François Ramade

The role of biomarkers in environmental assessment (5). Invertebrate populations and communities.

Although a number of biomarkers of pollutant exposure have been identified in invertebrate species, direct linkage with changes at population and/or community levels are poorly documented and, despite the ecological importance of invertebrates, there is no conclusive evidence that individual measurements of biochemical parameters may allow the effects of pollutants on populations and communities to be predicted. Among the various biochemical parameters used as biomarkers in invertebrates exposed to pollutants in the field, only those for which changes at population or community level can be suggested are discussed in the present review. At population and community levels, the development of resistance to pesticides and changes in behaviour, reproduction and development are analysed as putative consequences of biochemical and physiological alterations. Limits to the use of biochemical parameters as biomarkers of invertebrate exposure to pollutants are discussed. Future research trends and experimental approaches to the validation of invertebrate biomarkers in environmental pollution assessment are suggested.

Accumulation of lipophilic microcontaminants and biochemical responses in eels from the Camargue Biosphere Reserve.

We assessed the impacts of persistent organic micropollutants on aquatic trophic webs in brackish and freshwater communities in the Camargue National Nature Reserve (NNR). We found that organochlorine compounds affect fish communities, particularly those of the common eel (Anguilla anguilla). The aims of this study were (1) to determine the amount of lipophilic xenobiotics such as polycyclic aromatic hydrocarbons (PAHs), which are probably of atmospheric origin, and two organochlorines (OC), lindane and dieldrin, which are from irrigation waters, in liver and muscle (2) to define in situ biomarkers and (3) to identify the mode by which fish from ‘unpolluted’ areas become contaminated.All of the species were contaminated with low, but fluctuating quantities of PAHs and OCs, regardless of the sampling season. Lindane and dieldrin were always detected and naphtalene was the most abundant hydrocarbon. The OC and PAH content was rarely correlated with the lipid content in storage tissues and their concentrations in the lipidic fractions (neutral and polar) varied greatly. We found a number of correlations between persistent organic pollutant (POP) tissue concentrations and the activities of enzymatic membrane markers. For example, there is a relationship between the concentrations of the most volatile PAHs and the activity of muscle acetylcholinesterase (AChE) and between the concentration of benzo-PAH and the activities of ATPases in the gills and/or muscle.

Effects of lindane and deltamethrin on zooplankton communities of experimental ponds

Two insecticides, lindane (321 µg l−1) and deltamethrin (13 µg l−1) were employed in a four mesocosm experiment (two ponds of 10 m3 and two of 16 m3) to asses the impact of water pollution by pesticides. Resistance of the different zooplankton species was variable and depended upon both the group and the insecticide concentration. No effect of lindane was observed on macrozooplancton such as Cladocera and Copepoda. In the deltamethrin-treated pond, all species of zooplankton were found dead a day after the treatment. The microzooplankton (Rotifera and copepod nauplii) were highly susceptible to both insecticides. Although the larvae of Chaoborus were present in the ponds after the treatments, their density decreased (less than 1 individual l−1). The elimination of filter-feeding zooplankton by deltamethrin was followed by an increase of the concentration of chlorophyll a in the post-treatment period. Two months later the original zooplankton population recovered, with the addition of a new and dominant species: Ceriodaphnia reticulata.

Relationships between persistent organic chemicals residues and biochemical constituents in fish from a protected area: the French National Nature Reserve of Camargue

The Reserve of Biosphere of Camargue [French National Nature Reserve of Camargue (NNRC)] is a protected area frequently exposed to natural and anthropogenic environmental alterations. To evaluate potential contamination of fish with lipophilic chemicals-organochlorines (OCs) and polycyclic aromatic hydrocarbons (PAHs)-a biological monitoring survey was carried out. Metabolic reserve levels were evaluated to select appropriate biological indicators able to be significant biomarkers. In addition, the incorporation of xenobiotic molecules in the lipid compartments was investigated. The contents of glycogen, total lipids, proteins and lipidic phosphorus were analyzed in liver and skeletal muscles of three teleostean: the European eel (Anguilla anguilla); the crucian carp (Carassius auratus); and the catfish (Ictalurus melas). The atmospheric origin of the PAH detected in any season in the biomass and the OCs compounds contamination by derive from agricultural treatments are established. In contradiction with some laboratory acute intoxication studies, we observe a positive correlation between tissue concentrations of contaminants and the muscular glycogen amount, a sensitive energy reserve marker. Moreover, it seems likely that the incorporation of these xenobiotics is located preferentially in the membrane structures.

Qualitative and Quantitative Criteria Defining a “Healthy” Ecosystem

As Costanza et al. have previously pointed out (1992), the terms “health” and “integrity” are used widely in policy documents and scientific publications regarding environmental protection. However, although the term “healthy” ecosystem has been in use for a long time, its representativeness regarding ecological reality and therefore relevance may still be contended. Defining a “healthy” ecosystem is a more complex task than might be expected.

Introductory conference: on the relevance of protected areas for the research on conservation ecology: from fundaments to applications

Regarding the present rate of species extinction, preservation of biodiversity has become a prerequisite to achieve sustainable development. Among major challenges an urgent need in research in biological conservation is required to reach this goal. Protected areas deserve special importance due to their relevance for development of research both in fundamental and applied ecology. This papers aims at making a critical review of possibilities and priorities in conservation ecology in these areas.

Environmental and ecotoxicological problems in the Mediterranean countries

The Mediterranean area stretches over 2.2 × 10 6 k m 2. Throughout the area the geographical features are predominantly mountainous with narrow coastal plains. As a consequence, more than in any other area in the world, the Mediterranean countries display a strongly heterogeneous distribution of their population and industries, which are mainly concentrated in the coastal zones. Population pressure ranks amongst the major factors in ecotoxicological disturbances in the Mediterranean. In addition to the population explosion of the southern and eastern countries, tourism creates another considerable source of overcrowding, mainly in the European part of the Mediterranean but now in Turkey as well. According to UNEP projections (in Grenon and Batisse [1]), the population of the Mediterranean countries, which numbered 360 million inhabitants in 1985, will jump to 570 million in 2025. In the meantime, the number of tourists will increase from 170 to 341 million people per year, of whom 200 million will be so-called international, coming from nonMediterranean countries (Fig. 1).

On the occurrence of a widespread contamination by herbicides of coral reef biota in French Polynesia

Research has been conducted within the framework of the French Initiative for Coral Reefs (IFRECOR) to assess pesticide pollution levels in the coral reef trophic webs in French Polynesia. Unexpected widespread contamination by herbicides was found in algae, fishes and macro-invertebrates located at various levels of the reef trophic web. Concentrations in organisms investigated were for the majority below the lowest observable effect level and do not pose a dietary risk to native population who subsist on these fish. However, the widespread contamination may affect the reef ecosystem in the future as coral symbiotic algae, Symbidinium sp. (Dinophyta) are particularly sensitive to photosystem II herbicides, particularly the substituted urea and triazine derivatives.