Release and transformations of inorganic iodine by marine macroalgae     

Rosie Chance  Alex R. Baker  Frithjof C. Küpper  Claire Hughes  Bernard Kloareg  Gill Malin 《Estuarine, Coastal and Shelf Science》2009

A number of field and laboratory studies on the impact of marine macroalgae on dissolved inorganic iodine speciation are presented. Within tidally isolated rock pools, the brown macroalga Fucus serratus was found to both release stored iodide and to facilitate the reduction of iodate to iodide. In contrast, no discernible changes in iodine speciation were observed in rock pools containing green macroalgae of the genus Ulva. Incubation experiments confirmed that the macroalgae Laminaria digitata, F. serratus and Kallymenia antarctica release iodide, though the rate of release varied between species and between specimens of the same species. Application of oxidative stress by treatment with cell wall derived oligoguluronate elicitors increased the efflux of iodide by L. digitata approximately 20-fold. The release of iodide by macroalgae may impact upon the formation of volatile iodine species (molecular iodine and iodocarbons) that are of importance in the coastal atmosphere.  相似文献   

Atmospheric Pb pollution in N Iberia during the late Iron Age/Roman times reconstructed using the high-resolution record of La Molina mire (Asturias, Spain)     

Antonio Martínez Cortizas  Lourdes López-Merino  Richard Bindler  Timothy Mighall  Malin Kylander 《Journal of Paleolimnology》2013,50(1):71-86

Extensive mining took place in Spain during the Iron Age and Roman times, although a detailed chronology is still lacking due to the inherent difficulties in dating mining structures. In this study we sampled and analyzed a core from La Molina mire in the Asturias region, northern Spain. Because more than 100 Roman mines have thus far been found within 20 km of the mire, our aim was to shed light on local mining history, which we can then compare to the wider narrative of early mining pollution in Spain. We focus on the section from ~500 BC to AD ~600, which has a high temporal resolution of 6–15 year per sample. Geochemical analyses included the determination of major, minor and trace lithogenic elements (Si, Al, Fe, Ti, Ga, Rb, Y, Zr, Th) as markers of mineral content of the peat, and trace metals/metalloids (Mn, Cu, Ni, As, Pb) as well stable Pb isotopes, as potential markers of atmospheric metal pollution. The use of principal components analysis enabled the identification of a dominant geogenic component and a secondary pollution component. The earliest pollution signal of the covered period was recorded by ~300 BC, coinciding with the late local Iron Age. Average ²⁰⁶Pb/²⁰⁷Pb ratios of samples with ages older than this date was 1.204 ± 0.002, while all samples with a younger age had a less radiogenic ratio. Based on the metal pollution component four phases were identified: I, ~500 to 300 BC; II, ~300 to 20 BC; III, ~20 BC–AD 480; IV, AD ~480 to 600. The lowest isotopic ratio and highest proportion of pollution Pb (²⁰⁶Pb/²⁰⁷Pb ratio of 1.157 and 89 % of total accumulated Pb) was reached at peak Pb production during Roman times (AD ~180 to 340), indicating that this was the period of most intense metal contamination in the area over the studied period. It is remarkable that the La Molina record shows a more extended period (two centuries) of active mining in comparison with other areas in Iberia, and a pattern of repeated shifts in Pb pollution of short duration, which is likely related to the local history of exploitation and exhaustion of mines within the area.  相似文献   

Late Holocene high precipitation events recorded in lake sediments and catchment geomorphology,Lake Vuoksjávrátje,NW Sweden          下载免费PDF全文

Annika Berntsson  Krister N. Jansson  Malin E. Kylander  Francois De Vleeschouwer  Sebastien Bertrand 《Boreas: An International Journal of Quaternary Research》2015,44(4):676-692

In this paper, we show the potential of combining multi‐proxy analysis of lake sediments with catchment geomorphology to better understand palaeoenvironmental changes. Previous studies have suggested that alpine lakes in N Sweden may be highly sensitive to variations in catchment erosion and precipitation, and that this sensitivity may influence ecologically based reconstructions of past temperature changes. We analysed lake sediments covering the last 5100 years from the alpine Lake Vuoksjávrátje in NW Sweden in order to identify different erosional regimes in the lake catchment, sediment sources and lake sedimentary processes, which ultimately affect the palaeoecological record. The measured proxies include elemental geochemistry from XRF core scanning, grain size, sediment accumulation rates, fraction of terrestrial organic carbon and geomorphological mapping, supported by previously published chironomid and total organic carbon data. From the integrated results we identified time intervals when increased intensity of precipitation altered sedimentation and lake catchment erosional processes. The most prominent event occurred c. 2900 cal. a BP and is interpreted to be the result of excessive precipitation, possibly related to the climatic shift towards cooler and wetter conditions referred to as the 2.8 ka event.  相似文献   

The Swedish model for groundwater policy: legal foundations, decision-making and practical application     

Jeffrey Lewis  Jan Sjöström  Malin Höök  Bo Sundström 《Hydrogeology Journal》2013,21(4):751-760

Public policy concerning groundwater is often complex, with diverse competing interests. With many countries facing similar challenges, it is instructive to examine the policy approaches that have and have not worked abroad. This article contributes to an international exchange of ideas on how best to approach these common problems by explaining how Sweden regulates its groundwater resources. From constitutional foundations to the practical details associated with applying existing policy, a synopsis is provided of groundwater jurisprudence in Sweden. Multiple governmental agencies are involved with groundwater policy in Sweden; this decentralized approach is probably a function of the natural abundance of clean aquifers throughout the country. Historically, the easy accessibility of high-quality groundwater made it a low priority in the context of environmental policy. It has simply never been an economic necessity to control groundwater resources through a single, unified governmental agency. Sweden is lagging behind many industrialized countries when it comes to implementing policies that protect and manage groundwater. Despite this, there are elements of Sweden’s approach that are highly innovative and possibly unique globally and which therefore merit discussion.  相似文献   

The AAO/UKST SuperCOSMOS Hα survey     

Quentin A. Parker  S. Phillipps  M. J. Pierce  M. Hartley  N. C. Hambly  M. A. Read  H. T. MacGillivray  S. B. Tritton  C. P. Cass  R. D. Cannon  M. Cohen  J. E. Drew  D. J. Frew  E. Hopewell  S. Mader  D. F. Malin  M. R. W. Masheder  D. H. Morgan  R. A. H. Morris  D. Russeil  K. S. Russell  R. N. F. Walker 《Monthly notices of the Royal Astronomical Society》2005,362(2):689-710

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South polar residual cap of Mars: Features, stratigraphy, and changes     

P.C. Thomas  M.C. Malin  B.A. Cantor  P. Gierasch 《Icarus》2005,174(2):535-559

The south residual polar cap of Mars, rich in CO₂ ice, is compositionally distinct from the north residual cap which is dominantly H₂O ice. The south cap is also morphologically distinct, displaying a bewildering variety of depressions formed in thin layered deposits, which have been observed to change by scarp retreat over an interval of one Mars year (Malin et al., 2001, Science 294, 2146-2148). The climatically sensitive locale of the residual caps suggests that their behavior may help in the interpretation of recent fluctuations or repeatability of the Mars climate. We have used Mars Global Surveyor Mars Orbiter Camera (MOC) images obtained in three southern summers to map the variety of features in the south residual cap and to evaluate changes over two Mars years (Mars y). The images show that there are two distinct layered units which were deposited at different times separated by a period of degradation. The older unit, ∼10 m thick, has layers approximately 2 m thick. The younger unit has variable numbers of layers, each ∼1 m thick. The older unit is eroding by scarp retreat averaging 3.6 m/Mars y, a rate greater than the retreat of 2.2 m/Mars y observed for the younger unit. The rates of scarp retreat and sizes of the different types of depressions indicate that the history of the residual cap has been short periods of deposition interspersed with longer erosional periods. Erosion of the older unit probably occupied ∼100-150 Mars y. One layer may have been deposited after the Mariner 9 observations in 1972. Residual cap layers appear to differ from normal annual winter deposits by having a higher albedo and perhaps by having higher porosities. These properties might be produced by differences in the depositional meteorology that affect the fraction of high porosity snow included in the winter deposition.  相似文献   

The Modelling of Oceans by Spherical Caps     

V. C. L. Hutson  P. C. Kendall  S. R. C. Malin 《Geophysical Journal International》1973,33(4):377-387

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Revision of Chapman's Spherical Harmonic Model of L     

S. R. C. Malin 《Geophysical Journal International》1974,39(3):565-569

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Seasonal Variations in the Solar and Lunar Daily Geomagnetic Variations     

J. C. Gupta  S. R. C. Malin 《Geophysical Journal International》1972,30(1):11-18

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Isolation of a cytochrome P450 3A (CYP3A) cDNA sequence from the marine teleost fish Fundulus heteroclitus (Killifish) and phylogenetic analyses of CYP genes     

Malin Celander  John J. Stegeman 《Marine environmental research》1998,46(1-5)

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