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A benthic isotope record has been measured for core SO75-26KL from the upper Portuguese margin (1099 m water depth) to monitor the response of thermohaline overturn in the North Atlantic during Heinrich events. Evaluating benthic δ18O in TS diagrams in conjunction with equilibrium δc fractionation implies that advection of Mediterranean outflow water (MOW) to the upper Portuguese margin was significantly reduced during the last glacial (< 15% compared to 30% today). The benthic isotope record along core SO75-26KL therefore primarily monitors variability of glacial North Atlantic conveyor circulation. The 14C-accelerator mass spectrometry ages of 13.54±.07 and 20.46±.12 ka for two ice-rafted detritus (IRD) layers in the upper core section and an interpolated age of 36.1 ka for a third IRD layer deeper in the core are in the range of published 14C ages for Heinrich events H1, H2, and H4. Marked depletion of benthic δ13C by 0.7–1.1‰ during the Heinrich events suggests reduced thermohaline overturn in the North Atlantic during these events. Close similarity between meltwater patterns (inferred from planktonic δ18O) at Site 609 and ventilation patterns (inferred from benthic δ13C) in core SO75-26KL implies coupling between thermohaline overturn and surface forcing, as is also suggested by ocean circulation models. Benthic δ13C starts to decrease 1.5–2.5 kyr before Heinrich events Hl and H4, fully increased values are reached 1.5–3 kyr after the events, indicating a successive slowdown of thermohaline circulation well before the events and resumption of the conveyor's full strength well after the events. Benthic δ13C changes in the course of the Heinrich events show subtle maxima and minima suggesting oscillatory behavior of thermohaline circulation, a distinct feature of thermohaline instability in numerical models. Inferrred gradual spin-up of thermohaline circulation after Hl and H4 is in contrast to abrupt wanning in the North Atlantic region that is indicated by sudden increases in Greenland ice core δ18O and in marine faunal records from the northern North Atlantic. From this we infer that thermohaline circulation can explain only in part the rapid climatic oscillations seen in glacial sections of the Greenland ice core record.

Sedimentological, geochemical and benthic foraminiferal proxies were used to interpret changes of depositional environments in a mud entrapment inside the Guadiana River paleo-valley, northern Gulf of Cadiz, to understand the temporal variability of fluvial flooding events and to detect patterns of latitudinal climatic variability in western Iberia. The period between ca. 5800 and ca. 1250 cal yr BP was characterized by slowly accumulating coarse-grained sediments, high content of biogenic sand components, and high abundances of shallow-water benthic foraminiferal species. After ca. 1250 cal yr BP, the sedimentary environment was dominated by fine-grained sediments, with high abundances of opportunistic benthic foraminiferal species and successful colonizers, and high values of geochemical ratios indicative of enhanced terrigenous supply. Sedimentation rates increased drastically over the last ca. 500 years. The genesis of these environments was mainly driven by the variable frequency of fluvial flooding events driven by the regional climate variability. Low terrigenous sediment input under dry conditions prevailed in the older sedimentary unit. Flood frequency and terrigenous sediment supply increased during the younger unit. The variability of the North Atlantic Oscillation at centennial scales highly influenced the sediment supply during the last ca. 500 years, with high terrigenous supply during negative NAO conditions. Our results corroborate an N-S gradient along the Atlantic Iberia during middle and late Holocene, with more humid conditions in the northwestern and drier conditions towards the southeast. The gradient weakened over the past ca. 500 years, with increased rainfalls and flood events during the Little Ice Age., This study was made possible by the CADISED (Cadiz Shelf Sediment Depocentres) survey (MARUM research cruise POS482, Germany), and was also supported by projects UID/0350/2020 CIMA of the Portuguese Science Foundation (FCT) and CGL2011-30302-C02-02 and CTM2017-88237-P of the Spanish Ministry of Economy and Competitiveness. Isabel Mendes also thanks to FCT for Research Assistant contract DL57/2016/CP1361/CT0009.

Habitat patterns of subtropical and tropical planktic foraminifers in the Caribbean Sea were obtained from plankton samples collected in spring 2009 and 2013. The spatial distribution in surface waters (3.5 m water depth) and depth habitat patterns (surface to 400 m) of 33 species were compared with prevailing water-mass conditions (temperature, salinity, and chlorophyll-a concentration) and planktic foraminiferal test assemblages in surface sediments. Distribution patterns indicate a significant relationship with seawater temperature and trophic conditions. A reduction in standing stocks was observed close to the Orinoco River plume and in the Gulf of Paria, associated with high turbidity and concomitant low surface-water salinity. In contrast, a transient mesoscale patch of high chlorophyll concentration in the eastern Caribbean Sea was associated with higher standing stocks in near surface waters, including high abundances of Globigerinita glutinata and Neogloboquadrina dutertrei. Globorotalia truncatulinoides mainly lives close to the seasonal pycnocline and can be linked to winter conditions indicated by lower sea-surface temperatures (SSTs) of ∼20°C. Globigerinoides sacculifer and Globoturborotalita rubescens were associated with oligotrophic conditions in the pelagic Caribbean Sea during early spring and showed a synodic lunar reproduction cycle. The live assemblages in the water column from 2009 and 2013 were similar to those reported in earlier studies from the 1960s and 1990s and to assemblages of tests in the surface sediments. Minor differences in faunal proportions were attributed to seasonal variability and environmental differences at the local scale. An exception was the low relative abundance of Globigerinoides ruber in the Caribbean Sea in 2009 compared to surface sediment samples and plankton net samples collected in the 1960s and 1990s. Decreasing abundance of Gs. ruber white in the Caribbean Sea may be associated with increasing SSTs over past decades and changes in nutrient flux and primary production.

Highlights • Foraminiferal species were assigned to ecological groups according to AMBI procedure. • The benthic foraminifera-based Foram-AMBI was calculated using the AMBI formula. • Foram-AMBI was successfully tested on independent data sets. • Foram-AMBI correlates well with Shannon's diversity and TOC in test data sets. • Foram-AMBI reflects a stress gradient caused by increased organic carbon. The present study follows up the FOraminiferal BIo-MOnitoring (FOBIMO) working group's aim to explore methods which will improve the usefulness of benthic foraminifera in environmental monitoring. An internationally well-established marine biotic index, AMBI, commonly applied to assess ecological quality status was adapted for use on benthic foraminifera. As required by the AMBI formula, species were assigned to one of five ecological groups according to their sensitivity/tolerance to conditions along an increasing stress gradient (here increasing organic matter enrichment). For the assignments, we used 19 published data sets on fully marine NE Atlantic and Arctic fjord, continental shelf, and slope assemblages for which total organic carbon (TOC) data were available. Assignments were based on the relative abundance of the different species along associated TOC gradients. Of the 128 assigned species, the majority was assigned to Groups I–III dominating in low to moderately organic enriched environments with a high to good ecological quality status. Groups IV and V, representing strongly organically enriched environments with a moderate to poor ecological quality status, had 1 and 2 species, respectively. The resulting foraminifera-based Foram-AMBI was calculated using the AMBI formula and tested on four independent foraminiferal data sets from the same geographical region. The validation included correlations of the Foram-AMBI with Shannon's diversity (H′log2) as well as with the organic carbon content in the validation data sets. In two validation data sets from the Norwegian Skagerrak coast, a high proportion of the assemblages consisted of assigned species. The results showed a good correlation between the Foram-AMBI and both the TOC and Shannon's diversity H′log2. In two more southern validation data sets all TOC values were low and the abundance of unassigned species was too high for the Foram-AMBI to provide trustworthy results. The Foram-AMBI of the two validation data sets with high abundance of assigned species clearly reflected an increasing organic carbon-induced stress gradient. Hence, this first attempt to apply the AMBI formula on benthic foraminiferal data shows promising results. However, to improve the applicability of Foram-AMBI, there is a need to assign more species by obtaining data from studies along wide organic carbon pressure gradients, particularly from the southern North Sea and southwards.

Pleistocene and late Pliocene benthic foraminifera from the Manihiki Plateau (southwestern tropical Pacific) were studied at piston-core 34KL. A new benthic foraminiferal biozonation is proposed. It comprises the Nodogenerina sagriensis Partial Range Zone from core base to 566.5 cm and the Fissurina seminiformis Partial Range Zone from this level to core top. The boundary is defined by the last occurence of Nodogenerina sagriensis which is time equivalent to the ‘Stilostomella extinction’ in the Eastern Atlantic. High abundances of Cibicidoides wuellerstorfi indicate a strong influence of near-bottom currents. The absence of high-productivity sensitive species reveals a low flux of organic matter to the sea floor from which a considerable amount is adduced by lateral advection.

Benthic foraminifera have proven to be suitable for environmental monitoring because of their high levels of adaptation, small size and high abundance in Recent sediments and the fossil record. Foraminifera are scarcely used in monitoring studies because a standardization of methods has not been achieved to date. When particular methods were introduced and why they were applied is often hidden in the literature. This paper reviews the development of field and laboratory methods, their constraints and consequences for faunal and data analyses. Multiple and box corers and some grab samplers retrieve reliable surface sediment samples provided the bow wave is minimized as the sampler approaches the sea floor. Most disturbances are created during handling of the unit on deck and subsampling. Ethanol for preservation, rose Bengal as vital stain and a mesh size of 63 µm to wash foraminiferal samples are used extensively. Faunal analyses of a larger size fraction are occasionally necessary. The fractions >125 µm and >150 µm are often preferentially chosen even though this may artificially reduce specimen numbers and faunal diversity. Generally, a much lower level of common practice prevails in sample preparation and faunal analyses than in sampling or laboratory procedures. Increasing preference has been given to quantitative methods and the acquisition of independently revisable census data during recent decades.

Living benthic foraminiferal assemblages were monitored between January and July 2004 in the Kiel Bight, Baltic Sea. Phytoplankton blooms and the deposition of organic detritus were depicted by fluorometer hydro casts and pigment concentrations in surface sediments. Three depositional pulses of organic matter were identified by high phytoplankton concentrations above the sea floor and elevated pigment concentrations in the surface sediment. The foraminiferal assemblage composition remained rather constant but the population density of Elphidium excavatum clavatum showed a two- to six-fold increase within a few days after organic detritus deposition. The foraminiferal assemblage composition was compared to earlier studies in this area. Elphidium excavatum, Ammotium cassis and E. incertum dominated the living fauna in the 1960s and 1970s. The recent survey revealed a predominance of E. excavatum subspecies (more than 90% of the living assemblage). The average population densities were six times higher than in the 1970s. Data structure and model calculations suggested that E. excavatum clavatum is able to reproduce rapidly, with high offspring numbers at elevated food supply. The diminution of A. cassis has occurred in Kiel Bight during the last ten years and was most likely induced by a period of low deep-water salinities in the early 1990s.

Planktonic and benthic foraminifera are the most significant providers of information on the state of surface and deep oceans in the past. Many foraminiferal proxies rely on the knowledge of ecological preferences of individual species and the assumption that these remained similar through time. Consequently, the applicability of such proxies is limited in time by the extent of the modern fauna. By analysing extensive datasets of species occurrences, we show that the modern oceanic foraminifer fauna originated during the Neogene. This occurred during two distinct diversification pulses: one in the Middle Miocene (17–14 Ma) and the second at the Miocene/Pliocene transition (7–4 Ma). The first diversification coincides with the time of a major change in the frequency of the dominant climate cycles during the Miocene Climatic Optimum. The environmental driver of the second diversification could be related to an increased provincialism induced by the closure of the Panama Seaway, but the exact link is not clear, particularly for the plankton. Surprisingly, major changes of ocean circulation due to the growth of Antarctic ice-sheet and closure of low-latitude seaways appear to have caused mainly extinctions. Given the age of the latest diversification and extinction pulses that shaped the modern foraminiferal fauna, we conclude that calibrated proxies based on assemblage properties should not be interpreted quantitatively in sediments older than the late Pliocene. Much of what we know about the Cenozoic oceans comes from the study of fossil foraminifera. These microscopic protozoans occur in nearly all marine environments – from the bottom of the deepest trenches (Todo et al. 2005) to brine channels in Antarctic sea-ice (Dieckmann et al. 1991) – and their ornate shells are readily preserved in sediments. Foraminiferal species are sensitive to a range of environmental parameters and the chemical and isotopic composition of their calcite skeleton records the properties of ambient seawater and the nature of metabolic and kinetic processes that take place during calcification. This remarkable capacity to reflect the state of their habitat, coupled with the abundance of their fossils in marine cores, made foraminifera the main tool for reconstructions of past oceans and climate. Benthic foraminifera convey information about conditions prevailing on the ocean floor. Early research on benthic foraminifera was qualitative, aimed at assessing the faunal inventory, and obtaining a general understanding of past environmental conditions. Recent studies focused on the development of quantitative tools, in particular for the reconstruction of organic matter flux to the sea floor (Herguera & Berger 1991; de Rijk et al. 2000), oxygen content of near-bottom waters (Kaiho 1994), and intensity of bottom currents (Schonfeld 2002). Planktonic foraminiferal assemblages have long been used to estimate sea-surface temperature (Imbrie & Kipp 1971; Kucera et al. 2005), upwelling intensity (Thiede 1975; Conan et al. 2002) and productivity (Ivanova et al. 2003), and the modification of their assemblages on the sea floor has been used to reconstruct past bottom-water carbonate ion concentration (Conan et al. 2002). The elemental and isotopic chemistry of calcareous tests from both benthic and planktonic foraminifera forms the basis of an ever-increasing battery of proxies used to reveal the age, origin, chemical and physical properties of ocean waters (Fischer & Wefer 1999; Henderson 2002). The application of foraminifera as palaeoceanographic proxies is based on the recognition of ecological relationships in the modern ocean and their translation into the fossil realm. This method relies on a number of assumptions (e.g. Birks 1995), the most pertinent one being the stationarity through time of the individual ecological relationships. Some foraminiferal proxies are based on determination of broad functional and ecological types (benthic vs. planktonic) or preservational state (fragmentation) and their temporal applicability is therefore less of an issue. However, most quantitative proxies rely on species-specific calibrations and the interpretation of almost all chemical From: WILLIAMS, M., HAYWOOD, A. M., GREGORY, F. J. & SCHMIDT, D. N. (eds) Deep-Time Perspectives on Climate Change: Marrying the Signal from Computer Models and Biological Proxies. The Micropalaeontological Society, Special Publications. The Geological Society, London, 409–425. 1747-602X/07/$15.00 # The Micropalaeontological Society 2007. signals in foraminifera requires knowledge of the habitat and phenology of the analysed species. Because of circular evidence, the stability of the ecological preferences of taxa through time is often difficult to assess. Therefore, morphological similarity has been used as a first approximation of ecology and the fossil range of a given species has been taken to represent the duration of its specific, present-day ecological behaviour. This approximation is inevitably crude, as it is known that species’ ecology can change with little or no shift in morphology (Norris et al. 1996; Kucera & Kennett 2002), but it provides a consistent and objective means to estimate the maximum range of modern environmental calibrations. The purpose of this study is to review data on the age of extant species of planktonic and benthic foraminifera, determine the diversification history of the groups and assess its links with oceanographic events in the Cenozoic. A further aim is to produce objective guidelines for the use of foraminiferal proxies based on modern environmental calibrations in ‘deep time’. This review will only deal with oceanic foraminifera; shelf seas, brackish facies, marshes and other marginal environments will not be considered. Origin of the modern foraminiferal fauna The number of living benthic foraminiferal species is estimated at approximately 4000 (Thies 1991), and about 45 living planktonic species are commonly recognized (Hemleben et al. 1989). The number of all benthic and planktonic species since the Cambrian is estimated at about 10,000 (Vickermann 1992). This estimate would suggest that foraminiferal faunas are dominated by conservative, long-ranging taxa and that the modern fauna should have its roots in deep time. A direct assessment of the antiquity of extant foraminiferal species would require a thorough analysis of species occurrences on a global scale. However, information on the ranges of living benthic foraminifera is rather scattered. Biostratigraphic compendia typically cover a limited number of stages or a subsystem, have a regional bias and concentrate on stratigraphically important taxa. Only a few studies in the framework of the Deep Sea Drilling Project and Ocean Drilling Program go beyond that scope (see Berggren & Miller 1989; Thomas 1992; and Hayward 2001 for further discussion). Jones (1994) gives a list of stratigraphic ranges for 305 recent, mostly deep-sea benthic foraminifera and 26 planktonic species figured by Brady (1884). Less than 10% of the presumed living benthic species and only a half of the living planktonic foraminifera are covered by this compilation. Nonetheless, the dataset is methodologically and taxonomically consistent and provides the first approximation of the distribution of ages of modern oceanic foraminifera (Fig. 1). As many as 13 (4.2%) of the living benthic species listed by Jones (1994) have originated in the Cretaceous; the oldest was reported as being of Valanginian age. The number of survivors from the Palaeogene is with 58 (19.0%) still low. Clearly, the Miocene was the crucial time for the diversification of the modern benthic fauna. More than 50% of the recent benthic species included in Jones’ (1994) compilation have originated during this stage. Remarkably, almost a quarter of the modern species appear to have originated during the last 5 Ma in the Pliocene or Pleistocene. 0 20 40 60 80 100 120 140 160 180 Pleistocene Pliocene Miocene Oligocene Eocene Palaeocene Cretaceous O rig in s of r ec en t f or am in ife ra Planktonic species

Benthic foraminiferal faunas from the shelf and upper continental slope of the Celtic Sea (NE Atlantic) show a rich variety of Trochamminidae species. We recognized 31 taxa, of which 18 could be determined to species level. These 18 species comprise about 9% of all species of the family Trochamminidae that are described from Recent sediments worldwide. For species determination and generic classification, we used existing taxonomic concepts and assessed their applicability. Besides the morphology of the test and internal structures, different apertural. features play a fundamental role in the systematic subdivision of the Trochamminidae. The position of the aperture controls the chamber arrangement and, therefore, the final shape of the test. However, we found no relationship between the apertural features and shape of the chambers as well as between apertural features and mode of life. Using apertural features for a sound taxonomic designation of our specimens proves difficult, because apertures are often obscured. Further, combined morphological and molecular-phylogenetic studies are required to constrain the taxonomic relevance of apertural characteristics.

Alexander Volker Altenbach was born in 1953 in Frankfurt/Main, Germany. Alex attended school in Konigstein/Taunus, where he passed his Abitur in 1974. He then studied Geology and Paleontology at Goethe University, Frankfurt. During an internship on an oil rig in Denmark, he first experienced a professional working environment and the adventures of hydrocarbon exploration in the North Sea. For his diploma thesis Alex worked on the stratigraphy and tectonics of the Sierra de Montgai, in the Pyrenees, Spain, under the supervision of Rolf Schroeder, Senckenberg Museum, Frankfurt/M. The subject comprised a genuine geological mapping exercise and biostratigraphic dating of the exposed formations. Stratigraphic ages were determined with the Mesozoic orbitoids and planktonic foraminifera in thin sections. Alex shared the long travels to Spain with his two companions Hans-Joachim Wallrabe-Adams (aka Kolli) and Peter Brinnel, enjoying an old “concha naranja” Volkswagen van, as well as field work in the spectacular scenery of the Sierra de Montsec, and living the Catalonian lifestyle. As late as 1993, the theme of Alex’s habilitation defense again was the geology of the Sierra de Montsec, for which he had kept his fascination (cf. Wallrabe-Adams et al., 2005). Being challenged by disentangling the complicated tectonic structure of the Sierra de Montgai, Alex learnt Fortran78 to produce a virtual Schmid net on the central university computer, visualizing different deformation styles of the different tectonic units. His early professional computer programming probably gave rise to his later endeavor in computing. Attracted by the developments in Marine Geosciences at Kiel University during the early 1980s, Alex joined the Micropaleontology Group of Gerhard Friedrich Lutze, and commenced …

The benthic foraminiferal inventory and their assemblage composition was documented along five sediment cores from the Peruvian margin between 3°S and 18°S at water depths of 500 to 1250 m, covering the lower boundary of today’s Oxygen Minimum Zone (OMZ). Emphasis was given to certain time intervals during the last 22 thousand years when different climatic and oceanographic conditions prevailed than today. In total three agglutinated and 186 calcareous species were recognised. Bolivina costata, Bolivinita minuta, Cassidulina delicata and Epistominella exigua were most abundant. The foraminiferal distributions revealed a marked change in assemblage composition particularly at the deeper cores during and after the deglaciation. The diversity declined and Bolivina species became dominant. These changes took place gradually over several millennia, and high-frequency fluctuations were not recorded. This pattern provides evidence for rather stable ecological conditions and sluggish changes in bottom water circulation during the last deglaciation.

The faunal composition and diversity pattern of Recent benthic foraminifera from the shelf and slope of the South Western Approaches (Celtic Sea) were assessed. The sampling stations cover a depth range from 100 to 500 m. A total number of 294 species was recorded, of which 89 were found exclusively in the living fauna and 118 only in the dead assemblage, whereas 87 species were found in both assemblages. The faunal composition revealed a distinct bisection of the living fauna on the shelf. While certain distribution patterns of living dominant species were recognized along a NE-SW trending transect towards the shelf edge, the living fauna changed within small depth intervals and geographic position on the slope. Causes for these structured slope assemblages were probably along-slope currents of varying strengths, as well as variations in topography and bottom sediments. Analyses of population densities and diversity patterns determined high densities along the shelf edge and at one slope station, as well as an increasing diversity with water depth. A comparison with literature data from the same area yields distinct differences in faunal composition on the shelf and slope. The diversity was similar on the shelf, but higher at corresponding stations on the slope. We conclude that the faunal composition was highly influenced by the time and methods of sampling. In order to obtain consistent results in regional studies, all samples should be taken in a short time interval and by using the same sampling device. In addition, we depicted the influences of environmental parameters on dead faunal assemblages and their consequences for paleoenvironmental interpretations of fossil foraminiferal assemblages.

The present study investigated the combined effects of ocean acidification, temperature, and salinity on growth and test degradation of Ammonia aomoriensis. This species is one of the dominant benthic foraminifera in near-coastal habitats of the southwestern Baltic Sea that can be particularly sensitive to changes in seawater carbonate chemistry. To assess potential responses to ocean acidification and climate change, we performed a fully crossed experiment involving three temperatures (8, 13, and 18uC), three salinities (15, 20, and 25) and four pCO2 levels (566, 1195, 2108, and 3843 matm) for six weeks. Our results highlight a sensitive response of A. aomoriensis to undersaturated seawater with respect to calcite. The specimens continued to grow and increase their test diameter in treatments with pCO2 ,1200 matm, when Vcalc .1. Growth rates declined when pCO2 exceeded 1200 matm (Vcalc ,1). A significant reduction in test diameter and number of tests due to dissolution was observed below a critical Vcalc of 0.5. Elevated temperature (18uC) led to increased Vcalc, larger test diameter, and lower test degradation. Maximal growth was observed at 18uC. No significant relationship was observed between salinity and test growth. Lowered and undersaturated Vcalc, which results from increasing pCO2 in bottom waters, may cause a significant future decline of the population density of A. aomoriensis in its natural environment. At the same time, this effect might be partially compensated by temperature rise due to global warming.

The eastern Pacific benthic foraminifer Nonionella stella Cushman & Moyer, 1930 was recorded for the first time in the Skagerrak (North Sea) and its fjords. In this short note we evaluate its migration, considering both dispersal by propagules and ship ballast tanks. We suggest that the predominantly southward surface currents along the western European seaboard and Morocco would impede a wide-range dispersal of N. stella propagules and hypothesize transportation by ship ballast tanks as the possible vector of N. stella immigration into northern European seas.

The aim of the present study was to compare preservation, staining and preparation techniques to assess the influence of different sample treatments and analyses on the accuracy of benthic foraminiferal assemblage data from NE Atlantic shelf seas. Replicate surface samples from the SE North Sea were preserved with ethanol–rose Bengal or formalin, some were stained after processing, or foraminifera were concentrated by flotation. Coloration of living specimens was different between samples treated with an ethanol–rose Bengal solution and those stained after washing. In the latter case, only the last two or three chambers were stained. The aliquot sample preserved with formalin showed dissolution features in agglutinated and porcellaneous species. Population density varied between different preservation, picking modes and investigators. The accuracy of picking was in the range of ±2 % (1σ), while external reproducibility ranged from −34 to +16 %. There was no significant difference between wet and dry picking. Samples that were concentrated by flotation generally yielded a lower number of specimens. Agglutinated species were under-represented in samples that were stained after washing and in the flotation concentrate. Size fractions showed a reduction of population density and Fisher alpha diversity index with increasing mesh size. Only half of the specimens and less than two-thirds of the species are captured if the >125 µm rather than >63 µm fraction is analysed. In oxygen minimum zones, where small-sized species dominate the assemblage, the recovery in larger size fractions could be lower.

The pore-densities (PD) in the tests of 232 specimens of the shallow infaunal foraminiferal species Bolivina spissa from eight locations off the Peruvian continental margin were investigated and compared to different environmental factors as water-depth, temperature, bottom-water oxygen ([O2]BW) and nitrate concentrations ([NO3–]BW). There is a negative exponential PD-[O2]BW correlation, but at oxygen-concentrations >10 µmol/l PD approaches a constant value without any further correlation to [O2]BW. The PD-[NO3–]BW relationship is better constrained than that for PD-[O2]BW. We hypothesize that the pores in the tests of B. spissa largely reflect the intracellular nitrate, and to a smaller extent the oxygen respiration. We also compared PD and porosity (P) of two single B.spissa and B.seminuda specimens from the same habitat. The comparison showed that P is significantly higher in B.seminuda than in B. spissa indicating that B.seminuda is much better adapted to strong oxygen-depleted habitats than B.spissa.

The long-term climate cooling during Campanian - Maastrichtian times is not well understood to date, especially because of the uncertainty introduced by low temporal resolution of biostratigraphy and the pronounced provincialism between tropical and temperate taxa. Two new high-resolution carbon isotope records derived from the boreal shelf-sea section at Lagerdorf-Kronsmoor-Hemmoor, northern Germany and the tropical Pacific at Deep Sea Drilling Project Site 305, Shatsky Rise, reduce these uncertainties. The records can be correlated with an accuracy not achieved by biostratigraphic methods so far. Distinct carbon isotope events in the late Campanian and the early Maastrichtian can be identified at both localities suggesting to represent global carbon cycle perturbations. Especially, the negative carbon isotope excursion in the early Maastrichtian, a pronounced feature of open-ocean records from the Pacific and Southern oceans, is recognized for the first time at a shelf-sea locality related to the North Atlantic Ocean. Furthermore, two short-term positive excursions are identified as superimposed signals to this event. The improved stratigraphy provides the unique opportunity to recognize leads and lags between the carbon cycle and ocean circulation of different marine settings and ecosystems, leading to a better understanding of their causes and effects.

New carbonate records of the upper Campanian–lower Maastrichtian white chalk of northern Germany at Lagerdorf–Kronsmoor represent a continuous succession suitable for time series analysis. The boreal chalk succession is characterized by several intervals of reduced carbonate content in the basiplana/spiniger, polyplocum, upper langei and upper grimmensis/granulosus to pseudoobtusa boreal macrofossil zones, which are mainly related to periods of increased detrital supply. Results of spectral analysis on the carbonate time series allow the detection of the periodicities of long and short eccentricity. The long eccentricity signal can be extended to the entire Upper Campanian comprising a total of 15.25 long eccentricity cycles, a minimum time span of 6.2 Ma and an age of 77.5 ± 0.4 Ma for the lower–upper Campanian boundary. The long eccentricity cycles detected from chalk carbonate contents correlate with long eccentricity cycles detected in self-potential logs of boreholes proving their significance within different depositional settings and rates of subsidence in the North German Basin. The biostratigraphic consistent occurrence of long eccentricity cycles provides evidence for the completeness of the sedimentary record. The long-term intervals of increased detrital supply are the expression of increased progradation of clay minerals related to a long-term sea-level fall with superimposed short sea-level falls within a 2.5 million year interval spanning the Campanian–Maastrichtian boundary. It cannot be decided from the present state of knowledge if this signal is controlled by increased erosion due to uplift of inverted structures, by eustatic sea-level fall or a combination of both. The detection of the long eccentricity suggests an orbital forcing superimposed on a long-term regressive trend.

Cold-water coral ecosystems are characterised by a high diversity and population density. Living and dead foraminiferal assemblages from 20 surface sediment samples from Galway and Propeller Mounds were analysed to describe the distribution patterns of benthic foraminifera on coral mounds in relation to different sedimentary facies. Hard substrates were examined to assess the foraminiferal microhabitats and diversities in the coral framework. We recognised 131 different species, of which 27 prefer an attached lifestyle. Epibenthic species are the main constituents of the living and dead foraminiferal assemblages. The frequent species Discanomalina coronata was associated with coral rubble, Cibicides refulgens showed preference to the off-mound sand veneer, and Uvigerina mediterranea displayed abundance maxima in the main depositional area on the southern flank of Galway Mound, and in the muds around Propeller Mound. The distribution of these species is rather governed by their specific ecological demands and microhabitat availability than by the sedimentary facies. Benthic foraminiferal assemblages from coral mounds fit well into basin-wide-scale distribution patterns of species along the western European continental margin. The diversity of the foraminiferal faunas is not higher on the carbonate mounds as in their vicinity. The living assemblages show a broad mid-slope diversity maximum between 500 and 1,300 m water depth, which is the depth interval of coral mound formation at the Celtic and Amorican Margin. The foraminiferal diversity maximum is about 700 m shallower than comparable maxima of nematodes and bivalves. This suggests that different processes are driving the foraminiferal and metazoan diversity patterns.

Living benthic foraminifera of Flensburg Fjord were surveyed in June 2006. The muddy and organic-rich sediments of the inner fjord were dominated by Elphidium incertum. E. incertum and E. excavatum were frequent in muds and sandy muds of the fjord loop around Holnis Peninsula and in the outer part. Gelting Bay yielded a different biofacies, indicating a brackish and sandy habitat, poor in food supply and with microfauna dominated by Ammonia beccarii and E. albiumbilicatum. The central fjord and nearshore zones of the loop were characterized by sandy muds, relatively poor in food and occupied by A. beccarii, E. incertum and E. excavatum subspecies. High abundances of E. excavatum were encountered in the innermost fjord, with fine-grained and organic-rich muddy sediments.A comparison with previous studies revealed the profound changes in species composition in the outer Flensburg Fjord since the 1970s. A decline in numbers of Ammotium cassis and flourishing of Ammonia beccarii in Gelting Bay were recognized. These changes are most likely associated with decreased intensity and frequency of salt-water inflows into the Baltic Sea since the 1960s. It is inferred that the decline of A. cassis is similar to that of Eggerelloides scaber, which currently is found only in depressions of Kiel Bight with higher salinity.

The diatom spring bloom and response of the benthic foraminifera was monitored between January and July 2004 in the Kiel Bight, western Baltic Sea. Phytoplankton production, the deposition of organic detritus, and feeding of Elphidium excavatum clavatum and Reophax dentaliniformis were monitored by pigment concentrations and pigment composition in water samples, surface sediments, and foraminiferal protoplasm. The population dynamics of the dominant species, Elphidium e. clavatum, was assessed by using their size distributions. The main spring bloom was triggered by a sudden rise in the three-day average insolation to above 170 W m(-2) d(-1) and took place during late February. Chlorophyll a concentrations in the protoplasm of Elphidium e. clavatum followed those in the surface water. The chlorophyll a / fucoxanthin ratio was the same as in bacillariophycean diatoms suggesting a "bloom-feeding" behaviour of Elphidium e. clavatum. Alternatively, the pigment composition in Reophax dentaliniformis only occasionally mirrored that of diatoms, indicating prochlorophycean and cyanophycean algae as this species' preferred food source. The size distributions and the abundances of living Elphidium e. clavatum revealed two reproduction events, which were 17 days apart. Both events coincided with an increase in sedimentary chlorophyll a concentrations. The reproduction was preceded by growth and feeding of adult specimens and it was followed by distinct growth phases of young specimens, which lasted a few days only. One reproductive cycle covered the spring bloom and produced many more offspring than the subsequent cycle. The light carbon isotopic signal from diatoms was only transiently recorded in foraminiferal calcite and with a low offset during the spring bloom. The oxygen isotopic composition of foraminiferal calcite mirrors seasonal delta(18)O-seawater-salinity relationships rather than temperature.

The Mediterranean outflow water (MOW) paleocirculation during the last 50,000 years has been inferred from the grain-size distribution of contourite beds in core MD99-2341 from the Gulf of Cadiz (Southern Iberian Margin–Atlantic Ocean). Three main contourite facies are described. Their vertical succession defines two contourite sequences that reveal past variations of the MOW bottom-current velocity. A comparison of contourite sequences and the planktonic δ18O record of core MD99-2341 with the δ18O record from Greenland Ice Core GISP2 show a close correlation of sea-surface water conditions and deep-sea contouritic sedimentation in the Gulf of Cadiz with Northern Hemisphere climate variability on millennial timescales. A high MOW velocity prevailed during Dansgaard-Oeschger stadials, Heinrich events and the Younger Dryas cold climatic interval. The MOW velocity was comparatively low during the warm Dansgaard-Oeschger interstadials, Bolling-Allerod and the Early Holocene. Rapid sea-level fluctuations on the order of 35 m during Marine Oxygen Isotope Stage 3 are considered to have exerted limiting controls on the MOW volume transport and thus positively modulated the MOW behaviour during the last 50 kyr.

A novel technique was applied to estimate differences in core shortening in three gravity cores taken at the same core location on the Portuguese continental slope using different coring devices. No obvious deformational features are visible in the fresh core sediments; the isotope stratigraphy and abundance maxima of ice-rafted debris, representing North Atlantic Heinrich-events, indicate identical stratigraphic range in all three cores. However, one of the cores is significantly shorter than the others. X-ray radiographs of the cores reveal that the shorter core shows typical deformation structures, whereas the two other cores are lacking signs of deformation. This serious disturbance had likely gone unnoticed had it not been for the X-ray radiographs. As an approach to semi-quantitatively estimate the core shortening, we used the fragmentation and displacement of the pyritized trace fossil Trichichnus that is easily recognizable in X-ray radiographs through its high contrast. The Trichichnus data indicate that a shortening of 50–60% occurred in the lower part of the shorter core. This estimate is in good agreement with variations in apparent sedimentation rates for the interval considered. Accurate flux rates are essential for our understanding marine biogeochemical cycles in general and the marine budgets of nutrients such as carbon and phosphorus in particular. X-ray radiographs are very useful in assessing the intactness of the sedimentary records and the presented method has potential to become a valuable tool in correcting sedimentation rates in disturbed gravity cores.

Uvigerina peregrina Cushman 1923 and related taxa are extensively used for paleoceanographical studies. A high degree of inter- or intra-specific variability leaves the status of these species unclear and has hampered sound paleoenvironmental interpretations to date. The species concept and diagnostic features of Uvigerina peregrina and the closely related Uvigerina pigmea d’Orbigny 1826, Uvigerina peregrina parva Lutze 1986 are re-assessed in this paper. Uvigerina sp. 221 Lutze 1986 is formally described and named Uvigerina celtica n. sp. The overall size of the tests, the length/width ratio, and the morphology of costae are considered key diagnostic features while the presence or absence of spines is of minor importance for species characterization. Geographic and depth distributions of living Uvigerina taxa are described using faunal census data from the northwest African and western European continental shelf and slope from the 2 ° S to 70 ° N, and from the Caribbean. The regional distribution and inferred population dynamics reveal that Uvigerina peregrina, Uvigerina celtica n. sp. and Uvigerina pigmea are indeed different species. Uvigerina peregrina parva is most likely a subspecies of Uvigerina peregrina and not an ecophenotype.

Phases with massive abundances of Uvigerina species recorded in North Atlantic deep-sea cores were previously attributed to water mass properties or to extended high productivity during the last Glacial. We investigated the Uvigerina distribution in 53 sediment cores and 555 surface samples from the north-eastern Atlantic ranging from 308 to 708N and 1 to 4410 m water depth. Our results showed that Uvigerina pigmea dominated in late Pleistocene assemblages whereas Uvigerina peregrina and Uvigerina peregrina parva were common during the Holocene. Uvigerina pigmea lives today in the Gulf of Guinea and South Atlantic only (98N to 178S), but was present up to 548N during the Last Glacial Maximum. The species retreated north- and southwards during Termination I and disappeared in the north-eastern Atlantic off northern Portugal 6100 years ago. Uvigerina peregrina and U. peregrina parva spread out from isolated occurrences along the continental slope off western Iberia at the onset of Termination I. Uvigerina peregrina exhibited Recent abundance maxima at Goban Spur, Plateau des Landes, and the Iberian Margin. These areas are subjected to strong lateral advection by downslope transport and sediment focusing. The actual flux rate of particulate organic matter is locally raised by a factor of 4 to 5. Comparable flux rates were otherwise recorded at U. peregrina maxima under the NW-African coastal upwelling regime. The Recent distribution of U. pigmea and evidence from sediment cores show an organic carbon flux of 3.5 g C m-2 yr-1 as minimum for a sustainable population of this species. Alkenone, pigment and planktonic foraminiferal records from cores MD952039 and MD952040 revealed that a spring bloom dominated productivity dynamics and a balanced food particle composition of haptophyteae algae and diatoms were limiting environmental factors for U. pigmea during the Pleistocene. A widespread change from glacial to modern productivity characteristics during the last Deglaciation may have triggered the early Holocene disappearance of U. pigmea from the north-eastern Atlantic.

Biogenic structures in Late Quaternary sediments from the southwestern Iberian continental slope were studied by using X-ray images from two cores from 580 and 1750 m water depth. Eight different ichnocoenoses were observed: indistinct bioturbation, Planolites-dominated, Thalassinoides-dominated, Chondrites-dominated, Planolites and Thalassinoides-dominated, pyritized microburrows such as Trichichnus and ‘Mycellia’-dominated, Chondrites, Trichichnus, and ‘Mycellia’-dominated and Zoophycos. Variations of the ichnocoenoses within the cores show a striking correlation with climatically induced changes in the hydrographical regime, i.e. current strength and bathymetric position of the Mediterranean Outflow Water (MOW). Comparison of the response of the ichnocoenoses to changes in bottom-water conditions and substrate between the two cores studied indicate that bottom-water oxygenation and enrichment of particulate organic matter at the base of the MOW layer are the primary factors controlling the ichnocoenoses. The traces even recorded short-term climatic changes such as the Younger Dryas cold event. The spatial and temporal distribution patterns are in good agreement with earlier models of the MOW history, which gives reason to see a refinement of trace fossils as a complementary tool for paleoceanographical studies.

Living and dead benthic foraminiferal assemblages from two size fractions, 63–250 μm and >250 μm, were studied at 128 stations from the shelves down to abyssal plains of the Gulf of Guinea in the eastern equatorial Atlantic. The sample size ranged between 300 and 400 cm2 of the sediment/water interface, with a penetration depth of 1 cm. Environmental parameters were quantified for sediment composition, food webs, bottom-water oxygen concentrations, and benthic oxygen respiration. Seven major station groupings (named G1–G7) are subdivided by factor analysis. The three most abundant species therein are discussed with respect to their ecological requirements, for both size classes and for living and dead counts. For 49 living species, the range of environmental gradients is established, and for five species live observations are reported. Five station groupings can be attributed toward stepwise ranges scaled by bathymetry and flux rates of organic carbon (G4, 27–75 m; G5, 68–269 m; G6, 250–740 m; G2, 674–2007 m; G1, 1475–4970 m). Two geographically restricted station groupings locally interfinger with other groupings in the upper bathyal and abyssal water depths (G7, 82–451 m; G3, 1002–4658 m). G7 shows lowered oxygen concentrations and benthic oxygen respirations, whereas hemipelagic sediments are typical of G3. The interfingering of G7 and G3, however, is not purely a result of the increasing number of species most perfectly adapted to these environments but rather that these groupings are structured by the decrease of species with lower tolerance towards environmental perturbation. In fact, the more common species have an environmental range much broader than the environmental frame of the groupings they dominate. This observation holds for all size classes and for live and dead counts. We conclude that species-specific preferences and thresholds provide a more valuable and more consistent tool in environmental research than the environmental ranges observed for assemblages.

The benthic environment in the Gulf of Cadiz, north-eastern Atlantic, is strongly affected by the Mediterranean outflow water undercurrent (MOW) which flows northwards along the western Iberian Margin at 500–1500 m water depth. Foraminiferal census counts of living and dead assemblages from 27 surface samples ranging from 103 to 1917 m water depth, and the examination of hard substrates reveal a close correlation of the fauna with the local hydrography and sediment facies. Four different faunal groups are separated by factor analysis of the living fauna. Assemblage 1 contains typical lower slope species and dominates samples from the lower MOW core layer and in the North Atlantic deep water below. Shelf edge foraminifera are common in assemblage 2a which shows the highest proportions in samples from 103 to 272 m. Assemblage 2b is dominated by upper slope species and suspension-feeders that are frequent in the upper MOW core layer and in distal settings between 396 and 901 m. Species from assemblage 3 prefer epibenthic habitats and are recorded with high proportions exclusively in the immediate flow paths of the upper MOW between 496 and 881 m. Colonisation structures and species composition of epibenthic assemblages from the proximal facies largely differ from those in distal settings. In general, epibenthic foraminifers only use elevated substrates under the influence of near-bottom flow. Under high current velocities, epibenthic foraminifers prefer large and heavy objects. They colonise high attachment levels where a maximum yield of advected food particles can be achieved. In distal settings at lower flow velocities, the elevation height does not exceed 20 mm above the surrounding sediment surface. This level is related to a hydrologic transition layer with high concentrations of suspended particles. The comparison of microhabitat preferences and faunal structure under high and low current velocities reveal that substrate stability may be a confining environmental variable for endobenthic and shallow epibenthic foraminifers. The observations also indicate that the preferential settling height of epibenthic foraminifera is related to the highest lateral flux rates of food particles within reach from the sea floor. A dynamic selection of elevated microhabitats is only used by 7.8% of all species recognised in the Gulf of Cadiz area.

Present day oceans are generally well ventilated except mid-depth oxygen minimum zones (OMZs) under high surface water productivity regimes, regions of sluggish circulation, and restricted marginal basins. In the Mesozoic, however, entire oceanic basins transiently became dysoxic or even anoxic. In particular the Cretaceous Ocean Anoxic Events (OAEs) were characterised by laminated organic-carbon rich shales and low-oxygen indicating trace fossil assemblages preserved in the sedimentary record. Yet both, qualitative and quantitative assessments of intensity and extent of Cretaceous near-bottom water oxygenation have been hampered by deep or long-term diagenesis and the evolution of marine biota serving as oxygen indicators in today's ocean. Sedimentary features similar to those found in Cretaceous strata were observed in deposits underlying Recent OMZs, where bottom-water oxygen levels, the flux of organic matter, and benthic life are well known. Their implications for constraining past bottom-water oxygenation are addressed in this review, with emphasis on comparing OMZ sediments from the Peruvian upwelling with deposits of the late Cenomanian OAE 2 from the Atlantic NW African shelf. Holocene laminated sediments were encountered at bottom-water oxygen levels of 10 μmol kg−1 showed an inverse exponential relationship of bottom-water oxygen levels and organic carbon accumulation depicting enhanced bioirrigation and decomposition of organic matter with increased oxygen supply. In absence of seasonal laminations and under conditions of low burial diagenesis, this relationship may facilitate quantitative estimates of paleo-oxygenation under suboxic conditions. Similarities and differences between Cretaceous OAEs and late Quaternary OMZs have to be further explored to improve our understanding of sedimentary systems under hypoxic conditions.

The depth distribution of living (Rose Bengal-stained) benthic foraminifera in near-surface sediments was analyzed along 4 short cores from the western Iberian Margin and Gulf of Cadiz at water depths from 800 to 1920 m. Pore-water oxygen, Chloroplastic Pigment Equivalent (CPE), and total organic carbon (C org ) concentrations were measured in the same or adjacent cores. These values were used to constrain the limiting oxygen and nutrient levels that defined the ranges in sediment depth and abundance maxima of foraminiferal species. The population density showed a good correlation with pore-water oxygenation indicating that oxygen is a limiting factor for endobenthic foraminiferal assemblages at mid-depths between 800 and 1200 m. At the deep-water site, however, the fauna appeared nutrient limited. More than half of the benthic species occupied extended sediment depth habitats and a wide range of oxygen levels among the sites studied. Thirty-nine of 103 species occurred in two or more cores and showed distinct abundance maxima, 36 in the uppermost 2.0 cm where the CPE concentrations were high. Living foraminifers were not found at depths where the CPE-values were lower than 0.1 μg/g. This level indicates trophic conditions critical for the survival of endobenthic species. The frequency distribution of the lower oxygen range limits of all species showed maxima at the high oxic/low oxic (3 ml/l), low oxic/suboxic (1.5 ml/l), and suboxic/dysoxic (0.3 ml/l) boundaries and thus depicted the ecological significance of these previously recognized ecolimits. Only 30 % of the species display consistent patterns in relation to pore water oxygen. Dysoxic indicators were Globobulimina affinis, Chilostomella ovoidea and Bathysiphon capillare. Many species previously designated as suboxic indicators were ubiquitous or preferred microhabitats at oxic levels. Boundary conditions for the dysoxic indicator G. affinis were pelagic flux rates higher than 3.5 g C m −2 yr −1 , a habitat depth below the homogeneously bioturbated layer in areas outside of high productivity zones, and CPE concentrations of 0.1 to 1.0, preferentially 0.7 to 0.8 μg/g. The distribution pattern suggested that G. affinis thrives mainly on dysoxic bacteria and actively seeks this nutrient resource.

Records of benthic foraminiferal assemblage variations and benthic δ13C along 12 sediment cores from the western Iberian Margin, between 36° and 42°N at water depths from 820 to 3580 m, are used to monitor fluctuations of the Mediterranean Outflow Water (MOW) during the past 30 ka. The chronostratigraphy of the cores is based on planktonic δ18O records, 14C AMS-dating, and the recognition of Heinrich Events H1 through H4. Increased abundances of suspension feeding benthic foraminifers, denoted as ’Epibenthos Group‘, closely match areas where the recent MOW core layers impinge on the continental slope at 800 and 1300 m water depth, and near-bottom current velocities are enhanced. Elevated ‘Epibenthos Group’ abundances, increased benthic δ13C, and sedimentological evidence for winnowing and erosion are found in glacial sections up to the earliest Termination I in cores at water depths between 1600 and 2200 m off southern Portugal. The combined evidence reveals enhanced current activity at these depths due to a deep glacial MOW. The MOW advection at the Portuguese margin during the last Glacial was about 700 m deeper than today, conceivably forced by increased MOW density due to higher salinity and colder temperatures of Mediterranean waters. The deep MOW current gradually decreased in strength and shoaled to 1300 m water depth during the Termination and early Holocene. A shallow MOW core layer became active with the onset of Termination I at depths between 600 and 1000 m. Both the shallow and deep MOW current culminated during the Younger Dryas period. The present flow pattern with two MOW core layers centred at 800 and 1300 m water depth was established between 7.5 and 5.5 ka.

The Portuguese margin is at a critical location for studies of the ocean’s behaviour during glacial/interglacial climatic changes, and the rapid accumulation rates of the sediments enable high‐resolution palaeoclimatic investigation. The sedimentary record of the past 350 ka has been investigated in a 35 m long core from 3.5 km water depth on the slope at 40°N by geochemical, isotopic and micropalaeontological techniques. The CaCO 3 content of this core as a function of time contains significant Milankovitch orbital frequencies of 18.8, 23.7, 38.0 and 100.6 ka, but these are driven primarily by dilution by clay‐flux variations rather than by CaCO 3 productivity variations. The largest signals in the productivity indicators C org , Ba/Al and diatom abundance are all observed as simultaneous peaks at the oxygen isotope stage boundaries 10/9 and 6/5, with the signal magnitude in the order 10/9>6/5 for all three indicators. Smaller coincident signals in C org , Ba/Al but not diatoms are also observed at the oxygen isotope stage 2/1 boundary. Other less prominent peaks in the C org and Ba/Al profiles occur elsewhere, including Heinrich Event horizons, but these are not always simultaneous and none contain evidence of the dissolution‐prone diatom microfossils. The 10/9, 6/5 and 2/1 oxygen isotope stage transitions represent the three most extreme glacial/interglacial sea level rises in the past 350 ky, possibly in the same sequence of magnitude, when sea level rose rapidly by 120+m from glacial low stands to interglacial low stands to interglacial high stands. The productivity signals at these transitions are contained within

The Portuguese margin is well-suited for studies of the contrasts in North Atlantic circulation during glacial and interglacial times because of its rapid sediment accumulation rate. This paper reports a (230Thexcess)0-based study of sediment accumulation over the past 140 ky, a period which includes the last two glacial/interglacial transitions, in two cores at 2.4 and 3.5 km water depth on a slope transect at 40°N. Although the independently-determined mean sediment accumulation fluxes over the past 140 ky are unequivocally high with means of 13.2 and 10.5 g cm−2 ky−1 in the two cores, conventional application of the (230Thexcess)0 method yields consistently lower fluxes with means of 3.5 and 3.8 g cm−2 ky−1. These (230Thexcess)0 estimates are interpreted as representations of the regional depositional flux through time. This (230Thexcess)0 regional flux is composed of a carbonate flux of

The distribution of trace fossils and benthic foraminiferal assemblages in two sediment cores from 2160 m water depth at the northern and 1100 m at the southern Portuguese continental margin was used to reconstruct the bottom-water oxygenation during the last 40 ka. Emphasis was given to the Heinrich events, during which enhanced meltwater flux associated with the iceberg surges reduced or even halted deep water formation in the North Atlantic. Condensed trace-fossil tiering structures and high proportions of low-oxygen-tolerant benthic foraminifera suggest a major drawdown of bottom-water oxygenation during Heinrich events. Using the benthic foraminiferal oxygenation index (BFOI) of Kaiho (1991, 1994) that links benthic foraminiferal communities to ambient bottom-water oxygenation, we extracted apparent oxygen concentrations from benthic assemblages. BFOI values suggest low-oxic conditions during Heinrich events 1 and 4 with mean oxygen levels of 2.6 to 2.8 ml l −1 and high-oxic conditions with 4.1 ml l −1 during Heinrich event 2 at the shallower site. High proportions of low-oxygen-tolerant foraminiferal species and BFOI minima are recorded a few centimetres below the maximum concentrations of ice-rafted debris, indicating that the original microhabitat depth of dysoxic species is preserved beneath the Heinrich layers even though bioturbation continued during the events. Trace-fossil tiering calibrated with the redox boundary in low-oxic environments and dysoxic ichnotaxa commonly associated with black shales indicate oxygen levels lower than those implied by the BFOI. Oxygenation estimates derived from trace-fossil tiering denote low-oxic conditions during H1 (13.3 ka) with oxygen concentrations slightly above 1 ml l −1 , and dysoxic conditions during H2 (20.6 ka), H3 (27 ka) and H4 (33.5 ka) with oxygen concentrations between 0.1 and 1 ml l −1 . During the Younger Dryas, bottom waters likely were low oxic. Negative excursions of benthic carbon isotope values provide independent control on the oxygen drawdown during Heinrich events. Considering a bottom-water oxygenation of 6.1 to 6.5 ml l −1 during the last glacial, the benthic δ 13 C minima reveal an oxygen depletion to values between 3.4 and 5.0 ml l −1 during H1 through H4 at the shallower core site. Differences between estimates from benthic δ 13 C, BFOI and trace-fossil tiering suggest that benthic foraminiferal communities are rather robust to oxygen depletion if the level does not fall below 3 ml l −1 , whereas burrowing organisms react sensitively to depth variations of the redox boundary in near-surface sediments due to even small changes of bottom-water oxygenation.

Benthic foraminifera and surface sediments were analyzed from 23 box-core and core-top samples from 250 to 3600 m depth at the southern Portuguese continental margin between 37 and 38 °N. This area is affected by the MOW which flows northwards along the slope between 600 and 1500 m waterdepth. Sediment structures, grain-size distribution and clay mineral assemblages of surface sediments indicate active winnowing in the upper part of the MOW, and deposition of the fine fraction near its lower boundary. R-mode cluster analyses of foraminiferal census data from the > 250 μm fraction revealed four associations. The ‘Shelf Edge Association’ occurs on glauconitic shelf and upper slope sands down to 268 m. The ‘Upper Slope Association’ is recognized between 498 and 1300 m where sand-silt-clays to clayey silts are encountered. The ‘Lower Slope Association’ is found between 1405 and 2985 m and differs markedly from assemblages below 3000 m (‘Deep Water Association’) where the near-surface sediments are soft hemipelagic clays. The ‘Boundary Layer Association’ shows no significant depth limits but abundance maxima both in the density interface above the MOW and in the interval of decreasing turbulence below it. The boundaries of the ‘Shelf Edge’ and ‘Upper Slope Association’ correspond to these hydrographic boundary layers whereas the boundary between ‘Lower Slope’ and ‘Deep Water Assemblage’ is related to threshold values of nutrient flux to the benthic community. Examination of hard-substrates reveals 27 different species of epibenthic foraminifera. Six of these, the ‘Epibenthos Group’, were found attached to elevated substrates only within the MOW. Above the MOW, elevated substrates were inhabited by different species, whilst below the MOW they were not used by any epibenthic foraminifers. Evidently, the hydrodynamic environment of the MOW current provides an ecological niche which is efficiently used by opportunistic suspension feeders. The ‘Epibenthos Group’ is more abundant in the middle part of the study area between 37 °20′ and 37 °40′N where the sand content of surface sediments is also higher. Both indicate an enhanced sediment-water interaction in this area which results from an obstruction of the MOW flow by the ‘Principes d'Avis’ basement spur.

The objective of this work was to review the distribution of benthic foraminiferal species at the western European continental margin from 43–58uN, determine their diversity, and generate a standardized taxonomy based on 44 publications (1913–2010) and unpublished information. Qualitative and quantitative data based upon foraminiferal occurrences and species abundances were included together with supplementary sedimentological and hydrographical data. From the species inventory, as well as from differences in morphological, physical, and hydrographic conditions in the study area, we defined six regions. The investigation of 2902 stations revealed 1486 species, of which 26% are synonymous. Most of the species have a hyaline test and live free, on or in the sediment. We recorded 608 species whose distributions were confined only to one of the six regions. Quantitative faunal data showed a general diversity increase from shelf to slope and two mid-slope diversity maxima, one located on the Basque continental margin at 550–850-m water depth and the other west of Ireland at 700–1100 m. In addition, the number of living species on the shelf generally increased from N–S. The latitudinal vs. depth distribution of six dominant species showed an irregular, lobate distribution pattern for the shelf regions. These species displayed similar distribution patterns on the continental slope, despite different modes of life, and different food and substrate preferences. This suggests that they have the same ecohabitat throughout their depth range. The faunal distribution pattern revealed close relationships between the different regions despite their varying hydrologic regimes.A delineation of one or two regions based on faunal criteria has not been attempted to date. There were no major distinctions in diversity among the six regions of the NE Atlantic, but the whole area exhibits an interregional diversity (c-diversity of 16), similar in magnitude to that of the Gulf of Mexico. In some parts of the study area, gaps in data coverage and differences in foraminiferal taxonomy and hydrographic conditions prevented the calculation of diversity indices.

Colonization structures of the large parasitic foraminifer Hyrrokkin sarcophaga Cedhagen, 1994 on Lophelia pertusa, Acesta excavata and Delectopecten vitreus are described from a deep-water coral reef mound on the mid-Norwegian shelf at 240 to 300 m water depth. Hyrrokkin sarcophaga is the only epibiont which is capable of attaching itself on the soft tissue-protected coral skeleton where it tends to form clusters of 3 to 8 specimens close to the tentacles of Lophelia. The foraminifer excavates a pit up to 1.5 mm deep and etches a straight channel through the skeleton of the host which ends within the soft tissue. In contrast to Lophelia, infested bivalves show a strong wound repair reaction and seal the etched channels by intense calcification. The etching is only performed by adult specimens. Substrate pitting is considered to improve the attachment strength while boring enables the parasite to secure a persistent nutrient source.

Three contrasting sedimentary environments on the continental shelf off the Guadiana River (northern Gulf of Cadiz) were integrated in a chronological framework and analysed in terms of sedimentology and benthic foraminiferal assemblages to understand the Holocene paleoenvironmental evolution. The analysed environments differ in terms of their depositional regimes and benthic foraminiferal assemblages. However, a dominant fluvial origin of the sand fraction was observed in all three environments. Holocene sedimentary processes were mainly controlled by natural (sea level changes and climate variations) and human-induced processes (e.g. deforestation, agriculture) along four evolutionary stages. The three older stages were mainly influenced by natural processes, such as sea level variations and fluvial inputs, whereas the most recent stage reflects a combination of climatic- and human-induced processes. A deepening of sedimentary environments related to a period of rapid sea level rise, strongly influenced by river discharges occurred from c. 11,500 to c. 10,000 cal. yr BP. A reduction in sediment export to the shelf, as a result of the continuous and rapid sea level rise and enhanced estuary infilling reflects the second stage, from c. 10,000 to c. 5000 cal. yr BP. The beginning of the third stage, from c. 5000 to c. 1500–1000 cal. yr BP, is marked by a sea-level slowdown and the relatively stable climate and environmental conditions. The fourth stage, from c. 1500–1000 cal. yr BP to Recent times, reflects the intensification of human-induced processes and climatic variability in the Guadiana River basin. This stage also reflects modern depositional conditions, with the formation of a proximal prodeltaic wedge and a distal muddy body. PDCTM/P/MAR/15289/1999 info:eu-repo/semantics/publishedVersion

Living (stained) benthic foraminiferal faunas were analyzed in 51 surficial sediment samples taken from the northern Gulf of Cadiz continental shelf between the mouths of the Guadiana and Guadalquivir rivers. The distribution and abundance of 26 species with relative abundance .5% were related to water depth, sediment type, river discharge, water temperature, salinity, turbidity, and primary productivity. Hierarchical classification using R- and Q-mode cluster analyses, and individual distributions, allowed these taxa to be categorized into four general groups. Group 1 is represented by Bolivina ordinaria and Hopkinsina atlantica. These species are linked to river discharge, and are associated with muddy sediments. They are considered the most opportunistic species in the assemblage, and are associated with the limits of productivity. Group 2, contains Ammonia beccarii, Eggerelloides scaber, Elphidium gerthi, Quinqueloculina laevigata, and Q. stelligera, and is characteristic of shallow water depths. Its species are associated with different sediment types and their distribution is influenced by river discharge. Group 3 is dominated by Bulimina aculeata, B. elongata, Elphidium excavatum, E. cuvillieri, Epistominella vitrea, and Rectuvigerina phlegeri. These species display the highest abundances between 30–100 m water depths. They prevail in muds associated with weak hydrodynamics, low oxygenation, and high organic matter. Group 4 includes species that are more abundant in deep stations and is divided into two subgroups. Subgroup 4A includes Bolivina catanensis, B. italica, B. striatula, Cassidulina laevigata, Stainforthia sp., Nouria polymorphinoides, and Nouria sp., with higher abundances in one or two samples. Subgroup 4B, with Brizalina dilatata, B. spathulata, Bulimina marginata, Nonionella iridea, N. stella, and N. turgida, has patchy distribution. Higher abundances of Nonionella species off the Guadiana River are related to low temperature and salinity. info:eu-repo/semantics/publishedVersion

Modeling and proxy studies indicate that a reduction of Atlantic Meridional Overturning Circulation (AMOC) strength profoundly impacts temperatures and salinities in the (sub)tropical Atlantic, especially on subsurface levels. While previous studies focused on prominent periods of AMOC reduction during the last deglaciation, we aim to test whether similar reconfigurations of the subtropical hydrography occurred during the moderate climatic alterations punctuating the last interglacial Marine Isotope Stage (MIS) 5. Here, we present temperature and salinity records from a Florida Straits core by combining d18O and Mg/Ca analyses on surface (Globigerinoides ruber, white) and deep‐dwelling (Globorotalia crassaformis) foraminifera covering MIS 5 in high resolution. The data reveal increasing salinities at intermediate depths during interglacial cooling episodes, decoupled from relatively stable surface conditions. This probably indicates the spatial expansion of saline subtropical gyre waters due to enhanced Ekman downwelling and might also point to a changed density structure and altered geostrophic balance in Florida Straits. Notably, these oceanographic alterations are not consistently occurring during periods of AMOC reduction. The data suggest that the expansion of gyre waters into Florida Straits was impeded by the increasing influence of Antarctic Intermediate Water (AAIW) from MIS 5.5 to ∼107 kyr BP. Afterward, increasingly positive benthic d13C values imply a recession of AAIW, allowing the temporary expansion of gyre waters into Florida Straits. We argue that the inferred transient subtropical salt accumulation and warm pool expansion might have played a pivotal role in reinvigorating meridional overturning and dampen the severity of interglacial cold phases.

[1] This paper documents the migration of the Polar Front (PF) over the Iberian margin during some of the cold climatic extremes of the last 45 ka. It is based on a compilation of robust and coherent paleohydrological proxies obtained from eleven cores distributed between 36 and 42°N. Planktonic δ18O (Globigerina bulloides), ice-rafted detritus concentrations, and the relative abundance of the polar foraminifera Neogloboquadrina pachyderma sinistral were used to track the PF position. These three data sets, compared from core to core, show a consistent evolution of the sea surface paleohydrology along the Iberian margin over the last 45 ka. We focused on five time slices representative of cold periods under distinct paleoenvironmental forcings: the 8.2 ka event and the Younger Dryas (two recent cold events occurring within high values of summer insolation), Heinrich events 1 and 4 (reflecting major episodes of massive iceberg discharges into the North Atlantic), and the Last Glacial Maximum (typifying the highest ice volume accumulated in the Northern Hemisphere). For each event, we generated schematic maps mirroring past sea surface hydrological conditions. The maps revealed that the Polar Front presence along the Iberian margin was restricted to Heinrich events. The sea surface conditions during the Last Glacial Maximum were close to those at present day, except for the northern sites which briefly experienced subarctic conditions.

Gerhard Friedrich Lutze was born in Braunschweig, Germany, on 12 April 1932 to Hildegard and Paul Gustav Friedrich Lutze who was an electronic engineer. Gerd attended the Wilhelm-Gymnasium and reformed Oberrealschule in Braunschweig. He moved up a year because he was an extremely gifted student, and graduated from a class of five students. Gerd studied at the Universities of Tubingen and Braunschweig. At the latter, Professor Paul Dorn proposed that Gerd pursue the doctoral thesis in which he established a foraminiferal and ostracodal biostratigraphy for Lower Saxony (NW Germany) that closely correlated with the existing ammonite zonation. While pursuing his doctorate, Gerd developed and maintained contact with biostratigraphers and micropaleontologists in oil companies and at the Bundesanstalt fur Bodenforschung, Hanover, among which were Franz Bettenstaedt, Helmut Bartenstein, and Heinrich Hiltermann, and his first wife Brunhilde Grabert. He also became acquainted with Inge and Eugen Seibold in Tubingen. In discussions about his doctoral research, Gerd often emphasized the importance of the applicability of micro-fossil biostratigraphy to commercial needs, as well as his affection for the scientific approach. Upon completion of his thesis in January 1958, Gerd was awarded the title doctor rerum naturarum , and then became a postdoctoral research assistant (“Wissenschaftlicher Assistent”) at the Geological Institute of the University of Braunschweig. From there he left for Los Angeles, having been awarded a fellowship of the German Research Foundation (DFG) to work at the …

20 pages, 8 figures, 1 table.-- Printed version published Mar 30, 2004., The response of coccolithophore assemblages to short-term millennial and centennial climatic changes over the last 50 kyr is studied in core M39029-7 from the Gulf of Cadiz (Atlantic Ocean) and core MD95-2043 from the Alboran Sea (Western Mediterranean Sea). The nannoplankton data are compared with oxygen isotopes, U37k′-SST and other biogeochemical and sedimentological proxies to obtain a new perspective of the paleoceanography and paleoecology of the area during these short-term climatic changes. Coccolithophores indicate that Heinrich events (HE) were characterised by the presence of cold, low salinity and turbid water masses on both sides of the Strait of Gibraltar. High abundances of the Lower Photic Zone (LPZ) species Florisphaera profunda in the Gulf of Cadiz synchronous with HE are interpreted as being an evidence of upper water-column stratification on the Atlantic side. These episodes coincided with input of terrigenous material, especially during H2. Surface waters during Dansgaard-Oeschger (DO) Stadials were also cold and turbid, while most of DO Interstadials were characterised by warm-water flora. The increase in small placoliths (small Gephyrocapsa and Emiliania huxleyi (4 μm), which is considered here as a cold-water indicator. The sharp decrease in large specimens of E. huxleyi related to the warming trend in the last deglaciation can be used as a biostratigraphic reference level that marks—at least approximately—the deglaciation and the beginning of the Holocene. Peaks of F. profunda are observed during Termination 1 (T1) in the Alboran Sea. They are isochronous with the “Organic-Rich Layer 1” recognised in the Western Mediterranean. In this interval, the water column of the region was stratified as a consequence of the global increase in the sea level following the deglaciation. Quantitative analyses of the coccolithophore assemblage allow us to interpret that coccolithophore production has been higher in the Alboran Sea than in the Gulf of Cadiz during the Holocene., This study was supported by an FPU grant from the Ministry of Education, Culture and Sport of Spain to E. Colmenero-Hidalgo and by Spanish project CLI 1998-1002-CO2-O2 and FEDER project 1FD97-1178. Sedimentological and stable-isotope work on core M39029-7 was funded by the Deutsche Forschungsgemeinschaft (Grants Scha355/15 and Za157/15).

Sea surface temperature (SST) profiles over the last 25 kyr derived from alkenone measurements are studied in four cores from a W-E latitudinal transect encompassing the Gulf of Cadiz (Atlantic Ocean), the Alboran Sea, and the southern Tyrrhenian Sea (western Mediterranean). The results document the sensitivity of the Mediterranean region to the short climatic changes of the North Atlantic Ocean, particularly those involving the latitudinal position of the polar front. The amplitude of the SST oscillations increases toward the Tyrrhenian Sea, indicating an amplification effect of the Atlantic signal by the climatic regime of the Mediterranean region. All studied cores show a shelter cooling phase (700 years) for the Younger Dryas (YD) than that observed in the North Atlantic region (1200 years). This time diachroneity is related to an intra-YD climatic change documented in the European continent. Minor oscillations in the southward displacement of the North Atlantic polar front may also have driven this early warming in the studied area. During the Holocene a regional diachroneity propagating west to east is observed for the SST maxima, 11.5-10.2 kyr B.P. in the Gulf of Cadiz, 10-9 kyr B.P. in the Alboran Sea, and 8.9-8.4 kyr B.P. in the Thyrrenian Sea. A general cooling trend from these SST maxima to present day is observed during this stage, which is marked by short cooling oscillations with a periodicity of 730+/-40 years and its harmonics.

An undisturbed 16 m late Pliocene-Pleistocene sediment core spanning 2.6 Myr of deposition was recovered from the Manihiki Plateau by the German research vessel Sonne in 1990. This core 34KL complements the heavily disturbed late Pliocene-Pleistocene core sections of DSDP Site 317, and is well suited for stratigraphic correlation. The sediments consist of calcareous microfossils (93–97% CaCO3), minor portions of siliceous microfossils and detrital minerals. All important calcareous microfossil zones could be identified and correlated with the magnetostratigraphic and isotope stratigraphic events, stages and periods. Due to the high degree of silica dissolution, the late Quaternary radiolarian Buccinosphaera invaginata Zone is the only siliceous fossil zone which could be identified. An interval with Globigerinoides gomitulus/pink was found within the middle Pleistocene which is clearly distinguished from the Globigerinoides ruber/pink interval of the late Pleistocene. The magnetostratigraphic Gauss-Matuyama and Matuyama-Brunhes boundaries as well as the Olduvai and Jaramillo events were clearly identified. The δ180 curve displays the 100 kyr (Milankovitch) and the 41 kyr (Laplace) cyclicity periods. The beginning of the Laplace Period and the last occurrence of the calcareous nannofossil Discoaster brouweri, which marks the end of the Pliocene, fall within the base of the Olduvai Event. There is also a marked drop in sedimentation rates around this time, which seems to be a regional phenomenon. Prominent 3.5 kHz subbottom reflectors at 8 ms and 15 ms reflection time are related to lithologic changes near the Mid-Pleistocene Revolution (MPR) and the beginning of the Laplace Period or the Pleistocene, respectively. It is possible to trace these reflectors laterally to the eroded eastern edge of the Manihiki Plateau where they can be tied to older strata.