Description: Available online 27 December 2012 Publication year: 2012 Source: Palaeogeography, Palaeoclimatology, Palaeoecology In the Late Triassic (~ 235–201.3 Ma) scleractinian corals and hypercalcified sponges built large, diverse reef ecosystems, the most famous of which are the Dachstein reefs. This study presents a depth transect along an Upper Triassic (lower Rhaetian) Dachstein reef from the Gosausee margin of the Dachsteingebirge (Gosau, Austria). The Gosausee microbial-sponge-coral reef is a complete barrier reef with an almost continuous fore reef to lagoon transect preserved (a very rare occurrence for the Triassic), and thus provides a window into depth zonation of Dachstein-type reef facies and biotic succession. The Gosausee reef facies exhibit strong depth control and five classic reef facies or zones are identified: the fore reef, reef front, reef crest, back reef, and lagoon facies. Thin, rare microbial fabrics and a high abundance of fine-grained, mud-rich skeletal wackestones (transported reef debris) characterize the deepest fore reef. As the reef shallows, muddy sediments decrease in abundance and are replaced by microbial fabrics, corals, and cements. Abundant sponges, microbial crusts, and thick, marine cements typify the reef crest, whereas microbialite-coated phaceloid corals are dominant in the back reef facies. Heavily cemented oncoids or microbial-sponge bindstones are characteristic of the lagoon. Based on their compositional and biotic similarities, the Gosausee reef was likely part of the same barrier reef systems as the source reef for the Gosaukamm reef breccia (one of the classic Norian–Rhaetian Dachstein reefs). The reef zones of the Gosausee margin can be used to interpret the depth or reef zone of less well preserved reef fragments, can inform models of community ecology and niche utilization in the Late Triassic, and highlight the need for additional research into the environmental factors that controlled biotic distribution in Upper Triassic reefs. Highlights ► Gosausee reef (lower Rhaetian, Triassic) is a microbial-sponge-coral barrier reef. ► Reef transect through fore reef, reef front, reef crest, back reef, and lagoon. ► Deep zones have abundant muddy reef debris but thin, rare microbial fabrics. ► Shallow reef zones have thick microbial fabrics, cements, and bioconstructors. ► Sponges favor the crest and lagoon; corals prefer the back reef and reef front.

Description: Available online 28 December 2012 Publication year: 2012 Source: Palaeogeography, Palaeoclimatology, Palaeoecology The trace fossils Alcyonidiopsis isp., Chondrites isp. (small and large), Palaeophycus isp., Planolites isp., Taenidium isp . , Thalassinoides isp., Zoophycos isp., and unnamed small spreite burrow structures have been found in the Cenomanian–Turonian sediments in the Rybie section. They show significant stratigraphic variations in respect to the Bonarelli Level. In the Cenomanian, from the base of the section up to just below the Bonarelli Level (the „fucoid marl” in local lithostratigraphy), a decrease in diversity and abundance of trace fossils and benthic foraminifers is present and related mainly to decreasing benthic food levels. Oxygenation changes have comparatively minor incidence, but at least three thin anoxic layers occur about 2 m below the Bonarelli Level. The Bonarelli Level shows the at least episodically anoxic sedimentation. In the Turonian part, only small Chondrites isp. and Planolites isp. rarely occur. The burial of organic matter and probably benthic food content was extremely low as revealed by red marls. A gradual recovery of environmental conditions is marked by an increase in the diversity and abundance of trace fossils and benthic foraminifers by the Turonian, when grey marls (Żegocina Marl) accumulated above the red marls. The trends in ichnological record are confirmed by data on benthic foraminifers. Highlights ► Deep-sea sediments Cenomanian–Turonian sediments are strongly bioturbated. ► Trace fossil diversity and abundance fluctuate in the Bonarelli Level at Rybie. ► The fluctuations correspond to changes of benthic foraminifers. ► The data point to trophic level and oxygenation of pore waters changes.

Description: Available online 28 December 2012 Publication year: 2012 Source: Palaeogeography, Palaeoclimatology, Palaeoecology Dinoflagellate cyst (dinocyst), coccolith and planktic foraminiferal assemblages from a core in the western Iceland Sea were used to reconstruct and compare the surface ocean developments of the Holocene and the Last Interglacial (Marine Isotopic Stage or MIS 5e). While increasing subpolar planktic foraminifers from ~ 10 ka indicate subsurface warming peaking around 7.5 ka, the dinocyst data suggest that the uppermost ocean remained dominated by cold waters until ~ 6.5 ka. A reduced advection of cold polar waters through the East Greenland/East Icelandic Current thereafter entailed warmest and most saline Holocene conditions between 6.5 and 5 ka, in turn followed by a general cooling trend. By contrast, both planktic foraminifers and dinocysts show an increased presence of Atlantic (-type) waters from ~ 122 ka onward resulting in a MIS 5e thermal optimum around 120.5 ka. Nonetheless, occasional freshwater input from melting drift ice created stratified but also seasonally variable conditions during this first half of MIS 5e. This stratification signature disappeared at ~ 120 ka when a marked repositioning of the oceanographic fronts occurred. Slightly colder conditions are indicated by both phyto- and zooplankton from there on until the end of MIS 5e around ~ 117 ka. A late MIS 5e cooling at the Iceland Plateau is opposite to a late MIS 5e optimum observed in the eastern Nordic seas. This regional difference is likely explained by various feedback mechanisms following the major reorganisation of the oceanic fronts at ~ 120 ka. The Holocene and MIS 5e interglacial variability is not reflected in the (quasi-monospecific) coccolith assemblages and illustrates the low sensitivity of living coccolithophore communities to subtle temperature changes in the low-temperature regions of the Nordic seas. Overall, quite different surface water properties appear to have characterised both interglacial intervals, with a higher share of warm, Atlantic elements in the planktic communities during MIS 5e. This suggests a higher contribution of Atlantic waters in the southwestern Nordic seas probably due to a more northward expansion of the Irminger Current under weakened polar East Greenland/East Icelandic currents. Such a reduced influence of polar waters in the southwestern Nordic seas may thus explain other evidence for relatively warm conditions in MIS 5e all around southern Greenland. Highlights ► the Nordic seas surface ocean development differs for the Holocene and MIS 5e ► a significant repositioning of the oceanographic fronts occurred around 120 ka ► increased Atlantic components in the W Iceland Sea suggest a weakened MIS 5e EGC

Description: Available online 28 December 2012 Publication year: 2012 Source: Palaeogeography, Palaeoclimatology, Palaeoecology Integrated high resolution data from calcareous plankton assemblages (foraminifera and nannofossils) together with geochemical and mineralogical investigations have been collected at the on-land Montalbano Jonico section (southern Italy) in order to reconstruct the paleoenvironmental changes through Marine Isotope Stages (MIS) 23-37. Time-series analysis on Globigerina bulloides and Cassidulina carinata δ 18 O records and on selected calcareous plankton proxies mainly revealed the occurrence of precession and obliquity forcing. The deposition of sapropel layers, which are interbedded in the Montalbano Jonico section, was driven by water column stratification (insolation cycle i-104) and enhanced sea surface water productivity (insolation cycle i-112, i-102 and i-86). Different paleoenvironmental conditions mark the sedimentary evolution of the section. From 1240 to 1082 ka (MIS 37 – MIS 32), high percentage abundances of warm and oligotrophic planktonic foraminifera and calcareous nannofossil taxa indicate the establishment of oligotrophic and stratified surface water conditions. A key paleoenvironmental change occurred during MIS 31 (from about 1080 to 1065 ka), which was a very warm interglacial characterized by an increase of tropical-subtropical ( Globigerinoides ruber group and Globigerinoides trilobus ) and low salinity ( Braarudosphaera bigelowii ) sea surface water taxa. During this interval, more humid climate conditions coupled with changes in local paleomorphology may have triggered a higher and unusual freshwater input and the creation of a new entry point for sediment supply into the basin from a different drainage area. From about 1065 to 1010 ka (MIS 30- MIS 29), a cool and dry climate prevailed in the circum-Mediterranean area during a time of precession maxima. This favored lowered sea surface temperatures and an increase of polar-water Neogloboquadrina pachyderma left coiling . There are also indications of a reduction of the terrigenous input from the new source area. From 1010 ka upward (MIS 28-MIS 23), the higher abundances of Globigerina bulloides, Turborotalita quinqueloba and Calciosolenia spp. indicate enhanced productivity conditions probably related to high turbidity of sea surface waters triggered by a more conspicuous sediment input from land. Analysis of the long-term trends in the multiproxy patterns suggests that the major paleoenvironmental changes occurred as a consequence of the combined effect of orbitally-controlled global climate and regional processes. Highlights ► We investigate the on-land Montalbano Jonico section (Italy) through MIS 23-37. ► We adopt a mutiproxy approach to unravel complex paleoenvironmental changes. ► The paleoenvironmental changes are influenced by global climate and local tectonic. ► Calcareous plankton is controlled by nutrients, salinity and water column structure. ► Time-series analysis reveals the occurrence of precession and obliquity forcing.

Description: Available online 28 December 2012 Publication year: 2012 Source: Palaeogeography, Palaeoclimatology, Palaeoecology The high-resolution, multi-proxy investigation of microfossil and isotopic data from Shatsky Rise (ODP Site 1209B, NW Pacific Ocean) is presented to evaluate the potential of calcareous nannofossil assemblages as dissolution and paleoproductivity proxies over the last 450 ka. To identify the best nannofossil index to evaluate dissolution (in particular, under polarized light microscope), we calculate and compare the different nannofossil and planktonic foraminiferal dissolution-indices from our original dataset. The results demonstrate that the most reliable and reproducible nannofossil dissolution index is the Nannofossil Dissolution Index (NDI) proposed by Marino et al. (2009), particularly for records prior to 250 ka. The NDI data from the studied Site 1209B represent evidence of preservation maxima mainly during deglaciations, whereas dissolution peaks are recorded at the onset of glacial phases or during severe interglacials. These fluctuations are demonstrated to be basin-wide features in the Pacific. The synchronous timing in the fluctuations of the preservation indices, which consistently lagged behind the oxygen isotope cycles, clearly demonstrates the basin-wide changes in the ocean chemistry during the glacial-interglacial transitions. The Mid-Brunhes Dissolution Event, which was recorded in the Western Pacific at depths below the lysocline at the Marine Isotope Stage (MIS) 11, is not detectable at our relatively shallower site. At the studied site, the intervals of high productivity generally coincide with the time of good preservation and light carbon-isotope values and vice versa . Therefore, carbonate undersaturation and changes in ocean chemistry (carbonate ion concentration) rather than the variations in the organic carbon flux appear to have controlled the pattern of CaCO 3 preservation. In addition to the characterization of the dissolution proxies, changes in the calcareous nannofossil assemblages were used to evaluate the primary productivity fluctuations at the mid-latitudes of the NW Pacific over the last 450 ka. The results highlight a general decrease of paleoproductivity during the entire time period as well as shorter glacial/interglacial fluctuations from the base-core upwards. We interpret these features to be variations in the thermocline and nutricline dynamics related to the northward migration of the Kuroshio Extension, which was triggered by the Mid-Brunhes Event and may have caused deepening of the thermocline/nutricline at the site. The spectral and wavelet analyses performed on the microfossil database prove that the variations in paleoproductivity and carbonate dissolution over the last 450 ka were primarily driven by the glacial-interglacial variability (100 ka periodicity) and by the obliquity-controlled changes. Highlights ► High-resolution and multiproxy investigation of microfossil and isotopic data ► Significance and reliability of preservation nannofossil indices ► Comparison among nannofossil and planktonic foraminiferal dissolution-indices ► Paleoproductivity changes through nannofossil and isotopic data in the last 450ka ► Relationship among dissolution, paleoproductivity and glacial-interglacial cycles

Description: Available online 28 December 2012 Publication year: 2012 Source: Palaeogeography, Palaeoclimatology, Palaeoecology A critical need exists for quantitative reconstructions of long-term El Niño Southern Oscillation (ENSO) variability in the eastern tropical Pacific. Presented here is a method to quantitatively estimate past changes in 1) the seasonal amplitude of sea surface temperature (SST) in the Peruvian coastal upwelling system and 2) in the amplitude of ENSO-related interannual variability in the eastern tropical Pacific. The seasonal amplitude of SST (ΔT) along the length of the Peruvian coast is strongly correlated with the Niño1+2 index. We show that the frequency distribution of ΔT values provided by a modern sample of 13 Mesodesma donacium shells faithfully reflects modern ENSO variability at the regional scale, including the range of anomalies from La Niña to moderate El Niño events, but excludes extreme warm anomalies because of high shell mortality. We propose to use the frequency distribution of ENSO anomalies in paleoclimate studies for comparisons between shell records, coral records, and GCM simulations. Reconstruction uncertainties can be quantified using Monte Carlo simulations. The method presented here opens new perspectives for quantitative paleo-ENSO reconstructions in the Eastern Pacific since it may be applied with any mollusk species from Peru provided at least one annual cycle of SST is faithfully recorded by shell δ 18 O. Highlights ► The variance of the annual cycle of mollusk δ 18 O is an indicator of ENSO activity ► Coastal mollusk reconstructions in Peru reflect Niño1+2 index variability ► Frequency distributions of ENSO anomalies may be used for data-model comparisons

Description: Available online 28 December 2012 Publication year: 2012 Source: Palaeogeography, Palaeoclimatology, Palaeoecology Shallow marine ecosystems are experiencing significant environmental alterations as a result of changing climate and increasing human activities along coasts. Intensive urbanization of the southeast Florida coast and intensification of climate change over the last few centuries changed the character of coastal ecosystems in the semi-enclosed Biscayne Bay, Florida. In order to develop management policies for the Bay, it is vital to obtain reliable scientific evidence of past ecological conditions. The long-term records of subfossil diatoms obtained from No Name Bank and Featherbed Bank in Central Biscayne Bay, and from Card Sound Bank in the neighboring Card Sound, were used to study the magnitude of environmental change caused by climate variability and water management over the last ~ 600 years. Analyses of these records revealed that the major shifts in the diatom assemblage structures at No Name Bank occurred in 1956, at Featherbed Bank in 1966, and at Card Sound Bank in 1957. Smaller magnitude shifts were also recorded at Featherbed Bank in 1893, 1942, 1974 and 1983. Most of these changes coincided with severe drought periods that developed during cold phases of El Niño Southern Oscillation (ENSO), Atlantic Multidecadal Oscillation (AMO) and Pacific Decadal Oscillation (PDO), or when AMO was in warm phase and PDO was in the cold phase. Only the 1983 change coincided with an unusually wet period that developed during warm phases of ENSO and PDO. Quantitative reconstructions of salinity using the weighted averaging partial least squares (WA-PLS) diatom-based salinity model revealed a gradual increase in salinity at the three coring locations over the last ~ 600 years, which was primarily caused by continuously rising sea level and in the last several decades also by the reduction of the amount of freshwater inflow from the mainland. Concentration of sediment total nitrogen (TN), total phosphorus (TP) and total organic carbon (TOC) increased in the second half of the 20th century, which coincided with the construction of canals, landfills, marinas and water treatment plants along the western margin of Biscayne Bay. Increased magnitude and rate of the diatom assemblage restructuring in the mid- and late-1900s, suggest that large environmental changes are occurring more rapidly now than in the past. Highlights ► Climate change and anthropogenic drivers overwhelmed the Biscayne Bay resilience ► Intensification of ENSO, AMO and PDO restructured diatom assemblages in the bay ► Long-term salinity increase in the bay is primarily a result of rising sea level ► Urbanization of SE Florida contributed to salinity increase since the early 1900s

Description: Available online 28 December 2012 Publication year: 2012 Source: Palaeogeography, Palaeoclimatology, Palaeoecology The south-western edge of the Leitha Mountains in the southern Vienna Basin (Austria) exposes parts of an Upper Langhian (Middle Badenian) shallow water (〈 30 m) carbonate platform. The study of its ecospace comprises sedimentological and palaeontological data of four up to 36 m thick carbonate sections of the Müllendorf quarries which have been logged and subjected to detailed investigation and sampling. The sedimentary record is dominated by coralline algal debris sands which represent 7 distinct lithofacies (bioclastic coralline algal-mollusc facies, Hyotissa facies, Isognomon facies, coral facies, rhodolith facies, bryozoan facies). All these facies are described in detail in respect to lithology and biota and are palaeoecologically interpreted. Striking features of these limestone successions are periodical intercalations of coral- and mollusc-rich horizons. Their formation had been triggered by water turbidity and low amplitude changes in relative sea level. These relations are especially interesting as the platform carbonates formed at the northern edge of the Langhian Peri-Mediterranean reef belt. Water turbidity, as ecological master factor, and depth played the fundamental role in ecosystem and community expression within ecospace. The lateral distribution and the ecological relations between the various facies types allow proposing an ecospace-occupation model. Highlights ► We present a Langhian tropical shallow-water carbonate platform of the Vienna Basin. ► The platform reflects the northern edge of the Langhian Peri-Mediterranean reef belt. ► Water turbidity acted as ecological master factor in modulating the ecospace. ► An ecospace-occupation model for Miocene carbonate biofacies is presented. ► Cyclic sedimentary patterns point to low-amplitude sea-level fluctuations.

Description: Available online 28 December 2012 Publication year: 2012 Source: Palaeogeography, Palaeoclimatology, Palaeoecology Surface currents and sediment distribution of the SE South American upper continental margin are under influence of the South American Monsoon System (SAMS) and the Southern Westerly Wind Belt (SWWB). Both climatic systems determine the meridional position of the Subtropical Shelf Front (STSF) and probably also of the Brazil-Malvinas Confluence (BMC). We reconstruct the changing impact of the SAMS and the SWWB on sediment composition at the upper Rio Grande Cone off southern Brazil during the last 14 cal kyr combining sedimentological, geochemical, micropaleontological and rock magnetic proxies of marine sediment core GeoB 6211-2. Sharp reciprocal changes in ferri- and paramagnetic mineral content and prominent grain-size shifts give strong clues to systematic source changes and transport modes of these mostly terrigenous sediments. Our interpretations support the assumption that the SAMS over SE South America was weaker than today during most of the Late Glacial and entire Early Holocene, while the SWWB was contracted to more southern latitudes, resembling modern austral summer-like conditions. In consequence, the STSF and the BMC were driven to more southern positions than today's, favoring the deposition of Fe-rich but weakly magnetic La Plata River silts at the Rio Grande Cone. During the Mid Holocene, the northern boundary of the SWWB migrated northward, while the STSF reached its northernmost position of the last 14 cal kyr and the BMC most likely arrived at its modern position. This shift enabled the transport of Antarctic diatoms and more strongly magnetic Argentinean shelf sands to the Rio Grande Cone, while sediment contributions from the La Plata River became less important. During the Late Holocene, the modern El Niño Southern Oscillation set in and the SAMS and the austral tradewinds intensified, causing a southward shift of the STSF to its modern position. This reinforced a significant deposition of La Plata River silts at the Rio Grande Cone. These higher magnetic silts with intermediate Fe contents mirror the modern more humid terrestrial climatic conditions over SE South America. Highlights ► A sediment-core multi-proxy study off S Brazil covering last 14 kyr was performed ► Rock magnetic and element data reveal weathering conditions in the La Plata Basin ► Grain-size and diatom counts indicate source and trajectory of sediments ► Northward (southward) migration of the shelf front during the Mid (Late) Holocene ► First time considering paleoclimatic elements of SAMS / SWWB in closer conjunction

Description: Available online 27 December 2012 Publication year: 2012 Source: Palaeogeography, Palaeoclimatology, Palaeoecology We present the first 7500 year long multi-proxy record from a raised bog located at the southern Baltic coast, Poland. Testate amoebae, plant macrofossils, pollen and microscopic charcoal were used to reconstruct environmental changes in Pomerania (northern Poland, Kaszuby Lakeland) from a 7-m thick peat archive of Stążki bog dated 5500 BC–AD 1250. We obtained a record of proxies representing different spatial scales: regional vegetation changed simultaneously with local vegetation, and testate amoebae showed a pattern of change similar to that of pollen and plant macrofossils. On the basis of the combined proxies, we distinguished three hydroclimatic stages: moist conditions 5500–3450 BC, drier conditions with regionally increased fires up to 600 BC, and again moist conditions from 600 BC onward. During the drier interval, a first climatic shift to wetter conditions at 1700 BC is indicated by regional pollen as the replacement of Corylus by Carpinus , and locally by, e.g., the increase of Hyalosphenia elegans and mire plants such as Sphagnum sec. Cuspidata . Furthermore, we observed a correlation since 600 BC among the re-expansion of Carpinus (after a sudden decline ca. 950 BC), increased peat accumulation, increase of Hyalosphenia species, and fewer fires, suggesting lower evapotranspiration and a stable high water table in the bog. Fagus started to expand after AD 810 gradually replacing Carpinus , which was possibly due to a gradually more oceanic climate, though we cannot exclude human impact on the forests. Peat accumulation, determined by radiocarbon dating, varied with bog surface wetness. The hydroclimatic phases found in Stążki peatland are similar to moisture changes recorded in other sites from Poland and Europe. This is the first detailed record of hydroclimatic change during the Holocene in the southern Baltic region, so it forms a reference site for further studies on other southern Baltic bogs that are in progress. Highlights ► This is the first Holocene multi-proxy record from a southern-Baltic raised bog ► Testate amoebae, macrofossils and pollen revealed similar patterns ► Low water table associated with fires, supported inference of the climatic signal ► We recorded a response of the peatland to climatic transitions 3500 BC and 600 BC