4 resultados para BIOINDICATORS

em Aquatic Commons


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In the present study, intestinal helminth parasite fauna of 398 specimens of three species of kilkas, C. engrauliformis (N= 92), C. grimmi (N= 136) and C. cultriventris (N= 170) from Babolsar harbor were investigated. Five parasite species were found including: Corynosoma strumosum (Acanthocephala), Pronoprymna ventricosa (Trematoda), Contracaecum sp. (Nematoda), Raphidascaris sp. (Nematoda) and Anisakis sp. (Nematoda). The highest prevalence and abundance were observed in C. strumosum and P. ventricosa. The prevalence and abundance of C. strumosum in C. grimmi was significantly higher than C. engrauliformis. The prevalence and abundance of P. ventricosa in C. cultriventris was significantly higher than C. engrauliformis. The prevalence, mean intensity and mean abundance of the parasites were compared according to the sex, length group and season also effect of parasite on host growth parameters was considered. The diversity, equability, similarity, species richness, dominance Indices and specificity indices of helminth parasites of the three host species were studied. Also the lead and cadmium concentrations in the intestine, muscle, liver, kidney and gonad of kilkas and their parasites C. strumosum and P. ventricosa were measured and compared. The results revealed that lead and cadmium concentrations in C. strumosum and P. ventricosa were significantly higher than kidney, liver, intestine, gonad and muscle. The lead and cadmium concentrations of the parasites were compared according to the sex, parasitism and season.

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This review examines water quality and stress indicators at levels of organisation from the individual to the community and beyond by means of three case studies concentrating on rocky shores within the north-east Atlantic. Responses of dogwhelks (Nucella) to tributyltin pollution from antifouling paints is examined as the main case study. There are effects at the individual level (development of male sexual characteristics in the female leading to effective sterility) and population level (reduction in juveniles, few females and eventual population disappearance of dogwhelks in badly contaminated areas) but information on community level effects of dogwhelk demise is sparse. Such effects were simulated by dogwhelk removal experiments on well studied, moderately exposed ledges on shores on the Isle of Man. The removal of dogwhelks reduced the size and longevity of newly established Fucus clumps that had escaped grazing. Removal of dogwhelks also increased the likelihood of algal escapes. In a factorial experiment dogwhelks were shown to be less important than limpets \{Patella) in structuring communities but still had a significant modifying effect by increasing the probability of algal escapes. Community level responses to stress on rocky shores are then explored by reference to catastrophic impacts such as oil spills, using the Torrey Canyon as a case study. Recovery of the system in response to this major perturbation took between 10-15 years through a series of damped oscillations. The final case study is that of indicators of ecosystem level change in response to climate fluctuations, using ratios of northern \{Semibalanus balanoides) and southern (Chthamalus spp.) barnacles. Indices derived from counts on the shore show good correlations with inshore sea-water temperatures after a 2-year lag phase. The use of barnacles to measure offshore changes is reviewed. The discussion considers the use of bioindicators at various levels of organisation.

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Environmental managers strive to preserve natural resources for future generations but have limited decision-making tools to define ecosystem health. Many programs offer relevant broad-scale, environmental policy information on regional ecosystem health. These programs provide evidence of environmental condition and change, but lack connections between local impacts and direct effects on living resources. To address this need, the National Oceanic and Atmospheric Administration/National Ocean Service (NOAA/NOS) Cooperative Oxford Laboratory (COL), in cooperation with federal, state, and academic partners, implemented an integrated biotic ecosystem assessment on a sub-watershed 14-digit Hydrologic Unit Code (HUD) scale in Chesapeake Bay. The goals of this effort were to 1) establish a suite of bioindicators that are sensitive to ecosystem change, 2) establish the effects of varying land-use patterns on water quality and the subsequent health of living resources, 3) communicate these findings to local decision-makers, and 4) evaluate the success of management decisions in these systems. To establish indicators, three sub-watersheds were chosen based on statistical analysis of land-use patterns to represent a gradient from developed to agricultural. The Magothy (developed), Corsica (agricultural), and Rhode (reference) Rivers were identified. A random stratified design was developed based on depth (2m contour) and river mile. Sampling approaches were coordinated within this structure to allow for robust system comparisons. The sampling approach was hierarchal, with metrics chosen to represent a range from community to cellular level responses across multiple organisms. This approach allowed for the identification of sub-lethal stressors, and assessment of their impact on the organism and subsequently the population. Fish, crabs, clams, oysters, benthic organisms, and bacteria were targeted, as each occupies a separate ecological niche and may respond dissimilarly to environmental stressors. Particular attention was focused on the use of pathobiology as a tool for assessing environmental condition. By integrating the biotic component with water quality, sediment indices, and land- use information, this holistic evaluation of ecosystem health will provide management entities with information needed to inform local decision-making processes and establish benchmarks for future restoration efforts.

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The stress response, at the molecular level, of the soft corals Dendronephthya klunzingeri and Heteroxenia sp., hard corals Acropora hyacinthus and A. valenciennesi, an ascidian Symplegma sp. and sponges Latruncula cortica and Callyspongia crassa to germanium oxide (GeO sub(2)) was evaluated. Evaluation was carried out using bioindicators. such as the level of expression of each of the heat shock proteins (HSPs) and the silicatein enzyme in response to the compound. However, the expression was measured by SDS Polyacrylamide Gel Electrophoresis (SDS PAGE) and western blotting. The harmful concentration of GeO sub(2) that produced noticeable molecular changes in the studied samples during the first 6-24 hours was 6 μg/ml. The two studied soft corals as well as the ascidian responded to the harmful concentration of germanium oxide by expressing the heat-shock protein 90 (hsp90), while the two hard corals responded by expressing hsp70, C. crassa by decreasing the level of silicatein enzyme and sponge L. cortica produced no change by any of the used biomarkers, The soft coral Heteroxenia sp. was found to be sensitive to mechanical stress during the experiment and it was more sensitive to 6 μg/ml of GeO sub(2) than the other soft coral D. klunzingeri. The two studied hard corals were sensitive to mechanical stress during the experiment, but A. hyacinth us showed higher sensitivity than A. valenciennesi. However, these 2 corals displayed reverse response to GeO sub(2). Primitive evidences were found in the SDS PAGE to distinguish the tissue of the soft coral from that of the hard coral on the molecular level; the soft coral showed two prominent protein bands (45 and 50 kDa) while the two prominent protein bands for hard corals were 31 and 116 kDa.