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Reducing atmospheric carbon dioxide (CO2) concentrations to combat global warming is one of the greatest challenges of humanity.Marine alkalinity enhancement is a promising carbon dioxide removal measure with high potential to increase oceanic carbon uptake and storage. The natural processes of weathering on land sustains the alkalinity of the ocean and thereby removes CO2 from the atmosphere on geological time scales. The weathering can be enhanced by deploying fine-grained alkaline minerals to coastal areas, to directly supply more alkalinity to near-coastal waters. Nevertheless, the rate of CO2 consumption depends on the minerals used, grains size, temperature, pH, and salinity. During mineral dissolution, nutrients and trace elements are also released, which may affect marine biota. In order to evaluate the CO2 sequestration potential, ensuing biogeochemical and ecological impacts of alkalinity enhancement in intertidal environments, a novel in-situ experiment was installed in the Ria Formosa Coastal Lagoon, southern Portugal.The Ria Formosa is a highly dynamic lagoon system, with daily renewal of water and nutrients through multiple tidal inlets. A succession of salt marshes with varying zonation and faunal communities fringes the lagoon. The experiment was installed in an undisturbed zone colonized with Spartina maritima, in September 2022. The experimental set-up includes three replicate treatments with coarse olivine, fine olivine, coarse basalt, fine basalt, and an untreated control. Lagoonal, supernatant, and porewater waters are sampled from each treatment every month and analysed for temperature, salinity, oxygen concentration, pH, total alkalinity, nutrients, and trace metals. Preliminary data show an increase in total alkalinity in the supernatant and porewaters shortly after minerals deployment, by 0.36 and 2.05 mmol kg-1 on average, relative to the control. Lower values of total alkalinity were recorded in December 2022, followed by markedly lower salinities after heavy rainfall in the study area. The experiment will run over two years and monthly sampled for water properties. For monitoring potential biodiversity changes, sediment samples are analysed for faunal and floral composition. Results of this novel field experiment will provide strategic knowledge on the benefits and risks of alkalinity enhancement in intertidal environments.Acknowledgement. Research supported by the Portuguese Science Foundation, with the projects PTDC/CTA-CLI/1065/2021, UID/00350/2020CIMA and contracts DL57/2016/CP1361/CT0009, DL57/2016/CP1361/CT0002 and CEECINST/00146/2018/CP1493/CT0002.

Quantifying past oxygen concentrations in oceans is crucial to improving understanding of current global ocean deoxygenation. Here, we use a record of pore density of the epibenthic foraminifer Planulina limbata from the Peruvian Oxygen Minimum Zone to reconstruct oxygen concentrations in bottom waters from the Last Glacial Maximum to the Late Holocene at 17.5°S about 500 meters below the sea surface. We found that oxygen levels were 40% lower during the Last Glacial Maximum than during the Late Holocene (about 6.7 versus 11.1 µmol/kg, respectively). A comparison with other reconstructions of oxygen concentrations in the region reveals a shallow Oxygen Minimum Zone during the Last Glacial Maximum that was similar in water depth and extent but weaker than during the Late Holocene. Increased glacial oxygen concentrations are probably related to lower temperatures (higher oxygen solubility), decreased nutrient and increased oxygen supply by source waters, and a decrease in coastal upwelling.

Heavy metal pollution originating from anthropogenic sources like mining, industry and ship traffic is becoming an increasing threat for marine life. First evidences for human impacts on the heavy metal concentration in seawater were recorded in medieval times already. An emerging tool for palaeo-environmental applications is the heavy metal concentration in the tests of benthic foraminifera, which enable monitoring of the anthropogenic footprint on recent systems and the fossil record. The Helgoland mud area (HMA) in the German Bight is an important depositional area for fine sediments. Average sedimentation rates of up to 13 mm/yr offer high-resolution archives, which renders the site suitable for studying long-term variations of anthropogenic pollution on the marine system. The HMA also accumulates discharge from the Elbe and Weser rivers, which are affected by mining activities in their catchment areas since the Bronze Age. The concentration of chromium (Cr), manganese (Mn), nickel (Ni), copper (Cu), zinc (Zn), silver (Ag), tin (Sn) and lead (Pb) in tests of Ammonia batava was analysed along a sediment core from the HMA by laser ablation inductively coupled mass spectrometry (LA-ICP-MS). Radiocarbon datings and stable oxygen and carbon isotope stratigraphy revealed that the core is covering the Early Modern Period (~1550–1700 AD) and the post-World War II period (~1958–2009 AD). The basal unconformity of a tempestite depicts a hiatus and non-sequence between both periods ranging from 1700 to 1958 AD. The concentration of Cu, Zn, Ag and Pb was clearly elevated in the post-1950 AD part of the core indicating a markedly higher anthropogenic influence induced by industrialisation and rapid growth of cities since the 1950s. Variations in Cu, Zn, Ni, Ag and Pb concentrations were linked to mining activities and the production rates of Pb and Ag in the Harz Mountains. Redox-sensitive elements like Mn were correlated to storm surges resulting in the extensive reworking of sediment material. Therefore, the chemistry of the tests of A. batava reflects human activities and natural impacts at the same time, which allows its application for unravelling the environmental history of the North Sea and beyond.

Significance A substantial component of the global nitrogen cycle is the production of biologically inaccessible dinitrogen attributed to anaerobic denitrification by prokaryotes. Recent evidence identified a eukaryote, foraminifera, as new key players in this “loss” of bioavailable nitrogen. The evolution of denitrification in eukaryotes is a rare event, and the genetic mechanisms of the denitrification pathway in foraminifera are just starting to be elucidated. We present large-scale sequencing analyses of 10 denitrifying foraminiferal species, which reveals the high conservation of the foraminiferal denitrification pathway. We further find evidence for a complementation of denitrification by the foraminiferal microbiome. Together, these findings provide insights into the early evolution of a previously overlooked component in the marine nitrogen cycle. Abstract: Benthic foraminifera are unicellular eukaryotes that inhabit sediments of aquatic environments. Several foraminifera of the order Rotaliida are known to store and use nitrate for denitrification, a unique energy metabolism among eukaryotes. The rotaliid Globobulimina spp. has been shown to encode an incomplete denitrification pathway of bacterial origin. However, the prevalence of denitrification genes in foraminifera remains unknown, and the missing denitrification pathway components are elusive. Analyzing transcriptomes and metagenomes of 10 foraminiferal species from the Peruvian oxygen minimum zone, we show that denitrification genes are highly conserved in foraminifera. We infer the last common ancestor of denitrifying foraminifera, which enables us to predict the ability to denitrify for additional foraminiferal species. Additionally, an examination of the foraminiferal microbiota reveals evidence for a stable interaction with Desulfobacteraceae, which harbor genes that complement the foraminiferal denitrification pathway. Our results provide evidence that foraminiferal denitrification is complemented by the foraminifera-associated microbiome. The interaction of foraminifera with their resident bacteria is at the basis of foraminiferal adaptation to anaerobic environments that manifested in ecological success in oxygen depleted habitats.

Phosphorus is essential for all living organisms, being a component of DNA and RNA and the energy carrier ATP. Phosphogenesis is a main sink of reactive phosphorus in the oceans. The present study reports the presence of intracellular dissolved inorganic phosphate (DIP) in benthic foraminifera from the Peruvian oxygen minimum zone (OMZ). The mean intracellular DIP concentration was 28 ± 3 mM; two to three orders-of-magnitude higher than in the ambient pore waters. The biological implications of the high intracellular phosphate enrichment may be related to the synthesis of polyphosphates or phospholipids for cell-membranes. The comparative genomics analysis of multiple species of foraminifera from different environments reveals that foraminifers encode the genes required for both phospholipid and polyphosphate metabolism. Rapid phosphogenesis and phosphorite formation associated with foraminiferal tests is hypothesized due to the pre-concentration of intracellular phosphate in these organisms. The results indicate that foraminifera may play a key and previously overlooked role in the global phosphorus cycle.

Heavy metal pollution originating from anthropogenic sources, e.g. mining, industry and extensive land use, is increasing in many parts of the world and influences coastal marine environments even after the source has ceased to pollute. The elevated input of heavy metals into the marine system potentially affects the biota because of their toxicity, persistence and bioaccumulation. An emerging tool for environmental applications is the heavy metal incorporation into foraminiferal calcite tests, which facilitates monitoring of anthropogenic footprints on recent and past environmental systems. The aim of this study was to investigate whether the incorporation of heavy metals into foraminifera is a direct function of their concentration in seawater. Culturing experiments with a mixture of dissolved chromium (Cr), manganese (Mn), nickel (Ni), copper (Cu), zinc (Zn), silver (Ag), cadmium (Cd), tin (Sn), mercury (Hg) and lead (Pb) in artificial seawater were carried out over a wide concentration range to assess the uptake of heavy metals by the nearshore foraminiferal species Ammonia aomoriensis, Ammonia batava and Elphidium excavatum. Seawater analyses revealed increasing concentrations for most metals between culturing phases and high metal concentrations in the beginning of the culturing phases due to sudden metal addition. Furthermore, a loss of metals during the culturing process was discovered by an offset between the added and the actual concentrations of the metals in seawater. Laser ablation ICP-MS (inductively coupled plasma mass spectrometry) analysis of the newly formed calcite revealed species-specific differences in the incorporation of heavy metals. The foraminiferal calcite of all three species exhibited Pb and Ag concentrations strongly correlated with concentrations in the seawater culturing medium (partition coefficients and standard deviation for Ag – Ammonia aomoriensis, 0.50 ± 0.02; Ammonia batava, 0.17 ± 0.01; Elphidium excavatum, 0.47 ± 0.04; for Pb – Ammonia aomoriensis, 0.39 ± 0.01; Ammonia batava, 0.52 ± 0.01; Elphidium excavatum, 0.91 ± 0.01). Ammonia aomoriensis further showed a correlation with Mn and Cu, A. batava with Mn and Hg, and E. excavatum with Cr and Ni and partially also with Hg. However, Zn, Sn and Cd showed no clear trend for the species studied, which in the case of Sn was maybe caused by the lack of variation in the seawater Sn concentration. The calibrations and the calculated partition coefficients render A. aomoriensis, A. batava and E. excavatum as natural archives that enable the determination of variations in some heavy metal concentrations in seawater in polluted and pristine environments.

Benthic foraminifera are unicellular eukaryotes that inhabit sediments of aquatic environments. Several foraminifera of the order Rotaliida are known to store and use nitrate for denitrification, a unique energy metabolism among eukaryotes. The rotaliid Globobulimina spp. has been shown to encode an incomplete denitrification pathway of bacterial origin. However, the prevalence of denitrification genes in foraminifera remains unknown and the missing denitrification pathway components are elusive. Analysing transcriptomes and metagenomes of ten foraminiferal species from the Peruvian oxygen minimum zone, we show that denitrification genes are highly conserved in foraminifera. We infer of the last common ancestor of denitrifying foraminifera, which enables us to predict the ability to denitrify for additional foraminiferal species. Additionally, an examination of the foraminiferal microbiota reveals evidence for a stable interaction with Desulfobacteracea, which harbour genes that complement the foraminiferal denitrification pathway. Our results provide evidence that foraminiferal denitrification is complemented by the foraminifera-associated microbiome. The interaction of foraminifera with their resident bacteria is at the basis of foraminiferal adaptation to anaerobic environments that manifested in ecological success within oxygen depleted habitats.Significance StatementA substantial component of the global nitrogen cycle is the production of biologically inaccessible dinitrogen attributed to anaerobic denitrification by prokaryotes. Recent evidence identified a eukaryote – foraminifera – as new key players in this ‘loss’ of bioavailable nitrogen. The evolution of denitrification in eukaryotes constitutes a rare event and the genetic mechanisms of the denitrification pathway in foraminifera are just starting to be elucidated. We present large-scale sequencing analyses of ten denitrifying foraminiferal species, which reveals the high conservation of the foraminiferal denitrification pathway. We further find evidence for a complementation of denitrification by the foraminiferal microbiome. Together, these findings provide novel insights on the early evolution of a previously overlooked component in the marine nitrogen cycle.

Supratidal sands are vitally important for coastal defence in the German Wadden Sea. They are less affected by human activities than other areas as they are located far off the mainland shore, touristical and commercial activities are generally prohibited. Therefore, supratidal sands are of high ecological interest. Nevertheless, the faunal inventory and distribution pattern of microorganisms on these sands were studied very little. The composition of living and dead foraminiferal assemblages was therefore investigated along a transect from the supratidal sand Japsand up to Hallig Hooge. Both assemblages were dominated by calcareous foraminifera of which Ammonia batava was the most abundant species. Elphidium selseyense and Elphidium williamsoni were also common in the living assemblage, but Elphidium williamsoni was comparably rare in the dead assemblage. The high proportions of Ammonia batava and Elphidium selseyense in the living assemblage arose from the reproduction season that differed between species. While Ammonia batava and Elphidium selseyense just finished their reproductive cycles, Elphidium williamsoni was just about to start. This was also confirmed by the size distribution patterns of the different species. The dead assemblage revealed 20 species that were not found in the living assemblage of which some were reworked from older sediments (e.g., Bucella frigida) and some were transported via tidal currents from other areas in the North Sea (e.g., Jadammina macrescens). The living foraminiferal faunas depicted close linkages between the open North Sea and the mainland. Key species revealing exchange between distant populations were Haynesina germanica, Ammonia batava and different Elphidium species. All these species share an opportunistic behaviour and are able to inhabit a variety of different environments; hence, they well may cope with changing environmental conditions. The benthic foraminiferal association from Japsand revealed that transport mechanisms via tides and currents play a major ecological role and strongly influence the faunal composition at this site.

Highlights • Foraminifera responded faster to environmental perturbations than macroorganisms. • Population densities doubled and Asterigerinata mamilla bloomed under stronger flow. • Excess of threshold values and changes to new ecosystems induce acme occurrences. Abstract Benthic foraminifera are deemed sensitive indicators of environmental conditions. Triggers and magnitudes of faunal response to environmental changes are yet poorly constrained. Benthic foraminiferal faunas were monitored annually at Ria Formosa (Algarve, Portugal) coastal lagoon since 2013. Distinct environmental changes were recognised during the monitoring period. The relocation of a tidal inlet in winter 2015 effected faster flushing, higher tidal levels, and stronger currents in the Esteiro do Ancão tidal channel. The epibenthic foraminiferal species Asterigerinata mamilla increased in abundance and the population densities of the whole fauna were double as high as before inlet relocation. Enhanced sediment redeposition was recorded and extensive polychaete colonies successively replaced firmground patches with oysters. The standing stock of the foraminiferal fauna declined in the next year due to food impoverishment, while the high hydraulic energy levels and high percentages of Asterigerinata mamilla maintained. Benthic foraminifera responded much faster to environmental perturbations than macroorganisms identifying them as powerful proxies in environmental studies.

Highlights • Investigations of the benthic foraminiferal distribution in the Elbe Estuary. • Low diverse assemblages are dominated by Ammonia species. • Low salinities and high-frequency dredging confines foraminiferal proliferation. • Over 40 years, changes in hydrodynamic conditions induced assemblage modifications. Abstract For the past 200 years, estuarine environments experienced intense and rapid environmental degradations due to human interventions. In addition, Global Changes are modifying the estuarine physiography, leading to a re-structuration of marginal marine benthic communities. The aim of this study is to document, the modern assemblage composition and the species-environment relations of benthic foraminifera upstream the Elbe Estuary (southern North Sea) and to observe what has changed since the first survey in 1981. For this purpose, a surface sampling was carried out from 22 stations along the transitional area of the Elbe Estuary. Living (rose-Bengal stained) and dead foraminiferal assemblages were analysed as well as hydrological and sedimentological parameters (such as salinity, pH, grain-size, and organic matter). Living faunas are characterized by very low densities and largely dominated by Ammonia species. Dead assemblages are more diverse and dominated by Ammonia aomoriensis, Haynesina germanica, and Cribroelphidium selseyense. Salinity and grain-size seem to be the major factors influencing foraminiferal distributions in the transitional area. Under the ongoing climate changes, future strategies will be taken to foster the application of benthic foraminifera as biomonitoring tool in the Elbe Estuary, via this baseline investigation.

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.

Heavy metal pollution from anthropogenic sources increasingly influence marine environments and biota because of their toxicity, persistence and bioaccumulation. Especially coastal environments act as natural catchments for anthropogenic pollutants because these areas are highly affected by industry, agriculture and urban sewage runoff. In nearly all natural environments that are harmed by heavy metal pollution, a combination of several pollutants occurs at the same time. In marginal seas and coastal areas, benthic foraminifera are common in meiofaunal associations, and they can be used as biomonitoring tool for changes in environmental parameters like temperature, salinity, or redox conditions. Furthermore, foraminifera take up heavy metals from the seawater and incorporate those into their carbonate shells during calcification. Moreover, foraminifera have a short life cycle and can therefore react immediately to contaminations of the environment. Here, we will present results from culturing studies with Ammonia aomoriensis, Elphidium excavatum and Ammonia batava addressing the relationship of heavy metal concentration in the seawater and in the foraminiferal tests. The partitioning factor between the ambient seawater and the calcium carbonate of the foraminifera is constrained by continuous water monitoring and laser ablation ICP – MS measurements on single chambers grown during the experiment in a manipulated culturing medium. The foraminifera were exposed to a combination of ten different heavy metals over a range of concentrations comparable to current conditions in medium to high pollutedhigh-polluted areas. A correlation between the heavy metal concentration in the culture medium and in the foraminiferal calcite was recognised for several heavy metals (e.g. Cd, Cr, Pb). Once the carbonate/seawater metal partitioning coefficients are constrained with certainty, investigations of the chemistry of benthic foraminiferal shells offer an advanced and reliable method to monitor short-term changes in the concentrations and bioavailability of toxic elements in seawater.

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.

The Schrammstein Formation of the Upper Cretaceous Elbtal Group comprises 30–60 m thick medium- to coarse-grained sandstone units (named d and e) divided by thin marker beds of finer sands. The cyclic pattern of the re-occurring marker beds, named boundary horizons, and their widespread distribution suggested they were formed by sea-level fluctuations. Basinwards, they correlate to argillaceous marly units of several metres thickness. The geometry of sedimentary bodies, inventory of sedimentary structures, and grain size distribution of sandstones d and e, and boundary horizons γ3 and δ2 were investigated at the Schrammstein and Affensteine rock massifs close to Schmilka. The sedimentary facies indicated a shoaling from lower to upper shoreface and beach environments, from the massive sandstones to the basal boundary horizons and back. The influence of along shore currents and wave action was additionally inferred from grain size distributions and sedimentary structures. The geometry of the sandstones revealed that they were composed of stacked fan lobes with a diameter of a few hundred metres and a sediment source to the north. The geometry also reveals that synsedimentary tectonics along the Lausitz Thrust had only a minor influence on the sediment accumulation but southeastward currents along the ancient coast mainly effected the sediment redistribution. Sedimentary structures and large-scale geometry indicate that sea-level fluctuations shaped the sedimentary bodies. They reflect fast sediment accumulation during transgression and following rapid progradation during highstands. As the accommodation potential was rapidly exhausted, slow aggradation with low sedimentation rates and frequent reworking led to the almost massive appearance of sandstones. Kurzfassung Die Schrammstein-Formation der kreidezeitlichen Elbtal-Gruppe besteht aus 30 bis 60 m mächtigen, mittel- bis grobsandigen Quadersandsteinen (d und e), die durch dünne, feinsandige Schichten begrenzt werden. Das zyklische Wiederauftreten dieser Grenzhorizonte und ihre weite Verbreitung weisen darauf hin, dass sie durch Meeresspiegelschwankungen gebildet wurden. Die Grenzhorizonte gehen beckenwärts in mehrere Meter mächtige, tonig-mergelige Zwischenmittel über. Die Geometrie des proximalen Sandsteins d und der Grenzhorizonte γ3 und δ2, sowie ihre sedimentären Gefüge und Korngrößenverteilungen wurden an den Felsmassiven Schrammstein und Affensteine bei Schmilka in der Sächsischen Schweiz untersucht. Die Sedimentfazies weist auf eine zunehmende Verflachung hin, vom küstennahen, inneren Schelf, in dem die Quadersandsteine abgelagert wurden, zum Vorstrandbereich, wo die basalen Grenzhorizonte gebildet wurden. Der darüber folgende Sandstein zeigt wieder eine zunehmende Wassertiefe an. Die Sedimentstrukturen und Korngrößenkurven weisen auch auf überlagernde Einflüsse von küstenparallelen Strömungen und Welleneinwirkung hin. Die Lagerungsverhältnisse im Sandstein d zeigen, dass der Quadersandstein aus gestapelten, linsenförmigen Sedimentkörpern aufgebaut ist, die einen Durchmesser von mehreren hundert Metern haben und von einer Sedimentquelle im Norden gespeist wurden. Synsedimentäre Tektonik entlang der Lausitzer Überschiebung hatte nur einen untergeordneten Einfluss auf die Sedimentakkumulation, wobei persistente Strömungen entlang der ehemaligen Küste entscheidend zur Sedimentverteilung beigetragen haben. Sedimentstrukturen und Lagerungsverhältnisse belegen, dass die Geometrie der sedimentären Körper durch Meeresspiegelschwankungen geprägt wurde. Die Sedimentfazies spiegelt eine schnelle Akkumulation während der Transgressionen und nachfolgende Progradation während der Meeresspiegel-Hochstände wieder. Der zur Verfügung stehende Akkomodationsraum war schnell ausgefüllt, langsame Aggradation mit niedrigen Sedimentationsraten und häufigen Umlagerungsphänomenen generierte das homogene Erscheinungsbild der Quadersandsteine.

We describe for the first time subtropical intertidal foraminiferal assemblages from beach sands on São Vincente, Cape Verdes. Sixty-five benthic foraminiferal species were recognised, representing 47 genera, 31 families, and 8 superfamilies. Endemic species were not recognised. The new checklist largely extends an earlier record of nine benthic foraminiferal species from fossil carbonate sands on the island. Bolivina striatula, Rosalina vilardeboana and Millettiana milletti dominated the living (rose Bengal stained) fauna, while Elphidium crispum, Amphistegina gibbosa, Quinqueloculina seminulum, Ammonia tepida, Triloculina rotunda and Glabratella patelliformis dominated the dead assemblages. The living fauna lacks species typical for coarse-grained substrates. Instead, there were species that had a planktonic stage in their life cycle. The living fauna therefore received a substantial contribution of floating species and propagules that may have endured a long transport by surface ocean currents. The dead assemblages largely differed from the living fauna and contained redeposited tests deriving from a rhodolith-mollusc carbonate facies at20 m water depth. A comparison of the Recent foraminiferal inventory with other areas identified the Caribbean and Mediterranean as the most likely source regions. They have also been constrained as origin points for littoral to subtidal macroorganisms on other Cape Verdean islands. Micro-and macrofaunal evidences assigned the Cape Verde Current and North Equatorial Current as the main trajectories for faunal immigrations. The contribution from the NW African coast was rather low, a pattern that cannot be explained by the currently available information.

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.

This study reports for the first time boreal to subarctic intertidal foraminiferal assemblages from saltmarshes at Borgarnes and Faskrudsfjordur on Iceland. The composition of living and dead foraminiferal assemblages was investigated along transects from the tidal flat to the highest reach of halophytic plants. The foraminiferal assemblages from Borgarnes showed 18 species in the total foraminiferal assemblage of which only 7 species were recorded in the living fauna. The assemblages were dominated by agglutinated taxa, whereas 3 calcareous species were recorded, of which only Haynesina orbicularis was found in the living fauna. The distribution limit of calcifying species corresponds to the lower boundary of the lower saltmarsh vegetation zone. Furthermore, calcareous tests showed many features of dissolution, which is an indication of a carbonate corrosive environment. The species forming the dead assemblages were mainly derived from the ambient intertidal areas and were displaced by tidal currents into the saltmarsh. The foraminiferal assemblages from Faskrudsfjordur showed two species, of which only one species was recorded in the living fauna. The assemblage was dominated by the agglutinated foraminifer Trochaminita irregularis. The foraminiferal species recorded on Iceland were the same as commonly found elsewhere in Europa. Since no species was found which is endemic to North America, Iceland is considered part of the European bio province. The foraminiferal could have been immigrated to Iceland from Europe through warm water currents, migratory birds or marine traffic since the last Ice Age.

Changes in Atlantic Meridional Overturning Circulation (AMOC) strength exert a major influence on global atmospheric circulation patterns. However, the pacing and mechanisms of low-latitude responses to high-latitude forcing are insufficiently constrained so far. To elucidate the interaction of atmospheric and oceanic forcing in tropical South America during periods of major AMOC reductions (Heinrich Stadial 1 and the Younger Dryas) we generated a high-resolution foraminiferal multi-proxy record from off the Orinoco River based on Ba/Ca and Mg/Ca ratios, as well as stable isotope measurements. The data clearly indicate a three-phased structure of HS1 based on the reconfiguration of ocean currents in the tropical Atlantic Ocean. The initial phase (HS1a) is characterized by a diminished North Brazil Current, a southward displacement of the ITCZ, and moist conditions dominating northeastern Brazil. During subsequent HS1b, the NBC was even more diminished or yet reversed and the ITCZ shifted to its southernmost position. Hence, dryer conditions prevailed in northern South America, while eastern Brazil experienced maximally wet conditions. During the final stage, HS1c, conditions are similar to HS1a. The YD represents a smaller amplitude version of HS1 with a southward-shifted ITCZ. Our findings imply that the low-latitude continental climate response to high-latitude forcing is mediated by reconfigurations of surface ocean currents in low latitudes. Our new records demonstrate the extreme sensitivity of the terrestrial realm in tropical South America to abrupt perturbations in oceanic circulation during periods of unstable climate conditions.

Background: Clinical trials of bone marrow cell–based therapies after acute myocardial infarction (MI) have produced mostly neutral results. Treatment with specific bone marrow cell–derived secreted proteins may provide an alternative biological approach to improving tissue repair and heart function after MI. We recently performed a bioinformatic secretome analysis in bone marrow cells from patients with acute MI and discovered a poorly characterized secreted protein, EMC10 (endoplasmic reticulum membrane protein complex subunit 10), showing activity in an angiogenic screen. Methods: We investigated the angiogenic potential of EMC10 and its mouse homolog (Emc10) in cultured endothelial cells and infarcted heart explants. We defined the cellular sources and function of Emc10 after MI using wild-type, Emc10 -deficient, and Emc10 bone marrow–chimeric mice subjected to transient coronary artery ligation. Furthermore, we explored the therapeutic potential of recombinant Emc10 delivered by osmotic minipumps after MI in heart failure–prone FVB/N mice. Results: Emc10 signaled through small GTPases, p21-activated kinase, and the p38 mitogen-activated protein kinase (MAPK)–MAPK-activated protein kinase 2 (MK2) pathway to promote actin polymerization and endothelial cell migration. Confirming the importance of these signaling events in the context of acute MI, Emc10 stimulated endothelial cell outgrowth from infarcted mouse heart explants via p38 MAPK-MK2. Emc10 protein abundance was increased in the infarcted region of the left ventricle and in the circulation of wild-type mice after MI. Emc10 expression was also increased in left ventricular tissue samples from patients with acute MI. Bone marrow–derived monocytes and macrophages were the predominant sources of Emc10 in the infarcted murine heart. Emc10 KO mice showed no cardiovascular phenotype at baseline. After MI, however, capillarization of the infarct border zone was impaired in KO mice, and the animals developed larger infarct scars and more pronounced left ventricular remodeling compared with wild-type mice. Transplanting KO mice with wild-type bone marrow cells rescued the angiogenic defect and ameliorated left ventricular remodeling. Treating FVB/N mice with recombinant Emc10 enhanced infarct border-zone capillarization and exerted a sustained beneficial effect on left ventricular remodeling. Conclusions: We have identified Emc10 as a previously unknown angiogenic growth factor that is produced by bone marrow–derived monocytes and macrophages as part of an endogenous adaptive response that can be enhanced therapeutically to repair the heart after MI.

Rapid changes in ocean circulation and climate have been observed in marine-sediment and ice cores over the last glacial period and deglaciation, highlighting the non-linear character of the climate system and underlining the possibility of rapid climate shifts in response to anthropogenic greenhouse gas forcing. To date, these rapid changes in climate and ocean circulation are still not fully explained. One obstacle hindering progress in our understanding of the interactions between past ocean circulation and climate changes is the difficulty of accurately dating marine cores. Here, we present a set of 92 marine sediment cores from the Atlantic Ocean for which we have established age-depth models that are consistent with the Greenland GICC05 ice core chronology, and computed the associated dating uncertainties, using a new deposition modeling technique. This is the first set of consistently dated marine sediment cores enabling paleoclimate scientists to evaluate leads/lags between circulation and climate changes over vast regions of the Atlantic Ocean. Moreover, this data set is of direct use in paleoclimate modeling studies., Design Type(s)modeling and simulation objective • data collection and processing objective • source-based data analysis objectiveMeasurement Type(s)age-depth modelTechnology Type(s)computational modeling techniqueFactor Type(s)geographic location • depthSample Characteristic(s)Atlantic Ocean • marine sediment Machine-accessible metadata file describing the reported data (ISA-Tab format)

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

Past ocean temperatures and salinities are successfully approximated from combined stable oxygen isotopes (δ18O) and Mg / Ca measurements in fossil foraminiferal tests. To further refine this approach, we collected living planktic foraminifers by net sampling and pumping of seasurface waters from the Caribbean Sea, the eastern Gulf of Mexico, and Florida Straits. Analyses of δ18O and Mg / Ca in eight living planktic species (Globigerinoides sacculifer, Orbulina universa, Neogloboquadrina dutertrei, Pulleniatina obliquiloculata, Globorotalia menardii, Globorotalia ungulata, Globorotalia truncatulinoides and Globorotalia tumida) were compared to measured in situ properties of the ambient seawater (temperature, salinity and δ18Oseawater) and fossil tests of underlying surface sediments. "Vital effects" such as symbiont activity and test growth cause δ18O disequilibria to the ambient seawater and a large scatter in foraminiferal Mg / Ca. Overall, ocean temperature is the most prominent environmental influence on δ18Ocalcite and Mg / Ca. Enrichment of the heavier δ18 isotope in living specimens below the mixed layer and in fossil tests are clearly related to lowered in situ temperatures and gametogenic calcification. Mg / Ca-based temperature estimates of G. sacculifer indicate seasonal maximum accumulation rates on the seafloor in early spring (March) at Caribbean stations and later in the year (May) in the Florida Straits, related to the respective mixed layer temperatures of ~ 26 °C. Notably, G. sacculifer reveals a positive linear relationship between foraminiferal derived δ18Oseawater estimates and both measured in situ δ18Oseawater and salinity. Our results affirm the applicability of existing δ18O and Mg / Ca calibrations for the reconstruction of past ocean temperatures and δ18Oseawater reflecting salinity due to the convincing accordance of proxy data in both living and fossil foraminifers, and in situ environmental parameters. Large "vital effects" and seasonally varying proxy signals, however, need to be taken into account.

Apolipoprotein A-1 (Apo A-1) plays an important role in lipid transfer and obesity. Chemical unfolding of α-helical Apo A-1 is induced with guanidineHCl and monitored with differential scanning calorimetry (DSC) and CD spectroscopy. The unfolding enthalpy and the midpoint temperature of unfolding decrease linearly with increasing guanidineHCl concentration, caused by the weak binding of denaturant. At room temperature, binding of 50–60 molecules guanidineHCl leads to a complete Apo A-1 unfolding. The entropy of unfolding decreases to a lesser extent than the unfolding enthalpy. Apo A-1 chemical unfolding is a dynamic multi-state equilibrium that is analysed with the Zimm-Bragg theory modified for chemical unfolding. The chemical Zimm-Bragg theory predicts the denaturant binding constant KD and the protein cooperativity σ. Chemical unfolding of Apo A-1 is two orders of magnitude less cooperative than thermal unfolding. The free energy of thermal unfolding is ~0.2 kcal/mol per amino acid residue and ~1.0 kcal/mol for chemical unfolding at room temperature. The Zimm-Bragg theory calculates conformational probabilities and the chemical Zimm-Bragg theory predicts stretches of α-helical segments in dynamic equilibrium, unfolding and refolding independently and fast.

Highlights • High abundance of active anaerobic methanotrophs in sediments of the blowout crater suggests adaptation to methane seepage within at most two decades. • Fast exchange processes in permeable surface sediments prevent sulfate depletion and probably methane-derived carbonate precipitation. • Methane seepage impacts isotopic and assemblage composition of benthic foraminifera. Abstract Methane emissions from marine sediments are partly controlled by microbial anaerobic oxidation of methane (AOM). AOM provides a long-term sink for carbon through precipitation of methane-derived authigenic carbonates (MDAC). Estimates on the adaptation time of this benthic methane filter as well as on the establishment of related processes and communities after an onset of methane seepage are rare. In the North Sea, considerable amounts of methane have been released since 20 years from a man-made gas blowout offering an ideal natural laboratory to study the effects of methane seepage on initially “pristine” sediment. Sediment cores were taken from the blowout crater and a reference site (50 m distance) in 2011 and 2012, respectively, to investigate porewater chemistry, the AOM community and activity, the presence of authigenic carbonates, and benthic foraminiferal assemblages. Potential AOM activity (up to 3060 nmol cm−3 sediment d−1 or 375 mmol m−2 d−1) was detected only in the blowout crater up to the maximum sampling depth of 18 cm. CARD-FISH analyzes suggest that monospecific ANME-2 aggregates were the only type of AOM organisms present, showing densities (up to 2.2*107 aggregates cm−3) similar to established methane seeps. No evidence for recent MDAC formation was found using stable isotope analyzes (δ13C and δ18O). In contrast, the carbon isotopic signature of methane was recorded by the epibenthic foraminifer Cibicides lobatulus (δ13C −0.66‰). Surprisingly, the foraminiferal assemblage in the blowout crater was dominated by Cibicides and other species commonly found in the Norwegian Channel and fjords, indicating that these organisms have responded sensitively to the specific environmental conditions at the blowout. The high activity and abundance of AOM organisms only at the blowout site suggests adaptation to a strong increase in methane flux in the order of at most two decades. High gas discharge dynamics in permeable surface sediments facilitate fast sulfate replenishing and stimulation of AOM. The accompanied prevention of total alkalinity build-up in the porewater thereby appears to inhibit the formation of substantial methane-derived authigenic carbonate at least within the given time window.

Human apolipoprotein A-1 (Apo A-1) was used as a model protein to compare experimental methods and theoretical models for protein unfolding. Thermal unfolding was investigated in aqueous buffer, in β-octylglucoside solution, and with phospholipid bilayer vesicles. The α-helix content of Apo A-1 increased from 50% in aqueous buffer to 75% in the presence of lipid vesicles, but remained constant in solutions of β-octyl glucoside. Differential scanning calorimetry (DSC) measured the thermodynamic properties of the unfolding process and was our reference method. The increased heat capacity of the unfolded protein made an important contribution to the total enthalpy of unfolding. The structural properties of Apo A-1 were studied with circular dichroism (CD) spectroscopy. The CD-recorded unfolding transitions were broader than the corresponding DSC transitions and were shifted toward higher temperatures. DSC and CD data were analyzed with the two-state model and the Zimm-Bragg theory. The two-state model assumes just two species in solution, native (N) and unfolded (U) Apo A-1. However, Apo A-1 unfolding is a highly cooperative event with helical amino acid residues unfolding and refolding rapidly. For such a sequential process, the Zimm-Bragg theory provides an alternative and physically more realistic model. The Zimm-Bragg theory allowed perfect simulations of the DSC and CD experiments. In contrast, incorrect thermodynamic results were obtained with the two-state model. The Zimm-Bragg theory also provided a physically well-defined analysis of the cooperativity of the folding ⇄ unfolding equilibrium. The cooperative unfolding of Apo A-1 increased upon addition of lipids and decreased in detergent solution.

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.

Present day oceans are well ventilated, with the exception of mid-depth oxygen minimum zones (OMZs) under high surface water productivity, regions of sluggish circulation, and restricted marginal basins. In the Mesozoic, however, entire oceanic basins transiently became dysoxic or anoxic. The Cretaceous ocean anoxic events (OAEs) were characterised by laminated organic-carbon rich shales and low-oxygen indicating trace fossils preserved in the sedimentary record. Yet assessments of the 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 have been studied thoroughly. Their implications for constraining past bottom-water oxygenation are addressed in this review. We compared OMZ sediments from the Peruvian upwelling with deposits of the late Cenomanian OAE 2 from the north-west African shelf. Holocene laminated sediments are encountered at bottom-water oxygen levels of < 7 μmol kg−1 under the Peruvian upwelling and < 5 μmol kg−1 in California Borderland basins and the Pakistan Margin. Seasonal to decadal changes of sediment input are necessary to create laminae of different composition. However, bottom currents may shape similar textures that are difficult to discern from primary seasonal laminae. The millimetre-sized trace fossil Chondrites was commonly found in Cretaceous strata and Recent oxygen-depleted environments where its diameter increased with oxygen levels from 5 to 45 μmol kg−1. Chondrites has not been reported in Peruvian sediments but centimetre-sized crab burrows appeared around 10 μmol kg−1, which may indicate a minimum oxygen value for bioturbated Cretaceous strata. Organic carbon accumulation rates ranged from 0.7 and 2.8 g C cm−2 kyr−1 in laminated OAE 2 sections in Tarfaya Basin, Morocco, matching late Holocene accumulation rates of laminated Peruvian sediments under Recent oxygen levels below 5 μmol kg−1. Sediments deposited at > 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 the absence of seasonal laminations and under conditions of low burial diagenesis, this relationship may facilitate quantitative estimates of palaeo-oxygenation. 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.

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 …

An important tool for deep-sea temperature reconstruction is Mg/Ca paleothermometry applied to benthic foraminifera. Foraminifera of the genus Melonis appear to be promising candidates for temperature reconstructions due to their wide geographical and bathymetric distribution, and their infaunal habitat, which was suggested to reduce secondary effects from carbonate ion saturation (Δ[CO3 2−]). Here, we make substantial advances to previous calibration efforts and present new multi-lab Mg/Ca data for Melonis barleeanum and Melonis pompilioides from more than one hundred core top samples spanning in situ bottom temperatures from −1 to 16 °C, coupled with morphometric analyses of the foraminifer tests. Both species and their morphotypes seem to have a similar response of Mg/Ca to growth temperature. Compilation of new and previously published data reveals a linear dependence of temperature on Mg/Ca, with a best fit of Mg/Ca (mmol/mol) = 0.113 ± 0.005 ∗ BWT (°C) + 0.792 ± 0.036 (r2 = 0.81; n = 120; 1σ SD). Salinity, bottom water Δ[CO3 2−], and varying morphotypes have no apparent effect on the Mg/Ca-temperature relationship, but pore water Δ[CO3 2−] might have had an influence on some of the samples from the tropical Atlantic.

Environmental histories that span the last full glacial cycle and are representative of regional change in Australia are scarce, hampering assessment of environmental change preceding and concurrent with human dispersal on the continent ca. 47,000 years ago. Here we present a continuous 150,000-year record offshore south-western Australia and identify the timing of two critical late Pleistocene events: wide-scale ecosystem change and regional megafaunal population collapse. We establish that substantial changes in vegetation and fire regime occurred ∼70,000 years ago under a climate much drier than today. We record high levels of the dung fungus Sporormiella, a proxy for herbivore biomass, from 150,000 to 45,000 years ago, then a marked decline indicating megafaunal population collapse, from 45,000 to 43,100 years ago, placing the extinctions within 4,000 years of human dispersal across Australia. These findings rule out climate change, and implicate humans, as the primary extinction cause., Megafaunal extinction in Australia has been attributed to both climate change and human causation. Here, van der Kaars et al. present a 150,000 year record offshore southwest Australia in which they refine the timing and nature of regional ecosystem changes and megafaunal population collapse.

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 transition from benthos to plankton requires multiple adaptations, yet so far it remains unclear how these are acquired in the course of the transition. To investigate this process, we analyzed the genetic diversity and distribution patterns of a group of foraminifera of the genus Bolivina with a tychopelagic mode of life (same species occurring both in benthos and plankton). We assembled a global sequence data set for this group from single-cell DNA extractions and occurrences in metabarcodes from pelagic environmental samples. The pelagic sequences all cluster within a single monophyletic clade within Bolivina. This clade harbors three distinct genetic lineages, which are associated with incipient morphological differentiation. All lineages occur in the plankton and benthos, but only one lineage exhibits no limit to offshore dispersal and has been shown to grow in the plankton. These observations indicate that the emergence of buoyancy regulation within the clade preceded the evolution of pelagic feeding and that the evolution of both traits was not channeled into a full transition into the plankton. We infer that in foraminifera, colonization of the planktonic niche may occur by sequential cooptation of independently acquired traits, with holoplanktonic species being recruited from tychopelagic ancestors

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.

Paleoenvironmental studies and climate models demonstrate that fl uvial runoff and moisture availability in the Caribbean hinterland react very sensitively to climatic variations. Late Pleistocene and Holocene climate records document pronounced dry and wet periods over tropical South America mainly caused by shifts of the Intertropical Convergence Zone (ITCZ). However, forcing mechanisms for changes in the ITCZ position remain controversial. Here we present high-resolution foraminiferal Ba/Ca and δ18Oseawater records from a core located within the Orinoco River outfl ow documenting abrupt hydrological changes in the Orinoco catchment area during the deglacial and Holocene. Our data, obtained from the surface-dwelling foraminifera Globigerinoides ruber (pink), show an abrupt increase in Ba/ Ca ratios in the early Holocene, starting ~600 yr after the end of the Younger Dryas (YD) cold interval at ca. 10.8 ka and suggesting a massive reorganization of moisture sources in northern South America. In contrast, the salinity dependent δ18Oseawater from the same samples shows a gradual decrease starting at the end of the YD. The offset of our Ba/Ca peak excludes meltwater release in conjunction with the northern Andean glacier retreat well before the end of the YD as a forcing mechanism. We suggest that the Ba/Ca record documents an abrupt increase in Ba-rich waters of a northern Andean source caused by the insolation-driven shift of the ITCZ and/or enhanced monsoon activity.

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.

Past river run-off is an important measure for the continental hydrological cycle and the assessment of freshwater input into the ocean. However, paleosalinity reconstructions applying different proxies in parallel often show offsets between the respective methods. Here, we compare the established foraminiferal Ba/Ca and View the MathML source salinity proxies for their capability to record the highly seasonal Orinoco freshwater plume in the eastern Caribbean. For this purpose we obtained a data set comprising Ba/Ca and View the MathML source determined on multiple species of planktonic foraminifera from core tops distributed around the Orinoco River mouth. Our findings indicate that interpretations based on either proxy could lead to different conclusions. In particular, Ba/Ca and View the MathML source diverge in their spatial distribution due to different governing factors. Apparently, the Orinoco freshwater plume is best tracked by Ba/Ca ratios of G. ruber (pink and sensu lato morphotypes), while View the MathML source based on the same species is more related to the local precipitation-evaporation balance overprinting the riverine freshwater contribution. Other shallow dwelling species (G. sacculifer, O. universa) show a muted response to the freshwater discharge, most likely due to their ecological and habitat preferences. Extremely high Ba/Ca ratios recorded by G. ruber are attributed to Ba2+-desorption from suspended matter derived from the Orinoco. Samples taken most proximal to the freshwater source do not show pronounced Ba/Ca or View the MathML source anomalies. Here, the suspension loaded freshwater lid developing during maximum discharge suppresses foraminiferal populations. Both proxies are therefore biased towards dry season conditions at these sites, when surface salinity is only minimally reduced.

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 formation of mud volcanoes in the Gulf of Cadiz is closely linked to diapirism in the deep subsurface. The Mercator mud volcano (MMV) is a rare example where diapiric emplacement, in addition to being key for upward fluid migration, is also an important zone for fluid and mineral diagenesis. The most intriguing findings in the near-surface muds of the MMV are extremely high salinities of up to 5.2 M of NaCl from diapiric and evaporitic halite dissolution and the occurrence of authigenic gypsum and anhydrite crystals, both of which have not been observed to date in the Gulf of Cadiz. Employing a thermodynamic model we elucidate how the interplay of temperature pulses, strong salinity gradients, and fluid flow dynamically drive mineral dissolution and re-formation. The strong increase in salinity in the pore fluids has important implications for thermodynamic equilibria by significantly lowering the activity of water, thereby raising the gypsum–anhydrite transition zone from >1 km to about 400 m sediment depth at the MMV. This transition is further shifted to immediately below the seafloor during intervals of active mud and fluid expulsion when the MV surface temperature is heated up to at least 30 °C. As a consequence, precipitation of authigenic gypsum near the sediment surface (1–2 mbsf) has been linked to the dissolution of evaporites below the MMV. More precisely, the mechanisms generating supersaturation in the ascending gypsum-saturated MMV fluids are (1) the slow and constant cooling of these fluids along the geothermal gradient during their ascent leading to formation of ubiquitous micro-crystals and (2) the more rapid cooling after a heat pulse or transport from greater and warmer depth during an active mud volcano phase leading to the precipitation of cm-scale gypsum crystals or even fist-size concretions. The MMV fluids approaching the salt diapir from farther below have experienced a genesis similar to those of other mud volcanoes in the Gulf of Cadiz located above deep-rooted faults. These processes include clay mineral dewatering, thermogenic degradation of organic matter and deep high-temperature leaching of terrigenous sediments or continental crust.

Thermally-induced protein unfolding is commonly described with the two-state model. This model assumes only two types of protein molecules in solution, the native (N) and the denatured, unfolded (U) protein. In reality, protein unfolding is a multistep process, even if intermediate states are only sparsely populated. As an alternative approach we explore the Zimm–Bragg theory, originally developed for theα-helix-to-random coil transition of synthetic polypeptides. The theory includes intermediate structures with concentrations determined by the cooperativity of the unfolding reaction. We illustrate the differences between the two-state model and the Zimm–Bragg theory with measurements of apolipoprotein A-1 and lysozyme by differential scanning calorimetry (DSC) and CD spectroscopy. Nine further protein examples are taken from the literature. The Zimm–Bragg theory provides a perfect fit of the calorimetric unfolding transitions for all proteins investigated. In contrast, the transition curves and enthalpies predicted by the two-state model differ considerably from the experimental results. Apolipoprotein A-1 is ~50%α-helical at ambient temperature and its unfolding follows the classicalα-helix-to-random coil equilibrium. The unfolding of proteins with littleα-helix content, such as lysozyme, can also be analyzed with the Zimm–Bragg theory by introducing the concept of ‘folded’ and ‘unfolded’ peptide units assuming an average unfolding enthalpy per peptide unit. DSC is the method of choice to measure the unfolding enthalpy,$\Delta H_{\rm exp} ^0 $, but CD spectroscopy in combination with the two-state model is often used to deduce the unfolding enthalpy. This can lead to erroneous result. Not only are different enthalpies required to describe the CD and DSC transition curves but these values deviate distinctly from the experimental result. In contrast, the Zimm–Bragg theory predicts the DSC and CD unfolding transitions with the same set of parameters.

Nat. Med. 21, 140–149 (2015); published online 12 January 2015; corrected after print 19 November 2015 In the version of this article initially published, the article number in reference 13 is incorrectly stated as '100ra190' and should be '100ra90'. The error has been corrected in the HTML and PDF versions of the article.

Static and dynamic light scattering were employed to determine simultaneously the average relative molecular mass, Mr, and the average hydrodynamic radius, Rh, of protein molecules. The new method was applied to the association-dissociation equilibrium of apolipoprotein A-1 (Apo A-1) and its thermal unfolding. As a control, lysozyme was measured as a nonassociating protein. Apo A-1 forms oligomers as a function of concentration and temperature, and the equilibrium can be described by a cooperative association model, consisting of a nucleation step and a growth step. At concentrations of 1 and 2.7 mg/mL, the Apo A-1 solution contained mainly monomers and octamers, with intermediates occurring at very low concentrations. Oligomer formation was maximal at 22 °C and was characterized by a temperature-dependent association constant. The cooperative association model allows the quantitative analysis of both the average relative molecular mass, Mr, and the average hydrodynamic radius, Rh, with the same set of model parameters which, in turn, are also applicable to analytical ultracentrifugation experiments. The light scattering experiments were reversible as long as the Apo A-1 solution was not heated above 60 °C.