A SIMPLIFIED MODEL FOR PREDICTING DAILY TRANSMISSION LOSSES IN A STREAM CHANNEL1

ABSTRACT: A simplified approach for modeling transmission losses in a stream is presented. A theory relating seepage from a channel with the depth of flow is simplified to a one-parameter relationship. A power relationship is then utilized for the stage-discharge relationship, which is coupled with the seepage relationship. This combined equation is integrated over the channel reach to arrive at a general model for seepage loss through the reach, with one parameter needing calibration. An example is provided showing the development of the relationship and the calibration technique for the parameter. The results are shown, emphasizing the use of the model for simulation of channel transmission losses at low and moderate flow conditions.     

Bioventing pilot test results at the low point drain area at Offutt AFB,Nebraska

Bioventing is a relatively new technology that uses forced air movement to deliver supplemental oxygen to contaminated soils to stimulate the biodegradation of contaminants by indigenous microorganisms. A bioventing pilot test was initiated at Offutt Air Force Base, Nebraska, in August 1992, at a site contaminated with jet fuel. Air was injected into the subsurface over a period of 15 months, and tests were conducted at 6 months, and again at 15 months, to determine the effectiveness of the system. This article describes the bioventing process and its application at this test site. The results of the pilot test are discussed to illustrate the extent of the remediation accomplished through bioventing.     

Molecular phylogeny of metazoa (animals): Monophyletic origin

Dedicated to Prof. Dr. H. Risler and Prof. Dr. Dr. h. c. R. K Zahn     

Molecular biodiversity. Case study: Porifera (sponges)

Biological diversity--or biodiversity--is the term given to the variety of life on Earth and the natural patterns it forms. The biodiversity we see today is the fruit of billions of years of evolution, shaped by natural processes and, increasingly, by the influence of humans. It forms the web of life of which we are an integral part and upon which we so fully depend. The research on molecular biodiversity tries to lay the scientific foundation of a rational conservation policy that has its roots in various disciplines including systematics/taxonomy (species richness), present day ecology (diversity of ecological systems), and functional genetics (genetic diversity). The results of ongoing genome analyses (genome projects and expressed sequence tag projects) and the achievements of molecular evolution may allow us not only to quantitate the diversity of the present biota but also to extrapolate to their diversification in the future. A link between biodiversity and genomics/molecular evolution will create a platform which we hope may facilitate a sustainable management of organismic life and ensure its exploitation for human benefit. In the present review we outline possible strategies, using the Porifera (sponges) as a prominent example. On the basis of solid taxonomy and ecological data, the high value of this phylum for human application becomes obvious, especially with regard to the field of chemical ecology and the desire to find novel potential drugs for clinical use. In addition, the benefit of trying to make sense of molecular biodiversity using sponges as an example can be seen in the fact that the study of these animals, which are "living fossils", gives us a good insight into the history of our planet, especially with respect to the evolution of Metazoa.