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According to the UNCCD (United Nation Convention to Combat Desertification) affected country Parties have to prepare, make public and implement National Action Programmes (NAPs) as the central element of the strategy to combat desertification and mitigate the effects of drought. NAPs could involve strengthening of drought preparedness and management, including drought contingency plans at the local, national, sub-regional and regional levels, which take into consideration seasonal to interannual climate predictions. In this paper the question on application of climate predictions in (Eastern) European countries is discussed. Results from a survey on CLIPS (Climate Information and Prediction Services) activities in the National Meteorological and Hydrological Services (NMHSs) from Eastern Europe are considered. Capabilities of certain Eastern European countries in the development of their own seasonal to interannual predictions or adaptation and interpretation of predictions issued by specialized climate prediction centers are also listed. A short overview on the contemporarary approaches towards better seasonal to interannual prediction and climate forecasting is done within the paper, as well. Seasonal forecasts can be developed using mathematical models of the climate system. A recent trend is to examine the potential use of regional climate models. In Europe the multi-model approach seems to be the most adequate to produce reliable probabilistic climate forecasts. EU-funded project such as ENSEMBLES, EUROCLIM, CECILIA evaluating the merits of the current approaches and methods in the field are mentioned, too. [ABSTRACT FROM AUTHOR]

The complexity of the notion ‘land' and its scale features leads to many different definitions of land and land degradation. Among the components of land degradation are desertification, soil degradation and erosion. There is a wealth of literature claiming that land degradation is serious. These so-called doom papers are based on ‘hard' facts from remote sensing, computer models and measurements. However, other papers have raised the question ‘how serious is land degradation?' In any discussion of land degradation there are four spatial-temporal scales that should be distinguished: regional, watershed, field and point. At each scale, one may use different proxies for land degradation. When assessing land degradation, ‘experts' tend to overestimate the phenomenon; they should take better account of its spatial and temporal dimensions. One of the main reasons they currently overestimate land degradation is that they underestimate the abilities of local farmers, many of whom have been able to modify their land management. In order to study land degradation at multiple scales it is also necessary to study rainfall at multiple scales. Rainfall can be analysed for land degradation at four different scales: from the ‘small' annual scale to the ‘large' minute scale. Besides scales one may also distinguish between average values and temporal and spatial variations. In this paper, one or more examples of rainfall data are presented for each scale and interpreted with respect to land degradation. At the annual scale, trend analysis and rainfall probabilities are important. The decadal (10-day) scale is especially suitable for calculating the varying lengths of the growing season. At the scale of one day, the size classes of showers, return period (design storm), hydrological and agronomic modelling and dry spell analysis are discussed. At the minute scale, erosivity in El Niño and La Niña years is important. Rainfall meets land at the soil surface. Rainfall is divided over several pedohydrological components. Green water is that part of rainfall that is stored in the soil and available to plants. Land degradation decreases infiltration, waterholding capacity and transpiration, but enhances runoff and soil evaporation. These agrophysical processes decrease the Green Water Use Efficiency (GWUE; the ratio of transpiration to precipitation). Special attention is given to estimating the effects of land degradation on ‘computing available soil moisture' in order to understand what farmers perceive as drought. Rain falling on the land may be intercepted by vegetation, run off the ground surface, or infiltrate into the soil; this is reflected in the rainwater balance. Infiltrating water may be stored in the root zone or drain below the root zone to groundwater and stream base flow, contributing what is nowadays called ‘blue water'. These processes are reflected in the infiltration water balance. The maximum amount of water stored in the root zone available for plant growth is a very important soil characteristic because it determines the potential survival of plants in a dry spell. Water stored in the root zone may be lost as evaporation from the soil surface into the atmosphere, or taken up by plants and lost as transpiration. This is reflected in the soil water balance. In drylands in sub-Saharan Africa the GWUE ranges from 5-15%, which is very low. In East Africa it may reach 20%, but in comparable climates in the USA the GWUE may be above 50%. The concepts of land degradation mitigation are derived from the rainwater balance. After drawing a number of conclusions, it is suggested how we could improve our understanding of land degradation by improving the availability of rainfall data at multiple scales. [ABSTRACT FROM AUTHOR]

The impact of some meteorological parameters on land degradation in Tanzania is analysed. Rainfall is responsible for floods in case if it is in excess and drought in case of deficit. In recent years, parts of Tanzania have experienced recurring droughts. The most devastating droughts were those of 1983-1984 and 1993-1994. According to Tanzania historical data, droughts occur every four years which affect over 3.6 million people. The most frequently hit areas are, central areas of Dodoma, Singida and some parts of Pwani, Shinyanga, Mwanza and Mara. Experience over the twenty-year period from 1980 to 2000 has shown that floods occurred 15 times, killing 54 people and affecting 800,000 people. Flood prone regions are Tanga, Mbeya, Pwani, Morogoro, Arusha, Rukwa, Iringa, Kigoma and Lindi. The impact of El-Niño rains is discussed and the probability of rainfall exceeding specific thresholds is analysed. Wind erosion is discussed. The impact of climate change and its relationship to land degradation is analysed. Finally the impact of solar radiation, temperature and evaporation is discussed. The paper concludes that climate and weather contribute significantly to land degradation in Tanzania. The paper recommends that there is a need to: make an inventory of national land resources; assess potentials and constraints in dryland farming; identify agricultural options to safely increase cropping intensity and yields; adopt more sustainable forms of land use, including contingency crop planning in the case of droughts; study the reasons behind poor land use; encourage pastoralists to reduce their herds of stocks and finally encourage the use of indigenous knowledge in land preservation. [ABSTRACT FROM AUTHOR]

This paper presents the hypothesis that algal remains were precursors of the fullerenes in the hard carbonaceous rock Shungite (Russia), in carbonaceous matter from the hard rocks of the Black Member of the Onaping Formation at Sudbury (Canada), and in solid, hard bitumens from Mitov (Czech Republic). The paper argues further that PAHs from the biogenic matter were transformed, perhaps by cyclomerization followed by zip-up, during the geologic metamorphic stages experienced by these rocks. [ABSTRACT FROM AUTHOR]

This paper gives a brief overview of the field methods used to study the distribution of seabirds at sea in the German parts of the North and Baltic Seas. It demonstrates how the data were analysed, how seabird concentrations may be delineated, and how suggestions for protected areas were derived from the data. Seabird distribution was studied by transect counts from ships and aircraft. Species distribution maps produced from these data are based on densities. The distribution of widely dispersed species, e.g., lesser black-backed gull (Larus fuscus) and northern fulmar (Fulmarus glacialis), were analysed using grid maps. For species occurring in concentrations, a spatial interpolation procedure using ordinary kriging was adopted. Examples of distributions and maps are given for long-tailed duck (Clangula hyemalis; Baltic Sea), common eider (Somateria mollissima; Baltic Sea) and red-throated and black-throated divers (Gavia stellata and G. arctica; North Sea). For all specially important species (i.e., species listed in Annex I of the EU Birds Directive that should be the subject of special conservation measures, e.g., red-throated diver and sandwich tern Sterna paradisaea), concentration areas were identified and subsequently combined so that a set of potential areas for conservation could be determined. From this map, potential Special Protection Areas (SPAs) were established. Finally, this paper briefly discusses field methods and methods of analysis and gives further recommendations. [ABSTRACT FROM AUTHOR]

The role of isolated mountain forests in Central Asian drylands has been the subject of a number of recent studies. The present paper examines islands of birch and willow forest in the Mongolian Govi Altay Mountains. Using vegetation surveys, dendrochronological studies and charcoal findings, it is attempted to assess the present-day ecological state of the vegetation as well as the environmental history and ecological trends. One of the three forests studied seems to be expanding rapidly due to declining levels of utilization under climatically favourable conditions. The other forests however, situated about 350 km to the south-east of the former, are threatened by consistently high levels of anthropogenic pressure. Based on ecological evidence, the forest islands’ role as witnesses of a once coherent forest belt that may have been retreating since the mid-Holocene is discussed. [ABSTRACT FROM AUTHOR]

In the 20th century, the global climate has warmed about 0.6 K. High-mountain areas as well as areas of high latitudes are experiencing even greater increases in temperature especially in the last half century. With changing climatic conditions, the determinants of global, and in particular, altitudinal distribution of plants and plant communities are likely to change and a subsequent reaction of climate sensitive species and ecosystems is expected. The following paper focuses on observed climate-induced changes in the two uppermost altitudinal vegetational ecotones at the treeline and the upper limit of plant life at the alpine-nival transition zone. [ABSTRACT FROM AUTHOR]

Based on comprehensive evaluations and analyses of existing literature and data sources, a review of geographical and ecological aspects of the upper timberline in the Himalayan mountain system is presented. Upper timberline elevations increase along two gradients: a NW-SE gradient corresponds to higher temperature sums at same elevations along the mountain arc. However, mean temperatures of the warmest month are higher at timberlines in the NW, which develop at lower elevations than expected since extreme winter cold, later snow melt, and shorter growing seasons overcompensate the advantage of higher summer temperatures. A second gradient is developed in peripheral-central direction from the Himalayan south slope to the Great Himalayan range and the Tibetan highlands. Increasing timberline elevations along this gradient are related to the combined effects of continentality and mass-elevation, both leading to higher temperature sums. Juniperus tibetica stands in S-Central Tibet even reach 4600–4800 m, the most elevated timberline in the northern hemisphere. Potentially natural timberline elevations are higher at south-facing slopes compared to north-facing slopes. The difference in altitudinal position is up to several hundred meters. The pronounced effects of exposure to solar radiation result in a much higher utilization pressure at sunny slopes, in particular with regard to pastoral use. South-facing slopes have since long been subjected to massive human impacts throughout the mountain arc so that natural conditions are hard to reconstruct. The depression of upper timberline may amount to more than 500 m, largely depending on the local/ regional utilization potential of alpine pasture areas. With regard to physiognomy, high coniferous forests give way to medium-sized broadleaved tree stands and finally to a krummholz belt. This is the dominant timberline pattern on shady slopes, whereas remnant open coniferous forest stands on sunny slopes dissolve into isolated patches or single crippled trees higher up. Along the NW-SE gradient, north-facing slopes show a floristic change from deciduous Betula- to evergreen Rhododendron-dominated upper timberlines, which must be attributed to decreasing winter cold and strongly increasing humidity levels. Juniperus spp. are the principal timberline tree species on south-facing slopes throughout the mountain system. Relationships of Himalayan timberlines to other ecological conditions and processes such as carbon balance, freezing and frost drought, soil temperatures, wind, snow cover, soils, regeneration, etc., are still largely unexplored. The state of the art is summarized in this paper. More systematic, interdisciplinary timberline research in the Himalaya is strongly needed to better understand how complex ecological and socio-economic processes are expressed in present spatial and physiognomic timberline structures. [ABSTRACT FROM AUTHOR]

All species have limits to their distribution and individuals that demarcate margins demonstrate an end-point in adaptation to a changing environment. Limits to plant survival arise either from a failure to grow or from an inability to reproduce. Consequently, matching climatic data with geographical distribution has to consider the biological causes for the failure of plants to survive outside any given area. Physical factors, such as thermal time (day-degrees) and growing season length, differentiate between the broadly recognised vegetation zones of High, Low, and Subarctic. However, within these zones the limitations to plant distribution are less readily related to climatic factors. In peripheral areas, relating physical climatic factors to species occurrence requires a knowledge of the many interactions between physiology and genetics of populations as they approach their territorial margins. Examination of the extent of variation found in plants growing in cold habitats reveals large differences both between and within populations and at different seasons in metabolic rates, temperature responsiveness and metabolic efficiency. The High Arctic represents a peripheral zone where conditions are prone to large fluctuations. Consequently, plant distribution will be affected by aspects of the environment that are not permanent, but which occur irregularly with varying frequency and intensity. This paper considers the physiological and genetic properties of polar plant populations that may facilitate persistence in uncertain and heterogeneous adverse environments. Particular attention is given to those species that appear to have maintained a presence at high latitudes since pre-Pleistocene times and have therefore survived many past environmental fluctuations. [ABSTRACT FROM AUTHOR]

As awareness of deep-sea corals increases, global efforts to conserve them are increasing as well. Oceana, a non-governmental conservation organization that merged with the American Oceans Campaign in 2002, is focusing significant attention and resources on the conservation of deep-sea coral communities in United States’ waters. Oceana is carrying out a number of activities as part of its deep-sea coral campaign. These include: • Working to pass legislation that would ban the use of particularly destructive bottom trawls in all U.S. waters in collaboration with the Marine Conservation Biology Institute;• Working to pass legislation that would specifically protect known deep-sea coral and sponge areas and establish a process for future protections;• Working to protect deep-sea coral and sponge habitats in the U.S. through the regional fishery management councils;• Developing educational materials for decision-makers, the media, and the general public;• Developing a petition to achieve threatened or endangered species status for Oculina varicosa. The goal of Oceana’s deep-sea coral protection activities is to ban bottom trawling in all U.S. waters containing significant amounts of deep-sea corals and sponges by the end of 2006. The purpose of this paper is to discuss the activities that Oceana is engaged in to achieve this goal. As Oceana’s capacity develops in other parts of the world, its efforts to protect coral in other regions (especially Europe and South America) will increase as well. [ABSTRACT FROM AUTHOR]

This paper presents an overview of the spatial distribution and morphology of coral banks in the Porcupine Seabight in relation to their environmental settings. The study area is characterised by well-delimited clusters of coral banks, each featuring typical bank morphology and environmental setting. In the central part of the basin, two mound provinces can be identified: a set of complex fl at topped seafloor mounds in the Hovland Mound province is flanked to the north by a crescent of numerous north-south elongated buried coral banks in the Magellan Mound province, along the eastern margin of the basin partly buried and seabed coral banks represent the Belgica Mound province. The banks are mound-shaped elevations, many of them hosting living deep-water corals (Lophelia pertusa, Madrepora oculata, Desmophyllum cristagalli, Dendrophyllia sp.) and associated fauna. This active biological layer covers a dead assemblage of corals clogged with mud. All coral banks, buried or seabed, occur in association with current-induced features (e.g., scouring features, dunes) and steep palaeo- and present-seabed slopes. Only a few banks have a present-day seabed expression, which suggests that environmental conditions have been more favourable for bank development in the past. The depth range of the seabed coral banks coincides with the Mediterranean Outflow Water which may control indirectly the coral distribution. The distribution of corals in the southern part of the North Atlantic and the actual link with Mediterranean water suggest a possible migration of corals within the Mediterranean water along the NE Atlantic margin. The start-up phase of the coral bank development in the basin has taken place simultaneously for all provinces, and tentatively framed in times subsequent to a Late Pliocene period of erosion and non-deposition. It is considered that the sedimentary load of the currents plays an important role in the bank development. Coral banks accrete by the active baffling of sediment by the biological framework and growth of the biological cap. When sedimentation and biological growth get out of balance, the framework will progressively be clogged with sediment. Once sediment dominates the structure the coral banks get buried and draped by sediment. [ABSTRACT FROM AUTHOR]

This paper describes the associated fauna of the deep-sea gorgonian corals Paragorgia arborea and Primnoa resedaeformis. Composition and distribution of this fauna is described based on material from the continental shelf and slope off Atlantic Canada (300–600 m depth). Samples were collected from five areas with Remotely Operated Vehicle, video grab, and bottom trawl. The collected material consists of 25 samples, 13 from P. arborea and 12 from P. resedaeformis. A total of 114 species and 3915 individuals were recorded. The P. resedaeformis fauna was more abundant and diverse than the fauna of P. arborea, with 2651 specimens and 97 species found on the former and 1264 specimens and 47 species on the latter. Rarefaction analysis indicated that many more associated species are still to be found. Species richness and abundance was significantly correlated with coral morphology (e.g., number of branches, wet weight, and % exposed skeleton). Crustaceans dominated the fauna, contributing 46 % to the total number of individuals and 26 % to the total number of species. Two coral microhabitats were identified: 1) young and live parts of colonies and, 2) old parts with deposits and exposed skeleton. Most of the associated fauna was found in the latter habitat. There was a clear difference in fauna composition of the two coral species. Sessile hydroids, anemones, and molluscs were more abundant on P. resedaeformis. These organisms occurred attached to the hard substratum provided by the exposed skeleton. Parasitic copepods and polychaetes were more common on P. arborea. Two copepods, a lichomolgid ecto-parasite and a lamippid gall-forming endoparasite, were associated with P. arborea. The echinoderm Gorgonocephaluslamarckii was found in the high current environment on the outer branches of P. arborea. The shrimp Pandalus propinquus was hiding and resting on colonies of both coral species. Many of the associated taxa are also found on tropical gorgonians but the deepsea gorgonians lack the diverse decapod and gastropod-fauna of their tropical counterparts. The species richness of the deep-sea gorgonian coral fauna was higher than what has been observed for tropical gorgonians. In contrast to the tropical associates very few are obligate symbionts. Nevertheless, several of the species are rare in other habitats and have been recorded on the same and other gorgonian species in early studies from the eastern North Atlantic. The sampling gear collected the fauna differently. Corals from bottom trawls had a poorer associated fauna that differed in composition with material collected by ROV or video assisted grab. [ABSTRACT FROM AUTHOR]

Deep-water Oculina coral reefs, which are similar in structure and development to deep-water Lophelia reefs, stretch 167 km (90 nm) at depths of 60–100 m along the eastern Florida shelf of the United States. These consist of numerous pinnacles and ridges, 3–35 m in height, that are capped with thickets of living and dead coral, Oculina varicosa. Extensive areas of dead Oculina rubble are due in part to human impacts (e.g., fish and shrimp trawling, scallop dredging, anchoring, bottom longlines, and depth charges) but also may be due in part to natural processes such as bioerosion, disease, or global warming. In the 1970s, the reefs were teeming with fish. By the early 1990s, both commercial and recreational fisheries had taken a toll on the reefs, especially on the coral habitat and populations of grouper and snapper. In 1984, 315 km2 (92 nm2) was designated the Oculina Habitat of Particular Concern (OHAPC), prohibiting trawling, dredging, bottom longlines and anchoring, and establishing the first deep-sea coral marine protected area in the world. In 2000, the Oculina Marine Protected Area (MPA) was expanded to 1029 km2 (300 nm2). Despite these protective measures, manned submersible and ROV observations in the Oculina MPA between 1995 and 2003 suggest that portions of the coral habitat have been reduced to rubble since the 1970s, grouper spawning aggregations may be absent, and illegal trawling continues. This paper is a review of the results of the mapping, habitat characterization, and fish surveys from the early historical studies (1960–1980s) to the more recent surveys (1995–2003). [ABSTRACT FROM AUTHOR]

The Belgica Mound province is one of three provinces where carbonate mounds are associated with cold-water coral species in Porcupine Seabight, west of Ireland. Building upon extensive existing datasets, the Polarstern ARK XIX/3a cruise, deploying the robotic submersible VICTOR6000 (ROV), was undertaken in June 2003. This paper presents an overview of preliminary results from a reconnaissance video survey over and between several steep-flanked Belgica Mounds (giant mounds) and from a microbathymetric survey over some smaller mounds (Moira Mounds). Visual evidence for a strong hydrodynamic regime in the vicinity of the carbonate mounds is found with the interaction between currents and sedimentation having an important role in mound growth and development. Only some mounds show a high percentage of live coral coverage although there is a clear increase of megafaunal concentrations and species on mounds. One area of the province (the eastern ridge of aligned mounds) revealed very little live coral cover, asymmetrical drift accumulations burying the eastern sides and sediment-clogged dead coral frameworks at the western sides. This is in contrast to other areas (e.g., the western alignment of mounds) that show abundant live coral cover at present. In nearly all parts of the survey area the impact of fisheries, especially demersal trawling, is noted. [ABSTRACT FROM AUTHOR]

One of the critical information needs identified at the 2003 Deep-Sea Corals Workshop in Galway, Ireland, was to locate and chart deep-sea corals in order to develop reliable estimates of their distribution and abundance. While reports of deep-sea corals from the Gulf of Mexico date back to the 1860s, relatively little is known about their distribution or abundance. This paper attempts to provide a current assessment of the occurrence of Lophelia pertusa and Madrepora oculata in water depths greater than 200 m in the Gulf of Mexico by summarizing records from (1) published material, (2) the 2003 National Museum of Natural History Taxonomic Database, (3) findings obtained during the September-October 2003 NOAA-OE RV Ronald H. Brown cruise RB-03-07-leg-2 in the northern Gulf, and (4) from various unpublished sources. [ABSTRACT FROM AUTHOR]

The pollen data available for the Atlantic equatorial African region indicate that during the Late Quaternary, major climate changes occurred and caused important modifications in tropical lowland rain-forest in terms of composition and distribution (Maley 1991; Elenga et al. 1991; 1994; Farrera et al. 1999; Vincens et al. 1999). Nevertheless, despite a wealth of proxy evidence from various disciplines, there are very few terrestrial sites dated continuously since the Last Glacial Maximum (LGM) to the Late Holocene in this area (e.g., Lanfranchi and Schwartz (1990), Servant and Servant-Vildary (2000)). The oldest radiocarbon-dated sites are from Lake Barombi Mbo in Cameroon (Brenac 1988; Maley 1991; Maley and Brenac 1998a) and the Ngamakala Pond in the Congo (Elenga et al. 1994), although most Holocene sequences from this area start during the mid-Holocene (Vincens et al. 1999). This paper reviews the results available for some key sites, allowing regional correlations for major Late Quaternary periods.We have focused on the vegetation changes and the climate related to these changes. Numerous radiocarbon dates allowprecise palaeoenvironmental reconstructions, especially since the mid-Holocene to be made. In this paper all 14C dates are uncalibrated. [ABSTRACT FROM AUTHOR]

One of the most exciting questions in palaeoclimatology is the study of the complex interactions between the different components of the climate system in order to understand how climate changes occur at Milankovitch as well as at millennial and centennial time-scales. The primary objective of this paper is to place the PEP III transect palaeo-data within a global climate context in relation to oceanic climate variability during the last glacial. To take ocean-continent interactions into account is essential to develop our understanding of past climate change. Recently, several studies have brought to light the role of the tropical/subtropical areas in climate changes. Continental and oceanic low-latitude records have documented the high frequency climate variability during the last glacial period. The inferred continental climate conditions in the sub-tropics might provide evidence for the contribution of atmospheric processes associated with rapid climate variability. Another key question concerns the forcing mechanisms for rapid climate change. One of the most discussed hypotheses relies on ice sheet-ocean-atmosphere interactions driving millennial scale climate variations during the last glacial period (Alley et al. 1999; Ganopolski and Rahmstorf 2001). As already mentioned, ocean-atmosphere coupling is very sensitive to the freshwater flux into the North Atlantic. Modelling of the cryosphere shows that the internal dynamics of the northern hemisphere ice-sheets during periods of ice-building could lead to major reorganisation of the global climate (MacAyeal 1993). Likewise internal oscillations of the ocean-atmosphere system should also be considered as a potential candidate for climate forcing (Winton 1993; Paul and Schulz 2002). On the other hand, studies on rapid climate variability during the Younger Dryas and the Holocene point to an external forcing by revealing a possible connection between solar activity and global climate (Renssen et al. 2000; this volume; Bond et al. 2001). However, knowledge about the importance of the different potential triggers is poor, as climate components have different responses in space and time (and most probably during glacial and interglacial periods). Therefore, in this paper we concentrate on the interactions between the different climate sub-systems.Areviewof rapid climate variability during the last glacial period mostly based on marine sediment records with a focus on recent studies based on sub-tropical records is attempted. By compiling these high quality data, we discuss what can be learned about millennial climate changes and connections. [ABSTRACT FROM AUTHOR]

This volume contains a series of papers that collectively summarise evidence for climate change in Africa and Europe over approximately the last 200,000 years. It is a product of PEP III, the pole-equator-pole transect through Europe and Africa, that has been defined by the IGBP-PAGES project for palaeoclimate study along with PEP II (Asia-Australasia) and PEP I, the Americas (Fig. 1). The PEP transects focus on two time intervals, time-stream 1, the Holocene (with an emphasis on the last 2000 years), and time-stream 2, the last two glacial cycles. The principal long-term objectives of PEP III are (i) to understand how and why climate has varied in the past along the transect; (ii) to assess how climate change and variability has affected natural ecosystems and human society in the past; and (iii) to provide a basis both for developing and testing climate models that are needed to forecast climate change in the future. The specific papers contained in this volume were presented at a conference on "Climate Variability through Europe and Africa" held in Aix-en-Provence in August, 2001. The volume presents an attempt to bring together in a coherent way our present understanding of past climate change along the PEP III transect, providing a basis for the future work needed to make progress towards these objectives. This publication also complements other related syntheses that overview the scientific achievements of the PAGES community over the last decade, notably for the PAGES programme as a whole (Alverson et al. 2003), and for the PEP III sister transect, PEP I (Markgraf 2001) and PEP II (Dodson et al. 2004). [ABSTRACT FROM AUTHOR]

There is a growing body of evidence that the spatial distribution of bacteria and their relationships with other soil features play a significant role in the macroscopic function of soil. In the past this has not been widely appreciated, possibly due to the difficulty of studying soils at scales that are relevant to bacterial communities. This paper reviews the evidence for the influence of microscale interactions on function at larger scales and describes recent methodological advances that allow the microscale spatial distribution of bacterial cells and bacterial activities to be quantified. Approaches for integrating the microscale into models of soil function are briefly discussed as are new techniques that have the potential to improve our understanding of microbial - habitat interactions and of how these are linked to soil function. Keywords: bacterial spatial distribution, microscale, microhabitat, scale, biological thin sections, microsampling [ABSTRACT FROM AUTHOR]

Climatic warming in northern latitudes will undoubtedly create new ecological opportunities for vegetation advance as ice sheets retreat and permanent snow cover is reduced. Depending on proximity to the oceans, and this includes the Arctic Ocean, the degree of winter versus summer warming is likely to differ. In northern regions the influence of oceanicity on plant distribution is very marked. The models described in this paper show that among some of the commonest woody species winter warming may in some cases cause a significant retreat in areas that where the climate is influenced by the ocean, while in other areas the species may make significant advances. Due to seasonal differentiation in responses to temperature the nature of the migration of species into these vacated areas or changing communities is unlikely to be a mere latitudinal shift northwards of existing species assemblages. It appears therefore highly probable that species migration will be strongly influenced by seasonality of temperature change, and for any one species similar patterns of climatic change in different parts of its range, could result in migration in opposite directions. Consequently, changing thermal conditions will be likely to alter species composition of existing northern plant communities. Attention will therefore have to be given to the roles of seasonality gradients as potential barriers to migration notwithstanding overall warming. [ABSTRACT FROM AUTHOR]

Over the years, viruses have been shown to be mortality agents for a wide range of phytoplankton species, including species within the genus Phaeocystis (Prymnesiophyceae). With its polymorphic life cycle, its worldwide distribution, and the capacity of several of the Phaeocystis species to form dense blooms, this genus is a key player for our understanding of biogeochemical cycling of elements. This paper provides an overview of what is know to date about the ecological role of viruses in regulating Phaeocystis population dynamics. It explores which variables affect the algal host-virus interactions, and examines the impact of virally induced cell lysis of Phaeocystis on the function and structure of the pelagic food web as well as on the flow of organic carbon and nutrients. [ABSTRACT FROM AUTHOR]

The phytoplankton genus Phaeocystis has well-documented, spatially and temporally extensive blooms of gelatinous colonies; these are associated with release of copious amounts of dimethyl sulphide (an important climate-cooling aerosol) and alterations of material flows among trophic levels and export from the upper ocean. A potentially salient property of the importance of Phaeocystis in the marine ecosystem is its physiological capability to transform between solitary cell and gelatinous colonial life cycle stages, a process that changes organism biovolume by 6-9 orders of magnitude, and which appears to be activated or stimulated under certain circumstances by chemical communication. Both life-cycle stages can exhibit rapid, phased ultradian growth. The colony skin apparently confers protection against, or at least reduces losses to, smaller zooplankton grazers and perhaps viruses. There are indications that Phaeocystis utilizes chemistry and/or changes in size as defenses against predation, and its ability to create refuges from biological attack is known to stabilize predator-prey dynamics in model systems. Thus the life cycle form in which it occurs, and particularly associated interactions with viruses, determines whether Phaeocystis production flows through the traditional "great fisheries" food chain, the more regenerative microbial food web, or is exported from the mixed layer of the ocean. Despite this plethora of information regarding the physiological ecology of Phaeocystis, fundamental interactions between life history traits and system ecology are poorly understood. Research summarized here, and described in the various papers in this special issue, derives from a central question: how do physical (light, temperature, particle distributions, hydrodynamics), chemical (nutrient resources, infochemistry, allelopathy), biological (grazers, viruses, bacteria, other phytoplankton), and self-organizational mechanisms (stability, indirect effects) interact with life-cycle transformations of Phaeocystis to mediate ecosystem patterns of trophic structure, biodiversity, and biogeochemical fluxes? Ultimately the goal is to understand and thus predict why Phaeocystis occurs when and where it does, and the bio-feedbacks between this keystone species and the multitrophic level ecosystem. [ABSTRACT FROM AUTHOR]

Automated detection of fog and low stratus in nighttime satellite data has been implemented on the basis of numerous satellite systems in past decades. Commonly, differences in small-droplet emissivities at 11μm and 3.9μm are utilized. With Meteosat SEVIRI, however, this method cannot be applied with a fixed threshold due to instrument design: The 3.9μm band is exceptionally wide and overlaps with the 4μm CO2 absorption band. Therefore, the emissivity difference varies with the length of the slant atmospheric column between sensor and object. To account for this effect, the new technique presented in this paper is based on the dynamical extraction of emissivity difference thresholds for different satellite viewing zenith angles. In this way, varying concentrations of CO2 and column depths are accounted for. The new scheme is exemplified in a plausibility study and shown to provide reliable results. [ABSTRACT FROM AUTHOR]

The scientific community that includes meteorologists, physical scientists, engineers, medical doctors, biologists, and environmentalists has shown interest in a better understanding of fog for years because of its effects on, directly or indirectly, the daily life of human beings. The total economic losses associated with the impact of the presence of fog on aviation, marine and land transportation can be comparable to those of tornadoes or, in some cases, winter storms and hurricanes. The number of articles including the word "fog" in Journals of American Meteorological Society alone was found to be about 4700, indicating that there is substantial interest in this subject. In spite of this extensive body of work, our ability to accurately forecast/nowcast fog remains limited due to our incomplete understanding of the fog processes over various time and space scales. Fog processes involve droplet microphysics, aerosol chemistry, radiation, turbulence, large/small-scale dynamics, and surface conditions (e.g., partaining to the presence of ice, snow, liquid, plants, and various types of soil). This review paper summarizes past achievements related to the understanding of fog formation, development and decay, and in this respect, the analysis of observations and the development of forecasting models and remote sensing methods are discussed in detail. Finally, future perspectives for fog-related research are highlighted. [ABSTRACT FROM AUTHOR]

There is insufficient data on the extent, severity and trend of land degradation in Africa. Through a four steps approach, which is based on the identifi- cation of a pillar layer (FAO problem soils map) and the combination of dynamic factors (human activities, livestock, climate) to determine risk factors, the current paper aims at providing quantitative data on the status and trend of land degradation at agro-ecological and main river basin levels. The results revealed that: (i) "hot spots" of land degradation are largely predominant at continental level, compare to the "bright spots" of very low to low degradation; (ii) there is an increasing trend of severity and extend of land degradation from the humid zones of the Congo and Zambezi basins (24 to 29%) to the dry areas of the Nile, Niger and lake Chad basins (78 to 86%); (iii) the interrelation and cumulative effects of water and wind erosion are also increasing along these agro ecological zones. The study also stressed on the high spatial variability in the extent and trend of degradation process according to the various agro-ecological zones and river basins. This variability could be strongly linked to soils behaviour and level of resistance, to the quality of their surrounding environment as well as to the impact of investments for conservation of natural resources and for better land care. [ABSTRACT FROM AUTHOR]

The principle purpose of an early warning system is to collect an appropriate set of data and information regularly, in a consistent manner so as to provide a sense of trends and enable prediction of future status of the environment and events on a timely basis. This is done with a view to have populations at risk to be in a state of preparedness to prevent and respond to disasters. It enables them improve response, save lives and property, reduce damage to property and reduce human suffering from the extreme events and processes. The concepts and science and technology for early warning systems have been substantially improved and refined over the last 30 years. Broad institutional arrangements and networks at various levels have equally developed tremendously during the same period. Even if not always perfect, the systems have globally given results in terms of indications and trends that have often attracted interventions but unfortunately not in many countries. States are being urged to address the issue as apart of their national risk management responsibility. However, it requires states to have conviction, commitments, laws and other instruments like development strategies and programmes that include National Action Programmes to Combat Desertification (NAPs) to implement interventions that ideally should be driven by an existing early warning system (EWS). There are instances in the IGAD sub-region where early warnings were issued but "ignored" and regretfully governments and responsible institutions were blamed for not having done enough before, during and after the disastrous events and processes like desertification, droughts, famines and floods. Redressing the situation proves to be even more costly. This paper endeavors to demonstrate that although the science and systems have been developed in the IGAD sub-region where extreme events abound, responses have not always been adequate. It is proposed that the solutions may lie in formulating strong pro-EWS policies, legal and institutional frameworks to enable effective utilization of the available science and technological capabilities. This will save our environment, reduce disastrous processes and events and promote the culture of risk assessments and management by the state. One of the appropriate vehicles to promote this can be the NAPs. The emphasis is on placement of early warning systems in a legal and institutional framework. This is with a view to influencing decision and policy making on risk management of our environment. Some of the legal areas that can be targeted for repeal to accommodate EWS are those of national statistical services, disaster management laws, and environmental management laws. [ABSTRACT FROM AUTHOR]

By the 1950s, a significant proportion (over 15 000 km2) of the Ord River catchment in north-west Australia was severely degraded through excessive grazing pressure, in particular cattle and feral donkeys. Beginning in 1960, a ‘whole of government' approach to rehabilitation of the degraded area was taken by the Western Australian government. This extended regeneration program was characterized by a combination of changed government land use priorities with legislative and regulatory backing, animal control, reclamation works and sequences of years of both favourable and unfavourable rainfall. Various factors, both technical and non-technical, influenced the success of the regeneration program. These included resumption by the State government of all or part of five grazing leases (following an initial abortive attempt at rehabilitation while cattle production activities continued), a complete destocking program to remove both cattle and feral donkeys, and the initiation of a Government-funded grassland replanting program. The Government enacted specific legislation, the Ord River Dam Catchment Area (Straying Cattle) Act, 1967, which passed control of all cattle in the rehabilitation area to Government. Assessment in 2002 suggested that the regeneration program was remarkably successful, to the extent that, in 2006, the area was included in the Western Australian conservation estate. Rehabilitation of this type requires a certain combination of factors to be successful, although some, such as rainfall, are outside management control. This paper examines the rehabilitation program, assesses the factors important in its success and identifies those factors which may be relevant to other situations. [ABSTRACT FROM AUTHOR]

The relationship between agriculture and environment could be viewed as conflicting (win-lose) or as synergistic (win-win). A win-lose situation is occurring when agricultural activities such as clearing forest for cultivation is leading to environmental degradation or when environmental protection prevents agricultural activity. A synergistic approach, on the other hand, assumes that sustainable environmental management and agricultural production can be achieved simultaneously. One central goal of the Global Environment Facility (GEF) and UNEP is to mainstream sustainable land management into sectors such as agriculture and forestry, thus assuming that win-win situations are possible. The different conceptual frameworks that UNEP has applied and developed in its GEF-funded land degradation projects highlight different aspects of the relationship between agriculture and environment. The paper draws on 10 years of UNEP/GEF experience in working at the environment-agriculture nexus starting with the People, Land Management and Environmental Change Project (PLEC). PLEC illustrates the potential for synergies between environmental and developmental objectives by developing sustainable and participatory approaches to biodiversity management and conservation based on farmers' technologies and knowledge within agricultural systems. The Land Use Change, Impacts and Dynamics Project (LUCID) developed a model on how to use land use change analysis in combination with social and economic variables as a tool to assess biodiversity loss and land degradation across landscapes. The Millennium Ecosystem Assessment (MA) assessment framework offers a mechanism for decision-makers to: (1) identify options that can better achieve core human development and sustainability goals; and (2) better understand the trade-offs involved in decisions concerning the environment. The Land Degradation Assessment in Drylands (LADA) uses the Driving Forces-Pressures-State-Impact-Responses (DPSIR) framework in analysing the environment-agriculture nexus in drylands. This overview shows how the relationship between agriculture and environment can be analysed using different models and approaches depending of scale and level of analysis. The PLEC model is useful at the local level in reconciling environmental and livelihood goals. Land use change analysis is a useful tool at the landscape level in analysing drivers of land degradation and biodiversity loss. The ecosystem services approach by the MA provides a tool for decision-makers at national level to make informed decisions about trade-offs between agriculture/human well-being and the environment. Finally, LADA will use the DPSIR framework for integration of information collected at different scales, from the local to the global. [ABSTRACT FROM AUTHOR]

Recent national assessments document that nitrogen-driven coastal eutrophication is widespread and increasing in the United States. This significant coastal pollution problem includes impacts including increased areas and severity of hypoxic and anoxic waters; alteration of food webs; degradation and loss of sea grass beds, kelp beds and coral reefs; loss of biodiversity; and increased incidences and duration of harmful algal blooms. In this paper, we review two complementary approaches to assessing the causes and consequences of these trends, as well as potential remedies for them. The first is a national-scale assessment, drawn primarily from expert knowledge of those most familiar with the individual estuaries and integrated into a common analysis framework. The second approach, focused on the Mississippi/Atchafalaya basin — the largest US drainage basin — draws upon both quantitative and qualitative analyses within a comprehensive framework, Integrated Assessment. [ABSTRACT FROM AUTHOR]

Anthropogenic actions are altering fluxes of nitrogen (N) in the biosphere at unprecedented rates. Efforts to study these impacts have concentrated in the Northern hemisphere, where experimental data are available. In tropical developing countries, however, experimental studies are lacking. This paper summarizes available data and assesses the impacts of human activities on N fluxes in Puerto Rico, a densely populated Caribbean island that has experienced drastic landscape transformations over the last century associated with rapid socioeconomic changes. N yield calculations conducted in several watersheds of different anthropogenic influences revealed that disturbed watersheds export more N per unit area than undisturbed forested watersheds. Export of N from urban watersheds ranged from 4.8 kg ha−1 year−1 in the Rí o Bayamón watershed to 32.9 kg ha−1 year−1 in the highly urbanized Río Piedras watershed and 33.3 kg ha−1 year−1 in the rural-agricultural Río Grande de Añasco watershed. Along with land use, mean annual runoff explained most of the variance in fluvial N yield. Wastewater generated in the San Juan Metropolitan Area receives primary treatment before it is discharged into the Atlantic Ocean. These discharges are N-rich and export large amounts of N to the ocean at a rate of about 140 kg ha−1 year−1. Data on wet deposition of inorganic N (NH4+ + NO3−) suggest that rates of atmospheric N deposition are increasing in the pristine forests of Puerto Rico. Stationary and mobile sources of NOx (NO+NO2) and N2O generated in the large urban centers may be responsible for this trend. Comprehensive measurements are required in Puerto Rico to quantitatively characterize the local N cycle. More research is required to assess rates of atmospheric N deposition, N fixation in natural and human-dominated landscapes, N-balance associated with food and feed trade, and denitrification. [ABSTRACT FROM AUTHOR]

The alteration of the nitrogen (N) cycle by human activities is widespread and has often resulted in increased flows of nitrogen to the marine environment. In this paper we have attempted to know the changes of N fluxes in Cuba by quantifying the N inputs to the landscape from (1) fertilizer applications, (2) atmospheric deposition, (3) biological nitrogen fixation and (4) net import of food and feeds. N-inputs to the country progressively increased until the end of the 20th century, reaching a peak during the 80s when low cost fertilizer imported from the former Soviet Union led to heavy rates of application. This rapid growth represented more than a 5-fold increase with respect to pristine values; higher than the two-fold global increase of anthropogenic N reported by Vitousek et al. (1997 Human alteration of the global nitrogen cycle: sources and consequences. Ecol. Appl. 7:737-750). Inorganic fertilizer was the largest single source of reactive N, followed by atmospheric deposition, biological fixation, and net imports of foods and feed-stocks. Nitrogen inputs peaked in 1987 and data expressed on an area basis show that N flux to the Cuban landscape, in the 80s, was one of the highest reported in the literature. During the 90s, there was a dramatic drop in nitrogen inputs mainly associated to a decrease in the use of inorganic fertilizer. Other factors reducing nutrient inflows to Cuba, during the same period, were imports of foodstuff and livestock feeds, a decrease of nitrogen oxide emissions, and a decrease in the sugar cane crop area. Using an empirical relationship (Howarth et al. 1996 Regional nitrogen budgets and riverine N & O fluxes for the drainages to the North Atlantic Ocean: Natural and human influences. Biogeochemistry 35:75-139) we present a very preliminary estimate of N-inputs to coastal waters and discuss the consequences of these changes on the coastal zone. [ABSTRACT FROM AUTHOR]

The production of reactive nitrogen worldwide has more than doubled in the last century because of human activities and population growth. Advances in our understanding of the nitrogen cycle and the impacts of anthropogenic activities on regional to global scales is largely hindered by the paucity of information about nitrogen inputs from human activities in fast-developing regions of the world such as the tropics. In this paper, we estimate nitrogen inputs and outputs in Brazil, which is the world's largest tropical country. We determined that the N cycle is increasingly controlled by human activities rather than natural processes. Nitrogen inputs to Brazil from human activities practically doubled from 1995 to 2002, mostly because of nitrogen production through biological fixation in agricultural systems. This is in contrast to industrialized countries of the temperate zone, where fertilizer application and atmospheric deposition are the main sources of anthropogenic nitrogen. In Brazil, the production of soybean crops over an area of less than 20 million ha, was responsible for about 3.2 Tg N or close to one-third of the N inputs from anthropogenic sources in 2002. Moreover, cattle pastures account for almost 70% of the estimated 280 × 106 ha of agricultural land in Brazil and potentially fix significant amounts of N when well managed, further increasing the importance of biological nitrogen fixation in the nitrogen budget. Much of these anthropogenic inputs occur in the Brazilian savannah region (Cerrado), while more urbanized regions such as the state of São Paulo also have high rates of nitrogenous fertilizer inputs. In the Amazon, rates of anthropogenic nitrogen inputs are relatively low, but continuing conversion of natural forests into cattle pasture or secondary forests potentially add a significant amount of new nitrogen to Brazil given the vast area of the region. Better measurements of biological fixation rates in Brazil are necessary for improving the nitrogen budgets, especially at a more refined spatial scale. [ABSTRACT FROM AUTHOR]

Over the last decade, the growth in SPMD research and applications has been remarkable. Reports on thiswork have been in the form of graduate degree (masters and Ph.D.) theses, abstracts from presentations, laboratory reports, journal articles and book chapters. Herein, we provide the reader with a list of SPMD related peer-reviewed journal articles and book chapters. However, we do not claim that this list is complete and apologize in advance to authors of articles not included. In light of the current rate of the publication of SPMD related articles, additional papers will undoubtedly be available by the time this book is published. [ABSTRACT FROM AUTHOR]

This book is an attempt to blend an extended and cross-disciplinary research paper about an initially neglected obscure cosmic dust contamination of the early Earth into a kind of cosmic detective investigation, which should be comprehensible by the space sciences community and undergraduate students in general. The major objectives were to: [ABSTRACT FROM AUTHOR]

Increasing pressure on marine ecosystems resulting from various kinds of human activities has led to a number of global and regional international initiatives and conventions. Most prominent for northern European Seas are the Convention on Biological Diversity (CBD), the Helsinki Convention on the Protection of the Marine Environment of the Baltic Sea, the OSPAR Convention for the Protection of the Marine Environment of the North-East Atlantic, and the Birds and Habitats Directives of the EU. The fundamental goals of marine nature conservation can be described as to conserve, protect, restore and manage: the functioning of marine ecosystems and their services;the regenerative capacity of natural resources and their sustained availability for human use;natural diversity, population dynamics, density and age structure of marine fauna and flora;intact and diverse natural marine habitats and biotopes; andthe characteristic features and beauty of nature and viewscapes. These conservation objectives can only be achieved if human activities affecting our oceans and seas were conducted by applying six key principles: (1)the precautionary principle;(2)best environmental practices (BEP);(3)best available technologies (BAT);(4)the polluter-pays principle;(5)the compensation or substitution principle; and(6)the avoidance principle. Further, the ecosystem approach to the management of human activities as has been clarified by the Helsinki- and the OSPAR Conventions should always be applied. Probably the most effective measure to achieve substantial marine conservation is to establish coherent networks of Marine Protected Areas (MPAs) at regional and global levels. This needs to be complemented by general habitats and species protection and enhancement, as well as by undiminished efforts to reduce unsustainable extraction of natural resources, to minimize eutrophication and pollution and to hinder new discharges to the seas. Red lists of threatened, endangered and/or declining species, habitats or biotopes would help assess the status of marine biodiversity, the effects of human activities, and the possible success of interventions. This paper describes the most relevant international conventions and regulations with respect to marine nature conservation of the seas in Northern Europe (North East Atlantic and Baltic Sea). The current implementation status of conservation measures and specifically of MPAs and some next steps are also outlined. [ABSTRACT FROM AUTHOR]

The laws of thermodynamics constrain transformation of materials and energy, and thus have implications for economic processes. This paper provides an overview over the uses and applications of concepts from thermodynamics in economic analysis at the level of individual processes and explores potential constraints at larger system levels - the economy as a whole and the ecosystems within which economies are embedded. Specific emphasis will be placed on the ways in which insights from equilibrium and non-equilibrium thermodynamics can be used to better describe - and understand - economic activity and its interactions with the global environment. [ABSTRACT FROM AUTHOR]

In this paper I review some applications of nonequilibrium thermodynamics to planetary science. Of particular importance are the horizontal and vertical transports of heat in planetary atmospheres. It has been noted that Titan and Mars, like the Earth, appear to have equator-to-pole heat transports consistent with a Maximum Entropy Production principle. The transport of heat by convection in the atmospheres and interiors of the planets can be viewed in heat engine terms, and useful insights gained by considering the irreversibilities in these systems. Even bodies in space without an atmosphere can act as heat engines, their orbits being modified by the Yarkovsky effect wherein sunlight is downconverted into thermal radiation which is reradiated anisotropically - a rocket using thermal photons as propellant. Finally, spacefaring civilizations may seek to maximize the production of entropy from their parent stars by erecting a Dyson sphere in order to reject its power at a minimum temperature. [ABSTRACT FROM AUTHOR]

In this paper we provide an example of the alternative approach, based on the Banyoro people in the humid, Interlacustrine region of Western Uganda known historically as Kitara, the region roughly centred on Mubende and encompassing much of what was regarded as Bunyoro, Toro, Nkore, and perhaps western parts of Buganda in the late nineteenth century (Sutton 1993). Kitara has the advantage of being a locus for a range of relevant, multi-disciplinary information, sources of which include rich oral histories, archaeological excavations at a comparatively advanced state and sediment-based, palaeoenvironmental studies. [ABSTRACT FROM AUTHOR]

In this paper, we will present preliminary results from the working group on coupled experiments. We first describe the boundary conditions and the models (section 2) and some aspects of the simulated mid-Holocene changes (section 3) as shown by both the basic PMIP experiments and the coupled OAGCM experiments. In sections 4 and 5, we present the data-sets and the methodology used for the model-data comparisons. We then focus on the evaluation of the coupled simulations over Northern Africa (section 6) and compare them with the basic PMIPAGCMsimulations. Finally we discuss the implications of these results for the future. [ABSTRACT FROM AUTHOR]

To improve our understanding of climate variability on decadal to centennial time-scales, it is crucial to use a hierarchy of climate models in addition to palaeoclimate reconstructions based on proxy data. Climate models give a physically consistent overview of the global climate on all time-scales. They are useful tools in palaeoclimatology, since: (i) they can be used to test hypotheses that have been inferred from palaeo-data; and (ii) they can provide plausible explanations of observed phenomena (e.g., Isarin and Renssen (1999), Kohfeld and Harrison (2000)). In recent years, considerable progress in palaeoclimate modelling has been made with the extensive use of models that consider the coupling of the different components of the climate system (atmosphere, ocean, sea-ice, vegetation). The aim of this paper is to inform the palaeo-data community on recent developments in palaeoclimate modelling, with special reference to the Holocene climate. In the first section, different model types and experiments are discussed, together with a short overview of Holocene climate modelling studies and differences between models and palaeo-data. In the second section, three important issues are further illustrated by discussing in detail three studies that use state-of-the-art models. [ABSTRACT FROM AUTHOR]

The best available global climate information covering the last few thousand years is that obtained from the marine record, which averages worldwide effects of temperature and ice volume change, and is only marginally influenced by the localised climate changes that occur in areas less than continental in size. Consequently one of the key questions in palaeoclimate study is to understand climate changes occurring on land, and the sea-land relationships. Continental palaeoclimates have been studied using a variety of approaches such as geomorphological analyses, lake levels, archaeological studies, and pollen studies (e.g., Street and Grove (1976), Cerling et al. (1989), Gasse et al. (1990), Rossignol-Strick (1995), Weiss (2000), Magri et al. (this volume), Roberts et al. (this volume)). Recently there has been an increased interest in using the oxygen and carbon isotopic composition of speleothems as a climate proxy, because these isotopic compositions provide climate information, and U - series isotope dates give accurate chronological information. The study of the isotopic composition of speleothems has been performed throughout the world in different climatic zones in the northern hemisphere, the tropics, the Mediterranean, and the southern hemisphere (e.g., Dorale et al. (1992, 1998), Holmgren et al. (1995), Ayliffe et al. (1998), Burns et al. (1998, 2001), Bar-Matthews et al. (1999, 2000), Denniston et al. (1999), Frumkin et al. (1999), Lauritzen and Lundberg (1999), McDermott et al. (1999), Williams et al. (1999), Musgrove et al. (2001)). In this paper we integrate studies of the present-day parameters such as average cave and air temperature, rainfall amount and its isotopic composition, the isotopic composition of the sea-surface source, and of the host rock and soil, in order to understand how the isotopic composition of speleothems recorded palaeoclimate conditions during the last 185 kyr. [ABSTRACT FROM AUTHOR]

In this paper, we present a comprehensive synthesis of our recent studies on the past hydrological changes of the Mediterranean Sea (Kallel et al. 1997a; 1997b; 2000) and their relation with climatic change, which occurred in the Mediterranean area during the last two climatic cycles. In addition, we have generated a new detailed climatic record of the Holocene in a Western Mediterranean Sea core to determine the timing of the Holocene wet period.We therefore estimated variations of sea-surface temperature and salinity in the Mediterranean Sea during the last 200,000 years. Four cores recovered in the major basins were used. We first show that Mediterranean sediments record both changes observed in the North Atlantic temperature and salinity and in the local Mediterranean fresh-water budget by using a new data of a well-dated core recovered in the Tyrrhenian Sea. We then reconstruct a map of Mediterranean Sea surface salinity (SSS) at the time of the last sapropel (middle Holocene). These data, combined with the sea-surface temperature (SST) estimates, are used to propose a mode of formation for the sapropel. Finally, we have tested the validity of this model for five other sapropels, which occurred during the last 200,000 years. [ABSTRACT FROM AUTHOR]

Droughts and wet periods in recent earth history have a clear link with human habitation and migration notably in the Middle East and in Africa. Water availability in the form of perennial rivers, lakes and springs dictated the first settlement patterns. Reference is found in the first written records to dramatic climatic changes affecting water availability (Lambert and Millard 1969) and a fascinating challenge exists to reconstruct and to relate the hydrological records to the early historical and archaeological evidence (Issar 1990; Hassan 1997) as well as the rapidly growing body of data on palaeoclimate. Groundwater is emerging as an archive at both low and mid-latitudes of past climatic and hydrological change, which may be used alongside other proxy data. Indirect evidence of the palaeohydrology in the late Pleistocene and Holocene, has been deduced from various sources especially lake sediments (Fontes and Gasse 1991; Gasse 2000; Hoelzmann et al. 2000; this volume) and speleothems (Bar-Matthews et al. 1997). In contrast to other archives such as ice cores or tree rings, which contain high-resolution information, data available in large groundwater bodies are of low resolution (typically ±1000 yr). This is due to the advection or dispersion of any climatic input signal in the water body. Many groundwater data are obtained from pumped samples where sample intervals may extend over tens of metres. Nevertheless, specific indications of palaeo-temperature, air mass circulation and vegetation history may be retained in a range of different chemical and isotopic signals (Fontes et al. 1993a; Stute and Schlosser 1993), notably in confined aquifers where sequential changes may be recorded along flow lines, or in the stratification of phreatic aquifers. Dated groundwaters are important since these contain the direct evidence of prolonged wet episodes. Even the absence of dated waters over a specific time interval may indicate periods of drought (Sonntag et al. 1978). The correlation between groundwater records and aeolian deposition in semi-arid/arid regions (Stokes et al. 1998; Swezy 2001) can also provide complimentary evidence of wet and dry intervals. Moisture in the unsaturated zone may under favourable circumstances also contain records of past environments and climate at decadal to millennial scale resolution, contained mainly as variations in salinity and in stable isotope enrichments (Edmunds and Tyler 2002). Such records are found in porous media in areas of low moisture flux, notably beneath modern arid or semi-arid areas. The resolution of unsaturated (vadose) zone records will depend on the dispersion of the signal (Cook et al. 1992) but decadal scale records may be retained, as in West Africa, over several hundred years (Edmunds and Gaye 1997), or at the millennial scale over the late Pleistocene (Tyler et al. 1996). Some of the classical studies of hydrogeological systems that contain palaeo-waters have been conducted in Northern Africa and in Western Europe over the past three decades. In this paper the evidence contained in unsaturated zone profiles and especially in phreatic and confined aquifers in semi-arid and arid areas of Northern Africa is used to demonstrate the current possibilities in using groundwater archives. The results from Northern Africa are then compared with the evidence found in palaeowaters in Europe and elsewhere along the PEP III transect. [ABSTRACT FROM AUTHOR]

The Horn of Africa extends from the Sahara desert eastwards to the Red Sea, the Gulf of Aden and the Indian Ocean. Due to its complex volcano-tectonic evolution over the past 15 million years (Mohr 1971), the region is characterised by considerable changes in elevation within short distances. The Ethiopian highlands, which rise to altitudes exceeding 4000m above sea level, form an extensive uplifted plateau, delimited by pronounced escarpments on both east and west. In Southern Ethiopia the 1000 km-wide uplifted volcanic province is divided asymmetrically into northwestern and southeastern plateaux by the Main Ethiopian Rift which runs SSW-NNE and represents the northern end of the continental East African Rift. Eastward, the continental Afar Rift (Ethiopia and Republic of Djibouti) sits astride the Gulf of Aden—Red Sea sea-floor spreading axis, with several areas below sea level (e.g.,-155mat Lake Asal). These marked altitudinal gradients result in a wide variety of climates and environments, making the region particularly suitable for investigating past environmental change. The region is subject to the seasonal migration of the Inter-Tropical Convergence Zone (ITCZ) and is very sensitive to monsoon variability. Several studies have revealed climate variability from millennial to inter-annual timescales during the Late Quaternary (Gasse 2000). This paper provides a detailed overview of this region complementary to those of Hoelzmann et al. (this volume) and Barker et al. (this volume). It reviews Late Quaternary palaeoenvironmental and palaeoclimatic changes, as recorded from various archives (lakes, high altitude peat-bogs, glacial landforms, palaeosols), and proxies (geomorphology, sedimentology, geochemistry, pollen, diatoms). The chronological framework of most records is based on radiocarbon ages (14C yr BP). Radiocarbon ages are converted into calendar estimates (cal. yr) using the CALIB 4.0 program (Stuiver et al. 1998) back to 18,000 14C yr BP, or the polynomial equations established by Bard (1998) which allow calendar estimates back to 36,000 14C yr BP (41,516 cal. yr). Ages are first given in the time-scale provided in the original literature (14C kyr BP or cal. kyr), then the calibrated scale is indicated in brackets. [ABSTRACT FROM AUTHOR]

The large lakes of the East African Rift Valley provide a magnificent array of sedimentary basins that are actively recording the modern climate dynamics of tropical East Africa. The basins are perhaps 10 million or more years old (Cohen et al. 1993), and their deepest reaches have archived continuous records of past climate change that are unparalleled anywhere else in the tropics in terms of longevity coupled with resolution (Johnson 1993). These lakes are highly sensitive to climate variability, and their sediments carry rich signals of past environmental dynamics, inscribed in the assemblages of microfossils, the abundance and isotopic composition of endogenic minerals, bulk sediment texture and structure, and organic geochemistry. The International Decade for the East African Lakes (IDEAL) is a programme that has helped to steer and coordinate palaeoclimate studies on the rift lakes since the programme's inception in 1993 (Johnson 1993). The IDEAL community of scientists from North America, Europe, and Africa is investigating not only the climatic history of the large rift lakes, but modern processes within their basins as well. The "decade" of IDEAL officially started in 1995 with its first field programme on Lake Victoria (Lehman 1998). Since then IDEAL scientists have continued to carry on investigations on Lakes Edward, Malawi and Tanganyika, as well as on smaller lakes in East Africa. The IDEAL palaeoclimate community is presently turning its focus to Lake Malawi, where a major drilling programme is planned for the last two months of 2004. Lake Malawi is the southern-most of the rift lakes, and it appears to be exceptionally promising as a target for long, continuous records of past climate change. It has responded somewhat differently from lakes farther north in Africa to global climate forcing associated with orbital (Milankovitch) cycles of insolation. In contrast to Lake Tanganyika and the lakes of North Africa, Lake Malawi experienced relatively dry conditions during much of the early Holocene (Finney et al. 1996; Johnson 1996). The history of Lake Malawi derived from drilling operations therefore may provide important insight into how the southern tropics of Africa have responded differently from the northern tropics on time-scales ranging from millennia to decades. This paper presents recent data derived from piston cores recovered from the north basin of Lake Malawi. It focuses on the abundance and mass accumulation rate of biogenic silica (BSi MAR) measured in the cores, supplemented by some trace-element data and the species composition of the diatom assemblages. These results imply linkages between the climate dynamics of tropical Southern Africa and extratropical regions as far away as Greenland. [ABSTRACT FROM AUTHOR]

This special issue of the Journal of Pure and Applied Geophysics contains 15 papers related to fog, visibility, and low clouds that focus on microphysical and conventional surface observations, satellite detection techniques, modeling aspects, and climatological and statistical methods for fog forecasting. The results presented in this special issue come from research efforts in North America and Europe, mainly from the Canadian Fog Remote Sensing And Modeling (FRAM) and European COST-722 fog/visibility related projects. COST (http://www. cost.esf.org/) is an intergovernmental European framework for international cooperation between nationally funded research activities. COST creates scientific networks and enables scientists to collaborate in a wide spectrum of activities in research and technology. COST activities are administered by the COST Office. [ABSTRACT FROM AUTHOR]

The term "replenishment" is often misleading, as it suggests that soils are poor through depletion by farmers and that soils should be restored to their original state for agricultural production. This philosophy created awareness of the problems confronted by African farmers. It neglects, however, the heterogeneous redistribution of nutrients that is inherent to agricultural land use. Active and passive transport of organic matter causes centripetal concentration of nutrients around farms and villages and maintains or even improves the soil fertility of crucial fields at the cost of surrounding land. The advice to use fertilizers on bush fields in view of the use of compost and manure on compound fields is like "putting the cart before the horse"; the value-cost ratio of using inorganic fertilizer on compound fields is higher than that on bush fields because of the negative organic matter and nutrient balances in bush fields. The integrated use of inorganic fertilizers and organic forms of manure triggers a positive spiral of improved nutrient-use efficiency and improved soil organic matter status. The increase in value-cost ratio of fertilizer use improves access to fertilizer and other external inputs. Where crop- livestock integration is an important component of agricultural intensification, the centripetal concentration can even turn into the opposite; a centrifugal transport that replenishes (planned or unplanned) the depleted surroundings of farms and villages. Active replenishment of depleted soils is no requirement for agricultural development; intensification can start on village fields where fertility is maintained or improved. However, public investment in soils, focusing on reinforcement of the positive effects of the centripetal concentration of organic matter and nutrients, is recommended; it enables farmers to start fertilizer use where even if the compound fields at present do not allow it. [ABSTRACT FROM AUTHOR]

Cities are important driving forces in environmental trends as a consequence of the increase in the share of the global population that reside in urban areas and the large intensity of activities of urban dwellers. As the world continues to urbanize, however, humans have lost contact with soil and the services it provides to sustain life. A review of the literature shows that the ability of urban activities to influence the physical conditions and pollution levels in soils at a distance is increasing. Cities and urban processes have had dramatic but varying impacts on soil physical and biochemical properties and pollutant loads, all of which affect the life-supporting services of soils. As developing countries continue to industrialize, soil pollutant contamination in their cities continue to increase to levels warranting immediate action. We argue for a global assessment of urban soils to identify the patterns, processes, and unique circumstances of anthropogenic impacts. There is also the need for soil protection and remediation in areas already undergoing change as a result of urban development. [ABSTRACT FROM AUTHOR]

Globalization and increasing population pressure on food demand and land and water resources have stimulated interest in nutrient and virtual water flows at the international level. West Asia/North Africa (WANA), Southeast Asia, and sub-Saharan Africa are net importers not only of nitrogen, phosphorus, and potassium (NPK) but also of virtual water in agricultural commodities. Nevertheless, the widely recognized declines in soil fertility and problems related to water shortage continue to increase, especially in sub-Saharan Africa. The nutrients imported are commonly concentrated in the cities, creating waste disposal problems rather than alleviating deficiencies in rural soils. And also the water shortage problems continue to contribute to intensified desertification processes, which again lead to increased urbanization and thus water shortage problems in cities. Countries with a net loss of NPK and virtual water in agricultural commodities are the major food exporting countries-the USA, Australia, and some Latin American countries. Understanding the manifold factors determining the nutrient and water flows is essential. Only then can solutions be found which ensure a sustainable use of nutrients and water resources. The chapter ends by stressing the need for factoring environmental costs into the debate on nutrient and water management, and advocates more transdisciplinary research on these important problems. [ABSTRACT FROM AUTHOR]