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Macroalgal diversity along the Baltic Sea salinity gradient challenges Remane’s species-minimum concept Texte intégral
2011
Schubert, Hendrik | Feuerpfeil, Peter | Marquardt, Ronny | Telesh, Irena | Skarlato, Sergei
Remane’s species-minimum concept, which states that the lowest number of taxa occurs at the horohalinicum (5–8psu), was tested by investigating macroalgal diversity on hard substrates along the natural salinity gradient in the Baltic Sea. Field data on species occurrence and abundance were collected by SCUBA diving along 10 transects of the Finnish, Swedish and German coasts, covering a salinity range from 3.9 to 27psu. Macroalgal species numbers declined steadily with salinity, decreasing until 7.2psu was reached, but in the horohalinicum, a marked reduction of species number and a change in diversity were indicated by the Shannon index and evenness values. The non-linear decrease in macroalgal diversity at 5–8psu and the lack of increase in species numbers at salinities below 5psu imply a restricted applicability of Remane’s species-minimum concept to macroalgae.
Afficher plus [+] Moins [-]Accumulation of trace elements in harp seals (Phoca groenlandica) from Pangnirtung in the Baffin Island, Canada Texte intégral
2011
Agusa, Tetsuro | Nomura, Kumiko | Kunito, Takashi | Anan, Yasumi | Iwata, Hisato | Tanabe, Shinsuke
Nineteen trace elements were determined in liver, muscle, kidney, gonads, and hair of 18 harp seals (Phoca groenlandica) from Pangnirtung in the Baffin Island, Canada. Concentrations of V, Mn, Fe, Cu, Mo, Ag, and Hg in the liver, Co, Cd, and Tl in the kidney, and Ba and Pb in the hair were significantly higher than those in other tissues. Significant positive correlations between Hg concentrations in the hair, and liver, kidney and testis imply usefulness of the hair sample for non-destructive monitoring of Hg in the harp seals. It is suggested that whereas Hg preferentially accumulates in the liver, the accumulation in other tissues is induced at higher hepatic Hg levels. In contrast, Se may not be accumulated in other tissues compared with the liver even at higher hepatic Hg levels because of the presence of excess Se for Hg detoxification in other tissues.
Afficher plus [+] Moins [-]Coastal habitat degradation and green sea turtle diets in Southeastern Brazil Texte intégral
2011
Santos, Robson G. | Martins, Agnaldo Silva | Farias, Julyana da Nobrega | Horta, Paulo Antunes | Pinheiro, Hudson Tercio | Torezani, Evelise | Baptistotte, Cecília | Seminoff, Jeffrey A. | Balazs, George H. | Work, Thierry M.
To show the influence of coastal habitat degradation on the availability of food for green turtles (Chelonia mydas), we assessed the dietary preferences and macroalgae community at a feeding area in a highly urbanized region. The area showed low species richness and was classified as degraded. We examined stomach contents of 15 dead stranded turtles (CCL=44.0cm (SD 6.7cm)). The diet was composed primarily of green algae Ulva spp. (83.6%). In contrast, the macroalgae community was dominated by the green alga Caulerpa mexicana. We found a selection for red algae, seagrass and Ulva spp., and avoidance for C. mexicana and brown alga Dictyopteris delicatula. The low diversity of available food items, possibly a result of environmental degradation, likely contributed to the low dietary diversity. The nutritional implications of this restricted diet are unclear.
Afficher plus [+] Moins [-]Arsenic and trace metal contents in sediment profiles from the Admiralty Bay, King George Island, Antarctica Texte intégral
2011
Ribeiro, Andreza P. | Figueira, Rubens C.L. | Martins, César C. | Silva, Charles R.A. | França, Elvis J. | Bícego, Márcia C. | Mahiques, Michel M. | Montone, Rosalinda C.
Admiralty Bay (Antarctica) hosts three scientific stations (Ferraz, Arctowski and Macchu Picchu), which require the use of fossil fuel as an energy source. Fossil fuels are also considered the main source of pollution in the area, representing important inputs of major pollutants (organic compounds) and trace metals and metalloids of environmental interest. Accordingly, this work presents the results of As, Cd, Cr, Cu, Ni, Pb and Zn in sediment profiles from Admiralty Bay. The sediment results from Ferraz station were slightly higher than the other sampling sites. The highest contents were observed for Cu and Zn (from 44 to 89mgkg⁻¹). Otherwise, by using enrichment factors and geochronology analysis, the most relevant enrichment was observed for As in the samples collected close to the Ferraz station, indicating that increasing As content may be associated with the activities associated with this site.
Afficher plus [+] Moins [-]Molecular ecological responses of dinoflagellate, Karenia mikimotoi to environmental nitrate stress Texte intégral
2011
Lei, Qiang-Yong | Lü, Song-Hui
Karenia mikimotoi is one of the most important harmful algal species in the Chinese coastal waters, and which produce hemolytic toxins and ichthyotoxins, resulting in devastating economic losses. Previous studies demonstrated that the increase of nitrate concentration could promote the growth and reproduction of K. mikimotoi. However, the intrinsic mechanisms regarding the effects of nitrate on the K. mikimotoi photosynthesis, nucleic acid replication and differential protein expression remain to be elucidated. Our study demonstrated that nitrate stress inhibited growth of K. mikimotoi (p<0.01). Algal chlorophyll fluorescence intensity varied slightly while algal cell cycle succession was significantly retarded by nitrate stress (p<0.05). Sixteen proteins were detected only in nitrate-limited cultures which related to nitrate transport, signal transduction, amino acid metabolism, DNA repair and hemolysin manufacture. Eleven proteins were detected only in nitrate-replete sample and were related to photorespiration, reproduction and growth, assistance of protein modification, cytoskeleton stability and signal transduction. Based on analysis of differential proteomic functional annotations, we hypothesized a proteomic response mechanism of K. mikimotoi to environmental nitrate stress.
Afficher plus [+] Moins [-]Effects of the 2003 European heatwave on the benthic community of a severe transitional ecosystem (Comacchio Saltworks, Italy) Texte intégral
2011
Munari, Cristina
The summer of 2003 was the warmest summer in Europe since the 16th century. Its consequences on the fauna of a transitional ecosystem were studied through biodiversity, functional and ecological indicators, from summer 2002 to winter 2005. The heatwave caused considerable changes in the benthic community structure and relative composition, persisting in 2005. Animal assemblages switched from mollusc- to annelida-dominated. Biodiversity and functional indicators captured changes in community structure and composition, proving to be powerful tools to detect responses related to global warming. Ecological indicators rendered a monotonic response oscillating between bad and poor ecological status across the study period. The resilience of mollusc biocoenosis resulted limited with respect to other taxa, posing concerns about their conservation if, as predicted, the frequency of summers as hot as that of 2003 will progressively increase to become the norm at the end of this century.
Afficher plus [+] Moins [-]Integrated biomarker assessment of the effects exerted by treated produced water from an onshore natural gas processing plant in the North Sea on the mussel Mytilus edulis Texte intégral
2011
Brooks, Steven | Harman, Chris | Zaldibar, Beñat | Izagirre, Urtzi | Glette, Tormod | Marigómez, Ionan
The biological impact of a treated produced water (PW) was investigated under controlled laboratory conditions in the blue mussel, Mytilus edulis. Mussel health status was assessed using an integrated biomarker approach in combination with chemical analysis of both water (with SPMDs), and mussel tissues. Acyl-CoA oxidase activity, neutral lipid accumulation, catalase activity, micronuclei formation, lysosomal membrane stability in digestive cells and haemocytes, cell-type composition in digestive gland epithelium, and the integrity of the digestive gland tissue were measured after 5week exposure to 0%, 0.01%, 0.1%, 0.5% and 1% PW. The suite of biomarkers employed were sensitive to treated PW exposure with significant sublethal responses found at 0.01–0.5% PW, even though individual chemical compounds of PW were at extremely low concentrations in both water and mussel tissues. The study highlights the benefits of an integrated biomarker approach for determining the potential effects of exposure to complex mixtures at low concentrations. Biomarkers were integrated in the Integrative Biological Response (IBR/n) index.
Afficher plus [+] Moins [-]Induction of tributyltin-binding protein type 2 in Japanese flounder, Paralichthys olivaceus, by exposure to tributyltin-d27 Texte intégral
2011
Nassef, Mohamed | Tawaratsumita, Takahiko | Oba, Yumi | Satone, Hina | Nakayama, Kei | Shimasaki, Yohei | Honjo, Tsuneo | Ōshima, Yūji
In this study, individual Japanese flounder were intraperitoneally injected with 2μg tributyltin-d27 (TBT-d27) fish⁻¹. Blood samples were collected on day 7 after injection. TBT-binding protein types 1 and 2 (TBT-bp1, -bp2) in the blood serum were quantified by western blotting analysis. As a result, the concentration of TBT-bp2 in TBT-d27 treated group increased to 220% of that in the solvent control, whereas the TBT-bp1 concentration decreased to 65% of that in the solvent control. Additionally, a positive relationship between the concentrations of TBT-bp2 and TBT was observed in blood sera of wild and cultured flounder. We suggest that TBT-bp2 is produced in response to TBT exposure and may play an important role in fish physiology.
Afficher plus [+] Moins [-]Modelling temporal trends of ¹³⁷Cs and ⁹⁹Tc concentrations in Fucus vesiculosus from the eastern Irish coastline Texte intégral
2011
Cournane, S. | León Vintró, L. | Mitchell, P.I. | McMahon, C.A. | Smith, K. | Long, S.
Time series of ¹³⁷Cs and ⁹⁹Tc activity concentrations in the brown seaweed Fucus vesiculosus and seawater, gathered at three locations on the eastern Irish coastline during the period 1988–2008, have been modelled using a novel approach incorporating a variable uptake rate in the seaweed. Seasonal variations in the time series, identified using spectral analysis, were incorporated into the model which was used to determine transfer kinetic parameters and to predict ¹³⁷Cs and ⁹⁹Tc concentrations in seaweed, as influenced by levels in ambient seawater. An optimisation method combining evolutionary and grid search minimisation techniques was adopted to determine the best values for the model parameters, from which concentration factors (CF) and biological half-lives (tb₁/₂) for ¹³⁷Cs and ⁹⁹Tc in F. vesiculosus were calculated. CF values of 170–179 and 1.1×105lkg⁻¹ (dry weight) were obtained for ¹³⁷Cs and ⁹⁹Tc, respectively, while the corresponding tb₁/₂ values were 39–47 and 32days, respectively.
Afficher plus [+] Moins [-]Distribution of butyltins in the waters and sediments along the coast of India Texte intégral
2011
Garg, Anita | Meena, Ram M. | Jadhav, Sangeeta | Bhosle, Narayan B.
Water and surface sediment samples were analyzed for butyltins (TBT, DBT, MBT) from various ports along the east and west coast of India. The total butyltin (TB) in water samples varied between ∼1.7 and 342ngSnl⁻¹, whereas for sediments it varied between below detection limit to 14861ngSng⁻¹ dry weight of sediment. On an average Chennai port recorded the highest level of butyltins in the sediments while Paradip recorded the highest level of butylins in the waters. A fairly good relationship between the TB in the sediment and overlying water samples, as well as between organic carbon and TB, implicates the importance of adsorption/desorption process in controlling the levels of TBT in these port areas. In India the data on organotin pollution is very sparse; most of the port areas have been surveyed for butyltins for the first time during this study.
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