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Tracing decadal environmental change in ombrotrophic bogs using diatoms from herbarium collections and transfer functions
2013
Poulíčková, Aloisie | Hájková, Petra | Kintrová, Kateřina | Bat'ková, Romana | Czudková, Markéta | Hájek, Michal
Central European mountain bogs, among the most valuable and threatened of habitats, were exposed to intensive human impact during the 20th century. We reconstructed the subrecent water chemistry and water-table depths using diatom based transfer functions calibrated from modern sampling. Herbarium Sphagnum specimens collected during the period 1918–1998 were used as a source of historic diatom samples. We classified samples into hummocks and hollows according to the identity of dominant Sphagnum species, to reduce bias caused by uneven sampling of particular microhabitats. Our results provide clear evidence for bog pollution by grazing during the period 1918–1947 and by undocumented aerial liming in the early 90-ies. We advocate use of herbarized epibryon as a source of information on subrecent conditions in recently polluted mires.
Show more [+] Less [-]Bloom of Cochlodinium polykrikoides (Dinophyceae: Gymnodiniales) in Bahía de La Paz, Gulf of California
2013
Gárate Lizárraga, Ismael
As part of a continuing toxic microalgae monitoring program, phytoplankton samples were collected on 16–17 August 2012 at several sampling sites in the southern part of the Bahía de La Paz. A bloom of the dinoflagellate Cochlodinium polykrikoides was detected. Abundance of C. polykrikoides ranged from 73 to 276×103cellsL−1 on the first day to 980–1425×103cellsL−1 on the second day. Study of live specimens showed great variation in cell size and form, mainly as single cells or chains of two cells. Live cells were 30–47μm long and 20–35μm wide (n=30). Seawater temperature during the bloom was 29–30°C. Low densities of Cochlodinium convolutum, Cochlodinium helicoides, and Cochlodinium shuettii were also found in the samples of the bloom event. These high densities of C. polykrikoides did not lead to fish die-offs in the bay.
Show more [+] Less [-]Advanced diagnostics applied to fish liver tumours: Relating pathology to underlying molecular aetiology
2013
Lerebours, Adélaïde | Bignell, John P. | Stentiford, Grant D. | Feist, Stephen W. | Lyons, Brett P. | Rotchell, Jeanette M.
Liver tumours in flatfish have been diagnosed using histopathology for decades in order to monitor the impacts of marine pollution in coastal and estuarine environments. This traditional method has been coupled with molecular analyses of tumours in the liver of the dab, Limanda limanda, in order to elucidate underpinning molecular level aetiology of such disease. A laser capture microdissection technique for molecular investigation of cancer has been applied in fish. The present study provides optimized steps for environmental sample utilisation: a procedure for field sample collection and handling; a method allowing reliable identification of lesions on frozen tissue sections; and, downstream molecular analyses of tumourigenesis markers (retinoblastoma gene) in laser microdissected samples. This approach facilitates the use of wild flatfish as a model of environmentally-induced tumourigenesis, and has wide applicability to any disease pathology for which the underpinning molecular aetiology is required.
Show more [+] Less [-]Chemometric techniques in distribution, characterisation and source apportionment of polycyclic aromatic hydrocarbons (PAHS) in aquaculture sediments in Malaysia
2013
Retnam, Ananthy | Zakaria, Mohamad Pauzi | Juahir, Hafizan | Ahmad Zaharin Aris, | Zali, Munirah Abdul | Kasim, Mohd Fadhil
This study investigated polycyclic aromatic hydrocarbons (PAHs) pollution in surface sediments within aquaculture areas in Peninsular Malaysia using chemometric techniques, forensics and univariate methods. The samples were analysed using soxhlet extraction, silica gel column clean-up and gas chromatography mass spectrometry. The total PAH concentrations ranged from 20 to 1841ng/g with a mean of 363ng/gdw. The application of chemometric techniques enabled clustering and discrimination of the aquaculture sediments into four groups according to the contamination levels. A combination of chemometric and molecular indices was used to identify the sources of PAHs, which could be attributed to vehicle emissions, oil combustion and biomass combustion. Source apportionment using absolute principle component scores–multiple linear regression showed that the main sources of PAHs are vehicle emissions 54%, oil 37% and biomass combustion 9%. Land-based pollution from vehicle emissions is the predominant contributor of PAHs in the aquaculture sediments of Peninsular Malaysia.
Show more [+] Less [-]Chemometric evaluation of the heavy metals distribution in waters from the Dilovası region in Kocaeli, Turkey
2013
Bingöl, Deniz | Ay, Ümit | Karayünlü Bozbaş, Seda | Uzgören, Nevin
The main objective of this study was to test water samples collected from 10 locations in the Dilovası area (a town in the Kocaeli region of Turkey) for heavy metal contamination and to classify the heavy metal (Cr, Mn, Co, Ni, Cu, Zn, As, Cd, Pb and Hg) contents in water samples using chemometric methods. The heavy metals in the water samples were identified using inductively coupled plasma-mass spectrometry (ICP-MS). To ascertain the relationship among the water samples and their possible sources, the correlation analysis, principal component analysis (PCA), and cluster analysis (CA) were used as classification techniques. About 10 water samples were classified into five groups using PCA. A very similar grouping was obtained using CA.
Show more [+] Less [-]Distribution and geochemical speciation of heavy metals in sediments from coastal area suffered rapid urbanization, a case study of Shantou Bay, China
2013
Qiao, Yongmin | Yang, Yang | Gu, Jiguang | Zhao, Jiangang
Eight metals in sediment samples at 15 sites from the Shantou Bay were analyzed with BCR sequential extraction protocol to obtain the metal distribution patterns in the bay. The results showed that the heavy metal pollutions in upper bay were more severe than in middle and down reaches of the bay. Both total and non-residual fractions of metals with a exception of Mn showed a seaward decrease trend. More than 54% of the total concentrations of Cd, Mn and Zn existed in the acid soluble fraction. Ni, Co, Cr and Fe mainly (more than 51%) occurred in the residual fraction. While Pb and Cu dominantly presented in the reducible (50%) and oxidable (33%) fraction respectively. Principal component analysis (PCA) revealed that the heavy metals in the non-residual fractions resulted from largely anthropogenic sources, including river input, city runoff and port discharge. These contributing sources are highlighted by cluster analysis.
Show more [+] Less [-]Difficulties in obtaining representative samples for compliance with the Ballast Water Management Convention
2013
Carney, Katharine J. | Basurko, Oihane C. | Pazouki, Kayvan | Marsham, Sara | Delany, Jane E. | Desai, D.V. | Anil, A.C. | Mesbahi, Ehsan
As implementation of the Ballast Water Convention draws nearer a major challenge is the development of protocols which accurately assess compliance with the D-2 Standard. Many factors affect the accuracy of assessment: e.g. large volume of ballast water, the shape, size and number of ballast tanks and the heterogeneous distribution of organisms within tanks. These factors hinder efforts to obtain samples that truly represent the total ballast water onboard a vessel.A known cell density of Tetraselmis suecica was added to a storage tank and sampled at discharge. The factors holding period, initial cell density and sampling interval affected representativeness. Most samples underestimated cell density, and some tanks with an initial cell density of 100cellsml−1 showed <10cellsml−1 at discharge, i.e. met the D-2 standard. This highlights difficulties in achieving sample representativeness and when applied to a real ballast tank this will be much harder to achieve.
Show more [+] Less [-]Ecology of the ciguatera causing dinoflagellates from the Northern Great Barrier Reef: Changes in community distribution and coastal eutrophication
2013
Skinner, Mark P. | Lewis, Richard J. | Morton, Steve
Ciguatera fish poisoning (CFP) is known to be caused by the ciguatoxins from the dinoflagellate genus Gambierdiscus, however, there is the potential for other toxins such as okadaic acid and dinophysistoxins from the genus Prorocentrum, and palytoxin from the genus Ostreopsis, to contaminate seafood. These genera may also be indicators of ecosystem health and potentially impact on coral reef ecosystems and the role they may play in the succession of coral to macroalgae dominated reefs has not been researched. Sixteen GBR field sites spanning inshore, mid-lagoon and outer lagoon (offshore) regions were studied. Samples were collected from September 2006 to December 2007 and abundance of benthic dinoflagellates on different host macroalgae and concentration of nutrients present in the water column were determined. The maximum abundance of Prorocentrum, Ostreopsis and Gambierdiscus found was 112, 793 and 50 cells per gram wet weight of host macroalgae, respectively. The average level of Dissolved Inorganic Nitrogen (DIN) in the water column across all sites (0.03mg/L) was found to be more than double the threshold critical value (0.013mg/L) for healthy coral reefs. Compared to a previous study 1984, there is evidence of a major shift in the distribution and abundance of these dinoflagellates. Inshore reefs have either of Prorocentrum (as at Green Island) or Ostreopsis (as at Magnetic Island) dominating the macroalgal surface niche which was once dominated by Gambierdiscus, whilst at offshore regions Gambierdiscus is still dominant. This succession may be linked to the ongoing eutrophication of the GBR lagoon and have consequences for the sources of toxins for ongoing cases of ciguatera.
Show more [+] Less [-]Distribution and sources of polycyclic aromatic hydrocarbons in Cilician Basin shelf sediments (NE Mediterranean)
2013
This study corresponds to preliminary work representing an initial assessment for spatial distribution of polycyclic aromatic hydrocarbons (PAHs) in the Cilician Basin coastal sediments. The concentrations of PAHs in shelf sediments were determined from the three different regions of Cilician Basin (Eastern Mediterranean) in 2011. Concentrations of PAHs were low 5.43–271ngg−1 with respect to other coastal sediments in the Mediterranean and these results could be compared with concentrations found in open sea areas. PAH composed mainly of pyrolytic four and five-ring compounds. An abundance of high molecular weight PAHs indicated that atmospheric particles and urban aerosols are the major input route of hydrocarbons in the Cilician and Lattakia Basins. PAH levels were assessed in accordance with numerical Sediment Quality Guideline (SQG) of the USEPA. The results showed that no samples exceeded biological thresholds to pose biological impairments.
Show more [+] Less [-]Corals from the Persian/Arabian Gulf as models for thermotolerant reef-builders: Prevalence of clade C3 Symbiodinium, host fluorescence and ex situ temperature tolerance
2013
Hume, B. | D’Angelo, C. | Burt, J. | Baker, A.C. | Riegl, B. | Wiedenmann, J.
Corals in the Arabian/Persian Gulf endure summer temperatures of up to 36°C, making them ideal subjects to study the mechanisms underlying thermal tolerance. Unexpectedly, we found the “generalist” Symbiodinium clade C3 to be the prevalent symbiont among seven coral species from Abu Dhabi (UAE) waters. Moreover, C3 represented the only dominant symbiont type in Porites spp. from this region. The “thermotolerant” symbionts D1a and C15 were not encountered, indicating that the association with these symbionts cannot be the sole reason for the heat tolerance of Gulf corals. The association of Porites lobata with specific symbiont types (C3 vs. C15) in samples from habitats with very different temperature regimes (Abu Dhabi vs. Fiji) remained unaffected by laboratory culture. During temperature stress experiments specimens from both locations strongly downregulated green fluorescent protein (GFP)-like pigments. However, the Abu Dhabi samples were less prone to bleaching and showed lower mortality.
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