Effects of a phycotoxin,okadaic acid,on oyster heart cell survival

Okadaic acid (OA) is a dinoflagellate toxin which accumulates in shellfish producing diarrhetic shellfish poisoning (DSP) in humans. It was found that OA is a highly selective inhibitor of protein phosphatase types 1 (PP1) and 2A (PP2A) which produces a marked increase in phosphorylation of several proteins, including p38 mitogen-activated protein (MAP) kinase. The cytotoxicity attributed to OA and the effects on p38 MAP kinase and calcium current were examined in the oyster Crassostrea gigas in this study. Data showed that p38 MAP kinase is strongly expressed in oyster heart and that OA bioaccumulated in cultured heart cells. Hence the effects of OA was tested in vitro and in vivo on oysters. OA was found to (i) exert a positive chronotropic effect on cultured atrial cardiomyocytes which is related to an increase in calcium current via PKC as shown by patch clamp measurements, (ii) produce an activation/phosphorylation of MAP kinase as shown by Westernblot while the non-phosphorylated p38 remained constant during treatment, (iii) did not induce a pro-apoptotic effect. Data suggest that OA may also stimulate the anti-apoptotic pathway by phosphatase inhibition.     

Assessing the bioavailability of phenanthrene to soil microorganisms using the Tenax extraction method

The Tenax TA extraction technique followed by gas chromatography mass spectrometry (GC-MS) determinations was used to assess the actually bioavailable fraction of phenanthrene (ABF-Phe) in three different soils freshly contaminated with this compound at levels of 10, 100, and 1,000 mg kg⁻¹. The results were related to the ecotoxic effect of phenanthrene on soil nitrifying bacteria. Nitrification potential measurements were applied as an ecotoxicity end point. A strong positive linear relationship (r ² = 0.95) was obtained between the content of the actually bioavailable phenanthrene fraction and the inhibition of nitrifying bacteria activity.     

Metallakkumulation in Moosen: Standörtliche und regionale Randbedingungen des Biomonitoring von Luftverunreinigungen

Goal and Scope

Several studies show that the concentration of metals in mosses depends not only on metal deposition but also on factors such as moss species, canopy drip, precipitation, altitude, distance to the sea and the analytical technique used. However, contrasting results have been reported and the interpretation of the spatial variability of the metal accumulation in mosses remains difficult. In the presented study existing monitoring data from the European Heavy Metals in Mosses Surveys together with surface data on precipitation, elevation and land use are statistically analysed to assess factors other than emissions that have an influence on the metal accumulation in the mosses.

Main Features

Inference statistics and Spearman correlation analysis were applied to examine the association of the metal accumulation and the distance of the monitoring sites to the sea as well as the altitude. Whether or not significant differences of the metal loads in the mosses exist at national borders was examined with help of the U-test after Mann and Whitney. In order to identify and rank the factors that are assumed to have an influence on the metal uptake of the mosses Classification and Regression Trees (CART) were applied.

Results

No clear tendency could be derived from the results of the inference statistical calculations and the correlation analyses with regard to the distance of the monitoring site to the sea and the altitude. According to the results of the CART-analyses mainly the moss species, potential emission sources around the monitoring sites, canopy drip and precipitation have an effect on the metal bioaccumulation. Assuming that each participating country followed strictly the manual for sampling and sample preparation the results of the inference statistical calculations furthermore suggest that in most cases different techniques for digestion and analysis bias the measurements significantly.

Discussion

For the first time a national monitoring data base consisting of measurement data and metadata as well as surface information on precipitation, land use and elevation was applied to examine influence factors on the metal bioaccumulation in mosses. The respective results mirror existing knowledge from other national studies to a large extend, although further analyses are necessary to affirm the findings. These analyses should include data from other national monitoring programmes and should additionally be carried out with other decision tree algorithms than CART.

Conclusions

The local variability in the metal concentration in mosses can be uncovered in terms of predictors or underlying hidden causes by using CART. Ideally, such an approach should be applied across the whole of Europe. This will only be feasible if all participating countries provide additional information about site characteristics as currently is done in for example the German moss surveys.

Recommendations

The UNECE Metals in Mosses Survey experimental protocol should be improved in order to reduce the observed influences, to enhance standardisation, and to strengthen the quality control. This implies the integration of sampling site describing metadata into the assessment. Furthermore, basis research is needed to test the hypothesis concerning moss species-specific accumulation of depositions.

Perspectives

Provided that the presented results hold true in further analyses correction factors should be applied on the moss data in order to get the depicted spatial patterns and temporal trends of metal bioaccumulation unbiased. Such factors should be calculated for natural landscape units or ecoregions that are homogeneous with regard to climate, vegetation and altitude.     

Moosmonitoring als Spiegel der Landnutzung?

Goal, Scope and Background

The study was conducted to test the hypothesis that the regional variability of nitrogen (N) and metal accumulations in terrestrial ecosystems are due to historical and recent ways of land use. To this end, in two regions of Central Europe the metal and N accumulations in both regions should be examined by comparative moss analysis. The regions should be of quantitatively specified representativity for selected ecological characteristics of Europe. Within both regions these characteristics should be covered by the sites where the moss samples were collected. The number of samples should allow for geostatistical estimation of the measured nitrogen and metal loads.

Methods

The two regions of investigation were selected according to an ecological land classification of Europe which was computed by classification trees. Within each of both research areas the sampling points were localized according to the areas occupied by the ecologically defined land classes. The sampling and chemical analysis of mosses was conducted in accordance with an appropriate UNECE guideline by means of ICP-MS (metals) and combustion analysis (N). The quality of measurements was assured using certified reference materials. The differences of deposition loads were tested for statistical significance with regard to time and space. Variogram analysis was used to examine and model the spatial autocorrelation function of the measurements. Ordinary kriging was then applied for surface estimations.

Results

By use of the ecological regionalisation of Europe the Weser-Ems Region (WER) and the Euro Region Nissa (ERN) were selected for investigation. The sampling sites represent quite well the natural landscapes and the land use categories of both regions. The measurement values corroborate the decline of metal accumulation observed since the beginning of the European Mosses Monitoring Survey in 1990. The metal loads of the mosses in the ERN exceed those in the WER significantly. The opposite holds true for the N concentrations: those in the WER are significantly higher than those in the ERN.

Discussion

The decrease of heavy metal emissions is correlated with lowered deposition and accumulation rates in terrestrial ecosystems. The accumulation of nitrogen in the biosphere is not following this trend.

Conclusions

The technique of moss analysis is adequate for spatially valid biomonitoring of spatial and temporal trends of metals and nitrogen in terrestrial ecosystems. By this, it enables to prove the efficiency of environmental policies.

Recommendations and Perspectives

The accumulation of N in ecosystems is still a serious environmental problem. Related ecological impacts are the eutrophication of aquatic ecosystems like ground waters, lakes, rivers and oceans as well as the biocoenotic changes in terrestrial ecosystems. Thus, a statistically valid exposure analysis must encompass both, accumulation of metals and N bioaccumulation. Further, the bioaccumulation of persistent organic pollutants should be monitored. Finally, environmental biomonitoring should be conducted in much closer contact with human health aspects.     

Spatial modelling for the development of agri-environmental programs

Spatial modelling of environmental indicators has been well established in landscape ecology and in nature conservation on regional and national scales over the recent past. Yet, using spatial information as a basis for the coordination of environmental measures on a trans-national European level reveals several shortcomings and hindrances, ranging from data quality issues and methodological aspects to discussions on how to define ecological indicators across Europe. This paper analyzes the potential of spatial modelling for the development and implementation of agri-environmental measures as part of rural development policies, discussing critical aspects of spatial environmental modelling as well as chances, trends and demands.     

Near real time satellite tracking of striped marlin (Kajikia audax) movements in the Pacific Ocean

High-resolution satellite locations were obtained from striped marlin using Argos transmitters attached to the upper lobe of the caudal fin. Twenty-six striped marlin were tagged off New Zealand (2005–2007) and tracked as far as the central Pacific Ocean. Caudal fin mounted Argos tags generated 1,524 locations during a total of 659 tracking days [mean 25 (±21.24) days per fish and 2.3 (±2.30) locations per day]. 38% of locations have an estimated accuracy of ±1 km or better. Displacement rates from high quality locations ranged from 2.9 to 170.8 km in a 24 h period, with a mode at 20–30 km and a mean of 45 km/day. The caudal fin attachment methodology and antenna configuration was adjusted each season to improve transmission life and data quality, with the best results obtained in the last year of deployments (2007). The longest track duration was 102 days, with a total displacement of 4,959 km and a total track distance from all locations received of 6,850 km. Tag shedding and antenna failure appear to have limited the duration of tracks from SPOT tags. The high temporal and spatial resolution data revealed behaviours not previously observed in striped marlin, including associations to subsurface bathymetric features. High resolution location data such as these are useful inputs for statistical models used to investigate habitat selection and switching between different behavioural modes. The geolocations calculated using ukfsst estimates from PAT tag data had RMS errors of 1.01° latitude and 0.59° longitude when compared with SPOT tag Argos locations.