Microbial hydrolysis of polysaccharides and organic phosphates in the Northern Adriatic Sea

g -glucosidase and alkaline phosphatase, two ectoenzymes involved in the microbial decomposition of polysaccharides and organic phosphates, were evaluated in water samples collected from two areas of the Northern Adriatic Sea during the multidisciplinary Prisma II research project. The distribution of g -glucosidase and alkaline phosphatase is reported together with that of leucine aminopeptidase, an enzyme involved in the degradation of protein compounds. The data obtained showed the prevalence of g -glucosidase in summer months in the northern area, located in front of the Po delta, while in winter it is higher in the southern area (in front of Ancona). Phosphatase activity during February, 1998 had a maximum of 107 r nml m 1 h m 1 at a coastal station in the northern area; this enzyme appeared to be mainly associated with phytoplankton because the increase in alkaline phosphatase was associated with the increase of phytoplankton biomass, measured by chlorophyll a content. The relations between the microbial activities and environmental parameters are discussed.     

Microbial respiratory and ectoenzymatic activities in the Northern Adriatic Sea (Mediterranean Sea)

The carbon transfer through the microbial community in two areas of the Northern Adriatic Sea was estimated by proteolytic and respiratory activities during four oceanographic surveys carried out in June, 1996, 1997 and February, 1997, 1998. In front of the Po Delta (area A), the mean rates of proteolytic activity range from 4.9 to 9.9 r µg r C r h r l; near Ancona (area B), they range from 3.1 to 7.6 r µg r C r h r l. Respiratory rates vary between 0.19 and 2.29 and between 0.24 and 1.40 r µg r C r h r l in areas A and B, respectively. In general, high rates occur in the surface layers, within the first 10 r m of depth. In area A, proteolytic and respiratory rates undergo seasonal course, with high activity in warm periods. In area B, respiration and bacterioplankton abundance increase from the first to the second year, whilst proteolytic activity decreases. The sequence of metabolic steps in the carbon transfer within the bacteria, from the biotic vs . the abiotic compartment, was drawn in order to define the actual role of bacterial biomass in the biogeochemical fluxes in an ecosystem which often suffers distrophic crises. Respiratory turnover rates, in the upper 10 r m depth, reach low values in cold periods and high values in June, 1997. The carbon transfer versus mineralization flows better in the summer period, in particular in June, 1997. However, the bacterial growth efficiency ranges from 17 to 38% in area A and from 13 to 44% in area B with highest values in February, 1997, when bacteria contribute in a relevant way to the overall respiration.     

New methodological strategies for detecting bacterial indicators

The development of monitoring strategies for the early warning of seawater pollution, with particular reference to faecal and hydrocarbon contamination, has been the specific goal of research carried out within the Cluster 10-SAM (Advanced Systems for Coastal Marine Monitoring) Project, funded by the Italian Ministry for University and Scientific Research. Advanced analytical approaches have been designed and applied to detect bacterial species that have been selected as potential indicators of pollution in seawater samples. We report the results obtained using the fluorescent antibody and enzymatic assays for the detection of Escherichia coli, and a real-time PCR protocol for monitoring marine areas for hydrocarbon pollution. Immunofluorescence and enzymatic methods revealed the occurrence of different faecal pollution levels, reaching 10⁵ E. coli cells 100 ml^?1 in the Straits of Messina. Real-time PCR results corresponded to the different degree of oil pollution of the analysed samples. The specificity and speed make these methods promising for the detection and evaluation of marine pollution.     

Shared ways of thinking in Brazil about the science–practice interface in ecology and conservation

The debate in the literature on the science–practice interface suggests a diversity of opinions on how to link science and practice to improve conservation. Understanding this diversity is key to addressing unequal power relations, avoiding the consideration of only dominant views, and identifying strategies to link science and practice. In turn, linking science and practice should promote conservation decisions that are socially robust and scientifically informed. To identify and describe the viewpoints of scientists and decision makers on how the science–practice interface should work in order to improve conservation decisions, we interviewed Brazilian scientists (ecologists and conservation scientists, n = 11) and decision makers (n = 11). We used Q methodology and asked participants to rank their agreement with 48 statements on how the science–practice interface should work in order to improve conservation decisions. We used principal component analysis to identify shared viewpoints. The predominant viewpoint, shared by scientists and decision makers, was characterized by valuing the integration of scientific and strategic knowledge to address environmental problems. The second viewpoint, held mostly by decision makers, was distinguished by assigning great importance to science in the decision-making process and calling for problem-relevant research. The third viewpoint, shared only by scientists, was characterized by an unwillingness to collaborate and a perception of scientists as producers of knowledge that may help decision makers. Most participants agreed organizations should promote collaboration and that actors and knowledge from both science and practice are relevant. Disagreements concerned specific roles assigned to actors, willingness to collaborate, and organizational and institutional arrangements considered effective to link science and practice. Our results suggest there is ample room for collaborations and that impediments lie mainly in existing organizations and formal institutional arrangements rather than in negative attitudes between scientists and decision makers.     

Dissipation of glyphosate and aminomethylphosphonic acid in water and sediment of two Canadian prairie wetlands

Glyphosate [N-(phosphonomethyl)glycine] is the active ingredient of several herbicide products first registered for use in 1974 under the tradename Roundup. The use of glyphosate-based herbicides has increased dramatically over the last two decades particularly in association with the adoption of glyphosate-tolerant crops. Glyphosate has been detected in a range of surface waters but this is the first study to monitor its fate in prairie wetlands situated in agricultural fields. An ephemeral wetland (E) and a semi-permanent wetland (SP) were each divided into halves using a polyvinyl curtain. One half of each wetland was fortified with glyphosate with the added mass simulating an accidental direct overspray. Glyphosate dissipated rapidly in the water column of the two prairie wetlands studied (DT(50) values of 1.3 and 4.8 d) which may effectively reduce the impact of exposure of aquatic biota to the herbicide. Degradation of glyphosate to its major metabolite aminomethylphosphonic acid (AMPA) and sorption of the herbicide to bottom sediment were more important pathways for the dissipation of glyphosate from the water column than movement of the herbicide with infiltrating water. Presently, we are not aware of any Canadian guidelines for glyphosate residues in sediment of aquatic ecosystems. Since a substantial portion of glyphosate entering prairie wetlands will become associated with bottom sediments, particularly in ephemeral wetlands, guidelines would need to be developed to assess the protection of organisms that spend all or part of their lifecycle in sediment.     

Effect of solution pH on SO2, NO(x), and Hg removal from simulated coal combustion flue gas in an oxidant-enhanced wet scrubber

This paper presents a study on the simultaneous removal of SO2, NO(x) and Hg (both Hg0 and Hg2+) from a simulated flue gas by oxidant injection in a bench-simulated wet limestone scrubber for a wide range of slurry pH. The slurry pH strongly influenced the chemical mechanism in the scrubber and, therefore, affected pollutant removal. This paper also examines the potential ClO2(gas) reemission from a developed multipollutant scrubber at different slurry pHs. To better understand the chemical mechanisms at each slurry pH and to apply a mass balance to the process, detailed product ion analyses were performed for all experiments. Ion analysis covered three different chlorine species (chlorite, chloride, chlorate), sulfate, nitrite and nitrate. Different NO(x) removal efficiencies and mechanisms were found in acidic and alkaline pHs in the multipollutant scrubber. The acidic solution was favorable for NO and Hg0 oxidation, but increasing the slurry pH above 7.0 was disadvantageous for NO and Hg oxidation/removal. However the rate of NO(x) absorption (by percentage) was higher for the alkaline solution.     

Microscale Toxicity Identification Evaluation (TIE) for interstitial water of estuarine sediments affected by multiple sources of pollution

Estuaries in the world are affected by different contamination sources related to urbanisation and port/industrial activities. Identifying the substances responsible for the environmental toxicity in estuaries is challenging due to the multitude of stressors, both natural and anthropogenic. The Toxicity Identification and Evaluation (TIE) is a suitable way of determining causes of toxicity of sediments, but it poses difficulties since its application is labour intensive and time consuming. The aim of this study is to evaluate the diagnosis provided by a TIE based on microscale embryotoxicity tests with interstitial water (IW) to identify toxicants in estuarine sediments affected by multiple stressors. TIE showed toxicity due to different combinations of metals, apolar organic compounds, ammonia and sulphides, depending on the contamination source closest to the sampling station. The microscale TIE was able to discern different toxicants on sites subject to different contamination sources. There is good agreement between the results indicated in the TIE and the chemical analyses in whole sediment, although there are some disagreements, either due to the sensitivity of the test used, or due to the particularities of the use of interstitial water to assess the sediment toxicity. The improvement of TIE methods focused on identifying toxicants in multiple-stressed estuarine areas are crucial to discern contamination sources and subsidise management strategies.