Sub-surface precipitation of salts in supercritical seawater   总被引：2，自引：0，他引：2  

Martin Hovland  Tatyana Kuznetsova†  Håkon Rueslåtten‡  Bjørn Kvamme†  Hans Konrad Johnsen¶  Gunnar E. Fladmark§  Andreas Hebach† 《Basin Research》2006,18(2):221-230

Extremely low solubility of typical seawater salts within certain supercritical sections of their pressure–temperature composition space is a proven experimental fact. Its consequences are often referred to as either 'shock crystallization' or 'out-salting'. Our alternative model for the formation of salt deposits hypothesizes that high temperatures and pressures characteristic for the high heat-flow zones of tectonically active basins may bring submarine brines into the out-salting regions and result in the accumulation of geological-scale salt depositions.
To confirm the laboratory observations, molecular-scale simulations (molecular dynamics) have been employed to study structural changes in a model seawater system where temperature increased from ambient to near-critical and supercritical. Fluid properties and phase transition regions extracted from the simulations were then used as input parameters for a reservoir simulator program to model out-salting in a simple hydrothermal geological system. Both numerical simulations and laboratory experiments confirm that supercritical out-salting is a viable process of geological significance for the formation and accumulation of evaporites. We suggest two regions where hydrothermally associated salts may be depositing today: Atlantis II Deep, in the Red Sea, and Lake Asale, Ethiopia.  相似文献   

Book reviews     

Holt-Jensen  Arild  Tietze  Gunnar 《GeoJournal》1985,10(1):20-46

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Studies of a physostome swimbladder by resonance frequency analyses   总被引：1，自引：0，他引：1  

Sundnes  Gunnar; Sand  Olav 《ICES Journal of Marine Science》1975,36(2):176-182

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Regional co-development and security:: a comprehensive approach   总被引：1，自引：0，他引：1  

Gunnar Kullenberg   《Ocean & Coastal Management》2002,45(11-12)

Concepts of security are no longer limited to the military form, but other potential, economic, ecological, social aspects are becoming included.Emphasis needs to be put on integration of all dimensions of security. Many environmental problems present threats to human health and welfare and hence to the well-being of nations. The environmental issues cannot be ignored in context of any comprehensive security concept, but environmental security should not be treated in isolation.Integration of sustainable development and regional security may address many of the current maritime issues. Such integration may best be handled jointly and at regional levels.With this in mind and the realization that there is now a clear awareness and understanding that issues such as poverty, underdevelopment, population growth, environmental quality and sustainable resource use, are interrelated and interdependent and must be dealt with as such, the paper aims to highlight some aspects of regional security and sustainable development issues with reference to the Mediterranean basin. The aim is to initiate a process to pursue integration of sustainable development and comprehensive regional security with focus on the Mediterranean.The approach is based on the concept of the Common Heritage of Mankind as proposed by Arvid Pardo in 1967. It has 4 dimensions: economic; ethical; environmental; peace and security. In dealing with the proposal of Arvid Pardo the United Nations General Assembly decided to split up the concept: the Conference on the Law of the Sea was to deal with the peaceful uses of oceans and sea-beds; the Conference on Disarmament with the security aspects, then considered as military. UNCED 92 maintained the separation in addressing only environment and development, with management also included. However, peace and security were not included. It is time now to include these elements, and also consider the enforcement issue. The paper aims at illustrating this need through some examples from the Mediterranean basin.  相似文献   

Arsenic mobilisation in a new well field for drinking water production along the Red River,Nam Du,Hanoi     

Jenny Norrman  Charlotte J. Sparrenbom  Michael Berg  Dang Duc Nhan  Pham Quy Nhan  Håkan Rosqvist  Gunnar Jacks  Emma Sigvardsson  David Baric  Johanna Moreskog  Peter Harms-Ringdahl  Nguyen Van Hoan 《Applied Geochemistry》2008

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How climate metrics affect global mitigation strategies and costs: a multi-model study     

Mathijs J. H. M. Harmsen  Maarten van den Berg  Volker Krey  Gunnar Luderer  Adriana Marcucci  Jessica Strefler  Detlef P. Van Vuuren 《Climatic change》2016,135(2):203-209

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Chemical contamination in southwest Puerto Rico: an assessment of organic contaminants in nearshore sediments     

Pait AS  Whitall DR  Jeffrey CF  Caldow C  Mason AL  Lauenstein GG  Christensen JD 《Marine pollution bulletin》2008,56(3):580-587

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Map Comparison or Traditional Mass-balance Measurements: Which Method is Better?     

Gunnar Østrem  & Nils Haakensen 《Geografiska Annaler: Series A, Physical Geography》1999,81(4):703-711

A number of Norwegian glaciers were selected in the 1960s for long-term mass-balance measurements, to produce necessary hydrological information for hydropower exploitation. Special large-scale glacier maps were produced for field work and data processing, and some glaciers have been mapped more than once. Thus, comparison of glacier maps can be used to calculate changes in glacier volume for some of the glaciers, provided they are of sufficient accuracy.
Conventional mass-balance measurements were carried out on all the selected glaciers. A cumulative calculation of net balances for a series of years is used to indicate the change in a glacier's volume during that period. However, various errors originate in the field, some of which are systematic, particularly on glaciers with large winter accumulation.
The present study indicates that certain errors are difficult to define and determine, For the maritime glacier Ålfotbreen, a cumulative mass-balance calculation gives a positive total balance (+3.4 m water equivalent in the period 1968–88), whereas the map comparison indicates a total negative balance (−5.8 m water equivalent). This indicates a discrepancy between the methods, which must be accounted for.
Determination of errors in mass-balance measurements is difficult. Sinking of stakes in the accumulation area and the use of sounding sticks (steel probes) in heavy snowlayers cause problems.  相似文献   

A ferry making waves: A demonstration project ‘doing’ institutional work in a greening maritime industry     

Svein Gunnar Sjøtun 《Norsk geografisk tidsskrift. Norwegian journal of geography》2019,73(1):16-28

ABSTRACT

The objective of the article is to show how the demonstration project and battery ferry Ampere has contributed to a greening of public ferry procurement in Norway. Building on theories on demonstration projects in transition studies and institutional work, the author argues for a more integrated focus than hitherto on the dynamic interplay of materiality, organization, and discourse in demonstration projects, and how the agency of actor networks and the materiality connected to demonstration projects can affect institutional change accompanying transition processes. This is done by conceptualizing Ampere as a ‘performing project’: a complex of discursive and organizational strategies of framing and lobbying deployed by the actor networks connected to it and its materiality. Methodically, the author draws on semi-structured interviews and document analysis. The results suggest that Ampere’s ‘performance’ has contributed to changes in national and regional ferry procurement practices and been vital for an emerging maritime battery niche.  相似文献   

Helgoland Roads,North Sea: 45 Years of Change     

Karen Helen Wiltshire  Alexandra Kraberg  Inka Bartsch  Maarten Boersma  Heinz-Dieter Franke  Jan Freund  Christina Gebühr  Gunnar Gerdts  Karina Stockmann  Antje Wichels 《Estuaries and Coasts》2010,33(2):295-310

The Helgoland Roads time series is one of the richest temporal marine data sets available. Running since 1962, it documents changes for phytoplankton, salinity, Secchi disc depths and macronutrients. Uniquely, the data have been carefully quality controlled and linked to relevant meta-data, and the pelagic time series is further augmented by zooplankton, intertidal macroalgae, macro-zoobenthos and bacterioplankton data. Data analyses have shown changes in hydrography and biota around Helgoland. In the late 1970s, water inflows from the south-west to the German Bight increased with a corresponding increase in flushing rates. Salinity and annual mean temperature have also increased since 1962 and the latter by an average of 1.67°C. This has influenced seasonal phytoplankton growth causing significant shifts in diatom densities and the numbers of large diatoms (e. g. Coscinodiscus wailesii). Changes in zooplankton diversity have included the appearance of the ctenophore Mnemiopsis leidyi. The macroalgal community also showed an increase in green algal and a decrease in brown algal species after 1959. Over 30 benthic macrofaunal species have been newly recorded at Helgoland over the last 20 years, with a distinct shift towards southern species. These detailed data provide the basis for long-term analyses of changes on many trophic levels at Helgoland Roads.  相似文献