sampled in five 20-m SO119 a SBE 4-Conductivity Sensor was used. depth intervals between the ocean surface water and Nutrients (dissolved nitrate [NO3], phosphate [PO4] 100 m water depth (Appendices D and E) with a and silicate [SiO4]) were analyzed with a Continuous multiple-opening-closing-net (100-Am mesh size). Flow Analyzer according to Grasshoff et al. (1988). Samples were fixed on board by a 4% formaldehyde Samples were taken from the rosette sampler, along R. Schiebel et al. / Marine Micropaleontology 51 (2004) 345–371 349 with CTD measurements, in polyethylene bottles and lithophore and planktic foraminiferal species, which, in analyzed within 24 h after collection. Chlorophyll a turn, will allow for detailed paleoceanographic inter- analysis (M32/5) was performed according to Herb- pretation. Hydrographic circulation, trophic condition land et al. (1985). The data is available from http:// and biological productivity of the Arabian Sea are www.pangaea.de/home/rschiebel/. largely affected by the seasonal oscillation of the monsoon winds. Northeastern winds prevail between November and March (northeast monsoon, NEM), and 3. On the hydrography of the modern Arabian Sea southwestern winds prevail from May to October (SWM). Different heat capacity of land and sea causes Detailed knowledge of the hydrography is crucial barometric pressure differences and strong winds, for the understanding of the ecology of diatom, cocco- which result in the low-level atmospheric Findlater

Fig. 2. Temperature (jC) and salinity of the upper 100 m along the Sonne 119 (panels a and b) and Meteor 32/5 transect (panels c and d). The cross-hatched square at the lower left corner of panel c and d indicates the sea floor. For the exact position of the stations (numbers on top of panel a), see Fig. 1 and Table 1. Note the different latitudinal extension of the upper (a, b) and lower (c, d) panels. 350 R. Schiebel et al. / Marine Micropaleontology 51 (2004) 345–371

Jet, parallel to the Somalian coast during the SWM 3.1. Environmental conditions during sampling (Findlater, 1971) (Fig. 1). As a result, surface currents turn towards the northeast, surface waters are displaced In contrast to warm surface waters during May/ away from the coast, and strong upwelling occurs at the June 1997, comparatively cold surface waters during coast off Somalia and Oman. Two different upwelling July/August 1995 were observed, indicating strong modes have been suggested: (1) Ekman driven upwell- upwelling to the north of 15jN (Fig. 2). Concentration ing caused by the wind stress curl, between 15jN and of silicate, nitrate and phosphate in the coastal upwell- 22jN up to 30 km off the coast of Oman (Wyrtki, 1973; ing area off Oman increased with water depth (Fig. 3) Bauer et al., 1991), and also at the open ocean along the and was negatively related to water temperature (Ap- Findlater-Jet axis (Smith and Bottero, 1977; Swallow et pendices A–E) (cf. Tomczak, 1984). Concentration of al., 1983; Manghnani et al., 1998; Rixen et al., 2000) chlorophyll (>0.82 AglÀ 1) was high throughout the (Fig. 1). (2) Quasi-stationary filaments are tied off from upper water column close to the Oman coast and the coastal upwelling area. Filaments are tongues of indicates high primary production (Appendix A, cold and nutrient rich surface water (visible from M32/5, Stations 438 and 444). At Stations 423 and satellite images) associated to upwelling, and reach 460, at the southern margin of the upwelling area far beyond the coast (cf. Weaks, 1983; Washburn et al., (Fig. 1), updoming of isotherms from below 180 m 1991; Brink and Cowles, 1991; Brock et al., 1992; water depth possibly indicates a filament (cf. Waniek Waniek, 1997). Depending on the intensity of the et al., 1996). At the oligotrophic site in the open SWM winds, filaments are features that are supplied Arabian Sea (Station 404), a Deep Chlorophyll by coastal upwelling and often triggered by topography Maximum (DCM) indicates stratification of the (Strub et al., 1991). upper water column, nutrient concentrations were

Fig. 3. Concentration (Amol lÀ 1) of (a) silicate, (b) phosphate and (c) nitrate in the upper 100 m of the water column during July/August 1995. Sample positions are indicated by dots. R. Schiebel et al. / Marine Micropaleontology 51 (2004) 345–371 351 decreased, and nitrate was only detected below 90 m decreased towards the open ocean at the beginning of water depth (Von Bro¨ckel et al., 1996). August 1995 (Fig. 4). In the coastal area, vegetative The SWM in 1997 started on May 24, indicated by cells of Chaetoceros with more than 80% of the total a sudden shift of wind direction from 315j to 225– assemblage were most abundant. In general, lowest 270j, and increased wind speed from 3 to 9 m sÀ 1 species richness occurred along with high valve (Bange et al., 1999). The sea surface temperature concentration in the upwelling area close to the Oman (SST) remained high between 29 and 30 jC at the coast and the highest species richness occurred along open ocean Stations 6 to 31 (Fig. 2). Close to the with decreased nutrient concentration (Appendix A). Oman coast, at Stations 36 and 37, slight upwelling Most Chaetoceros species in the coastal area belong was indicated by decreased SST at 18–20jN (Fig. 2). to the group of hyalochaetes. In addition, Thalassio- To the southeast of the coastal upwelling area, updom- nema nitzschioides var. nitzschioides was also pre- ing of isotherms was recorded, which possibly indi- dominant, and Stephanopyxis turris occurred as a cates diverging currents and slight upwelling caused typical species of this assemblage (Appendix A). by the atmospheric Findlater Jet (Stations 5, 7, 12 and Further from the coast, absolute and relative abun- 28). To the southeast of the divergence, in the oligo- dances of Pseudo-nitzschia spp. (mainly P. delicatis- trophic open Arabian Sea, surface waters were strat- sima and P. pseudodelicatissima) and species of the ified between 10jN and 14jN (Fig. 2). oceanic Nitzschia bicapitata-group increased. Highest numbers of N. bicapitata species, as well as taxa related to the Palgiotropis-group, occurred at Station 4. Results 446. In the open Arabian Sea (Station 423), the diatom assemblage was still characterized by the N. 4.1. Diatom distribution bicapitata-group, Chaetoceros and Pseudo-nitzschia. In May/June 1997, the number of diatom specimens The highest numbers of diatom valves off the off the Oman coast (Station 37) resembled that at Oman coast occurred closest to land and numbers Stations 440 and 444, in July/August 1995. Virtually,

Fig. 4. Distribution of the diatom taxa (a) Chaetoceros spp., (b) Nitzschia bicapitata-group, (c) Thalassionema nitzschioides and (d) Pseudo- nitzschia spp. along a transect from the Oman coast (left) towards the central Arabian Sea (right), given in percent of total diatoms. The total number of diatoms (valves  104 lÀ 1) is given as bold line in panel a. The break between 1995 (Stations 438–423) and 1997 (Station 37) is indicated by the dashed vertical line. 352 R. Schiebel et al. / Marine Micropaleontology 51 (2004) 345–371 no freshwater diatoms were observed during May/ periods. The highest species richness (48 taxa) June 1997 (Appendix A). During May/June 1995, was recorded at Station 31 during June 1997, diatom valve numbers were positively related to and the overall diversity increased towards the nutrient concentration (N = 6, linear regression: SiO4, oligotrophic open ocean during both sampling r = 0.68, P = 14.0%; NO3, r = 0.80, P =5.6%; PO4, campaigns (Appendices B and C). However, the r = 0.81, P = 5.2 %) (Appendix A). diversity varied significantly between the two cruises with 80 taxa during May/June 1997 and 4.2. Coccolithophore distribution 40 taxa during July/August 1995. Standing stock increased from the upwelling area towards the In total, 83 coccolithophore taxa were recorded oligotrophic open ocean, although in different in the Arabian Sea during the analyzed time modes during both sampling periods. Total cell

Fig. 5. Coccolithophore cell numbers are negatively related to nitrate [NO3] and phosphate [PO4] concentration (N = 46 for both [NO3] and À 1 3 À 1 [PO4]). Below lower threshold of 4 Amol NO3 and 0.35 Amol PO4 l more than 70 Â 10 coccolithophore cells l occurred, and above the À 1 3 À 1 upper threshold of 14 Amol NO3 and >1.25 Amol PO4 l cell densities are lower than 10 Â 10 cells l . Nutrient thresholds are similar for total coccolithophore cell numbers (panel a) and for distinct species (panels b to g), although cell numbers ( Â 103 cells lÀ 1) vary between species. R. Schiebel et al. / Marine Micropaleontology 51 (2004) 345–371 353 density varied between 0 and 112 Â 103 cells lÀ 1, oligotrophic central Arabian Sea Station 6, Umbel- and in the oligotrophic central Arabian Sea cell losphaera irregularis was most abundant (Fig. 7c densities were lower during May/June 1997, than and d). The high cell concentrations of up to during July/August 1995. 45 Â 103 cells lÀ 1 of O. antillarum (Station 5, 20 Standing stocks were negatively related to NO3 m) and Calcidiscus leptoporus (Station 7, 20 m; and PO4 concentrations. In the oligotrophic Arabi- ‘type A’ after Kleijne, 1993; ‘small morphotype’ an Sea, high cell densities (>70 Â 103 cells lÀ 1) after Knappertsbusch et al., 1997) during May/June À 1 occur at < 4 Amol NO3 l and < 0.35 Amol PO4 1997, are remarkable, as both species usually show À 1 À 1 l . At a concentration below 14 Amol NO3 l much lower cell densities. G. oceanica shows a À 1 and below 1.25 Amol PO4 l cell densities general decrease of the proportion of its ‘larger exceeded 10 Â 103 cells lÀ 1 (Fig. 5a). At these morphotype’ (after Bollmann, 1997) from the up- levels of NO3 and PO4 concentration, cell numbers welling area (Stations 37 and 438; diameter of 4.3– of the total coccolithophore flora (Fig. 5a) and 4.5 Am) towards the oligotrophic open ocean (Sta- of all frequent species (Fig. 5b–g) changed tions 7 and 404) where the ‘equatorial morphotype’ distinctly. of G. oceanica (diameter of 3.5–3.9 Am) was During July/August 1995, G. oceanica was the dominant. most abundant species (Fig. 6b) with up to 51 Â 103 cells lÀ 1. The joint second most abundant 4.3. Planktic foraminiferal distribution species were and the ‘lower species’ Florisphaera profunda with During the beginning of the SWM in May/June up to 22 Â 103 cells lÀ 1 (Appendix C). Oolithotus 1997, high average planktic foraminiferal abundance antillarum reached up to 20 Â 103 cells lÀ 1 at the was restricted to the upper 40 m of the water open ocean Station 404 (Fig. 1, Appendix C). In column (Fig. 8) with maximum numbers at Station contrast, during May/June 1997, F. profunda was 7. Medium numbers were recorded at the open the most abundant species with up to 31 Â 103 cells Arabian Sea (Stations 5 and 6) and low numbers lÀ 1 at the Stations 3 and 7, and at the stratified occurred at the two sites closest to the Oman coast

Fig. 6. (a) Total coccolithophore cell densities ( Â 103 cells lÀ 1) and (b) relative floral part of G. oceanica from the upwelling area off Oman (left) to the central Arabian Sea (right) during July/August 1995 (see Appendix C). 354 R. Schiebel et al. / Marine Micropaleontology 51 (2004) 345–371

Fig. 7. (a) Total coccolithophore cell densities ( Â 103 cells lÀ 1) and (b, c, d) relative floral part of frequent species from the upwelling area off Oman (left) to the central Arabian Sea (right) during May/June 1997 (see Appendix B). Along the transect, from the north to the south, three hydrographic regimes can be distinguished: upwelling (Stations 37, 3, 36 and 31), an area of diverging currents (Stations 28, 12, 7 and 5) and stratified waters in the central Arabian Sea (Station 6).

(Appendix D: Stations 28 and 37). The most fre- dutertrei also occurred in high numbers. South of quent species were Globigerinoides ruber at Station the upwelling area G. bulloides and N. dutertrei 7 and Globigerinoides sacculifer at Station 6, in- were rare. Globigerinoides glutinata was rare at creasing in numbers from the north towards the the northern Station 37 and numbers only slightly south. High relative frequency of G. ruber and G. increased at Stations 28, 6 and 5 (Fig. 1, Appendix sacculifer was recorded only south of the area of D). In 1995, numbers of planktic foraminifers were coastal upwelling (Fig. 8). In the area of the coastal much higher than in 1997 and the main depth upwelling (Station 37) G. bulloides was most fre- habitat was broadened to 80 m instead of 40 m in quent, constituting up to 60% of the assemblage in 1997 (Appendices D and E). The species composi- the uppermost 60 m (Fig. 8) and Neogloboquadrina tion was different comparing both years and, in R. Schiebel et al. / Marine Micropaleontology 51 (2004) 345–371 355

Fig. 8. Distribution of (a) total planktic foraminifers and (b, c, d) frequent species in the upper 100 m of the water column (see Appendix D), from the upwelling area off Oman (left) to the central Arabian Sea (right), during May/June 1997, indicates three different hydrographic and trophic regimes (on top of panel a). addition to G. ruber and G. sacculifer, high numb- concentration and negatively related to coccolitho- ers of Globoturborotalita tenella and Globigerina phore cell numbers (Fig. 9). The general distribution falconensis occurred at Stations 5 and 7 during of planktic foraminifers (Fig. 8) did not correlate to a July/August 1995 (Appendix E). high degree to both the diatom and the coccolithophore distribution (cf. Appendices A, C and E). However, 4.4. Succession of diatoms, coccolithophores and highest planktic foraminiferal abundance occurred in planktic foraminifers along the trophic gradient the area of divergence where mesotrophic conditions were recorded, and which resembles the distribution of Along transect sampled in the northern to central coccolithophores during May/June 1997 (Figs. 7 and Arabian Sea during early (May/June 1997) to mid 8). Lowest frequency of planktic foraminifers occurred SWM (July/August 1995), a gradient from high to along with high nutrient concentration under upwelling low nutrients was observed (Fig. 3). In general, diatom conditions and was negatively related to the distribu- valve numbers were positively related to nutrient tion of diatoms (Figs. 8 and 9). 356 R. Schiebel et al. / Marine Micropaleontology 51 (2004) 345–371

5. Discussion frequency decreased by two orders of magnitude and the species composition changed (Fig. 4). Enhanced 5.1. Specific diatom flora in different upwelling biological productivity towards the central Arabian Sea regimes was indicated by Nitzschia bicapitata, a diatom spe- cies, which is possibly related to upwelled open-oce- Diatoms are the dominant phytoplankton group in anic waters (cf. Lange et al., 1994) or to filaments, upwelled coastal waters during SWM off Oman, in propagating from the Oman upwelling. The cooccur- terms of valve concentration in surface waters, carbon rence of more coastal Pseudo-nitzschia spp. and Chae- cycling and mass flux (cf. Garrison et al., 2000). The toceros spp. with the more open marine N. bicapitata abundance of diatoms is closely related to the avail- points towards mixing of different nutrient rich water ability of nutrients (Fig. 9). The dominating diatom masses (cf. Cupp, 1943; Hasle, 1965; Pitcher et al., species were Chaetoceros spp. and Thalassionema 1991, Lange et al., 1994; Treppke et al., 1996). nitzschioides during both investigated years 1995 and 1997 (cf. Brock et al., 1991). The Chaetoceros species 5.2. Coccolithophores, nutrient concentration and that occurred along with upwelling off Oman are surface water stratification hyalochaete taxa, which are characteristic of the high productive coastal regime (Pitcher et al., 1991), and co- Coccolithophore cell densities (up to 107 Â 103 lÀ 1) occurring T. nitzschioides, which is related to coastal and species richness in the Arabian Sea are comparable waters and high nutrient levels (Abrantes, 1988; to cell densities in the Atlantic at Bermuda (BATS) and Treppke et al., 1996) and to enhanced biological in the Pacific Ocean near Hawaii (HOT) (cf. Haidar and productivity caused by river runoff (e.g., off southwest Thierstein, 2001; Corte´s et al., 2001). The significant Africa; Van Iperen et al., 1987). Both Chaetoceros and differences in coccolithophore cell densities and diver- T. nitzschioides indicated coastal upwelling and high sity in the Arabian Sea, comparing May/June 1997 and primary productivity during the sampling campaigns July/August 1995, may be related either to the seasonal M32/5 and SO119. Outside the upwelling area, diatom succession or to interannual variations in the strength of

Fig. 9. Diatom (open bars) and coccolithophore (black bars) abundance are negatively related (r = À 0.69, N = 6) along transect of varying nutrient concentration (exemplified by [NO3], bold line; linear regression: r = 0.80, N = 6) in the northern Arabian Sea. High nutrient concentration occurs in the upwelling area off Oman (NW of transect, left side) and in the central Arabian Sea nutrient concentration is low (SE of transect, right side). The break between 1995 (Stations 438–423) and 1997 (Station 37) is indicated by the dashed line. R. Schiebel et al. / Marine Micropaleontology 51 (2004) 345–371 357 the monsoonal upwelling. Seasonal variation in cell photypes that was previously inferred from Holocene densities was also reported from the time series Stations sediments (Bollmann, 1997). BATS and HOT, and, in addition, significant interan- In contrast to the observation that the lower-photic- nual variability was observed at HOT (Haidar and zone-species Florisphaera profunda occurs mainly in Thierstein, 2001; Corte´s et al., 2001). subsurface waters of 75–200 m depth (Okada and The general increase of cell density and species Honjo, 1973; Reid, 1980; Corte´s et al., 2001; Haidar richness towards the oligotrophic open ocean supports and Thierstein, 2001), F. profunda occurred in high cell the assumption that coccolithophores are adapted to numbers in waters of 20–60 m depth during May/June low to medium nutrient concentration (Fig. 5), low 1997 (Fig. 7, cf. Andruleit et al., 2003). The occurrence turbulence and stratified surface waters (cf. Winter, of F. profunda throughout the upper water column 1985; Mitchell-Innes and Winter, 1987; Kleijne, 1993). supports the assumption that F. profunda has rather From the complete Arabian Sea data set on coccolitho- an affinity to enhanced nutrient concentration (Fig. 5) phore cell density, [NO3] and [PO4], there is striking and low light intensity than for a specific water depth evidence that coccolithophore cell density does not (cf. Ahagon et al., 1993; Corte´s et al., 2001; Haidar and follow nutrient concentration in some negative linear or Thierstein, 2001). F. profunda was most frequent in the exponential way, but is limited by thresholds of nitrate area of divergence between 13jN and 17jN(Fig. 7, and phosphate (Fig. 5). This assumption is true for the Appendix B), where updoming isotherms indicated total coccolithophore flora and for at least the most nutrient entrainment into surface waters from below, frequent species observed in the study presented here. and stimulated primary productivity at depths of suit- Complete ecological preferences of coccolitho- able light intensity. However, updoming isotherms may phores, however, are difficult to infer from our data also indicate upward transportation of coccolitho- set because of missing data on, for example, light and phores from below, and not their normal habitat. Along turbulence, and due to the complex relations between with F. profunda, also Gladiolithus flabellatus, Calci- environmental parameters and differential biologic discus leptoporus and Oolithotus antillarum were prerequisites of species. Unfortunately, cell densities frequent close to the nutricline. of more than 106 cells lÀ 1, as reported from neritic Calcidiscus leptoporus is attributed to oligotrophic environments of the North Atlantic (e.g., Birkenes and open marine conditions (Blasco et al., 1980; Mitchell- Braarud, 1952; Burkill et al., 2002), were neither Innes and Winter, 1987; Giraudeau, 1992; C˘ epek, observed during the study presented here, nor at BATS 1996). However, there are at least three different and HOT, and, therefore, the upper end of cell density morphotypes of C. leptoporus with specific environ- and maybe a lower threshold of nutrient concentration mental preferences, out of which the small morphotype could be missing here (Fig. 5). is present here. The small morphotype (type A after The dominance of Gephyrocapsa oceanica in the Kleijne, 1993; type small after Knappertsbusch et al., studied area confirms the results obtained in Holocene 1997) appears to prefer water temperature higher than sediments (Martini and Mu¨ller, 1972; Guptha, 1985; 26 jC, which is confirmed by our observations. Umbel- Houghton and Guptha, 1991; Andruleit and Rogalla, losphaera irregularis was the most characteristic spe- 2002) and supports the general assumption that G. cies, dominating the flora in warm, stratified, and oceanica morphotypes are adapted to upwelling, nerit- oligotrophic waters (Fig. 7d), confirming earlier obser- ic settings, and equatorial open-ocean warm-water vation of Kleijne (1993), Haidar and Thierstein (2001) conditions (Bollmann, 1997 and references therein). and Corte´s et al. (2001). Our morphometric data show that the ‘larger morpho- type’ of G. oceanica is positively related to upwelling 5.3. Planktic foraminifers and phytoplankton prey and neritic settings, whereas the ‘equatorial morpho- type’ appears to be adapted to the open ocean warm Enhanced availability of nutrients and prey water conditions. G. oceanica ‘equatorial’ is negatively (particularly diatoms) in the upwelling area off Oman, related to the concentration of nitrate and exhibits much at Station 37, was mirrored by high numbers of the higher cell densities than G. oceanica ‘larger’. These planktic foraminiferal species Globigerina bulloides findings confirm the ecological model of these mor- and Neogloboquadrina dutertrei (cf. Kroon, 1988; 358 R. Schiebel et al. / Marine Micropaleontology 51 (2004) 345–371

Ivanova et al., 1998), while the total number of planktic planktic foraminifers in 1995 and 1997 resembled foraminifers decreased (Fig. 8, Appendix D). G. bul- the hydrography and followed a gradient in nu- loides is reported as an upwelling species (e.g., Kroon trient concentration (Fig. 10). In the Arabian Sea, and Ganssen, 1988; Hemleben et al., 1989; Brock et al., three microplankton associations were identified 1992; Naidu and Malmgren, 1996; Kiefer, 1999), and assigned to different hydrographic situations indicating highest levels of primary production (Berger (Fig. 10). et al., 1988), and high concentration of chlorophyll a (Appendix E). Chlorophyll a is linearly correlated to (A) In the upwelling area off Oman, turbulent the concentration of , the autotrophs serving mixing caused high nutrient concentration at as prey for larger including planktic the sea surface. At Station 438 in the central foraminifers (Hemleben et al., 1989; Garrison et al., upwelling area (Fig. 1), Chaetoceros spp. 2000). We found high faunal parts of G. bulloides and Thalassionema nitzschioides diatoms synchronous to high numbers of diatoms, during the occurred in high numbers, and among low early ‘upwelling phytoplankton stage’, not only during coccolithophore numbers the ‘larger morpho- the ending ‘upwelling zooplankton stage’ (cf. Kroon type’ of Gephyrocapsa oceanica was most and Ganssen, 1988). Therefore, we suggest that G. frequent. To the northeast of the upwelling bulloides increases production at local upwelling cells center, at Station 37, though still under not only during a final stage of upwelling but during upwelling conditions and with a species the whole upwelling season. Enhanced numbers of G. composition similar to Station 438, diatom bulloides always occurred together with an increase of numbers were reduced and coccolithophore numbers of N. dutertrei. Although G. glutinata is numbers were still low. Therefore, we specialized on a diatom diet (Hemleben et al., 1989), assume that coccolithophores are not actively G. glutinata was rare in the upwelling region where replaced by diatoms but by environmental diatoms were frequent (Appendices D and E) Fig. 4a). conditions, which, however, needs further G. glutinata is not as opportunistic as G. bulloides and investigation. The planktic foraminiferal fau- N. dutertrei, and is more adapted to nutrient entrain- na under coastal upwelling conditions was ment at nutricline depth, and therefore deep production dominated by the opportunistic species of diatoms (cf. Schiebel et al., 2001). Globigerina bulloides. To the south of the upwelling region off Oman, in (B) Updoming of isotherms and entrainment of May/June 1997, Globigerinita bulloides and Neo- nutrients into surface waters from below was globoquadrina dutertrei were rare and the fauna caused by strong Findlater Jet winds to the was dominated by subtropical to tropical species southeast of the coastal upwelling area. Dia- Globigerinoides ruber and Globigerinoides sacculifer toms occurred in much lower numbers than (cf. Conan and Brummer, 2000). According to a under upwelling conditions and the diatom higher salinity (Fig. 2), G. ruber dominated the fauna flora was characterized by Nitzschia bicapitata. at Station 7 (Fig. 9b), while G. sacculifer dominated Coccolithophore and planktic foraminifer at Station 6 where the upper ocean salinity was lower numbers were very high. The most frequent ( < 35.5) than at Station 7 (>36.4) (cf. Be´ and coccolithophore species was Florisphaera pro- Tolderlund, 1971; Be´ and Hutson, 1977; Shenoi et funda at nutricline depths. The foraminiferal al., 1993). Along with G. ruber, Globoturborotalita fauna was characterized by Globigerinoides tenella was frequent in 1995 and may favour similar ruber; Globigerinoides sacculifer was the temperature and salinity conditions as G. ruber in the second most frequent species. Arabian Sea. (C) In the open Arabian Sea, the water column was well stratified and nutrient concentration 5.4. Microplankton succession in the Arabian Sea in surface waters was low. Diatoms occurred in low numbers and coccolithophores were During SW monsoon in the Arabian Sea, the very abundant. The coccolithore flora was succession of diatoms, coccolithophores and characterized by Umbellosphaera irregularis R. Schiebel et al. / Marine Micropaleontology 51 (2004) 345–371 359

Fig. 10. Model of the diatom, coccolithophore and planktic foraminiferal succession (A, B, C), according to hydrographic zonation and trophic condition along transect (. – .) from the Oman coast to the central Arabian Sea during the southwest monsoon. A= coastal upwelling, turbulent mixing, eutrophic; B = strong Findlater Jet, updoming isotherms and isohalines; C = stratified water column, oligotrophic.

throughout the upper 100 m of the water compete with coccolithophores for nutrients (Fig. 9) column. Globigerinoides sacculifer was the (cf. Margalef, 1978). In addition, diatoms are part most frequent species in the upper 40 m, of the foraminiferal diet (Hemleben et al., 1989). below 40 water depth Globigerinoides ruber Coccolithophores are the assumed main producer dominated the planktic foraminiferal fauna. of alkenones that are applied as paleo-thermometer although their ecology is not fully understood to 5.5. Paleoceanographic implications of modern date (e.g., Mix et al., 2000; Bard, 2001; Niebler et microplankton ecology in the Arabian Sea al., 2003). Modern coccolithophores are negatively related to nutrient concentration and, therefore, Mechanistical understanding of modern diatom, during upwelling, alkenones are produced only to coccolithophore and planktic foraminiferal ecology a minor amount. Highest coccolithophore abun- is essential for reconstructing paleoceanography and dance occurs in regions with low nutrient concen- À 1 À 1 paleoclimatology using their fossil remains (cf. tration ( < 3 Amol NO3 l and < 0.3 Amol PO4 l ) Fischer and Wefer, 1999; Henderson, 2002). and possibly also during low-productive seasons, Planktic foraminifers are widely used to reconstruct namely non-upwelling periods (cf. Niebler et al., water temperature and ancient current systems by 2003). Therefore, alkenones could not unequivocally transfer calculations, stable isotopes and element be applied to reconstruct water temperature during ratios (e.g., Pflaumann et al., 1996; Schulz et al., upwelling. 2002; Rohling et al., 2004). Although diatoms are Under a paleoclimatological perspective, upwell- suited for transfer calculations of marine paleo- ing regions in general, and the Arabian Sea in temperature in high latitudes (Zielinski et al., particular, are of main interest, because a major 1998), they could not successfully be applied to part of the global release of greenhouse gases, CO2, the low latitudes until now. However, diatoms add N2O and CH4, takes place in these areas (Ko¨rt- information on the plankton succession and seem to zinger et al., 1997; Patra et al., 1999; Bange et al., 360 R. Schiebel et al. / Marine Micropaleontology 51 (2004) 345–371

1999; Bange, 2000; Sarma et al., 2003).The According to nutrient concentration, coccolitho- greenhouse gases are relevant to global climate phore cell numbers as well as diversity was low in change. In turn, global does trigger the upwelling area close to the Oman coast. To- productivity in the Arabian Sea through monsoonal wards the open ocean, coccolithophore cell concen- activity and its teleconnection to other major sys- tration increased along with decreasing nutrient tems of the Earth’s climate, as, for example, ENSO concentration and increasing stratification of the up- and NAO (Ivanova et al., 2003; Zahn, 2003). per water column. Coccolithophore cell number is Combining coccolithophore data with informa- possibly limited by thresholds in nutrient concentra- tion on planktic foraminifers and diatoms will add tion. High standing stocks occur at low nitrate and information on oceanographic settings with en- phosphate concentration. Below the lower threshold of À 1 hanced nutrient concentration (mesotrophic to eu- 4 Amol NO3 and 0.35 Amol PO4 l more than trophic regions and high-productive seasons). 70 Â 103 coccolithophore cells lÀ 1 occurred, and Seasonality is of particular importance to under- above the upper threshold of 14 Amol NO3 and >1.25 À 1 3 stand teleconnection of the climatic dipoles like Amol PO4 l cell densities are lower than 10 Â 10 ENSO and the Indian Monsoon, because all of cells lÀ 1. The nutrient thresholds are similar for total these dipoles are seasonal features. coccolithophore numbers and for the abundance of single species. The complex microplankton succession must be 6. Conclusion understood in detail before each of its components, diatoms, coccoliths and planktic foraminifers (and Different planktic foraminiferal, coccolithophore others), can unequivocally be used as a paleocea- and diatom species are adapted to differential scales nographic proxy. Models on plankton ecology in trophic condition and hydrography. During SWM should be resolved at least for the seasonality in 1995 and 1997, the distribution of total cocco- and for the hydrography on mesoscale, to account lithophores and planktic foraminifers was positively for the ecological bias of, for example, transfer related, and both were negatively related to the function and alkenone derived paleotemperature abundance of diatoms. estimate. High valve numbers of diatoms, in particular Chaetoceros spp. and Thalassionema nitzschioides, were related to low water temperature and high Acknowledgements nutrient concentration caused by upwelling driven by SWM winds in the northern Arabian Sea in The masters and crews of R/V METEOR 1995 (Fig. 10). To the southeast of the upwelling cruise 32/5 and R/V SONNE cruise 119 are area, diatom frequency decreased by two orders of gratefully acknowledged for their technical assis- magnitude, and the species composition changed to tance. We thank B. Hiller, M. Bayer and S. Flaiz a dominance of N. bicapitata. The diatom assem- for support with sampling and preparation of blage further offshore points towards mixing of water and net samples, and T. Mitzka (Dept. of different water masses and to the existence of Marine Planktology, IfM, Kiel University) and R. filaments. Heuermann (Physical Institute, Oldenburg Univer- Total planktic foraminiferal numbers were lower sity) who provided CTD data. Nutrient data was in the upwelling area off Oman than in lower gratefully provided by P. Fritsche, I. Kriest and K. productive waters to the southeast. In contrast, Nachtigall (Meteor 32/5, Dept. of Marine Plank- Globigerinita bulloides and Neogloboquadrina tology, IfM, Kiel University, German JGOFS). dutertrei numbers were increased along with up- This project was funded by the German Ministry welling and enhanced chlorophyll concentration. of Technology and Science (BMBF), JGOFS-Indic Low productive waters were dominated by subtrop- grant number 03F0183E, and by the German ical to tropical species Globigerinoides ruber and Science Foundation (DFG), grant number He 697/ Globigerinoides sacculifer. 29 to CH. R. Schiebel et al. / Marine Micropaleontology 51 (2004) 345–371 361

Appendix A . Diatom species (Â103 valves lÀ1). Taxa are arranged according to absolute frequency

Cruise SO119 M32-5 M32-5 M32-5 M32-5 M32-5 M32-5 M32-5 Station 37 438 440 444 446 430 460 423 Water Depth (m) 20 10 10 20 20 60 20 20 Number of counted cells 194 509 315 370 166 224 71 114 Analyzed water volume (ml) 0.53 0.34 0.93 2.52 2.52 6.16 2.47 3.14 Counted area of filter (1250 mm2) 0.24 0.11 0.67 1.26 1.05 1.93 0.77 0.98 Filtered water (1) 2.80 4.00 1.75 2.50 3.00 4.00 4.00 4.00 Temperature (jC) 25.99 20.51 20.49 25.99 26.05 26.61 25.21 25.59 Salinity 36.25 35.70 35.69 36.03 36.03 36.20 35.94 36.07 Total Chl a (AglÀ 1) n.d.a 0.82 n.d.a 1.10 0.55 0.36 0.43 0.34 À 1 a NO3 (Amol l ) 0.15 16.91 n.d. 10.95 4.39 1.60 8.03 0.00 À 1 a PO4 (Amol l ) 0.10 1.54 n.d. 0.99 0.54 0.39 0.73 0.00 À 1 a SiO4 (Amol l ) 0.27 6.50 n.d. 5.81 3.20 1.49 3.41 0.50 Taxa Chaetoceros Hyalochaete 144.4 1303.6 154.7 42.1 – 3.9 2.0 3.5 Thalassionema nitzschioides 100.4 178.6 135.9 11.9 0.8 1.1 0.6 1.8 Nitzschia bicapitata-group – – 1.1 15.5 41.3 14.0 13.0 12.1 Thalassiosira spp. 16.9 – 33.3 19.4 2.0 0.8 1.2 4.8 Stephanopyxis turris – 32.7 3.2 – – – – – Pseudo-nitzschia spp. 1.9 – – 22.6 0.6 2.4 1.0 1.3 Tropidoneis-group 3.8 – – 0.8 10.7 0.5 1.6 1.0 Eucampia spp. 9.4 – 2.1 2.8 – 0.2 – – Thalassiosira delicatula 13.1 – – – Rhizosolenia spp. 5.6 – 2.1 3.2 – 1.0 0.8 0.3 Proboscia alata 5.6 – 1.1 1.6 – – – – Chaetoceros Phaeoceros – – – 4.8 – 2.3 – Nitzschia spp. – – – 4.0 – 1.1 – 1.6 Corethron sp. – – – 6.3 – – – – Nitzschia sicula – – 1.6 1.2 – 0.6 0.8 1.6 Pleurosigma spp. – – 1.1 2.8 0.4 – – 1.0 Fragilariopsis pseudonana – – – 1.2 2.8 0.2 0.4 0.6 Leptocylindrus mediterraneus 3.8 – – 0.4 – 0.8 – – Dactyliosolen spp. 3.8 – – – – 0.8 – – spp. 1.9 – – 0.8 – 0.5 – 1.0 Thalassiosira partheneia/T. oceanica – – – – – 1.5 – 2.6 Thalassiosira lineata – – – – – 0.2 1.2 1.0 Rhizosolenia setigera 1.9 – – – 0.4 – – – Cerataulina pelagica – – – 1.6 – 0.6 – – Thalassionema nitzschioides var. parva – – – 1.2 0.4 0.2 0.4 – Chaetoceros resting spore 1.9 – – – – – – – Stauroneis spp. 1.9 – – – – – – – spp. – – – – 0.4 – – 1.3 Fragilaria spp. – – 1.1 – – – – – Asteromphalus sarcophagus – – – 0.4 – 0.2 0.4 – Porosira denticulata – – – 0.4 – 0.5 – – Thalassiosira subtilis – – – – – 0.3 – 0.3 Eunotia spp. – – – – 0.4 – – – Roperia tesselata – – –0.4–––– Asteromphalus heptactis – – – 0.4 – – – Rhizosolenia af. antennata f. semispina – – –0.4–––– Coscinodiscus spp. – – – 0.4 – – – – Thalassiothrix spp. – – – – – 0.2 0.2 – Climacodium frauenfeldianum – – – – – 0.3 – – Pseudohimantidium pacificum – – ––––– 0.3 Azpeitia spp. – – – – – 0.2 – – Centrale, other 30.0 – 1.1 – – 0.6 2.0 0.3 Pennale, other 16.9 – – 0.4 5.8 1.4 3.0 – Total 363.0 1514.9 338.3 146.8 65.9 36.3 28.8 36.2 a n.d. = not determined. 362

Appendix B. Coccolithophore species (Â103 cells lÀ1 ) recorded during SO119. Taxa are arranged according to absolute frequency. Taxonomy refers to Jordan and Green (1994)

SO119,Station 373737363631313128281212127 7 7 3 3 3 5 5 5 6 6 6 Water depth (m) 20 60 100 20 60 20 60 100 60 100 20 60 100 20 60 100 20 60 100 20 60 100 20 60 100 Number of counted 18 42 7 51 89 115 186 113 75 159 55 115 63 382 226 122 149 105 8 249 44 26 164 173 74 specimens Analyzed water 2.55 3.03 3.79 3.79 4.55 3.79 3.79 3.79 4.55 3.79 3.48 3.79 3.79 3.79 4.55 3.79 4.55 5.30 3.79 3.79 3.79 3.79 3.79 3.79 3.79 volume (ml) Counted filter area 1.136 0.946 0.946 0.946 1.136 0.946 0.946 0.946 1.136 0.946 0.946 0.946 0.946 0.946 1.136 0.946 1.136 1.325 0.946 0.946 0.946 0.946 0.946 0.946 0.946 (mm2) Filtered Water (l) 2.80 4.00 5.00 5.00 5.00 5.00 5.00 5.00 5.00 5.00 4.60 5.00 5.00 5.00 5.00 5.00 5.00 5.00 5.00 5.00 5.00 5.00 5.00 5.00 5.00 Temperature (jC) 25.99 24.65 22.80 27.73 24.36 29.14 24.98 23.73 26.66 24.51 29.09 26.61 22.95 29.77 24.55 23.41 28.84 24.80 22.19 29.89 28.36 24.67 30.24 28.25 25.81 Salinity 36.25 36.37 36.26 36.22 36.10 36.41 36.26 36.41 36.20 36.41 36.44 36.24 36.16 36.50 36.04 36.16 36.42 36.39 36.13 35.43 36.08 35.99 34.95 35.66 35.88 345–371 (2004) 51 Micropaleontology Marine / al. et Schiebel R. Total Chl a (AglÀ 1 )n.da n.da n.da 0.089 0.149 n.da n.da n.da 0.196 0.066 0.060 0.147 0.092 0.071 0.322 0.117 0.077 n.da n.da 0.047 0.086 0.096 0.035 0.088 0.114 À 1 NO3 (Amol l ) 0.15 1.96 7.90 0.36 7.70 0.01 2.70 13.71 3.68 9.17 1.66 1.50 10.21 1.12 4.11 12.84 0.56 7.63 11.97 0.24 2.46 14.51 0.18 0.24 4.30 À 1 PO4 (Amol l ) 0.10 0.50 1.20 0.64 0.63 0.15 0.34 1.11 0.34 0.94 0.03 0.14 0.74 0.04 0.34 0.63 0.24 0.76 1.43 0.56 0.22 0.91 0.17 0.24 0.52 À 1 SiO4 (Amol l ) 0.27 1.60 5.41 0.73 3.00 0.42 1.20 5.30 1.02 3.90 0.24 1.05 8.70 0.00 1.46 5.38 0.70 2.20 7.30 0.69 1.20 6.40 0.83 1.05 2.44 Taxa

F. profunda var. – 1.32 0.26 – 15.19 – – 14.00 – 21.13 – – 2.11 10.30 31.48 21.66 14.75 16.60 1.58 9.24 0.26 – – – – elongata U. irregularis – 0.33 – 3.70 – 10.30 13.47 0.53 3.96 0.26 4.59 2.64 – – – – – – – – – 2.91 20.60 28.26 5.02 O. antillarum 0.39 3.63 0.26 0.26 0.44 – 0.26 3.17 – 8.19 – 0.79 2.64 13.21 1.10 0.26 2.42 0.38 – 45.17 0.79 – – – – G. oceanica 5.50 4.62 1.32 1.85 0.88 1.58 6.60 2.91 – 0.53 0.86 3.17 7.66 14.00 1.10 1.06 3.30 0.57 – 0.53 0.26 0.53 0.53 – 1.85 C. leptoporus – – – 0.26 – – – 0.26 – – – – – 44.11 0.88 0.53 0.88 0.19 – – – – – – – E. huxleyi var. 0.79 0.66 – 5.55 0.66 – 8.45 0.26 2.42 – 0.86 6.08 0.53 0.79 – – 1.32 0.19 – 0.26 0.26 – 3.70 – – huxleyi G. flabellatus – 0.66 – – – – – 3.96 – 5.28 – – 0.26 – 6.16 6.87 0.88 1.13 0.26 – – – – – – R. xiphos – – – – – 10.83 2.64 – 1.54 0.53 3.16 1.85 1.06 – – 0.26 – – – 0.53 – – 1.85 0.26 0.79 Ophiaster spp. – – – – – 0.26 0.26 1.06 0.44 1.32 – 5.02 – 0.53 1.54 – – – – 3.17 1.06 – 0.26 1.06 0.79 A. robusta – 0.99 – 0.26 – – 0.26 1.06 – 1.58 0.29 0.26 – 2.91 2.20 0.26 1.76 – – 3.17 0.26 – – – – C. murrayi – – – 0.53 – 0.53 3.70 – 0.22 – – 3.43 0.26 – – – – – – 0.26 3.96 – 1.85 – – F. profunda – – – – – – – – – 0.79 – – – 0.53 2.64 0.53 5.94 0.75 – 0.79 – – – – – with spine S. nodosa – – – – – – 0.53 – – – – 0.53 – 9.51 – – 0.22 – – 0.53 – – – – – Syracosphaera spp. – – – – – – 0.53 1.06 0.44 0.26 – 0.26 – 0.26 0.22 0.53 – – – – – – 2.11 4.23 1.06 M. adriaticus – – – – – – 1.32 – 0.22 – – 0.53 0.26 0.26 – – 0.22 – – – 0.53 0.26 0.79 1.06 – U. hulburtiana – – – – 0.22 – – – – – – – – 0.53 – – – – – – – – 1.06 2.11 1.32 U. tenuis – – – – – 1.06 – – – – 0.57 – – – – – – – – – – – 0.79 – 2.64 D. tubifera – – – – – 0.79 1.58 – – – 1.15 – – – – – – – – – – – – – 1.06 Corisphaera sp. – – – – – 0.26 0.53 – 0.22 – 0.29 – – – – – – – – – – – 0.26 1.58 0.26 S. pulchra – – – 0.26 – – 0.53 – 0.22 – – 0.26 – 0.26 – – – – – – – – 0.79 0.53 – M. elegans – – – – 0.22 – 0.53 – 0.44 0.26 – 0.79 – – – – – – – – – 0.26 0.26 – – H. triarcha – – – – – 1.32 – – – – 1.44 – – – – – – – – – – – – – – R. clavigera var. – – – – – – 0.53 – 0.88 – – – – – – – – – – – – – 0.79 0.53 – stylifera Gephyrocapsa sp.––––––2.11––––0.53–– – – ––––––– – – S. dilatata – – – – – – 0.26 – 0.44 – – 0.26 – – – – – – – – – 0.26 0.53 0.26 0.53 C. rigidus – – – – – – 0.26 0.26 – – – 0.79 – 0.26 – – – – – 0.79 – – – – – S. prolongata – – – 0.26 – – 0.26 – – – – 0.26 – – – – – – – – – – 1.32 – 0.26 P. maximus – – – – – – – – – – – – – – – – – – – – – 0.26 1.32 0.26 0.26 A. pinnigera ––– – – ––– – – – – – 1.58– – – ––0.53– – – – – S. noroitica ––– – – –0.53–– – – – – – – – – –– – – 0.53– 1.06– A. quattrospina – – – – – 0.79 – – – – – 0.79 – – – – – – – 0.26 – – – 0.26 – S. lamina – – – – – – – – – – – – – 0.26 0.66 – 0.88 – 0.26 – – – – – – H. carteri var. carteri – – – – – – 0.26 – – – – – – 0.53 0.44 – – – – – – 0.53 0.26 – – P. lepida – – – – – – – 0.53 – – – – 1.06 – 0.44 – – – – – – – – – – G. corolla – – – – – – 0.79 – – – – 0.26 – – – – – – – – – – 0.79 – – A. brasiliensis – – – – – – 0.26 – – – – 1.06 – – – – – – – – 0.53 – – – – S. ossa – – – – – – 0.26 – – – – – – 0.26 – – – – – – 1.06 – – 0.26 – C. mediterranea – – – – – 0.26 – – 0.22 – 0.29 – – – – – – – – – 0.26 0.26 – – 0.53 S. marginaporata – – – – 0.44 – – – 0.22 – 0.29 0.53 – – – – – – – – – – – 0.26 – F. profunda var. –0.33––1.32–––––––––––––––––––– profunda S. epigrosa – – – – – – – – 0.22 – – – – 0.26 – – – – – 0.53 0.26 – – – 0.26 H. carteri var. hyalina – – – 0.26 – – 0.26 – 0.44 – – – – – – – – – – – – – 0.53 – – S. halldalii – – – – – 0.79 – – – – 0.29 – – – – – – – – – – – – 0.26 – C. gracilis – – – – – – – – – – – – – – – – – – – – – 0.53 0.79 – – H. corn‘ifera – – – – – – – – – – – – – – – – – – – – – 0.26 – – 1.06

S. molischii – – –0.26– –0.79–0.22– – – – – – – – – – – – – – –– 345–371 (2004) 51 Micropaleontology Marine / al. et Schiebel R. U. sibogae var. sibogae – – – – – – – – – – – – – 0.26 0.22 – – – – – 0.53 – – 0.26 – C. multipora – – – – – – – – 0.22 0.26 – – – – – – – – – – – – – 0.79 – S. orbiculus 0.39 0.33 – – – – – – – – – – – – – – – – – – – – – 0.53 – C. papillifera – – – – – – 0.26 – 0.88 – – – – – – – – – – – – – – – – S. rotula – – – – – – 0.26 – 0.22 – 0.57 – – – – – – – – – – – – – – R. sessilis – – – – – – – 0.53 – 0.53 – – – – – – – – – – – – – – – C. oblonga – – – – – – 0.26 – 0.22 – – – – – – – – – – – 0.26 – – – 0.26 S. ampliora – – – – – – 0.26 – – 0.26 0.29 – – – – – – – – – – – – – – S. pirus ––––––––––––––––––––––0.530.26– P. poritectus –––––0.26–––––––––––––––––0.53– C. acuelata ––––––––0.22–0.29–––––––––––0.26–– A. periperforata – – – – – 0.26 – – 0.22 – 0.29 – – – – – – – – – – – – – – A. unicornis – – – – – – – – 0.22 – – – – – – – – – – – – – 0.26 – 0.26 S. anthos – – – – 0.22 – – – – – – 0.26 0.26 – – – – – – – – – – – – C. cucullata – – – – – – – – – – – – – 0.26 0.22 – 0.22 – – – – – – – – S. sp. II cf. S. epigrosa – – – – – – – – 0.44 – – – – – – – – – – – – – – – 0.26 P. galapagensis – – – – – – – – – – 0.29 – – – – – – – – – – – 0.26 – – C. diconstricta – – – – – – – – – – – – – – – – – – – – – – – – 0.53 O. fragilis var. fragilis ––––––––––––––––––––0.53–––– P. magnaghii – – – – – 0.26 – – – – – – – – – – – – – – – – – – 0.26 Syracolithus sp. – – – – – 0.53 – – – – – – – – – – – – – – – – – – – S. dilatata var. I – – – – – – – – 0.22 – – – – – – – – – – – 0.26 – – – – C. valliformis –––––––0.26––––––––––––––––– S. exigua – – – – – – – – – – – – – – – – – – – – – – – – 0.26 A. fragaria ––––––––––––––––––––––0.26–– S. confusus –––––––––––––––––––––0.26––– Z. hellenica – – – – – – 0.26 – – – – – – – – – – – – – – – – – – P. flabellifera ––––––––––––0.26–– – –––––– – – – Acanthoica sp.––––––––––––––––––––0.26–––– A. cidaris –––––––––––––––––––––––0.26– A. spatula ––––––––––––––––––––0.26–––– T. latericioides ––––––––––––0.26–– – –––––– – – – S. histrica – – – – – – – – 0.22 – – – – – – – – – – – – – – – – S. adenensis – – – – – – – – 0.22 – – – – – – – – – – – – – – – – Heterococcolithophore – – – – – 0.26 – – – 0.26 – – – – – – – – – – – – – – – spp. Holococcolithophore spp. – 0.66 – – – – – – 0.22 0.53 – – – – 0.44 0.26 – – – – – – 0.26 – – Indet spec. – – – – – – – – – – – – – – – – – – – – – – 0.26 0.79 – Total 7.1 13.5 1.8 13.5 19.6 30.4 49.1 29.8 16.3 42.0 15.8 30.4 16.6 100.9 49.7 32.2 32.8 19.8 2.1 65.8 11.6 6.9 43.3 45.7 19.5 a n.d. = not determined. 363 364 .Shee ta./Mrn irplotlg 1(04 345–371 (2004) 51 Micropaleontology Marine / al. et Schiebel R.

Appendix C. Coccolithophore species (Â103 cells lÀ1 ) recorded during M32/5. Taxa are arranged according to absolute frequency. Taxonomy refers to Jordan and Green (1994)

M32/5, Station 438 438 440 440 440 444 444 446 446 446 430 430 460 460 460 423 423 423 414 414 414 404 404 404 Depth (m) 40 75 10 40 75 60 100 20 60 100 60 100 20 60 100 20 60 100 20 60 100 20 60 100 Number of counted 15 7 3 0 2 21 20 81 35 15 191 24 19 169 5 182 38 0 166 241 94 325 339 266 specimens Analyzed water 3.03 1.33 1.52 1.52 2.27 3.03 3.03 2.27 3.03 3.03 3.03 3.03 2.12 3.06 3.03 3.03 3.03 3.03 2.65 2.62 3.03 3.03 3.03 3.03 volume (ml) Counted filter area 0.947 0.947 0.947 0.947 0.947 0.947 0.947 0.947 0.947 0.947 0.947 0.947 0.661 0.954 0.947 0.947 0.947 0.947 0.947 0.818 0.947 0.947 0.947 0.947 (mm2) Filtered water (1) 4.00 1.75 2.00 2.00 3.00 4.00 4.00 3.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 3.50 4.00 4.00 4.00 4.00 4.00 Temperature (jC) 19.75 18.58 20.49 20.24 18.76 26 22.64 26.05 25.95 21.34 26.61 24.71 25.21 23.81 20.94 25.59 24.93 21.87 27.42 27.30 24.68 27.90 27.88 27.78 Salinity 35.74 35.7 35.69 35.69 35.68 36.03 36.14 36.03 36.02 35.83 36.2 36.16 35.94 35.98 36.01 36.07 36.13 36.09 36.49 36.47 36.29 36.55 36.57 36.55 Total Chl a (AglÀ 1 ) 0.384 0.139 n.da n.da n.da 0.038 0.038 0.547 0.523 0.022 0.36 0.038 0.43 0.48 0.01 0.34 0.34 0.01 0.60 0.60 0.11 0.21 0.43 0.07 À 1 a a a NO3 (Amol l ) 21.48 24.13 n.d n.d n.d 17.35 21.42 4.39 4.47 17.93 1.6 9.94 8.03 13.33 22.77 0.00 9.25 24.11 0.00 0.00 8.86 0.00 0.00 0.74 À 1 a a a PO4 (Amol l ) 1.69 2.07 n.d n.d n.d 1.39 1.73 0.54 0.49 1.34 0.39 0.86 0.73 0.99 1.64 0.00 0.87 1.95 0.29 0.29 0.85 0.18 0.19 0.28 À 1 a a a a a SiO4 (Amol l )n.dn.d n.d n.d n.d 9.61 12.52 3.20 3.09 7.61 1.49 3.50 3.41 6.21 12.20 0.50 3.89 10.97 0.48 0.48 2.31 0.01 0.11 0.45 Taxa

G. oceanica 3.6 2.3 1.5 – 0.4 3.3 4.0 14.5 5.0 2.3 24.1 2.6 3.3 10.8 0.7 22.8 5.0 – 29.8 51.6 1.7 48.8 51.2 42.3 E. huxleyi var. – – – – – 0.7 1.0 7.9 1.7 – 13.9 1.3 3.3 4.3 0.3 14.2 1.0 – 15.1 20.3 0.3 22.1 22.1 20.8 huxleyi O. antillarum – – – – – 0.3 0.3 0.9 – 0.3 4.3 1.7 – 3.3 – 1.7 0.3 – 4.5 3.8 1.7 19.8 20.5 16.2 F. profunda var. 0.3 – – – – 1.3 0.3 – – 1.7 – 1.0 – 18.0 0.7 – 4.0 – – 0.8 21.8 – – – elongata C. murrayi ––––––––––0.7–0.50.7–2.0––4.53.4–5.99.23.3 A. robusta – – – – – – – 2.2 0.3 0.7 4.6 – – 7.2 – 6.6 0.3 – 1.1 1.1 0.3 0.7 – 1.3 U. hulburtiana ––––––––––0.3––0.3––––2.37.30.33.02.32.0 C. leptoporus 0.3–––0.41.30.34.83.3–3.6–0.91.0–0.70.7––––––– C. mediterranea –––––––1.30.3–0.7––––7.30.7–––––0.7– Ophiaster spp.––0.8–––––––3.0–0.92.6–0.7–––––1.00.30.3 C. rigidus ––––––––––3.0––1.0–0.70.3––––2.01.3– A. brasiliensis ––––––––––2.3––––1.0––1.1––0.71.71.3 G. flabellatus ––––––0.7––––1.0––––––––4.3––– H. carteri var. –––––––2.20.7––––1.3–1.30.3––––––– carteri Gephyrocapsa sp.–––––––––––––0.3–0.3––1.52.3–––– M. adriaticus ––––––––––0.3–––––––1.10.8–1.30.7– U. sibogae var. –––––––1.8––0.30.3–0.7–––––––––– foliosa M elegans ––––––––––0.3–––––––0.8––––– S. nodosa –––––––––––––––––––0.4––0.7– A. quattrospina –––––––––––––––0.3–––––0.30.3– P. lepida –––––––––––––1.0–––––––––– T. quadrilaminata –––––––––––––1.0–––––––––– A. unicornis –––––––––––––––––––0.4–0.3–– G. ericsonii ––––––––––––––––––0.4–––0.3– U. sibogae var. ––––––––––––––––––0.4–0.3––– sibogae S. exigua ––––––––––––––––––––0.3–0.3– S. halldalii ––––––––––0.7––––––––––––– Syracosphaera spp.––––––––––––––––––––––0.30.3

F. profunda var. 0.7––––––––––––––––––––––– 345–371 (2004) 51 Micropaleontology Marine / al. et Schiebel R. profunda S. pirus –––––––––––––0.3–––––––0.3–– O. fragilis var. ––––––––––0.3––––––––––––– fragilis H. carteri var. ––––––––––0.3––––––––––––– hyalina S. lamina ––––––––0.3––––––––––––––– S. orbiculus –––––––––––––––0.3–––––––– S. adenensis –––––––––––––––0.3–––––––– S. marginaporata –––––––––––––––––––––0.3–– S. rotula –––––––––––––––––––––0.3–– U. irregularis –––––––––––––––––––––0.3–– R. xiphos –––––––––––––0.3–––––––––– A. periperforata –––––––––––––0.3–––––––––– Holococcolithophore –––––––––––––0.7–––––––––– spp. Indetspec.––––––––––0.3––0.3–––––––––– Total 5.0 2.3 2.3 0.0 0.9 6.9 6.6 35.7 11.6 5.0 63.1 7.9 9.0 55.4 1.7 60.1 12.5 0.0 62.6 92.1 31.0 107.1 111.9 87.8

a n.d. = not determined. 365 366

Appendix D. Planktic foraminiferal species >125 Am (numbers mÀ3 ) recorded during SO 119. Species are arranged according to absolute frequency

SO119,Station5555566666 77728282828283737373737 Water depth (m) 0 – 20 20 – 40 40 – 60 60 – 80 80 – 100 0 – 20 20 – 40 40 – 60 60 – 80 80 – 100 0 – 20 20 – 40 40 – 60 0 – 20 20 – 40 40 – 60 60 – 80 80 – 100 0 – 20 20 – 40 40 – 60 60 – 80 80 – 100 Number of counted tests 357 318 86 131 129 458 236 86 109 122 758 525 144 242 242 173 86 51 213 75 40 24 85 Temperature (jC) 29.92 29.89 28.74 27.35 26.08 30.23 29.91 28.87 27.43 26.06 29.92 29.51 25.87 29.96 29.89 27.95 25.41 24.65 28.07 27.6 25.07 23.72 23.02 Salinity 35.42 35.43 36.04 36.05 36.17 34.79 35.44 35.64 35.67 35.64 36.51 36.44 36.11 36.49 36.48 36.24 36.18 36.37 36.26 36.23 36.14 36.06 36.13

Total Chl a (AglÀ 1 ) 0.051 0.044 0.059 0.119 0.130 0.027 0.041 0.065 0.120 0.145 0.051 0.091 0.395 0.046 0.076 0.150 0.156 0.156 0.075 n.da n.da n.da n.da 345–371 (2004) 51 Micropaleontology Marine / al. et Schiebel R. À 1 NO3 (Amol l ) 0.00 0.43 1.41 3.74 9.40 0.20 0.16 0.21 0.29 1.88 1.27 0.97 2.11 1.99 1.76 2.88 5.68 8.41 0.33 0.00 0.05 3.67 6.61 À 1 PO4 (Amol l ) 0.90 0.31 0.14 0.33 0.65 0.13 0.20 0.22 0.27 0.39 0.01 0.07 0.27 0.18 0.12 0.24 0.52 0.52 0.10 0.10 0.34 0.65 1.00 À 1 SiO4 (Amol l ) 0.65 0.73 0.78 1.50 4.30 0.83 0.83 0.83 1.10 1.80 0.00 0.00 0.53 0.80 1.04 1.00 1.40 2.83 0.25 0.32 0.74 2.50 4.60 Species

Globigerinoides sacculifer 46.2 38.6 6.2 6.2 4.6 58.2 26.6 3.0 1.0 1.4 35.4 7.8 4.6 20.2 22.4 11.2 6.6 0.2 1.2 – – – 0.6 Globigerinoides ruber 6.8 4.6 1.0 1.8 2.4 15.6 10.8 5.8 10.0 6.2 88.6 81.2 13.0 17.0 16.2 14.8 3.6 2.8 1.4 – 0.4 0.4 0.4 Globigerina bulloides – 0.4 – – 0.2 – 0.2 0.6 0.4 0.4 – 0.2 0.4 0.4 0.2 – 0.2 – 14.6 10.2 4.0 1.0 4.4 Globigerinita glutinata 6.8 6.4 – 1.6 1.8 6.8 2.2 0.6 0.6 2.8 1.6 – 0.4 6.6 6.8 1.4 0.8 0.2 2.2 1.0 0.2 0.4 1.8 Neogloboquadrina dutertrei 2.4 3.2 2.4 2.4 1.6 2.2 0.8 – – 0.2 1.6 0.2 – 2.6 0.8 1.8 2.8 2.8 18.2 2.4 1.6 0.8 1.8 Globigerina falconensis –––– ––––––––––0.4–– –––––0.4 Globoturborotalita tenella – 1.4 0.2 0.8 2.8 2.8 1.2 1.0 2.2 5.0 16.8 9.0 9.2 0.4 – – 0.4 – 0.2 – – – 0.6 Globorotalia menardii – 0.6 1.2 2.6 0.4 0.8 1.2 0.8 1.8 1.2 0.2 – – – 0.6 0.4 0.4 1.4 – – – – – Globoturborotalita rubescens ––0.2–0.6––––0.8–0.20.2–––––––––1.6 Globigerinella siphonifera 3.6 3.6 3.6 7.4 8.8 2.2 0.4 0.8 0.2 0.2 0.8 1.0 0.4 0.2 – 0.2 0.4 – 0.2 – 0.4 0.4 1.2 Globigerinita minuta 1.2 – – – 0.6 0.8 1.6 0.2 1.4 0.6 – – 0.2 – – – – – – – – – 0.8 Pulleniatina obliquiloculata –––– –––––––––––––0.2–––0.20.2 Globigerinella calida – 0.6 – – – – – – – 0.8 – 0.2 – – 0.8 – 0.4 1.0 3.0 1.0 1.0 1.4 2.8 Globigerinoides conglobatus –0.2–– –––––2.05.24.80.4––0.80.2––––– – Hastigerina pelagica 0.4 0.2 0.2 0.8 1.0 – – – – 0.2 – – – – 0.2 0.2 – – – – – – – Globigerinella adamsi – – 1.8 1.8 0.2 0.6 0.6 0.4 1.4 1.4 0.2 – – – – – – – 0.4 – – 0.2 0.2 Tenuitella parkerae –––– –––––––––––––––––– – Globoquadrina conglomerata 2.4 2.4 – 0.4 0.2 1.0 0.2 – 0.2 – – – – – – – – – – – – – – Orbulina universa – – – 0.2 0.2 – 1.0 2.6 0.8 0.2 1.0 – – 0.4 – 0.2 1.0 0.8 – – – – – Dentagloborotalia anfracta –––– –––––––––––––––––– – Globigerinita uvula –––– –––––––––––––––––– – Neogloboquadrina incompta –––– –––––––0.2–––––––––– – Globorotaloides hexagonus –0.20.2– –0.60.21.21.80.6–––––––––––– – Globorotalia scitula –––– –––––––––––3.40.40.8–––– – Turborotalita quinqueloba –––– –––––––––––––––––– – Globorotalia inflata –––– –––––––––––––––––– – Globorotalia theyeri –––– ––0.2–– ––––––––––––– – Globorotalia tumida –––– ––––––––––––––––0.2– – Indet spec. 1.6 1.2 0.2 0.2 0.4 – – 0.2 – 0.4 0.2 0.2 – 0.6 – 0.2 – – 1.2 0.4 0.2 – 0.2 Total 71.4 63.6 17.2 26.2 25.8 91.6 47.2 17.2 21.8 24.4 151.6 105.0 28.8 48.4 48.4 34.6 17.2 10.2 42.6 15.0 8.0 4.8 17.0

a n.d. = not determined. R. Schiebel et al. / Marine Micropaleontology 51 (2004) 345–371 367

Appendix E. Planktic foraminiferal species >125 Am (numbers mÀ3) recorded during M32/5. Species are

M 32/5, Station 414 414 414 414 414 430 430 430 430 430 Water depth (m) 0–20 20–40 40–60 60–80 80–100 0–20 20–40 40–60 60–80 80–100 Number of counted tests 1215 891 908 1166 542 1732 882 1344 2165 471 Temperature (jC) 27.42 27.36 27.31 27.29 24.68 26.65 26.66 26.62 26.61 24.71 Salinity 36.49 36.47 36.48 36.47 36.29 36.22 36.22 36.21 36.20 36.16 Total Chl a (AglÀ 1) 0.672 0.552 0.576 0.576 0.187 0.336 0.360 0.360 0.228 0.067 À 1 NO3 (Amol l ) 0.00 0.00 0.00 4.42 8.86 1.45 1.39 1.50 3.42 7.59 À 1 PO4 (Amol l ) 0.29 0.29 0.29 0.57 0.85 0.38 0.38 0.39 0.51 0.75 À 1 SiO4 (Amol l ) 0.49 0.37 0.40 1.23 2.31 1.50 1.49 1.47 1.94 2.95 Species Globigerinoides sacculifer 18.4 21.4 12.8 21.2 10.4 32.6 19.8 25.2 40.6 5.2 Globigerinoides ruber 15.2 17.6 13.4 17.8 10.4 29.2 10.8 22.0 43.8 7.6 Globigerina bulloides 34.2 17.0 29.0 36.4 15.6 28.8 26.6 74.0 83.8 14.4 Globigerinita glutinata 29.4 14.2 19.4 17.2 8.4 53.6 21.4 33.0 58.8 11.4 Neogloboquadrina dutertrei 33.4 25.2 22.2 14.4 12.6 40.4 19.0 21.0 44.4 7.2 Globigerina falconensis 25.2 24.4 19.6 51.2 8.0 55.2 23.0 17.6 28.8 5.6 Globoturborotalita tenella 34.0 24.0 27.0 23.6 14.0 12.8 5.6 24.0 13.6 3.8 Globorotalia menardii 6.8 2.8 3.6 7.4 3.0 39.4 18.6 18.2 50.6 9.6 Globoturborotalita rubescens 16.0 7.2 10.4 14.4 8.8 12.8 7.2 9.6 16.8 10.0 Globigerinella siphonifera 4.4 3.0 4.0 7.2 1.2 18.6 7.2 8.8 19.8 4.6 Globigerinita minuta 13.2 6.4 4.8 12.8 8.8 8.0 3.2 9.6 4.8 0.6 Pulleniatina obliquiloculata 7.2 12.8 9.8 8.0 2.4 11.6 5.2 4.6 11.4 2.2 Globigerinella calida 1.6 2.0 2.8 0.8 2.4 – – – – 2.2 Globigerinoides conglobatus –––––––––– Hastigerina pelagica – – 2.2 – – 1.6 2.0 – 3.6 0.4 Globigerinella adamsi – – – – – – – 0.4 2.0 – Tenuitella parkerae – – – – – – 2.4 0.8 5.6 1.0 Globoquadrina conglomerata – – – – 2.4 0.2 – – – – Orbulina universa –––––––––0.2 Dentagloborotalia anfracta 0.8 – – 0.8 – 1.6 – – 0.8 3.6 Globigerinita uvula 1.6 – – – – – 1.6 – 2.4 1.4 Neogloboquadrina incompta ––––––2.4––2.2 Globorotaloides hexagonus –––––––––– Globorotalia scitula –––––––––– Turborotalita quinqueloba 1.6––– –––––0.2 Globorotalia inflata – – 0.2 – – – – – – – Globorotalia theyeri –––––––––– Globorotalia tumida –––––––––– Indet spec. – 0.2 0.4 – – – 0.4 – 1.4 0.8 Total 243.0 178.2 181.6 233.2 108.4 346.4 176.4 268.8 433.0 94.2 1n.d. = not determined.

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