Multi-specimen and multi-site calibration of Aleutian coralline algal Mg/Ca to sea surface temperature

Higher latitude oceanic and climatic reconstructions are needed to distinguish natural climate variability from anthropogenic warming in regions projected to experience significant increases in temperature during this century. Clathromorphum nereostra turn is a long-lived coralline alga abundant along the Aleutian archipelago that records seasonal to centennial fluctuations in seawater temperatures in its high-Mg calcite skeleton. Thus, C. nereostratum is an important proxy archive to reconstruct past seawater temperature variability in this data-poor subarctic region. Here, we measured magnesium to calcium ratios (Mg/Ca) by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) along the growth axis in six live-collected specimens from three islands in the Aleutian archipelago to assess Mg/Ca reproducibility and to calibrate algal Mg/Ca against modern gridded sea surface temperature (SST) data products. The master Mg/Ca SST transfer function, determined by averaging the algal Mg/Ca SST from each island (n = 6), resulted in a reconstruction error of +/-0.45 degrees C, a 31-46% reduction in error compared to the reconstruction error for a single alga. The master algal-SST record interpolated to monthly and annual resolution significantly varied with gridded SST data products (r(2) = 0.98, p < 0.0001, n = 517 and r(2) = .27, p < 0.0003, n = 44, respectively) for the period from 1960 to 2003. Therefore, coralline algal Mg/Ca-derived SST reconstructions record absolute changes in past SST variability in the Aleutian archipelago. The transfer functions developed here can be applied to Mg/Ca records generated from long-lived specimens of C. nereostra turn to reconstruct northern North Pacific and Bering Sea SST variability for the past several hundred years

Coralline alga reveals first marine record of subarctic North Pacific climate change

While recent changes in subarctic North Pacific climate had dramatic effects on ecosystems and fishery yields, past climate dynamics and teleconnection patterns are poorly understood due to the absence of century-long high-resolution marine records. We present the first 117-year long annually resolved marine climate history from the western Bering Sea/Aleutian Island region using information contained in the calcitic skeleton of the long-lived crustose coralline red alga Clathromorphum nereostratum, a previously unused climate archive. The skeletal δ18O-time series indicates significant warming and/or freshening of surface waters after the middle of the 20th century. Furthermore, the time series is spatiotemporally correlated with Pacific Decadal Oscillation (PDO) and tropical El Niño-Southern Oscillation (ENSO) indices. Even though the western Bering Sea/Aleutian Island region is believed to be outside the area of significant marine response to ENSO, we propose that an ENSO signal is transmitted via the Alaskan Stream from the Eastern North Pacific, a region of known ENSO teleconnections

North Pacific twentieth century decadal-scale variability is unique for the past 342 years

Reconstructed sea surface temperatures (SSTs) derived from Mg/Ca measurements in nine encrusting coralline algal skeletons from the Aleutian archipelago in the northernmost Pacific Ocean reveal an overall increase in SST from 1665 to 2007. In the Aleutian SST reconstruction, decadal-scale variability is a transient feature present during the 1700s and early 1800s and then fully emerging post-1950. SSTs vary coherently with available instrument records of cyclone variance and vacillate in and out of coherence with multicentennial Pacific Northwest drought reconstructions as a response to SST-driven alterations of storm tracks reaching North America. These results indicate that an influence of decadal-scale variability on the North Pacific storm tracks only became apparent during the midtwentieth century. Furthermore, what has been assumed as natural variability in the North Pacific, based on twentieth century instrumental data, is not consistent with the long-term natural variability evident in reconstructed SSTs predating the anthropogenic influence

Doing transnational family im Kontext von Flucht und Krisenmigration: Stand der Forschung

In den vergangenen Jahren ist die Zahl gewaltsam Vertriebener stetig gestiegen, und auch die Anzahl der Menschen, die in weiter entfernte Staaten fliehen, hat laut UNHCR weltweit stark zugenommen. In Deutschland wurden im Zeitraum von 2015 bis 2017 fast 1,4 Mio. Asylerstanträge gestellt, hauptsächlich von Menschen aus Syrien, Afghanistan, Irak sowie Eritrea. Aufgrund der Aktualität des Themas hat sich seit Kurzem eine eigen-ständige Forschung zu Flucht und Geflüchteten in Deutschland entwickelt, wobei sich die deutsche Forschungslandschaft über die Disziplinen hinweg vor allem auf die Themen Aufnahme und Teilhabe von Geflüchteten in Deutschland konzentriert. Bisher gibt es nur sehr wenige Arbeiten, die sich mit Familien von Geflüchteten auseinandersetzen, obwohl unbestritten ist, dass Familien sowohl für die Migrationsentscheidung als auch für die Integration und Teilhabe im Zielland eine wichtige Rolle spielen. In Vorbereitung auf eine eigene empirische Studie, die diese Forschungslücke schließen möchte, wurde das vorliegende Working Paper erstellt. Es fasst die internationale Literatur zu den Fragen nach der Entstehung, Beibehaltung und Veränderung von transnationalen Familien, den transnationalen Alltagspraktiken sowie Unterstützungsleistungen und den Konsequenzen von Transnationalität auf die Beziehungsstabilität und -qualität zwischen Partnern, Kindern und Eltern sowie deren (subjektivem) Wohlbefinden, Einstellungen und Geschlechterrollen zusammen. Das Working Paper versucht darüber hinaus, die Anschlussfähigkeit der vorliegenden Studien zu transnationalen Familien auf den Fluchtkontext herzustellen und Forschungslücken im Themenfeld transnationaler Familien und Fluchtmigration aufzuzeigen

Coralline algal Barium as indicator for 20th century northwestern North Atlantic surface ocean freshwater variability

During the past decades climate and freshwater dynamics in the northwestern North Atlantic have undergone major changes. Large-scale freshening episodes, related to polar freshwater pulses, have had a strong influence on ocean variability in this climatically important region. However, little is known about variability before 1950, mainly due to the lack of long-term high-resolution marine proxy archives. Here we present the first multidecadal-length records of annually resolved Ba/Ca variations from Northwest Atlantic coralline algae. We observe positive relationships between algal Ba/Ca ratios from two Newfoundland sites and salinity observations back to 1950. Both records capture episodical multi-year freshening events during the 20th century. Variability in algal Ba/Ca is sensitive to freshwater-induced changes in upper ocean stratification, which affect the transport of cold, Ba-enriched deep waters onto the shelf (highly stratified equals less Ba/Ca). Algal Ba/Ca ratios therefore may serve as a new resource for reconstructing past surface ocean freshwater changes

FAK acts as a suppressor of RTK-MAP kinase signalling in Drosophila melanogaster epithelia and human cancer cells

Receptor Tyrosine Kinases (RTKs) and Focal Adhesion Kinase (FAK) regulate multiple signalling pathways, including mitogen-activated protein (MAP) kinase pathway. FAK interacts with several RTKs but little is known about how FAK regulates their downstream signalling. Here we investigated how FAK regulates signalling resulting from the overexpression of the RTKs RET and EGFR. FAK suppressed RTKs signalling in Drosophila melanogaster epithelia by impairing MAPK pathway. This regulation was also observed in MDA-MB-231 human breast cancer cells, suggesting it is a conserved phenomenon in humans. Mechanistically, FAK reduced receptor recycling into the plasma membrane, which resulted in lower MAPK activation. Conversely, increasing the membrane pool of the receptor increased MAPK pathway signalling. FAK is widely considered as a therapeutic target in cancer biology; however, it also has tumour suppressor properties in some contexts. Therefore, the FAK-mediated negative regulation of RTK/MAPK signalling described here may have potential implications in the designing of therapy strategies for RTK-driven tumours

Multicentennial record of Labrador Sea primary productivity and sea-ice variability archived in coralline algal barium

Accelerated warming and melting of Arctic sea-ice has been associated with significant increases in phytoplankton productivity in recent years. Here, utilizing a multiproxy approach, we reconstruct an annually resolved record of Labrador Sea productivity related to sea-ice variability in Labrador, Canada that extends well into the Little Ice Age (LIA; 1646 AD). Barium-to-calcium ratios (Ba/Ca) and carbon isotopes (δ13C) measured in long-lived coralline algae demonstrate significant correlations to both observational and proxy records of sea-ice variability, and show persistent patterns of co-variability broadly consistent with the timing and phasing of the Atlantic Multidecadal Oscillation (AMO). Results indicate reduced productivity in the Subarctic Northwest Atlantic associated with AMO cool phases during the LIA, followed by a step-wise increase from 1910 to present levels—unprecedented in the last 363 years. Increasing phytoplankton productivity is expected to fundamentally alter marine ecosystems as warming and freshening is projected to intensify over the coming century

Modern rhodolith-dominated carbonates at Punta Chivato, Mexico

Rhodolith-dominated carbonate environments, characterized by high abundances of free-living coralline algae, have been described globally from a wide range of Recent and fossil shallow marine settings. In the present-day warm-temperate Gulf of California, Mexico, rhodolith-dominated systems are important contributors to carbonate production. One of the most prolific rhodolith factories is located on the Punta Chivato shelf, in the central Gulf of California, where due to a lack of input of terrigenous material from the arid hinterland, carbonate content averages 79%. Punta Chivato rhodoliths thrive above the shallow euphotic zone under normal saline, warm-temperate and meso- to eutrophic conditions. A detailed sedimentologic study combined with acoustic seafloor mapping indicates the presence of extensive rhodolith-dominated facies at subtidal water depth covering an area of \u3e17 km2. Additional facies, surrounding the rhodolith-dominated facies include a fine-grained molluscan, a transitional bivalve-rhodolith and a bivalve facies. While the Punta Chivato shelf yields average abundances of 38% rhodolith-derived coralline algal components in the gravel-sized sediment fraction, the rhodolith facies itself is characterized by more than 60% coralline algal components. Other important carbonate producers at Punta Chivato include bivalves (35%), bryozoa (11%) and gastropods (8%). The present study shows that acoustic sediment mapping yields highly resolved continuous coverage of the seafloor and can distinguish modern rhodolith facies from surrounding sediment. This has important implications for quantifying rhodolith-dominated settings globally, as well as for ecological and conservation studies. © Publications Scientifiques du Muséum national d\u27Histoire naturelle, Paris

A Drosophila Model for EGFR-Ras and PI3K-Dependent Human Glioma

Gliomas, the most common malignant tumors of the nervous system, frequently harbor mutations that activate the epidermal growth factor receptor (EGFR) and phosphatidylinositol-3 kinase (PI3K) signaling pathways. To investigate the genetic basis of this disease, we developed a glioma model in Drosophila. We found that constitutive coactivation of EGFR-Ras and PI3K pathways in Drosophila glia and glial precursors gives rise to neoplastic, invasive glial cells that create transplantable tumor-like growths, mimicking human glioma. Our model represents a robust organotypic and cell-type-specific Drosophila cancer model in which malignant cells are created by mutations in signature genes and pathways thought to be driving forces in a homologous human cancer. Genetic analyses demonstrated that EGFR and PI3K initiate malignant neoplastic transformation via a combinatorial genetic network composed primarily of other pathways commonly mutated or activated in human glioma, including the Tor, Myc, G1 Cyclins-Cdks, and Rb-E2F pathways. This network acts synergistically to coordinately stimulate cell cycle entry and progression, protein translation, and inappropriate cellular growth and migration. In particular, we found that the fly orthologs of CyclinE, Cdc25, and Myc are key rate-limiting genes required for glial neoplasia. Moreover, orthologs of Sin1, Rictor, and Cdk4 are genes required only for abnormal neoplastic glial proliferation but not for glial development. These and other genes within this network may represent important therapeutic targets in human glioma