CHIRONOMID FAUNA OF CENTRAL YAKUTIAN LAKES (NORTHERN RUSSIA) IN PALAEOENVIRONMENTAL INVESTIGATION

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CHIRONOMID FAUNA OF CENTRAL YAKUTIAN LAKES (NORTHERN RUSSIA) IN PALAEOENVIRONMENTAL INVESTIGATION

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Nuclear localised more sulphur accumulation1 epigenetically regulates sulphur homeostasis in Arabidopsis thaliana

Sulphur (S) is an essential element for all living organisms. The uptake, assimilation and metabolism of S in plants are well studied. However, the regulation of S homeostasis remains largely unknown. Here, we report on the identification and characterisation of the more sulphur accumulation1 (msa1-1) mutant. The MSA1 protein is localized to the nucleus and is required for both S adenosylmethionine (SAM) production and DNA methylation. Loss of function of the nuclear localised MSA1 leads to a reduction in SAM in roots and a strong S-deficiency response even at ample S supply, causing an over- accumulation of sulphate, sulphite, cysteine and glutathione. Supplementation with SAM suppresses this high S phenotype. Furthermore, mutation of MSA1 affects genome-wide DNA methylation, including the methylation of S-deficiency responsive genes. Elevated S accumulation in msa1-1 requires the increased expression of the sulphate transporter genes SULTR1;1 and SULTR1;2 which are also differentially methylated in msa1-1. Our results suggest a novel function for MSA1 in the nucleus in regulating SAM biosynthesis and maintaining S homeostasis epigenetically via DNA methylation

Perspectives and Integration in SOLAS Science

Why a chapter on Perspectives and Integration in SOLAS Science in this book? SOLAS science by its nature deals with interactions that occur: across a wide spectrum of time and space scales, involve gases and particles, between the ocean and the atmosphere, across many disciplines including chemistry, biology, optics, physics, mathematics, computing, socio-economics and consequently interactions between many different scientists and across scientific generations. This chapter provides a guide through the remarkable diversity of cross-cutting approaches and tools in the gigantic puzzle of the SOLAS realm. Here we overview the existing prime components of atmospheric and oceanic observing systems, with the acquisition of ocean–atmosphere observables either from in situ or from satellites, the rich hierarchy of models to test our knowledge of Earth System functioning, and the tremendous efforts accomplished over the last decade within the COST Action 735 and SOLAS Integration project frameworks to understand, as best we can, the current physical and biogeochemical state of the atmosphere and ocean commons. A few SOLAS integrative studies illustrate the full meaning of interactions, paving the way for even tighter connections between thematic fields. Ultimately, SOLAS research will also develop with an enhanced consideration of societal demand while preserving fundamental research coherency. The exchange of energy, gases and particles across the air-sea interface is controlled by a variety of biological, chemical and physical processes that operate across broad spatial and temporal scales. These processes influence the composition, biogeochemical and chemical properties of both the oceanic and atmospheric boundary layers and ultimately shape the Earth system response to climate and environmental change, as detailed in the previous four chapters. In this cross-cutting chapter we present some of the SOLAS achievements over the last decade in terms of integration, upscaling observational information from process-oriented studies and expeditionary research with key tools such as remote sensing and modelling. Here we do not pretend to encompass the entire legacy of SOLAS efforts but rather offer a selective view of some of the major integrative SOLAS studies that combined available pieces of the immense jigsaw puzzle. These include, for instance, COST efforts to build up global climatologies of SOLAS relevant parameters such as dimethyl sulphide, interconnection between volcanic ash and ecosystem response in the eastern subarctic North Pacific, optimal strategy to derive basin-scale CO2 uptake with good precision, or significant reduction of the uncertainties in sea-salt aerosol source functions. Predicting the future trajectory of Earth’s climate and habitability is the main task ahead. Some possible routes for the SOLAS scientific community to reach this overarching goal conclude the chapter

Accretion, structure and hydrology of intermediate spreading-rate oceanic crust from drillhole experiments and seafloor observations

Downhole measurements recorded in the context of the Ocean Drilling Program in Hole 504B, the deepest hole drilled yet into the oceanic crust, are analyzed in terms of accretion processes of the upper oceanic crust at intermediate spreading-rate. The upper part of the crust is found to support the non steady-state models of crustal accretion developed from seafloor observations (Kappel and Ryan, 1986; Gente, 1987). The continuous and vertical nature of borehole measurements provides stratigraphic and structural data that cannot be obtained solely from seafloor studies and, in turn, these models define a framework to analyze the structural, hydrological, and mineralogical observations made in the hole over the past decade.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43190/1/11001_2005_Article_BF01204282.pd

Holocene Cyclic Records of Ice-Rafted Debris and Sea Ice Variations on the East Greenland and Northwest Iceland Margins

The dynamics of the Greenland Ice Sheet and drift of sea ice from the Arctic Ocean reaching Denmark Strait are poorly constrained. We present data on the provenance of Fe oxide detrital grains from two cores in the Denmark Strait area and compare the Fe grain source data with other environmental proxies in order to document the variations and potential periodicities in ice-rafted debris delivery during the Holocene. Based on their Fe grain geochemistry, the sediments can be traced to East Greenland sources and to more distal sites around the Arctic Basin. On the Holocene time scales of the two cores, sea ice biomarker (IP25) data, and quartz weight percent reveal positive associations with T°C and inverse associations with biogenic carbonate wt%. Trends in the data were obtained from Singular Spectrum Analysis (SSA), and residuals were tested for cyclicity. Trends on the environmental proxies explained between 15 and 90% of the variance. At both sites the primary Fe grain sources were from Greenland, but significant contributions were also noted from Banks Island and Svalbard. There is a prominent cyclicity of 800 yrs as well as other less prominent cycles for both Greenland and arctic sources. The Fe grain sources from Greenland and the circum-Arctic Ocean are in synchronization, suggesting that the forcings for these cycles are regional and not local ice sheet instabilities

Geochemical and petrological studies of lavas, pyroclastica and associated xenoliths from the Christiana Islands, Aegean Sea

Geochemical and petrological investigations of the volcanic islands of Christiana proved their genetic connection with the calc-alkaline volcanism of the Santorini group and the submarine Kolombos volcano. The lavas of Christiana range from andesite to dacite while pumice is of rhyolithic chemistry. Rather constant K/Rb ratios indicate consanguine magmas. Increased Ni, Cr and Mg concentrations in several lavas indicate a certain admixture of peridotite material to the calc-alkaline magmas. Xenoliths found below an autochthonous pumice layer prove penetration of granites, phyllites and limestone by the rising magma. The geochemical investigations support a subduction type origin of the volcanic material of the Christiana Islands

Relationships among active layer soil properties and vegetation across a latitudinal gradient in Victoria Land, Continental Antarctica

Through the cooperative efforts of the Scientific Committee on Antarctic Research (SCAR) Evolution and Biodiversity in Antarctica (EBA) Project and the Latitudinal Gradient Project (LGP), a monitoring network was established in Victoria Land in 2002 to assess the impacts of climate change on vegetation, soils, active-layer dynamics, and permafrost across a latitudinal gradient. In this study, we report on the key factors influencing soil development across the gradient, including vegetation, parent material characteristics, and climate. Physical and chemical soil properties at depths of 2-8 and 10-20 cm were investigated at 7 sites and on 14 permanent plots from Apostrophe Island in Northern Victoria Land (73°30′S, 167°50′E) to Granite Harbour in Southern Victoria Land (77°00′S, 162°26′E) along the Ross Sea coast. The relationships among vegetation, parent material, and regional climate and soil properties were tested with Principal Component Analyses. There were no significant correlations or relationships in soil properties across the climate gradient. In fact, local microclimatic appears to be more effective than the regional gradient in influencing the properties. Microclimate was also important relative to active-layer depth and vegetation distribution. Lithology was strongly related to several chemical parameters, notably extractable Al, Fe, Ca, K, but was unrelated to grain-size distribution. Vegetation was related to the chemistry of the surface-soil layer, including nitrate, organic carbon, C/N ratio and water content, and also the active-layer depth. Penguins had the greatest influence on soil properties in initiating the development of ornithogenic soils. Further analyses on soil properties, including a greater number of sites, will be required to represent more extensively the lithological variability and to extend the latitudinal extremes of the gradient. The results presented here are an important reference for future monitoring activities in Victoria Land