CRITICAL ELEMENTS IN DESCRIBING AND UNDERSTANDING OUR NATION'S AQUATIC RESOURCES1

ABSTRACT: Despite spending $115 billion per year on environmental actions in the United States, we have only a limited ability to describe the effectiveness of these expenditures. Moreover, after decades of such investments, we cannot accurately describe status and trends in the nation's aquatic ecosystems or even those in specific regions. Why? This situation has arisen in part because we have excluded the fundamental principles of probability designs that are widely used in other fields and we have often ignored direct measures of biota, the subjects of greatest concern. To demonstrate the results of ignoring these powerful statistical and biological tools, we present four case studies. These studies compare estimates of aquatic resource status derived from using (1) a probability-based study design, often with biological measures of condition; and (2) a nonstatistical study design, often using chemical surrogates. In three of the four cases, the results derived from the nonstatistical perspective underestimate the degree of biological degradation.     

Microalgal communities epibiontic on the marine hydroid <Emphasis Type="Italic">Eudendrium racemosum</Emphasis> in the Ligurian Sea during an annual cycle

The microalgal community associated with Eudendrium racemosum, a marine hydroid widely distributed in the Mediterranean Sea, was studied during an annual cycle, at monthly frequency, in a coastal station of the Ligurian Sea. Microalgae were represented mainly by diatoms, which exhibited higher abundance and biomass values between autumn and spring (max 46,752 cells mm⁻² and 1.94 μg C mm⁻², respectively), while during summer a significant decrease was observed (min 917 cells mm⁻² and 0.013 μg C mm⁻²). High levels of abundance of filamentous cyanobacteria were observed in summer. Spatial distribution of epibiontic microalgae showed a markedly increasing gradient from the basal to the apical part of hydroid colonies. Considering the growth forms of diatom communities, motile diatoms (mainly small naviculoid taxa) were the most abundant in all the periods. Adnate (Amphora and Cocconeis spp.) were distributed mainly in the basal and central part of hydroid colonies and showed two peaks (autumn and summer). Erect forms (mainly Tabularia tabulata, Licmophora spp., Cyclophora tenuis) were mainly distributed in the apical part of the colonies and showed their maximum densities in spring–summer. Tube-dwelling (Berkeleya rutilans, Parlibellus sp.) were observed at low densities throughout the study period, without any significant temporal or spatial variability. Comparing the microalgal communities on marine hydroid to those grown on mimic substrata placed in the sampling station during summer, significantly higher values of abundance were observed in the hydroid, suggesting that microalgae may benefit from the polyp catabolites. This fact was particularly evident for the adnate diatoms, whose temporal trend paralleled the cycle of hydroid host.     

Abundance and population structure of perch (Perca fluviatilis L.) in some acidic Norwegian lakes

Abundance (catch per unit effort, n=3752) and population structure of perch Perca fluviatilis were studied in 30 acidic Norwegian lakes with relation to pH (4.3-5.9), calcium (0.41-2.44 mg litre(-1)), labile aluminium (24-255 microg litre(-1)) and total organic carbon (TOC, 1.7-13.8 mg C litre(-1)). Standard series of bottom gill-nets were used to sample fish populations. A multiple regression analysis showed that abundance was significantly correlated to TOC (P<0.05) and, to a smaller extent, to the Ca in lakes with concentrations between 0.41 and 1.70 mg litre(-1) (P=0.07). The lakes which were inhabited by pike were excluded from the analysis. Recruitment failure seems to be the main cause of reductions in perch numbers in the lakes studied. However, high mortality among adult individuals was also evident, and an episode of fish kill was observed in one of the lakes.     

Life cycle assessment of offset printed matter with EDIP97: how important are emissions of chemicals?

Existing product life cycle assessment (LCA) studies on offset printed matter all point at paper as the overall dominating cause of environmental impacts. All studies focus on energy consumption and the dominating role of paper is primarily based on the energy-related impact categories: global warming, acidification and nutrient enrichment. Ecotoxicity and human toxicity, which are related to emissions of chemicals, etc., are only included to a limited degree or not at all. In this paper we include the impacts from chemicals emitted during the life cycle of sheet fed offset printed matter. This is done by making use of some of the newest knowledge about emissions from the production at the printing industry combined with knowledge about the composition of the printing materials used. In cases with available data also upstream emissions from the production of printing materials are included. The results show that inclusion of the chemical emission-related impacts makes the EDIP97 impact profile of sheet fed offset products much more varied, as well for the normalised profiles as for the profiles weighted by distance to political environmental targets. Especially the ecotoxicity impact potential related to the production stage may contribute significantly, and the use of paper no longer becomes the overall dominating factor driving the environmental impacts.     

Recent developments in the analysis of Large Wood dynamics in fluvial systems

Environmental Fluid Mechanics -     

Decision support in urban water management based on generic scenarios: The example of NoMix technology

Urine source separation (NoMix technology) followed by processing the concentrated nutrient solution has the potential to become a cost-efficient alternative to conventional end-of-pipe nutrient elimination. A choice of processing technologies can only be made for specific scenarios, and there is currently no methodology for analyzing generic situations. In setting up a formalized decision-support methodology (based on STEEPLED analysis), we discuss how to create such generic scenarios, how to couple them with process engineering objectives, how to define the technology requirements, and finally how to produce a realistic subset of technology alternatives. The methodology is tested in five real scenarios. We also touch on the criteria for a final choice of technology taking into account large uncertainties about the performance of real technologies. We conclude that technology development is one of the most important requirements for implementing urine source separation in practice. There is an urgent need to develop cost-efficient processing technologies that satisfy the requirements of stakeholders.