Identifying ecological production functions for use in ecosystem services-based environmental risk assessment of chemicals.

There is increasing research interest in the application of the ecosystem services (ES) concept in the environmental risk assessment of chemicals to support formulating and operationalising regulatory environmental protection goals and making environmental risk assessment more policy- and value-relevant. This requires connecting ecosystem structure and processes to ecosystem function and henceforth to provision of ecosystem goods and services and their economic valuation. Ecological production functions (EPFs) may help to quantify these connections in a transparent manner and to predict ES provision based on function-related descriptors for service providing species, communities, ecosystems or habitats. We review scientific literature for EPFs to evaluate availability across provisioning and regulation and maintenance services (CICES v5.1 classification). We found quantitative production functions for nearly all ES, often complemented with economic valuation of physical or monetary flows. We studied the service providing units in these EPFs to evaluate the potential for extrapolation of toxicity data for test species obtained from standardised testing to ES provision. A broad taxonomic representation of service providers was established, but quantitative models directly linking standard test species to ES provision were extremely scarce. A pragmatic way to deal with this data gap would be the use of proxies for related taxa and stepwise functional extrapolation to ES provision and valuation, which we conclude possible for most ES. We suggest that EPFs may be used in defining specific protection goals (SPGs), and illustrate, using pollination as an example, the availability of information for the ecological entity and attribute dimensions of SPGs. Twenty-five pollination EPFs were compiled from the literature for biological entities ranging from 'colony' to 'habitat', with 75% referring to 'functional group'. With about equal representation of the attributes 'function', 'abundance' and 'diversity', SPGs for pollination therefore would seem best substantiated by EPFs at the level of functional group.

Monoclonal antibodies as tools to quantify mycelium of aquatic hyphomycetes.

Quantitative ELISAs have been developed to determine the biomass of two aquatic hyphomycetes in natural mixed assemblages. These assays employ a species specific rat monoclonal antibody (MAb) raised to Alatospora acuminata and a genus-specific murine MAb raised to Tetracladium marchalianum. The respective antigens are produced constitutively and their production is not affected by a range- of culture conditions. The MAbs can also be used to study the spatial distribution of these fungi using Immunofluorescence. Both antibodies recognize carbohydrate epitopes and belong to the immunoglobulin class IgM. The potential applications of these immunoassays are discussed.

Use of a Monoclonal Antibody-Based Immunoassay for the Detection and Quantification of Heliscus lugdunensis Colonizing Alder Leaves and Roots.

A genus-specific monoclonal antibody, NG-CF10, raised in a previous study to the fungal pathogen Nectria galligena, was found to recognize the aquatic hyphomycete Heliscus lugdunensis (anamorph) and its teleomorph Nectria lugdunensis. Using this MAb in a plate trapped antigen- ELISA we could detect and determine the biomass of Heliscus lugdunensis in mixed assemblages in both naturally occurring and artificially inoculated leaves and roots of Alnus glutinosa trees. Initial studies indicate that the biomass associated with naturally occurring leaf material is significantly lower than that recorded with laboratory inoculated leaves, suggesting that biomass production is limited in the natural environment. Significantly lower biomass was associated with roots when compared with leaf material, which supports the proposition that rather than a major substrate for the growth of aquatic hyphomycetes, roots act as a refugium for fungal growth.

Importance of fungi in the diet of Gammarus pulex and Asellus aquaticus : II. Effects on growth, reproduction and physiology.

An important component of the interaction between macroinvertebrates and leaf litter in streams in the extent to which consumers can differentiate between undecomposed and decomposing leaves. The detritivores Gammarus pulex and Asellus aquaticus fed preferentially on conditioned rather on unconditioned leaf material. Growth in A. aquaticus was significantly reduced when unconditioned leaves were provided, but in G. pulex no significant effect of conditioning on growth was observed. The capacity of G. pulex to tolerate reductions in food quality seems to be a consequence of a compensatory system in which respiration rates change to compensate for reductions in food quality. In this way a constant growth rate is maintained. Increases in ingestion rates to compensate for low quality food were not observed.

Importance of fungi in the diet of Gammarus pulex and Asellus aquaticus I: feeding strategies.

The importance of fungi in the trophic biology of the freshwater detritivores Gammarus pulex and Asellus aquaticus was investigated. Inspection of leaves used in feeding trials indicated that whereas A. aquaticus scrapes at the leaf surface, G. pulex bites through the leaf material. Both species discriminated between fungal mycelia, fungally colonized and uncolonized leaf material but, although A. aquaticus selectively consumed fungal mycelia, G. pulex fed preferentially on leaf material. Fungi appear to be an important food source for A. aquaticus and selection of food material was positively correlated with fungal biomass. In contrast, for G. pulex, fungi appear to be more important as modifiers of leaf material. However, no significant correlations were found between food preference and any of the leaf modifications measured.

Responses of Gammarus pulex (Amphipoda, Crustacea) to metalliferous effluents: identification of toxic components and the importance of interpopulation variation.

This study was designed to evaluate the ability of an in-situ bioassay to assess the impact of complex effluents on freshwaters and to identify toxic components. Reductions in the feeding rate of Gammarus pulex proved to be a sensitive indicator of the impact of metalliferous effluents on receiving water quality. The effluents contained a mixture of five potentially toxic metals. By combining information on feeding rates with bioaccumulation data, two metals, iron and manganese, were identified as the probable toxic agents. Laboratory experiments validated the conclusions reached from the field study and confirmed that iron was a major toxicant. The sensitivities of Gammarus pulex from a metal-contaminated site and a clean site were compared during both the field and laboratory studies. Interpopulation differences in the response of G. pulex to toxicants were detected in the field study but not in the laboratory experiments. Possible reasons for this are discussed.

Acute toxicity tests on the freshwater isopod, Asellus aquaticus using FeSO4. 7H2O, with special reference to techniques and the possibility of intraspecific variation.

Techniques are described for assessing the toxicity of Fe(II), an important component of the effluent from mines, to the freshwater isopod, Asellus aquaticus. These techniques either involve buffer systems or working at low pH. Both techniques indicate that A. aquaticus is very tolerant of Fe(II). Furthermore, the low-pH technique suggests that animals from sites exposed to mine-waste pollution are more tolerant than those from sites not so exposed. This difference is masked in the buffer experiments, possibly due to the formation of less toxic buffer-Fe(II) complexes.

Cadmium resistance in Gammarus pulex (L.).

The ability of Gammarus pulex to develop cadmium resistance through physiological acclimation was investigated. Organisms were found to be significantly more tolerant to acute cadmium toxicity after pre-exposure to sublethal concentrations of cadmium and zinc. The induced elevation in cadmium tolerance was shown to be associated with an increase in the body concentration of a metallothionein-like protein. Pre-exposure had no apparent effect on cadmium uptake, although it did influence the distribution of cadmium within the organisms. Whereas pre-exposure to low levels of zinc and cadmium increased cadmium tolerances in acute tests, it had no observable effects on sublethal responses measured during chronic exposure.

The effects of motorway runoff on freshwater ecosystems: 3. Toxicant confirmation.

Previous studies have demonstrated that small streams receiving road runoff have reduced water and sediment quality. These changes in quality are associated with alterations in the structure and functioning of stream communities. Laboratory studies have indicated that the community changes are due to sediment-associated contaminants, and toxicant identification evaluations have shown that the major toxicants are contained probably in a fraction of sediment extract that contains polycyclic aromatic hydrocarbons (PAHs). The aim of the present study was to determine whether PAHs were indeed the major toxicants in sediment extracts. Toxicity tests were performed with PAH mixtures, the toxic fraction of an extract of runoff-contaminated sediment, and a whole sediment extract. These indicated that three PAHs accounted for the toxicity of a sediment extract: pyrene, fluoranthene, and phenanthrene. The possibility of spatial or temporal variation in major toxicants was also investigated and tests on a number of sediment extracts obtained from a number of sites at different times demonstrated that the three PAHs accounted for 30.8 to 120% of an extract's toxicity. When the PAHs were considered individually, pyrene was shown to account for most of the toxicity (44.9%), followed by fluoranthene (16%) and phenanthrene (3.5%).

Effect of stress on a freshwater benthic detritivore: scope for growth in Gammarus pulex.

Scope for growth (SfG), a measure of energy balance (between food intake and metabolic output) within animals, has been used as an indicator of pollution stress in marine systems. However, it has not been used commonly in freshwater systems and here we investigate the sensitivity of SfG in Gammarus pulex, a benthic freshwater crustacean, under conditions often associated with pollution. The effects of four specific substances were investigated; a metal (zinc), an organic (3,4-dichloroaniline), and two dissolved gases (oxygen and ammonia). In all cases SfG was reduced by the stress, primarily due to a depression in energy intake. Only with ammonia was energy output (respiration) significantly affected.

Field deployment of a scope for growth assay involving Gammarus pulex, a freshwater benthic invertebrate.

Scope for growth (SfG) is a measure of the energy balance of an animal (i.e., the difference between energy intake and metabolic output). The SfG of marine invertebrates, particularly the mussel Mytilus edulis, has been successfully used as the basis of a field bioassay to detect a range of stresses both natural (temperature, food, salinity) and anthropogenic (hydrocarbons, sewage sludge). SfG of the freshwater amphipod Gammarus pulex was found to be a sensitive indicator of stress under laboratory conditions and here we describe the field deployment of this technique and present data from three field trials. In every case, SfG was reduced at the downstream polluted site compared with that at an upstream reference site. This reduction in SfG was the result of a decrease in energy intake (absorption) rather than an increase in energy expenditure (respiration).

Development of a monoclonal antibody-based immunoassay for the detection and quantification of Anguillospora longissima colonizing leaf material.

Monoclonal antibodies (MAbs) to the aquatic hyphomycete Anguillospora longissima were raised in mice by using a coimmunization program. A cell line was raised that produced a MAb of the immunoglobulin M class that was specific for A. longissima both in an enzyme-linked immunosorbent assay (ELISA) and by immunofluorescence but that did not recognize other members of the aquatic hyphomycetes. This MAb (AL-HH8c) was used to develop a quantitative ELISA in vitro. The antigen recognized by AL-HH8c is produced throughout the mycelium, irrespective of mycelial age and culture conditions. By using this MAb, mycelium of A. longissima colonizing leaf material can be detected by ELISA, immunofluorescence, and immunoenzymatic staining methods.

Conserved cis-elements bind a protein complex that regulates Drosophila ras2/rop bidirectional expression.

The Drosophila ras2 promoter region exhibits bidirectional activity, as has been demonstrated for the human c-Ha-ras1 and the mouse c-Ki-ras. Here we address a unique case of ras regulation, as Drosophila ras2 provides the only example to date in which the flanking gene (rop) and its product have been isolated. A linking mechanism of control suggests a mutual interaction between the two gene products. Our studies indicate that the Drosophila ras2 promoter region shares with the human c-Ha-ras1 promoter a CACCC box and an AP-1-like sequence. A 14 bp promoter fragment which holds a CACCC element is demonstrated to interact with a specific transcription factor (factor B). This CACCC promoter element represents a stretch of imperfect palindrome. We present evidence that this factor can form a complex with another specific DNA-binding protein (factor A). The binding sites (A + B) for these protein factors are essential for 95% expression of both genes flanking the promoter (ras2 and rop). Region A consists of four overlapping consensus sequences: a TATA-like element, a DSE-like motif (the core sequence of the serum response element), a DRE octamer, which has been shown to play a role in cell proliferation, and a 5 bp direct repeat representing the GATA consensus sequence. Factor A has a very weak affinity to the full promoter region, but when complexed with factor B binding efficiency is enhanced. We also show that alterations of DNA-protein binding specificities can be achieved by supplementing the growth media with different sera.