Innovation and the dynamics of global warming

Global warming and the carbon cycle are a dynamic system with positive feedbacks. Fossil fuels are exhaustible resources. These two facts mean that innovation in clean energy technology, rather than mitigating global warming, can lead to a permanently higher temperature path. This paper explores the impact of innovation in the simplest model linking the economic theory of exhaustible resources with positive feedback dynamics in the carbon cycle.     

Limitations for heavy metal release during thermo-chemical treatment of sewage sludge ash

Phosphate recycling from sewage sludge can be achieved by heavy metal removal from sewage sludge ash (SSA) producing a fertilizer product: mixing SSA with chloride and treating this mixture (eventually after granulation) in a rotary kiln at 1000 ± 100 °C leads to the formation of volatile heavy metal compounds that evaporate and to P-phases with high bio-availability. Due to economical and ecological reasons, it is necessary to reduce the energy consumption of this technology. Generally, fluidized bed reactors are characterized by high heat and mass transfer and thus promise the saving of energy. Therefore, a rotary reactor and a fluidized bed reactor (both laboratory-scale and operated in batch mode) are used for the treatment of granulates containing SSA and CaCl₂. Treatment temperature, residence time and - in case of the fluidized bed reactor - superficial velocity are varied between 800 and 900 °C, 10 and 30 min and 3.4 and 4.6 m s⁻¹. Cd and Pb can be removed well (>95 %) in all experiments. Cu removal ranges from 25% to 84%, for Zn 75-90% are realized. The amount of heavy metals removed increases with increasing temperature and residence time which is most pronounced for Cu.In the pellet, three major reactions occur: formation of HCl and Cl₂ from CaCl₂; diffusion and reaction of these gases with heavy metal compounds; side reactions from heavy metal compounds with matrix material. Although, heat and mass transfer are higher in the fluidized bed reactor, Pb and Zn removal is slightly better in the rotary reactor. This is due the accelerated migration of formed HCl and Cl₂ out of the pellets into the reactor atmosphere. Cu is apparently limited by the diffusion of its chloride thus the removal is higher in the fluidized bed unit.     

Increasing extremes of heat and drought associated with recent severe wildfires in southern Greece

Mountains of the northern Mediterranean basin face two major threats under global change. Aridity and available fuel are both expected to increase because of climatic and land-use changes, increasing fire danger. There may already be signs of such effects in the case of the Pinus nigra and Abies cephalonica forests on Mt. Taygetos (southern Greece). We reconstructed climate (mid- to late-fire-season drought) using tree-rings for the last 150 years and compared it with the mountain’s fire history reconstructed from P. nigra fire scars. Seven, out of the ten, large fires Mt. Taygetos experienced were associated with below-normal precipitation (P) or above-normal maximum temperature (T _max). The largest fires occurred in late summer of 1879, 1944, 1998, and 2007. However, only the recent fires (1998 and 2007) had both low P and high T _max, also confirmed from long-term meteorological data. The synergy between climate and fuel availability may explain the very high intensity of 1998 and 2007 fires that burned mostly as stand-replacing crown fires. The other two large fire events (1879 and 1944) most likely occurred under reduced availability in burning fuel and were related to above-normal T _max. Our findings are among the first based on long-term and site-specific empirical data to support the prediction that Mediterranean mountainous areas will face a very large threat from wildfires in the twenty-first century, if socioeconomic changes leading to land abandonment and thus burning fuel accumulation are combined with the drought intensification projected for the region under global warming.     

Monitoring the formation of structures and patterns during initial development of an artificial catchment

The objective of this paper is to present observations, results from monitoring measurements, and preliminary conclusions about the development of patterns and structures during the first 5 years of development of an artificial catchment starting from point zero. We discuss the high relevance of initial system traits and external events for the system development and draw conclusions for further research. These investigations as part of a Collaborative Research Center, aim to disentangle and understand the feedback mechanisms and interrelationships of processes and their co-development with spatial and temporal structures and patterns by studying an initial, probably less complex ecosystem. Therefore, intensive measurements were carried out in the catchment with regard to the development of surface structures, hydrological patterns, vegetation dynamics, water chemistry, and element budgets. During the first 5 years, considerable changes within the catchment were observed. Both internal and external factors could be identified as driving forces for the formation of structures and patterns in the artificial catchment. Initial structures formed by the construction process and initial substrate characteristics were decisive for the distribution and flow of water. External factors like episodic events triggered erosion and dissection during this initial phase, promoted by the low vegetation cover, and the unconsolidated sandy substrate. The transformation of the initial geosystem into areas with evolving terrestrial or aquatic characteristics and from a very episodic to a more permanent stream network and discharge, together with the observed vegetation dynamics increased site diversity and heterogeneity with respect to water and nutrient availability and transformation processes compared with the more homogenous conditions at point zero. The processes and feedback mechanisms in the initial development of a new landscape may deviate in rates, intensity, and dominance from those known from mature ecosystems. It is therefore crucial to understand these early phases of ecosystem development and to disentangle the increasingly complex interactions between the evolving terrestrial and aquatic, biotic, and abiotic compartments of the system. Long-term monitoring of initial ecosystems may provide important data and parameters on processes and the crucial role of spatial and temporal structures and patterns to solve these problems. Artificially created catchments could be a suitable tool to study these initial developments at the landscape scale under known, designed, and defined boundary conditions.     

Predicting species dominance shifts across elevation gradients in mountain forests in Greece under a warmer and drier climate

Regional Environmental Change - The Mediterranean Basin is expected to face warmer and drier conditions in the future, following projected increases in temperature and declines in precipitation....     

Solid and liquid residues as raw materials for biotechnology

In the past few decades huge amounts of solid and paste-like wastes of domestic and industrial origin have been deposited on sanitary landfills worldwide. Only a small proportion was incinerated, where incineration plants were available. Since primary resources, such as ores for metal production or crude oil for the production of gasoline, diesel, solvents and plastics, or coal and natural gas as sources for energy or chemicals are not available in unlimited quantities, and because the deposition of residues, wastes and worn-out commodities on sanitary landfills causes pollution of the atmosphere, the soil and the groundwater due to hazardous gaseous emissions and toxic leachates, wastes from households and from industry must be avoided or minimized at an early stage. Whenever waste material can be recycled it must be re-introduced into production processes and the non-recyclable fractions should be used as a fuel for energy recovery. After incineration, the highly toxic dust fractions of ashes and slags resulting from burning the wastes should be deposited on sanitary landfills, while the granulated mineral slag fractions could be used as a substitute for the sand in cement as a construction material. Here we review various processes for the treatment of organic fractions of differently composed wastes to upgrade them to more valuable, re-usable products or at least to recover their energy content. Upgrading processes of organic wastes include composting, biogas fermentation, production of organic acids and solvents, and biopolymer or biosurfactants production. We also include biological purification procedures for the most important components of wastes, such as chitin from the shells of Crustaceae. Typical examples from pilot-scale or full-scale studies are discussed for each process.     

Relation between pesticide exposure and intrauterine growth retardation

The increased use of organophosphorus insecticides in agriculture and their widespread existence in the environment poses a potential health hazard. To determine the relationship between exposure to pesticides and intrauterine growth retardation (IUGR), live newborns from singleton pregnancies, with (n = 79) and without (n = 292) IUGR were studied. During the gestational period the mothers were living in agricultural communities in the state of Chihuahua, Mexico. Exposure to agrochemical products was evaluated. A significant association between the history of positive exposure to pesticides (i.e. the women themselves or their newborns who showed acetylcholinesterase activity levels lower than 20%) and the presence of IUGR was found. The proportions of exposure in the cases were 18% and 8% in the control group; the adjusted OR (fat free mass, anti-cytomegalovirus antibodies and placental weight) was 2.33 (p = 0.04).     

Effects of golf course construction and operation on water chemistry of headwater streams on the Precambrian Shield

To investigate the effects of golf course construction and operation on the water chemistry of Shield streams, we compared the water chemistry in streams draining golf courses under construction (2) and in operation (5) to streams in forested reference locations and to upstream sites where available. Streams were more alkaline and higher in base cation and nitrate concentrations downstream of operational golf courses. Levels of these parameters and total phosphorus increased over time in several streams during golf course construction through to operation. There was evidence of inputs of mercury to streams on two of the operational courses. Nutrient (phosphorus and nitrogen) concentrations were significantly related to the area of unmanaged vegetation in a 30 x 30 m area on either side of the sampling sites, and to River Bank Quality Index scores, suggesting that maintaining vegetated buffers along the stream on golf courses will reduce in-stream nutrient concentrations.     

Organochlorine compounds in a three-step terrestrial food chain

The concentrations of 15 organochlorine chemicals (PCBs and pesticides) were studied in a Central European oak wood food chain system: Great tit (Parus major), caterpillars (Tortrix viridana, Operophtera brumata, Erannis defoliaria), and oak-leaves (Quercus robur). Juvenile tits receive organochlorines from the mother via egg transfer and, eventually to a greater extent, from the caterpillar food source during nestling period. The concentrations of PCB 153 (2,2′,4,4′,5,5′-hexachlorobiphenyl, the most abundant in this study) was found in leaf material at ca. 1 ng/g, in caterpillars 10 ng/g, and in bird eggs 170 ng/g on an average and on a dry mass basis.