Development and application of a catchment scale diffuse nitrate modelling tool

Water pollution from diffuse sources is a problem of increasing concern. Efforts to control diffuse pollution have been confined mainly to agricultural land and forests. Little attention has been paid to sources of diffuse pollution from urban areas. A diffuse nitrate modelling tool (DNMT) has been developed for modelling the fate of nitrate in urban areas. This tool works at the catchment scale and has a modular structure that consists of three components: the hydrological module, the nitrogen cycle module and the nitrate transport module. The hydrological model describes the possible flow pathways. The nitrogen cycle model accounts for the mass balance of nitrate and calculates the amount of nitrate for potential loss. The nitrate transport module simulates the movement of nitrate within and from the soil to the receiving water. This paper demonstrates the development of the tool and its application in the White Cart Water catchment. This implementation of the tool shows that it has a good capability for simulating the fate of nitrate in urban catchments. Copyright © 2005 John Wiley & Sons, Ltd.     

Kepler's Equation and Newton's method

Power series solutions of Kepler's Equation associated with Lagrange, Levi-Civita and Stumpff may be obtained by Newton's method as an algorithm for formal power series.     

Jurassic‐to‐present thermal history of the central High Atlas (Morocco) assessed by low‐temperature thermochronology

Apatite fission track (AFT) and (U–Th)/He data from the High Atlas have been obtained for the first time to constrain the tectono‐thermal evolution of the central part of the chain. Results from Palaeozoic basement massifs indicate long residence at low temperatures, consistently with their original location out of the deepest Mesozoic rift troughs and indicating minor exhumation. The best rocks for extracting the Alpine history of the Atlas Mountains are Jurassic intrusives, which yield AFT ages centred on c. 80 Ma; thermal models based on AFT data and constrained by (U–Th)/He suggest that these ages are included in a slow cooling trend from intrusion age to c. 50 Ma ago that we attribute to post‐rift thermal relaxation. This is followed by a stability period of c. 30 Ma and then by a final exhumational cooling until present exposure. Eocene intrusives yield AFT ages similar to those of Rb–Sr and K–Ar suggesting rapid emplacement in the uppermost crust.     

Thermochronological evidence for Mio‐Pliocene late orogenic extension in the north‐eastern Albanides (Albania)

New apatite and zircon (U–Th)/He and apatite fission‐track (FT) data allow constraining the timing of Miocene–Pliocene extensional exhumation that affected the central part of the Dinarides‐Albanides‐Hellenides orogen. Apatite (U–Th)/He ages in the northern and western Internal Albanides range from 57 to 17 Ma, contrasting to younger ages of 5.2–9.3 Ma in the eastern Internal Albanides. Eastward younging is also reflected in zircon (U–Th)/He ages varying from 101 Ma in the north‐western Internal Albanides to 19–50 Ma in the east, as well as in recently published apatite FT ages. Thermal history predictions with the new data point to a phase of rapid exhumation of the eastern Internal Albanides around 6–4 Ma, while the western Internal Albanides record slower continuous exhumation since the Eocene. This asymmetric exhumation pattern is most likely linked to extensional reactivation of NE–SW‐trending thrusts east of the Mirdita zone and within the Korabi zone of the eastern Internal Albanides.     

Peat porewater chloride concentration profiles in the Everglades during wet/dry cycles from January 1996 to June 1998: field measurements and theoretical analysis

Water quality is a key aspect of the Everglades Restoration Project, the largest water reclamation and ecosystem management project proposed in the United States. Movement of nutrients and contaminants to and from Everglades peat porewater could have important consequences for Everglades water quality and ecosystem restoration activities. In a study of Everglades porewater, we observed complex, seasonally variable peat porewater chloride concentration profiles at several locations. Analyses and interpretation of these changing peat porewater chloride concentration profiles identifies processes controlling conservative solute movement at the peat–surface water interface, that is, solutes whose transport is minimally affected by chemical and biological reactions. We examine, with an advection–diffusion model, how alternating wet and dry climatic conditions in the Florida Everglades mediate movement of chloride between peat porewater and marsh surface water. Changing surface water–chloride concentrations alter gradients at the interface between peat and overlying water and hence alter chloride flux across that interface. Surface water chloride concentrations at two frequently monitored sites vary with marsh water depth, and a transfer function was developed to describe daily marsh surface water chloride concentration as a function of marsh water depth. Model results demonstrate that porewater chloride concentrations are driven by changing surface water chloride concentrations, and a sensitivity analysis suggests that inclusion of advective transport in the model improves the agreement between the calculated and the observed chloride concentration profiles. Published in 2007 by John Wiley & Sons, Ltd.     

THE IMPACT-FLOOD CONNECTION: DOES IT EXIST?*

In a recent article in Terra Nova, Kristan-Tollmann and Tollmann (1994) suggested that the Biblical Flood can be explained by seven fragments of a comet that impacted the ocean at seven locations on Earth at 03.00h (C.E.T.) on 23 September, 9545 yr BP. We demonstrate that all the ‘geological proofs’ that allegedly support their conclusions are not supported by the available data on impact cratering. Their hypothesis is based on insufficient and ambiguous data, selective citation, and incomplete comprehension of previous research.