Petrologic data from Site U1308 over the last three glaciations

A composite North Atlantic record from DSDP Site 609 and IODP Site U1308 spans the past 300,000 years and shows that variability within the penultimate glaciation differed substantially from that of the surrounding two glaciations. Hematite stained grains exhibit similar repetitive down-core variations within the Marine Isotope Stage (MIS) 8 and 4-2 intervals, but little cyclic variability within the MIS 6 section. There is also no petrologic evidence, in terms of detrital carbonate-rich (Heinrich) layers, for surging of the Laurentide Ice Sheet through the Hudson Strait during MIS 6. Rather, very high background concentration of ice-rafted debris (IRD) indicates near continuous glacial meltwater input that likely increased thermohaline disruption sensitivity to relatively weak forcing events, such as expanded sea ice over deepwater formation sites. Altered (sub)tropical precipitation patterns and Antarctic warming during high orbital precession and low 65° N summer insolation appears related to high abundance of Icelandic glass shards and southward sea ice expansion. Differing European and North American ice sheet configurations, perhaps aided by larger variations in eccentricity leading to cooler summers, may have contributed to the relative stability of the Laurentide Ice Sheet in the Hudson Strait region during MIS 6.

Clay mineral assemblages for the last 10 Ma off northeastern Australia

Clay mineral assemblages for the last 10 m.y. are described for Site 823, at 16°S in the Queensland Trough, to the northeast of Australia. Largely unaffected by diagenetic influences, these mostly express the evolution of northeastern Australian continental environments during the late Neogene: (1) beginning during the late Miocene at about 7.0 Ma is an increase of illite derived from rocky substrates at the expense of smectite from deeply weathered soils; this increase was the result of increasing aridity in the Australian interior and globally cooler temperatures, associated with increases in Antarctic glaciation; (2) concomitant and further increases of kaolinite fluxes to the Queensland Trough during the late Miocene-early Pliocene largely reflect an increase in rainfall in northeastern Australia; (3) increases in both soil- and rock-derived minerals probably intensified as a result of late Neogene uplift of the eastern highlands; (4) clay-mineral associations during the Pliocene and Pleistocene display minor variations only and probably resulted in part from differential settling and sea-level changes; (5) similar trends of clay-mineral variations occur at both ODP Site 823 and DSDP Site 588 (Lord Howe Rise). Less abundant kaolinite relative to illite at Site 588 nevertheless suggests a southward decrease of continental humidity and/or of the eastern highlands uplift; (6) influences of global climate and oceanic and atmospheric circulations on clay-mineral associations dominated during the late Miocene and were progressively replaced by influences of more regional environmental variations during the Pliocene and especially the Pleistocene.

Paleoenvironmental changes in the western Mediterranean since the last glacial maximum: High resolution multiproxy record from the Algero-Balearic basin

The present study uses a multiproxy approach in order to further understand the evolution of climate responses in the western Mediterranean as of the Last Glacial Maximum. Sediments from ODP Site 975 in the Algero-Balearic basin have been analysed at high resolution, both geochemically andmineralogicallly. The resulting data have been used as proxies to establish a sedimentary regime, primary marine productivity, the preservation of the proxies and oxygen conditions. Fluctuations in detrital element concentrations were mainly the consequence of wet/arid oscillations. Productivity has been established using Ba excess, according to which marine productivity appears to have been greatest during cold events Heinrich 1 and Younger Dryas. The S1 time interval was not as marked by increases in productivity as was the eastern Mediterranean. In contrast, the S1 interval was first characterized by a decreasing trend and then by a fall in productivity after the 8.2 ky BP dry-cold event. Since then productivity has remained low. Here we report that there was an important redox event in this basin, probably a consequence of the major oceanographic circulation change occurring in the western Mediterranean at 7.7 ky BP. This circulation change led to reventilation as well as to diagenetic remobilization of redox-sensitive elements and organic matter oxidation. Comparisons between our paleoceanographic reconstruction for this basin and those regarding other Mediterranean basins support the hypothesis that across the Mediterranean there were different types of responses to climate forcing mechanism. The Algero-Balearic basin is likely to be a key area for further understanding of the relationships between the North Atlantic and the eastern Mediterranean basins.

Sea surface temperature oscillations in southern Okinawa Trough during last 2700 years from ODP Hole 195-1202B

Most of the temperature reconstructions for the past two millennia are based on proxy data from various sites on land. Here we present a bidecadal resolution record of sea surface temperature (SST) in Southern Okinawa Trough for the past ca. 2700 years by analyzing tetraether lipids of planktonic archaea in the ODP Hole 1202B, a site under the strong influence of Kuroshio Current and East Asian monsoon. The reconstructed SST anomalies generally coincided with previously reported late Holocene climate events, including the Roman Warm Period, Sui-Tang dynasty Warm Period, Medieval Warm Period, Current Warm Period, Dark Age Cold Period and Little Ice Age. However, the Medieval Warm Period usually thought to be a historical analogue for the Current Warm Period has a mean SST of 0.6-0.8°C lower than that of the Roman Warm Period and Sui-Tang dynasty Warm Period. Despite an increase since 1850 AD, the mean SST in the 20th century is still within the range of natural variability during the past 2700 years. A close correlation of SST in Southern Okinawa Trough with air temperature in East China, intensity of East Asian monsoon and the El-Niño Southern Oscillation index has been attributed to the fluctuations in solar output and oceanic-atmospheric circulation.

On the improvement of urban regeneration processes from more than thirty years of rehabilitation experiences

At this moment of extended economic, social and environmental crisis within which new interventions on the consolidated city are being set out, it is essential to count on the acquired experience in urban rehabilitation processes that were carried out in Spain during the last thirty years. Despite the complexity of this kind of processes and the diversity of the situations and actions that happened, this paper addresses the analysis of common patterns in twenty urban rehabilitation experiences. Different stages of the processes were studied, from the management to the regenerated areas in order to ease the design of new intervention initiatives.

Emergence of the ZNF91 Krüppel-associated box-containing zinc finger gene family in the last common ancestor of anthropoidea.

The ZNF91 gene family, a subset of the Krüppel-associated box (KRAB)-containing group of zinc finger genes, comprises more than 40 loci; most reside on human chromosome 19p12-p13.1. We have examined the emergence and evolutionary conservation of the ZNF91 family. ZNF91 family members were detected in all species of great apes, gibbons, Old World monkeys, and New World monkeys examined but were not found in prosimians or rodents. In each species containing the ZNF91 family, the genes were clustered at one major site, on the chromosome(s) syntenic to human chromosome 19. To identify a putative "founder" gene, > 20 murine KRAB-containing zinc finger protein (ZFP) cDNAs were randomly cloned, but none showed sequence similarity to the ZNF91 genes. These observations suggest that the ZNF91 gene cluster is a derived character specific to Anthropoidea, resulting from a duplication and amplification event some 55 million years ago in the common ancestor of simians. Although the ZNF91 gene cluster is present in all simian species, the sequences of the human ZNF91 gene that confer DNA-binding specificity were conserved only in great apes, suggesting that there is not a high selective pressure to maintain the DNA targets of these proteins during evolution.

Variability of the ocean heat content during the last millennium - an assessment with the ECHO-g Model

Studies addressing climate variability during the last millennium generally focus on variables with a direct influence on climate variability, like the fast thermal response to varying radiative forcing, or the large-scale changes in atmospheric dynamics (e. g. North Atlantic Oscillation). The ocean responds to these variations by slowly integrating in depth the upper heat flux changes, thus producing a delayed influence on ocean heat content (OHC) that can later impact low frequency SST (sea surface temperature) variability through reemergence processes. In this study, both the externally and internally driven variations of the OHC during the last millennium are investigated using a set of fully coupled simulations with the ECHO-G (coupled climate model ECHAMA4 and ocean model HOPE-G) atmosphere-ocean general circulation model (AOGCM). When compared to observations for the last 55 yr, the model tends to overestimate the global trends and underestimate the decadal OHC variability. Extending the analysis back to the last one thousand years, the main impact of the radiative forcing is an OHC increase at high latitudes, explained to some extent by a reduction in cloud cover and the subsequent increase of short-wave radiation at the surface. This OHC response is dominated by the effect of volcanism in the preindustrial era, and by the fast increase of GHGs during the last 150 yr. Likewise, salient impacts from internal climate variability are observed at regional scales. For instance, upper temperature in the equatorial Pacific is controlled by ENSO (El Nino Southern Oscillation) variability from interannual to multidecadal timescales. Also, both the Pacific Decadal Oscillation (PDO) and the Atlantic Multidecadal Oscillation (AMO) modulate intermittently the interdecadal OHC variability in the North Pacific and Mid Atlantic, respectively. The NAO, through its influence on North Atlantic surface heat fluxes and convection, also plays an important role on the OHC at multiple timescales, leading first to a cooling in the Labrador and Irminger seas, and later on to a North Atlantic warming, associated with a delayed impact on the AMO.