Evidence needed to manage freshwater ecosystems in a changing climate: turning adaptation principles into practice.

It is widely accepted that climate change poses severe threats to freshwater ecosystems. Here we examine the scientific basis for adaptively managing vulnerable habitats and species. Our views are shaped by a literature survey of adaptation in practice, and by expert opinion. We assert that adaptation planning is constrained by uncertainty about evolving climatic and non-climatic pressures, by difficulties in predicting species- and ecosystem-level responses to these forces, and by the plasticity of management goals. This implies that adaptation measures will have greatest acceptance when they deliver multiple benefits, including, but not limited to, the amelioration of climate impacts. We suggest that many principles for biodiversity management under climate change are intuitively correct but hard to apply in practice. This view is tested using two commonly assumed doctrines: "increase shading of vulnerable reaches through tree planting" (to reduce water temperatures); and "set hands off flows" (to halt potentially harmful abstractions during low flow episodes). We show that the value of riparian trees for shading, water cooling and other functions is partially understood, but extension of this knowledge to water temperature management is so far lacking. Likewise, there is a long history of environmental flow assessment for allocating water to competing uses, but more research is needed into the effectiveness of ecological objectives based on target flows. We therefore advocate more multi-disciplinary field and model experimentation to test the cost-effectiveness and efficacy of adaptation measures applied at different scales. In particular, there is a need for a major collaborative programme to: examine natural adaptation to climatic variation in freshwater species; identify where existing environmental practice may be insufficient; review the fitness of monitoring networks to detect change; translate existing knowledge into guidance; and implement best practice within existing regulatory frameworks.

Mercury in soils, lakes, and fish in Voyageurs National Park (Minnesota): importance of atmospheric deposition and ecosystem factors.

Concentrations of methylmercury in game fish from many interior lakes in Voyageurs National Park (MN, U.S.A.) substantially exceed criteria for the protection of human health. We assessed the importance of atmospheric and geologic sources of mercuryto interior lakes and watersheds within the Park and identified ecosystem factors associated with variation in methylmercury contamination of lacustrine food webs. Geologic sources of mercury were small, based on analyses of underlying bedrock and C-horizon soils, and nearly all mercury in the 0- and A-horizon soils was derived from atmospheric deposition. Analyses of dated sediment cores from five lakes showed that most (63% +/- 13%) of the mercury accumulated in lake sediments during the 1900s was from anthropogenic sources. Contamination of food webs was assessed by analysis of whole, 1-year-old yellow perch (Perca flavescens), a regionally important prey fish. The concentrations of total mercury in yellow perch and of methylmercury in lake water varied substantially among lakes, reflecting the influence of ecosystem processes and variables that affect the microbial production and abundance of methylmercury. Models developed with the information-theoretic approach (Akaike Information Criteria) identified lake water pH, dissolved sulfate, and total organic carbon (an indicator of wetland influence) as factors influencing methylmercury concentrations in lake water and fish. We conclude that nearly all of the mercury in fish in this seemingly pristine

A review of the possible impacts of long-term oceanic and climate changes and fishing mortality on recruitment of anguillid eels of the Northern Hemisphere.

Possible causes of declines in recruitment of European, American and Japanese eels to continental waters are reviewed. Negative correlations between the Den Oever glass eel recruitment index (DOI) and the North Atlantic Oscillation Index since 1938 are discussed, together with older anecdotal evidence. Correlations are established between the DOI and sea surface temperature anomalies at 100-250 m between 1952 and 1995 in the Sargasso Sea/Sub-Tropical Gyre (STG) spawning area. It is hypothesised that, associated with global warming trends, STG warming inhibits spring thermocline mixing and nutrient circulation, with negative impacts on productivity and hence food for leptocephalus larvae. Concurrent gyre spin-up also affects major currents and slowing of oceanic migration has probably enhanced starvation and predation losses. Local factors, such as unfavourable wind-driven currents, can also affect recruitment of glass eels on continental shelves. In contrast, evidence is discussed that indicates fishing mortality and continental climate change appear to have had lesser impacts. Similar starvation-advection explanations for declines in Japanese eel recruitment are proposed. Predictions for the future are made and multidisciplinary and integrated monitoring and research are recommended for managing eel stocks and fisheries.

Paradoxical approach to the management of faecal incontinence in normal children.

Three children with faecal incontinence, in whom conventional treatment had failed, were managed with a regimen that focuses on the symptoms and present behaviour. It is short term and uses a paradoxical approach.

The biotransformation of three 14C-labelled phenolic compounds in twelve species of freshwater fish.

1. The urinary and biliary excretion of 14C-labelled m-cresol, 1-naphthol and o-chlorophenol were investigated in 12 species of freshwater fish (bitterling, Rhodeus sericeus amarus; bream, Abramis brama; crucian carp, Carassius carassius; goldfish, Carassius auratus; gudgeon, Gobio gobio; guppy, Poecilia reticulata; minnow, Phoximus phoximus; perch, Perca fluviatilis; roach, Rutilus rutilus; rudd, Scardinius erythropthalmus; three-spined stickleback, Gasterosteus aculeatus; tench, Tinca tinca) when immersed in sub-lethal concentrations of the compounds in the aquarium water for 48 h. 2. The sulphate and glucuronic acid conjugates of 1-naphthol and o-chlorophenol were detected in both the aquarium water and the bile of all the fish species. 3. The oxidation product of m-cresol, m-hydroxybenzoic acid, and the sulphate conjugate of the phenol, were excreted into the aquarium water of all species except the guppy, which did not excrete m-hydroxybenzoic acid. In addition to these two metabolites, the glucuronic acid conjugate of m-cresol was found in the bile of all species, except for guppies whose small size precluded study of biliary excretion.

Hydrolysis of the biliary glucuronic acid conjugate of phenol by the intestinal mucus/flora of goldfish (Carassius auratus).

1. An investigation was carried out on the hydrolytic activity of the intestinal mucus/flora on phenylglucuronide in the bile of goldfish. 2. Approximately 79% of the total phenylglucuronide (3.4 mumol) in the bile was hydrolysed after 16 h incubation with the intestinal mucus/flora. 3. Of the total phenol in the aquarium water of goldfish exposed previously to phenol for 48 h, 41% was found to be phenylglucuronide when fish were placed in a phenol-free medium and were dosed hourly for 8 h with D-saccharic acid 1,4-lactone to inhibit beta-glucuronidase activity in the intestine.

Uptake and interconversion of cholesterol and cholesteryl esters byPhytophthora cactorum.

When cholesterol, cholesteryl palmitate and cholesteryl acetate were added individually to sterol-free cultures ofPhytophthora cactorum, the free sterol was at first taken up more rapidly. By 24 hr, the uptake of esters and free sterol was similar. The 2 esters apparently are taken up by different mechanisms, since much acetate was found in extracts of the mycelium at early harvests, but very little palmitate. In cultures supplemented with a mixture of cholesterol and cholesteryl palmitate, the palmitate-derived cholesterol was preferentially incorporated into the free sterol fraction of mycelial extracts. Cholesteryl palmitate and acetate were both hydrolyzed, and free cholesterol esterified by filtrates of cultures grown on sterol-free medium. Reverse-phase chromatography on hydroxyalkoxy-propyl-Sephadex resolved the sterol esters of mycelial extracts into 3 zones, the most polar comprising mainly the linolenate ester, the next linoleate, and the least polar mainly oleate. Linoleate was predominant among the first sterol esters synthesized by the mycelium whether the supplement was free sterol, palmitate or acetate. Later, oleate became predominant.

Sterols of male and female flowers of Cucumis sativus.

Sterols of male and female flowers of Cucumis sativus L. were similar in composition. The principal compound was 24ξ-ethyl-5α-cholesta-7,22-dien-3ß-ol. Five other 5α-Δ(7) were detected: 24ξ-methyl-7-ene, 24ξ-ethyl-7-ene, 24-ethyl-7,24(28)Z-diene, 24ξ-ethyl-7,25-diene and 24ξ-ethyl-7,22,25-triene. Small amounts of Δ(5) (cholesterol, 24ξ-methylcholesterol and 24ξ-ethylcholesterol) were detected. The possible significance of these sterols is discussed.

Metabolism of delta7- and delta5,7-sterols by Phytophthora cactorum.

delta7- and delta5,7-Sterols are converted to the corresponding delta5-sterols by Phytophthora cactorum. When delta7-sterols were supplied to the fungus, delta5- and delta7-sterols were recovered in an acetone extract of the mycelium, the proportion of delta5-sterol being higher in the free sterol fraction than in the esters. When delta5,7-sterols were supplied, delta5-sterols were recovered. No delta5,7-sterols were found in the mycelium. The initial rate of uptake of the sterols was in the order delta5 greater than delta7 greater than delta5,7.

Immunosuppressive effect in mycobacterial adjuvant emulsions of mineral oils containing low molecular weight hydrocarbons.

Bayol F preparations from different commercial sources were incorporated into water-in-oil emulsions containing mycobacterial fractions and a protein antigen. It was found that an adjuvant effect was obtained with some mineral oils and a toxic immunosuppressive effect with others.

Sterols of male and female compound inflorescences of Zea mays L.

A comparison has been made between the sterols of male and female inflorescences and of pollen from Zea mays. The female inflorescence was shown to contain cholesterol, 24-methylcholesterol, 24-ethyl-5,22-cholestadien-3ß-ol, 24-ethylcholesterol and (28Z)-24-ethylidenecholesterol. Themale inflorescence contained the same five compounds together with 24-methylenecholesterol. Pollen contained 24-methylenecholesterol as its main sterol together with lesser amounts of cholesterol, 24-ethylcholesterol, (28Z)-24-ethylidenecholesterol, 24-methylene-5α-cholest-7-en-3ß-ol and 4α-methyl-24-methylene-5α-cholest-7-en-3ß-ol.

Use of high-resolution open tubular glass capillary columns to separate acidic metabolites in urine.

We used high-resolution glass capillary columns to study the trimethylsilyl derivatives of some acidic metabolites found in pooled urine specimens form control and postpartum subjects. About 30 compounds were identified by gas chromatography-mass spectrometry-computer techniques. In general, open tubular capillary columns effect better resolution of trimethylsilyl derivatives of organic acids than do conventional packed columns. GESE-30 proved to be a good general-purpose stationary phase, whereas OV-17 offered certain advantages in resolving aromatic acid components.

Abscisic acid in leaves of Hedera helix L.

Abscisic acid was detected by gas-liquid chromatography of the methyl esters in the acid fraction of extracts from leaves of juvenile and adult Hedera helix L. Combined gas chromatography-mass spectrometry data were obtained for the extract of adult tissues and thin-layer chromatography, gas-liquid chromatography and gas chromatography-mass spectrometry data for that of juvenile tissues. An estimation of the amounts of abscisic acid present in extracts from both growth phases was carried out using a single ion monitoring technique.