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Bloom forming and toxic phytoplankton in transitional and coastal waters of Cantabria region coast (Southeastern Bay of Biscay, Spain)
2012
Seoane, Sergio | Puente, Araceli | Guinda, Xabier | Juanes, Jose Antonio
Phytoplankton monitoring has extended to practically all the regions of the European coast due to the implementation of the European Water Framework Directive. In this way, the study of phytoplankton taxonomic composition and dynamic is being performed in many areas poorly studied or not studied before. During the last years, a monitoring programme has been carried out at the coast of Cantabria region (SE Bay of Biscay); the presence of some potentially toxic and bloom forming species (>7.5×10⁵cells per litre) has been observed. Diatoms and cryptophytes are the main blooming taxa in this region in the majority of the estuaries and in some of the coastal sites. All estuaries and coastal stations showed at least one potentially toxic species, being the dinoflagellates the group with the highest number of taxa observed. The potentially toxic species found in highest concentrations were the genera Pseudo-nitzschia and Chrysochromulina.
Afficher plus [+] Moins [-]Multi-biomarker responses in fishes from two typical marine aquaculture regions of South China
2012
He, Xiuting | Nie, Xiangping | Yang, Yufeng | Liu, Xinyu | Pan, Debo | Cheng, Zhang | Liang, Ximei
The impact of typical pollutants upon the fish-farming was assessed by use of a battery of biomarkers in two typical marine aquaculture regions in South China. Biotransformation parameters including 7-ethoxyresorufin-O-deethylase (EROD), aminopyrine N-demethylase (APND), erythromycin N-demethylase (ERND), glutathione-S-transferase (GST) and Malondialdehyde (MDA) were measured in five cultured fish species. Pollutants such as polycyclic aromatic hydrocarbon (PAHs), organochlorinated compounds (OCs), heavy metals and antibiotics (quinolones and sulfonamides) in sediments were characterized. Higher pollutant residue levels were observed in Dapeng Cove. EROD, APND and ERND activities were lower in fish from Dapeng Cove compared with fish from Hailing Island, while it is just on the contrary for GST and MDA. ERND, APND and GST showed sensitivity corresponding to different pollutants. Small fish species seemed to exhibit more sensitive to pollutants. The study further supports usefulness of multi-biomarker approach considering multiple species to define the effects of anthropogenic inputs in marine aquaculture systems.
Afficher plus [+] Moins [-]The impact of coastal urbanization on the structure of phytobenthic communities in southern Brazil
2012
Martins, Cintia D.L. | Arantes, Noele | Faveri, Caroline | Batista, Manuela B. | Oliveira, Eurico C. | Pagliosa, Paulo R. | Fonseca, Alessandra L. | Nunes, José Marcos C. | Chow, Fungyi | Pereira, Sonia B. | Horta, Paulo A.
The anthropogenic pressures on coastal areas represent important factors affecting local, regional, and even global patterns of distribution and abundance of benthic organisms. This report undertakes a comparative analysis of the community structure of rocky shore intertidal phytobenthos in both pristine like environments (PLE) and urbanized environments (UBE) in southern Brazil, characterizing variations on different spatial scales. Multivariate analysis of variance indicated that the PLE is characterized by a larger number of taxa and an increased occurrence of Rhodophyta species in relation to UBE. In contrast, UBE were dominated by opportunistic algae, such as Cladophora and Ulva spp. Significance tests further indicated higher species richness and Shannon–Wiener diversity on the PLE in relation to UBE. Here we provide data showing the magnitude of seaweed biodiversity loss and discuss direct and indirect consequences of unplanned urbanization on these communities.
Afficher plus [+] Moins [-]Testing benthic foraminiferal distributions as a contemporary quantitative approach to biomonitoring estuarine heavy metal pollution
2012
Foster, William J. | Armynot du Châtelet, Eric | Rogerson, M. (Mike)
Biomonitoring of estuarine pollution is the subject of active research, and benthic foraminifera are an attractive group to use for these purposes due to their ubiquitous presence in saline water and wide diversity. Here, we describe a case study of biomonitoring using benthic foraminifera in the French Mediterranean lagoon, Bages-Sigean lagoon. In this case, the major pollutants of interest are heavy metals in the sediment, particularly contaminated by Cu and Cd derived from industrial and agricultural sources. The foraminiferal assemblages of the Bages-Sigean lagoon are typical of normal paralic environments, but unusually almost completely lack agglutinated forms. The density of benthic foraminifera was shown to be more influenced by the sediment characteristics rather than heavy metal pollution. However, the relative abundance of Quinqueloculina bicostata was shown to increase in the most polluted areas and we propose that this taxon may be used as an indicator of heavy metal pollution.
Afficher plus [+] Moins [-]There is no 1954 in that core! Interpreting sedimentation rates and contaminant trends in marine sediment cores
2012
Johannessen, S.C. | Macdonald, R.W.
Marine sediment preserves a useful archive for contaminants and other properties that associate with particles. However, biomixing of sediments can smear the record on a scale of years to thousands of years, depending on sedimentation rate and on the depth and vigour of mixing within a particular sediment. Where such mixing occurs, dates can no longer be associated with discrete sediment depths. Nevertheless, much can still be learned from biomixed profiles, provided that mixing is accounted for. With no modelling at all, it is possible to calculate an inventory of a contaminant at a site and a maximum possible sedimentation rate, and to determine whether the contaminant has increased or decreased over time. Radiodating the core with ²¹⁰Pb permits the estimation of sedimentation and mixing rates, which can be combined with the surface contaminant concentration to estimate an approximate flux of the contaminant. Numerical models that incorporate sedimentation and mixing rates (determined using ²¹⁰Pb and other transient signals with known deposition histories) can provide the basis to propose plausible histories for contaminant fluxes.
Afficher plus [+] Moins [-]Molecularly imprinted polymer for selective extraction of malachite green from seawater and seafood coupled with high-performance liquid chromatographic determination
2012
Lian, Ziru | Wang, Jiangtao
In this paper, a highly selective sample cleanup procedure combining molecular imprinting technique (MIT) and solid-phase extraction (SPE) was developed for the isolation of malachite green in seawater and seafood samples. The molecularly imprinted polymer (MIP) was prepared using malachite green as the template molecule, methacrylic acid as the functional monomer and ethylene glycol dimethacrylate as the cross-linking monomer. The imprinted polymer and non-imprinted polymer were characterized by scanning electron microscope and static adsorption experiments. The MIP showed a high adsorption capacity and was used as selective sorbent for the SPE of malachite green. An off-line molecularly imprinted solid-phase extraction (MISPE) method followed by high-performance liquid chromatography with diodearray detection for the analysis of malachite green in seawater and seafood samples was also established. Finally, five samples were determined. The results showed that malachite green concentration in one seawater sample was at 1.30μgL⁻¹ and the RSD (n=3) was 4.15%.
Afficher plus [+] Moins [-]Pathways of marine debris derived from trajectories of Lagrangian drifters
2012
Maximenko, Nikolai | Hafner, Jan | Niiler, Peter
Global set of trajectories of satellite-tracked Lagrangian drifters is used to study the dynamics of marine debris. A probabilistic model is developed to eliminate the bias in spatial distribution of drifter data due to heterogeneous deployments. Model experiments, simulating long-term evolution of initially homogeneous drifter array, reveal five main sites of drifter aggregation, located in the subtropics and maintained by converging Ekman currents. The paper characterizes the geography and structure of the collection regions and discusses factors that determine their dynamics. A new scale Rc=(4k/|D|)¹/² is introduced to characterize tracer distribution under competing effects of horizontal divergence D and diffusion k. Existence and locations of all five accumulation zones have been recently confirmed by direct measurements of microplastic at the sea surface.
Afficher plus [+] Moins [-]Metals in sediments and fish from Sea Lots and Point Lisas Harbors, Trinidad and Tobago
2012
Mohammed, Azad | May, Thomas | Echols, Kathy | Walther, Mike | Manoo, Anton | Maraj, Dexter | Agard, John | Orazio, Carl
Concentrations of heavy metals were determined in nearshore marine sediments and fish tissue from Sea Lots area on the west coast, at Caroni Lagoon National Park, and in the Point Lisas harbor, Trinidad. The most dominant metals found in sediments were Al, Fe and Zn with mean concentrations highest at Sea Lots (Al-39420μg/g; Fe-45640μg/g; Zn-245μg/g), when compared to sediments from Point Lisas (Al-11936μg/g; Fe-30171μg/g; Zn-69μg/g) and Caroni (Al-0400μg/g; Fe-19000μg/g; Zn-32μg/g), High concentration of Cu, Al, Fe and Zn were also detected in fish tissue from Point Lisas and Caroni. Metal concentrations in fish tissue showed significant correlation with sediment metals concentration, which suggests that tissue levels are influenced by sediment concentration. Of the metals, only Zn, Hg and Cu had a bioaccumulation factor (BAF) greater than one, which suggests a high bioaccumulation potential for these metals.
Afficher plus [+] Moins [-]NH₄⁺ enrichment and UV radiation interact to affect the photosynthesis and nitrogen uptake of Gracilaria lemaneiformis (Rhodophyta)
2012
Xu, Zhiguang | Gao, Kunshan
Solar ultraviolet radiation (UVR, 280–400nm) is known to inhibit the photosynthesis of macroalgae, whereas nitrogen availability may alter the sensitivity of the algae to UVR. Here, we show that UV-B (280–315nm) significantly reduced the net photosynthetic rate of Gracilaria lemaneiformis. This inhibition was alleviated by enrichment with ammonia, which also caused a decrease in dark respiration. The presence of both UV-A (315–400nm) and UV-B stimulated the accumulation of UV-absorbing compounds. However, this stimulation was not affected by enrichment with ammonia. The content of phycoerythrin (PE) was increased by the enrichment of ammonia only in the absence of UVR. Ammonia uptake and the activity of nitrate reductase were repressed by UVR. However, exposure to UVR had an insignificant effect on the rate of nitrate uptake. In conclusion, increased PE content associated with ammonia enrichment played a protective role against UVR in this alga, and UVR differentially affected the uptake of nitrate and ammonia.
Afficher plus [+] Moins [-]The use of dinoflagellate cysts to separate human-induced from natural variability in the trophic state of the Po River discharge plume over the last two centuries
2012
Zonneveld, Karin A.F. | Ma, Yukun | Elshanawany, Rehab | Fischer, Helmut W. | Hoins, Mirja | Ibrahim, Mohammed I. | Pittauerova, Daniela | Versteegh, Gerard J.M.
To obtain insight into the natural and/or human-induced changes in the trophic state of the distal portion of the Po River discharge plume over the last two centuries, high temporal resolution dinoflagellate cyst records were established at three sites. Cyst production rates appear to reflect the natural variability in the river’s discharge, whereas cyst associations reflect the trophic state of the upper waters, which in turn can be related to agricultural development. The increased abundances of Lingulodinium machaerophorum and Stelladinium stellatum found as early as 1890 and 1920 correspond to the beginning of the industrial revolution in Italy and the first chemical production and dispersion of ammonia throughout Europe. After 1955, the increased abundances of these species and of Polykrikos schwartzii, Brigantedinium spp. and Pentapharsodinium dalei correspond to agriculturally induced alterations of the hypertrophic conditions. A slight improvement in water quality can be observed from 1987 onward.
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