Monitoring and modelling of the solid-solution partitioning of metals and As in a river floodplain redox sequence

For a period of 2 a, pore water composition in a heavily contaminated river floodplain soil was monitored in situ. Pore water samples were collected 12 times over all seasons in a profile ranging from aerobic to sulphidic redox conditions, and As, Cd, Cr, Cu, Pb, Zn, Mn, Fe, Ca, Cl, SO₄, DOC, IOC and pH were determined. The variability of pH, IOC, DOC and Ca was found to be rather small during the year and within the profile (rsd < 0.04, 0.16, 0.24 and 0.22, respectively). The temporal variability of the metal and As concentrations was small, too, whereas changes with depth were distinct. Under sulphidic conditions, concentrations were below 1 μg L⁻¹ (Cd, Cu, Pb) or 10 μg L⁻¹ (Zn, As). The data set was compared with results from a geochemical model that was fully parameterised from literature data and included equilibrium speciation, sorption and mineral dissolution. The general pattern of the solid–solution partitioning of Cd, Cu, Zn and As in the profile was predicted well by mechanistic geochemical modelling on the basis of solid phase composition. Metals strongly bound to organic matter such as Cd and Cu were predicted better than metals mainly present within a mineral. Detailed information regarding the presence of colloidal Fe and Mn in pore water might improve the prediction of the solid–solution partitioning of a number of metals. The study also indicates that the chemical behaviour of Pb is still not understood sufficiently.     

Holocene relative sea‐level changes in Harris,Outer Hebrides,Scotland, UK

Evidence for relative sea‐level changes during the middle and late Holocene is examined from two locations on the Atlantic coast of Harris, Outer Hebrides, Scotland, using morphological mapping and survey, stratigraphical, grain size and diatom analysis, and radiocarbon dating. The earliest event identified is a marine flood, which occurred after 7982–8348 cal. a (7370 ± 80 ¹⁴C a) BP, when the sea crossed a threshold lying at ?0.08 m Ordnance Datum Newlyn (OD) (?2.17 m mean high water springs (MHWS)) before withdrawing. This could have been due to a storm or to the Holocene Storegga Slide tsunami. By 6407–6122 cal. a (5500 ± 60 ¹⁴C a) BP, relative sea levels had begun to fall from a sandflat surface with an indicated MHWS level of between 0.08 and ?1.96 m (?2.01 to ?4.05 m). This fall reached between ?0.30 and ?2.35 m (?2.39 to ?4.44 m) after 5841–5050 cal. a (4760 ± 130 ¹⁴C a) BP, but was succeeded by a relative sea‐level rise which reached between 0.54 and ?1.57 m (?1.55 to ?3.66 m) by 5450–4861 cal. a (4500 ± 100 ¹⁴C a) BP. This rise continued, possibly with an interruption, until a second sandflat surface was reached between 2.34 and ?0.26 m (0.25 to ?2.35 m) between 2952–3375 cal. a (3000 ± 80 ¹⁴C a) and 1948–2325 cal. a (2130 ± 70 ¹⁴C a) BP, before present levels were reached. The regressive episode from the earliest sandflat is correlated with the abandonment of the Main Postglacial Shoreline. It is maintained that the fluctuations in relative sea level recorded can be correlated with similar events elsewhere on the periphery of the glacio‐isostatic centre and may therefore reflect secular changes in nearshore sea surface levels. Despite published evidence from trim lines of differential ice sheet loading across the area, no evidence of variations in uplift between the locations concerned could be found. Copyright © 2009 John Wiley & Sons, Ltd.     

Dynamite fishing in northern Tanzania - pervasive, problematic and yet preventable

Dynamite fishing, although illegal, has resurfaced in recent years as a major threat to the reefs of northern Tanzania. This is despite the fact that institutional arrangements for co-management of the inshore fisheries by local communities and the district governments have been put in place and, through a 12-year donor-funded programme, numerous activities undertaken to build capacity for effective fisheries management. The use of dynamite is having widespread negative impacts, including damage to the reefs and their long-term productivity, deterrence of tourism investors, and potential threat to the large population of coelacanths in the area. The dynamite fishers are able to continue, even though enforcement efforts have been stepped up, because they are members of influential families or otherwise well-connected. Previous similar cases in Tanzania, and examples from elsewhere in the world, suggest that a major initiative is now needed to develop a zero-tolerance approach on the part of fishers and local and national leaders, that will shame the dynamiters through peer pressure, promote full implementation of sanctions and penalties by the judiciary, and lead to public recognition of and support for the work of the enforcement agencies.     

Climate change impacts on environmental geosciences: Introduction

正Climate change and its impacts have become topical issues of global news, scientific research and conferences. Environmental Geosciences incorporate the various disciplines of geosciences and their multifaceted interactions with life. Research discussions on the interaction of climate change, geosciences and environment may often be blur, and Schmidt-Thoméet al.(2010) stated that"Often past climate changes that can be deduced from geological records may help in understanding the speed of potential climate change effects, i.e. how quickly have sea levels changed, how drastic has nature reacted to ups and downs in temperature, etc. These analyses of past events help in giving outlooks on potential changes in our living environment. It is also of important to understand the magnitude and potential effects of extreme events, such as droughts and floods".     

Economic impact upon agricultural production from extreme flood events in Quang Nam,central Vietnam

Natural Hazards - Quang Nam province, central Vietnam, is situated within the tropical monsoon and typhoon zone of south-east Asia and is susceptible to extreme floods. Historical water level data...     

The nature of molecular cloud material in interplanetary dust

Eight interplanetary dust particles (IDPs) exhibiting a wide range of H and N isotopic anomalies have been studied by transmission electron microscopy, x-ray absorption near-edge structure spectroscopy, and Fourier-transform infrared spectroscopy. These anomalies are believed to have originated during chemical reactions in a cold molecular cloud that was the precursor to the Solar System. The chemical and mineralogical studies reported here thus constitute direct studies of preserved molecular cloud materials. The H and N isotopic anomalies are hosted by different hydrocarbons that reside in the abundant carbonaceous matrix of the IDPs. Infrared measurements constrain the major deuterium (D) host in the D-enriched IDPs to thermally labile aliphatic hydrocarbon groups attached to macromolecular material. Much of the large variation observed in D/H in this suite of IDPs reflects the variable loss of this labile component during atmospheric entry heating. IDPs with elevated ¹⁵N/¹⁴N ratios contain N in the form of amine (-NH₂) functional groups that are likely attached to other molecules such as aromatic hydrocarbons. The host of the N isotopic anomalies is not as readily lost during entry heating as the D-rich material. Infrared analysis shows that while the organic matter in primitive anhydrous IDPs is similar to that observed in acid residues of primitive chondritic meteorites, the measured aromatic:aliphatic ratio is markedly lower in the IDPs.     

Contextualizing social vulnerability: findings from case studies across Europe

Social vulnerability is a term that has been widely used in the natural hazards literature for quite a few years now. Yet, regardless of how scholars define the term, the approaches and indicators they use remain contested. This article presents findings from social vulnerability assessments conducted in different case studies of flood events in Europe (Germany, Italy and the UK). The case studies relied upon a common set of comparable indicators, but they also adopted a context-sensitive, qualitative approach. A shared finding across the case studies was that it was not possible to identify a common set of socio-economic–demographic indicators to explain social vulnerability of groups and/or individuals for all phases of the disastrous events. Similarly, network-related indicators as well as location- and event-specific indicators did not have the relevance we expected them to have. The results underline that vulnerability is a product of specific spatial, socio-economic–demographic, cultural and institutional contexts imposing not only specific challenges to cross-country research concerning social vulnerability to flooding but also to attempts at assessing social vulnerability in general. The study ends with some reflections upon the methodological, practical and theoretical implications of our findings.     

Reconstruction of palaeoceanographic conditions in the South Atlantic Ocean at the last two Terminations based on calcareous dinoflagellate cysts

 Despite the increasing interest in the South Atlantic Ocean as a key area of the heat exchange between the southern and the northern hemisphere, information about its palaeoceanographic conditions during transitions from glacial to interglacial stages, the so-called Terminations, are not well understood. Herein we attempt to increase this information by studying the calcareous dinoflagellate cysts and the shells of Thoracosphaera heimii (calcareous cysts) of five Late Quaternary South Atlantic Ocean cores. Extremely high accumulation rates of calcareous cysts at the Terminations might be due to a combined effect of increased cyst production and better preservation as result of calm, oligotrophic conditions in the upper water layers. Low relative abundance of Sphaerodinella albatrosiana compared with Sphaerodinella tuberosa in the Cape Basin may be the result of the relatively colder environmental conditions in this region compared with the equatorial Atlantic Ocean with high relative abundance of S. albatrosiana. Furthermore, the predominance of S. tuberosa during glacials and interglacials at the observed site of the western Atlantic Ocean reflects decreased salinity in the upper water layer. Received: 9 November 1998 / Accepted: 26 October 1999