Longitudinal trends in river functioning: Patterns of nutrient and carbon processing in three Australian rivers

Understanding longitudinal trends in the processing of carbon in rivers represents a much conceptualised, but infrequently tested, issue in aquatic ecology. In this study, we conducted concurrent longitudinal examinations of three very different rivers in eastern Australia to determine whether general principles in river functioning exist across broad geographic and hydrologic scales. Specifically, we examined trends in ambient basic water chemistry, nutrient concentrations, dissolved organic carbon (DOC), extracellular enzymes and food web structure and functioning and conducted bioassays to examine the degree to which DOC and nutrients limit heterotrophic bacterial respiration. These parameters revealed striking similarities across all sites. For metazoan communities, stable isotope analysis showed that algal carbon was the dominant basal resource utilised by consumers in all three rivers, suggesting that in‐stream primary producers strongly underpin trophic pathways regardless of the position within a catchment or catchment condition. Analyses of extracellular enzymes revealed that microbial communities are actively utilising DOC at all sites. In fact, heterotrophic microbial respiration was strongly limited by DOC at all sites, with nutrient additions resulting in only relatively minor increases in respiration. Ultimately, this study demonstrates that DOC and algal carbon are critically important drivers of ecosystem processes in Australian riverine ecosystems. Furthermore, across all of our sites and rivers, ambient nutrient concentrations did not influence carbon processing. The consistent longitudinal trends in river function identified in this study provide useful insights for catchment managers and modellers with respect to identifiying key principles that underpin ecosystem functioning in Australian rivers. Copyright © 2009 John Wiley & Sons, Ltd.     

Comparison of performance of statistical models in forecasting monthly streamflow of Kizil River,China

This paper presents the application of autoregressive integrated moving average(ARIMA),seasonal ARIMA(SARIMA),and Jordan-Elman artificial neural networks(ANN)models in forecasting the monthly streamflow of the Kizil River in Xinjiang,China.Two different types of monthly streamflow data(original and deseasonalized data)were used to develop time series and Jordan-Elman ANN models using previous flow conditions as predictors.The one-month-ahead forecasting performances of all models for the testing period(1998-2005)were compared using the average monthly flow data from the Kalabeili gaging station on the Kizil River.The Jordan-Elman ANN models,using previous flow conditions as inputs,resulted in no significant improvement over time series models in one-month-ahead forecasting.The results suggest that the simple time series models(ARIMA and SARIMA)can be used in one-month-ahead streamflow forecasting at the study site with a simple and explicit model structure and a model performance similar to the Jordan-Elman ANN models.     

From the gardens of the Qur'an to the “gardens” of Lahore

Mughal gardens are often interpreted as symbols of an Islamic paradise, but the precise relations between historical gardens and religious meaning remain vague. To clarify these relations, this paper compares garden imagery of the Qur'an with historical places of Lahore, Pakistan, “the Mughal City of Gardens”. Part one surveys garden imagery in the Qur'an to identify theological and aesthetic attributes of paradise. Part two shows how historical gardens, mosques, and shrines in Lahore exemplify different aspects of paradise symbolism. The results suggest new directions for the study of historical gardens and paradise symbolism in Muslim cultural landscapes.     

A preliminary modeling analysis of water quality in Lake Okeechobee, Florida: Calibration results

To gain understanding of nutrient and phytoplankton dynamics in Lake Okeechobee, Florida, we developed and applied a deterministic, mass balance, water quality model at the whole-lake spatial scale. The model was calibrated to a comprehensive set of field data for 1985–1986, and then used to simulate the period 1973–1992. The model represented the mean behavior of in-lake total phosphorus, dissolved available phosphorus, total nitrogen and chlorophyll a concentrations reasonably well during the calibration period. The model did not represent dissolved available nitrogen concentrations very well, nor did it capture much of the observed temporal variability during the calibration period. The model results identified important information needs to improve our understanding of the nitrogen cycle including, sediment-water nitrogen fluxes, denitrification and nitrogen fixation. Results from the 1973–1992 simulation indicated that model assumptions and/or calibration parameters were not uniformly applicable over this period. Total phosphorus concentration results from this model were compared with results from two site-specific, empirical loading models for the lake. None of these models represented annual average concentrations uniformly well over the entire 20-year period, and none captured much of the observed inter-annual variability. External total phosphorus loadings and lake hydrology are not sufficient to fully describe total phosphorus dynamics in Lake Okeechobee. Other important factors are diffusive sediment-water fluxes, wind-induced sediment resuspension, and the spatial heterogeneity in the lake.     

Analysis of signature patterns for discriminating fire detection with multiple sensors

Incorporating intelligence into a fire detector so that it can recognize signature patterns is intended to permit prompt fire detection while allowing the detector to discriminate between signatures from fire and nonfire sources. The primary purpose of this preliminary study is to investigate the patterns of signatures associated with fire and environmental sources using small-scale experiments. We generated products from a wide range of conditions, from flaming or pyrolyzing samples, to heated samples and samples obtained with an atomizer. We also measured gas concentrations, light obscuration, and temperature to characterize the products. By analyzing the data, we identified trends from which an elementary expert system can be formulated to identify the source of the airborne products. Several patterns are evident. The maximum CO₂ concentrations achieved during experiments with flaming fires are significantly greater than the maximum CO₂ concentrations achieved during experiments with nonflaming fires (pyrolyzing fires, heated liquids, and environmental odors). The nonflaming sources can be identified based on the CO and metal oxide sensor peak measurements. Except for three experiments using pyrolyzing solids, the peak CO concentration is greater—though the Taguchi detector response is less—for nonflaming fires than for environmental sources. Subsequent application of a neural network properly classifies all except one pyrolyzing fire.     

Spatial and temporal variation in distribution of larval lake whitefish in eastern Lake Ontario: Signs of recovery?

The lake whitefish (Coregonus clupeaformis) is one of the native Lake Ontario fishes that declined severely over the past century. Recent evidence of larval lake whitefish production in a historic spawning area (Chaumont Bay) might signal a recovery of this species in New York waters. We surveyed coastal and open water areas to evaluate densities and estimate total abundance of larval lake whitefish in Chaumont Bay. Other historic spawning areas and embayments with appropriate spawning and nursery habitat were also surveyed, but only a few larvae were found outside of Chaumont Bay. Lake whitefish larvae were found in every embayment sampled within Chaumont Bay, with larval densities of nearly 600/1000 m² in some samples. Greatest abundances occurred in the northern sectors and near the mouth of the bay. Open water densities were generally less than half that of nearshore sites. The total bay-wide estimate for 2005 was approximately 644,000 lake whitefish larvae, but dropped to 230,000–400,000 in 2006 and 2007, respectively. Mean larval growth rates (0.36 mm/day) did not differ by year, but were consistently higher in early May than in late April. Lake whitefish production in Chaumont Bay is encouraging for this species, but the cause and persistence of the decline after 2005 can be determined only by continued monitoring. Other possible bottlenecks of survival may exist at juvenile and adult stages and could significantly affect recruitment dynamics. This species is sensitive to normal climatic fluctuations and increased variability associated with global climatic change could make winter nursery conditions unfavorable for this species.     

Dreissenid mussels from the Great Lakes contain elevated thiaminase activity

We examined thiaminase activity in dreissenid mussels collected at different depths and seasons, and from various locations in Lakes Michigan, Ontario, and Huron. Here we present evidence that two dreissenid mussel species (Dreissena bugensis and D. polymorpha) contain thiaminase activity that is 5–100 fold greater than observed in Great Lakes fishes. Thiaminase activity in zebra mussels ranged from 10,600 to 47,900 pmol g^− 1·min^− 1 and activities in quagga mussels ranged from 19,500 to 223,800 pmol g^− 1·min^− 1. Activity in the mussels was greatest in spring, less in summer, and least in fall. Additionally, we observed greater thiaminase activity in dreissenid mussels collected at shallow depths compared to mussels collected at deeper depths. Dreissenids constitute a significant and previously unknown pool of thiaminase in the Great Lakes food web compared to other known sources of this thiamine (vitamin B₁)-degrading enzyme. Thiaminase in forage fish of the Great Lakes has been causally linked to thiamine deficiency in salmonines. We currently do not know whether linkages exist between thiaminase activities observed in dreissenids and the thiaminase activities in higher trophic levels of the Great Lakes food web. However, the extreme thiaminase activities observed in dreissenids from the Great Lakes may represent a serious unanticipated negative effect of these exotic species on Great Lakes ecosystems.     

Cycle-life model for graphite-LiFePO4 cells

In this report, cycling induced capacity fade of a LiFePO₄ battery was studied and cycle-life models were established. Cell life data for establishing the model were collected using a large cycle-test matrix. The test matrix included three parameters, temperature (−30 to 60 °C), depth of discharge (DOD) (90-10%), and discharge rate (C-rate, ranging from C/2 to 10C, with the 1C rate corresponding to 2A). At the low C-rates, experimental results indicated that the capacity loss was strongly affected by time and temperature, while the DOD effect was less important. At the high C-rates, the charge/discharge rate effects became significant. To establish a life model, we adopt a power law equation in which the capacity loss followed a power law relation with time or charge throughput while an Arrhenius correlation accounted for the temperature effect. This model, when parameters were allowed to change with C-rates, was found to represent a large array of life cycle data. Finally, we discuss our attempts in establishing a generalized battery life model that accounts for Ah throughput (time), C-rate, and temperature.     

Zur Methodik der Linientaxation bei der Erhebung von Sch?lereignissen

Zusammenfassung Zwischen 1995–1997 wurden im Rotwildgebiet Nord- und Rureifel, Nordrhein-Westfalen, 124 Schälaufnahmen nach der Methode der Linientaxation durchgeführt (Tab. 3). Die Untersuchung zeigt anhand von ca. 150.000 ausgezählten Stämmen eine Methodenoptimierung zur Schälerhebung auf. Von wesentlicher Bedeutung ist eine ausreichend große Stichprobenzahl an Stämmen im schälgefährdeten Bestand (Tab. 1). Es hat sich als hinreichend erwiesen, je Aufnahmefläche 1.000 Stämme in zehn 100-Stamm-Reihen auszuzählen (Abb. 1). Die durchschnittliche Zeitdauer einer Schälaufnahme mit Anfahrtsweg von Bestand zu Bestand und kurzer Vor- und Nachbereitung der Aufnahme, von einer Person durchgeführt, beträgt etwa 3 Stunden, maximal 4 Stunden. Um das Schälereignis möglichst vollständig zu erfassen, erfolgte die Schälaufnahme der Buche im August und die der Fichte Mitte September. Die Datenreihen wurden mittels Binomialverteilung auf eine ausreichende Genauigkeit in der Ermittlung des Schälprozentes statistisch überprüft (Tab. 4 und 5). Im Vergleich der bundesweit aktuell sieben verschiedenen Länder-Verfahren der forstwirtschaftlichen Schälschadenserhebung bringt die Linientaxation gegenüber den Stichprobenverfahren nach dem System der Klumpenstichproben den wesentlichen Vorteil eines hohen Stichprobenumfanges mit einer entsprechend hohen Genauigkeit des ermittelten Schälprozentes. Zudem entfällt die zeitaufwendige Suche und Identifizierung der einzelnen Anlaufpunkte in den Probekreisen.

---

On the method of line taxation for determining amounts of bark stripping

Summary Between 1995 – 1997 the method of line taxation was used to survey 124 samples of bark stripping damage incurred in the red deer districts of North and Ruhreifel, Northrhine Westfalia (Tab.3). On the basis of 150000 counted trunks this investigation showed an optimal method for the determination of bark stripping. Of paramount importance here is a sufficiently large sample size of trunks in bark stripping prone stands (Tab.1). The inclusion of 1000 trunks in 10 100 trunk rows per sample plot suffices (Fig.1) The average sampling time including driving time from stand to stand and brief preparation time before and after sampling is about 3 hours, maximally 4 hours for one person. In order to determine the amount of bark stripping as completely as possible, beech stands were sampled in August and spruce in mid-September. The data were statistically tested using a binomial distribution to provide sufficient accuracy in the determination of percent stripping (Tabs. 4 and 5). In comparing the present various methods for the determination of bark stripping damage to line taxation, this method has the clear advantage of a high degree of precision in determining percent bark stripping and large sample size in comparison to spot sampling. In addition the time consuming search for the individual sample plots in the selected sample areas can be circumvented.

---

A propos de l'estimation linéaire lors des relevés d'écorcements importants

Résumé De 1995 à 1997, 124 relevés d'écorcement ont été effectués dans les territoires à Cerf du Nordeifel et du Rureifel en Rhénanie-Westphalie au moyen de la méthode d'estimation linéaire (Tabl. 3). L'étude montre, sur base d'environ 150.000 arbres dénombrés, une optimisation de la méthode d'estimation des écorcements. Il est déterminant de disposer d'un échantillon suffisamment important d'arbres susceptibles d'être écorcés (Tabl. 1). Il s'est avéré suffisant de relever 1.000 pieds sur 100 rangées d'arbres par parcelle (Fig. 1). La durée moyenne du relevé pour une personne, en tenant compte des déplacements de parcelle à parcelle et d'un temps nécessaire avant et après le relevé, est de 3 à maximum 4 heures. Afin de procéder à un relevé aussi exhaustif que possible, les relevés d'écorcement du Hêtre ont lieu en août et ceux de l'Epicéa mi-septembre. Les séries de données ont été statistiquement vérifiées, en ce qui concerne la précision des relevés, au moyen d'une répartition binomiale (Tabl. 4 et 5). Comparée aux 6 différentes méthodes appliquées dans les différents Länder pour le relevé des dégâts d'écorcement, la méthode d'estimation linéaire présente l'avantage important, par rapport à la méthode par échantillonnage par blocs aléatoires, d'un échantillonnage important auquel correspond une précision élevée de la proportion des arbres écorcés. En outre, on fait l'économie de la recherche et de l'identification, exigeantes en temps, des différents points d'intersection du maillage où se situent les placettes de référence.

---

---

Eingesetzt wurde ein Druckkostenzuschuß der LÖBF/LAfAO NRW, Dezernat Forschungsstelle für Jagdkunde und Wildschadenverhütung, für dessen Gewährung verbindlich gedankt wird. — Die Schriftleitung     

Future bottlenecks in international river basins: where transboundary institutions,population growth and hydrological variability intersect

Using global data, this article examines the nexus of transboundary flood events and future social vulnerability. Which international river basins are forecast to experience an increase in both hydrological variability and population in the future, but currently lack institutional provisions to deal with these shared events? Concentrations of elevated risk are found in several basins in Central Asia, Central America and Central Africa. The article ends by highlighting transboundary basins that merit further investigation and possibly additional institution building to reduce urban flood risk.