Mercedes Conradi

Qualitative assessment of genotoxicity using random amplified polymorphic DNA: Comparison of genomic template stability with key fitness parameters in Daphnia magna exposed to benzo[a]pyrene

A method of DNA profiling using the random amplified polymorphic DNA (RAPD) was used to assess toxicant-induced DNA effects in laboratory populations of Daphnia magna exposed to varying concentrations of the genotoxic hydrocarbon benzo[a]pyrene. These effects, represented by changes in the RAPD profiles, were compared with a number of key ecological fitness parameters (age-specific survival, age-specific fecundity, net reproductive rate, and intrinsic rate of population increase). Not only was the RAPD profiling method shown to be a rapid and reproducible assay of toxicant-induced DNA effects, but the qualitative measure of genomic template stability compared favorably with the traditional indices of fitness. The RAPD profiles, however, exhibited higher sensitivity in detecting toxic effects. The significance of these findings for future ecotoxicological studies is discussed.

Long-term exposure to 4-nonylphenol affects sexual differentiation and growth of the amphipod Corophium volutator (#Pallas, 1766)

Concern has been growing recently over the aquatic toxicity and reproductive effects of the non-ionic surfactant 4-nonylphenol (NP). NP appears to interact with development in some crustaceans. Using exposure response experiments based on nominal NP concentrations, the 96-h LC50 for adult Corophium volutator, was 1670 μg l−1 (95% Cl 1370–2170 μg l−1). Juveniles were subsequently exposed to sublethal concentrations of NP for 120 days and effects on growth, sexual differentiation and reproduction were assessed. At the lowest NP exposure of 10 μg l−1 the density of surviving amphipods was reduced and growth was retarded. Fertility of female C. volutator increased in NP exposed populations. Sex ratio was not affected by NP exposure, however, the second antennae of exposed male animals were significantly longer than those of control animals (P<0.001). It is hypothesised that NP may act via the androgenic gland which controls the development of male secondary sex characteristics in crustaceans. Males with large antennae are potentially at a selective disadvantage in the wild being more vulnerable to predation.

Sediment quality in the Guadalquivir estuary: lethal effects associated with the Aznalcóllar mining spill.

Monitoring from 1998 to 2001 has assessed the impact of the Aznalcóllar mining spill on the sediment quality in the Guadalquivir estuary. Chemical analysis has been completed with biological effects measured in different organisms. The toxicity of sediments obtained from dilutions of toxic mud and from environmental stations affected by the accidental spill was tested using the amphipod Ampelisca brevicornis and the clam Scrobicularia plana. The results obtained show that amphipods are more sensitive to the accidental spill than the clams. A dilution of clean sediment by more than 1.8% of toxic mud produced 100% mortality of amphipods. In GR2 station is detected toxicity to amphipods but not to clams. The rest of the environmental stations show no toxicity. Toxicity to amphipods in GR2 station decreased along time (from 50% to 60% of mortality in 1998 to 10 to 15% in 2001) and it can be associated with a recovery of the areas impacted by the accidental spill.

ANALYSIS OF MACROBENTHIC COMMUNITY STRUCTURE IN RELATION TO DIFFERENT ENVIRONMENTAL SOURCES OF CONTAMINATION IN TWO LITTORAL ECOSYSTEMS FROM THE GULF OF CADIZ (SW SPAIN)

Selected chemicals in sediments and the abundances and biomasses of macrobenthic species were determined at seven stations from two littoral ecosystems in the Gulf of Cádiz. The marine macrobenthic communities were described in both ecosystems that are subjected to different sources and levels of contamination. A qualitative relationship between source of contamination and biological effects for each station is proposed and the results of the univariate and multivariate analysis used are discussed. Univariate analyses using conventional community descriptive parameters (number of species, abundance and richness, Shanon–Weaver and evenness indices) and the numerial contribution of major taxonomic groups (i.e., Polychaeta, Oligochaeta, Mollusca and Crustacea) could not be used as a means of classifying the sites as clean or polluted with respect to the contamination measured. The results showed that multivariate methods are much more sensitive than univariate techniques. Abundance/biomass comparison (ABC) plots classified the macrobenthic communities into different classes mainly related to organic contamination. However, this analysis did not reflect the alteration due to inorganic sources of contamination. This kind of analysis is valuable for the evaluation of alteration of effects but it cannot discriminate between two different phenomena: pollution (adverse effect associated with chemical concentrations) and alteration (adverse effect associated with chemical concentrations or with natural variations).

Population responses of the marine amphipod Corophium volutator (Pallas, 1766) to copper

The effects of copper concentrations on the life-history, growth and reproduction of Corophium volutator were investigated. Amphipods were exposed for 100 days to five sublethal copper concentrations (0.2, 0.4, 0.6, 0.8 and 1 mg l−1). Copper exposure significantly reduced the age-specific survivorship and longevity (P<0.001). Life-expectancy differed at the various exposure concentrations of copper (P<0.005). Growth was greatly reduced with copper exposure. The degree of reduction in growth rate increased with increasing metal concentration. Animals exposed to 0.2 mg Cu l−1 exhibited a reduction of 2.4% in the specific growth rate (SGR), while those grown at 0.4, 0.6, and 0.8 mg Cu l−1 exhibited reductions in SGR of 16.7, 23.5 and 20%, respectively. The length of the mature animals was also reduced following copper exposure (P<0.05). Although sex ratio was not affected (P=0.225), maturation and fertility were greatly reduced. Survival of ovigerous females and fertility were also affected by copper when mature animals were exposed to these concentrations. These results suggest that long-term exposure of C. volutator to low concentrations of copper could lead to a severe local population density decline because of the reduction of juvenile survivorship and fertility. Long-term exposure of C. volutator to higher concentrations of copper could have more serious consequences such as the local extinction of this species since the juveniles experienced such severe reductions in growth that they were unable to reach mature stage.

The benthic Gammaridea (Crustacea, Amphipoda) fauna of Algeciras Bay (Strait of Gibraltar): distributional ecology and some biogeographical considerations

Abstract The Gammaridea fauna of Algeciras Bay, located on the Mediterranean side of the Strait of Gibraltar, was studied with regard to the species composition, distribution and ecology. Of the 116 species identified, 13 are recorded for the first time along the Iberian Peninsula coast, 30 for the Spanish coast and 78 for the Andalusian coast. Two species, Apherusa bispinosa (Bate 1857) and Idunella nana (Schiecke 1973), were collected for the second time in the Mediterranean Sea; this represents the first record of I. nana since its original description. The abundances of the various species and their distribution in terms of bathymetry and type of substrate were analysed, as was the enlargement of the distributional range of some species in the Mediterranean Sea. With regard to biogeographical distribution, Algeciras Bay can be considered a typical Mediterranean locality despite being situated in the Strait of Gibraltar. This is in agreement with previous studies on the amphipod fauna of the Portuguese coast.

Alterations in the macrobenthic fauna from Guadarranque River (Southern Spain) associated with sediment-seawater acidification deriving from CO2 leakage.

Nowadays, Carbon Storage in Sub-Seabed Geological Structures (CS-SSGS) is having much interest. Nonetheless, these technologies are still under development, especially the leakage of the stored CO2 and the consequent acidification of the environment. Therefore, the goal of this study is to test the impact of CO2-induced acidification on a macrobenthic community due to leakages from CS-SSGS using a mesocosm-based experiment. Results confirmed the significant correlation between the abundance of the species and the pH (positively), and the alkalinity (negatively). Additionally, the BIOENV analysis showed that the majority of the variability in the abundance of the total species was explained for the alkalinity. The correlation analysis showed differential vulnerabilities of different species, especially Cyathura carinata and a non-calcifier species as Hediste diversicolor. Nevertheless, these results showed the importance of taking into account the indirect effect associated with acidification processes, as metal release from sediment.

Asterocheres hirsutus, a new species of parasitic copepod (Siphonostomatoida: Asterocheridae) associated with an Antarctic hexactinellid sponge

The asterocherid siphonostomatoid copepod Asterocheres hirsutus, a new species, is described from a hexactinellid sponge of the genus Rossella Carter collected during the Polastern cruise ANT XVII/3, off South Shetland Islands. The distinctive features of this new species are: a female with 21-segmented and a male with 17-segmented antennules, praecoxal endite of maxillule more than four times longer than palp and the ornamentation of the posterior surface of legs 1–4. A detailed description of both sexes is presented.

Several benthic species can be used interchangeably in integrated sediment quality assessment

The selection of the best management option for contaminated sediments requires the biological assessment of sediment quality using bioindicator organisms. There have been comparisons of the performance of different test species when exposed to naturally occurring sediments. However, more research is needed to determine their suitability to be used interchangeably. The sensitivity of two amphipod species (Ampelisca brevicornis and Corophium volutator) to sediments collected from four different commercial ports in Spain was tested. For comparison the lugworm, Arenicola marina, which is typically used for bioaccumulation testing, was also tested. Chemical analyses of the sediments were also conducted. All species responded consistently to the chemical exposure tests, although the amphipods, as expected, were more sensitive than the lugworm. It was found that C. volutator showed higher vulnerability than A.brevicornis. It was concluded that the three species can be used interchangeably in the battery of tests for integrated sediment quality assessment.

Two new asterocherid species (Siphonostomatoida: Asterocheridae) from Madeira and the Canary Islands (eastern Atlantic)

Abstract The siphonostomatoid family Asterocheridae Giesbrecht, 1899 uses a wide range of host phyla, mainly due to the host diversity of two genera – Asterocheres Boeck, 1859 and Orecturus Humes, 1992. In the present paper, two new asterocherid species from the eastern Atlantic are described and compared with their congeners. One of these species belongs to the genus Asterocheres, A. madeirensis, and was found associated with the sponge Petrosia ficiformis (Poiret, 1789) in Madeira Island. This sponge occurs both in the Mediterranean and on nearby Atlantic coasts, although currently there are no records of the presence of symbiotic asterocherids for its Mediterranean populations. The second new species, Orecturus canariensis, is the first record of the genus on the eastern Atlantic coasts and was found in association with the gorgonian Villogorgia bebrycoides (Koch, 1887) in the Canary Islands. The diagnosis of the genus Orecturus is slightly modified to include some features shown by this new species and some of its plesimorphic and derived characteristics compared with the remaining asterocherid genera. Although the gorgonian Paramuricea grayi (Johnson, 1861) occurs in the same ecological assemblages as the infested colonies of V. bebrycoides, no specimens of asterocherid copepods were found on Paramuricea colonies. Therefore, O. canariensis may be a monoxenous symbiont.