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Near real time monitoring of platform sourced pollution using TerraSAR-X over the North Sea Полный текст
2014
Singha, Suman | Velotto, Domenico | Lehner, Susanne
Continuous operational monitoring by means of remote sensing contributes significantly towards less occurrence of oil spills over European waters however, operational activities show regular occurrence of accidental and deliberate oil spills over the North Sea, particularly from offshore platform installations. Since the areas covered by oil spills are usually large and scattered over the North Sea, satellite remote sensing particularly Synthetic Aperture Radar (SAR) represents an effective tool for operational oil spill detection. This paper describes the development of a semi-automated approach for oil spill detection, optimized for near real time offshore platform sourced pollution monitoring context. Eight feature parameters are extracted from each segmented dark spot. The classification algorithm is based on artificial neural network. An initial evaluation of this methodology has been carried out on 156 TerraSAR-X images. Wind and current history information also have been analyzed for particular cases in order to evaluate their influences on spill trajectory.
Показать больше [+] Меньше [-]An overview of historical harmful algae blooms outbreaks in the Arabian Seas Полный текст
2014
Al Shehhi, Maryam R. | Gherboudj, Imen | Ghedira, Hosni
Harmful algae blooms (HABs), often composed of oceanic plants called phytoplankton, are potentially harmful to the marine life, water quality, human health, and desalination plants, a chief source of potable water in the Arabian Gulf. The last decade has seen a noticeable increase in the frequency of HAB outbreaks in the Arabian Seas. This increase is mainly caused by the unprecedented economic growth in the region. The increased human activities in the region have added more stress to the marine environment and contributed to the changes observed in the properties of the marine ecosystem: high temperature and salinity, high evaporation rates, limited freshwater inflow, shallow nature, pollution. However, very few studies that cover the HAB outbreaks, causes, impacts and biological characteristics over the region have been published. This work presents a comprehensive overview of historical HAB outbreaks recorded in the region, and investigate their causes and impact, and seasonal variability.
Показать больше [+] Меньше [-]Comparison of the efficacy of MODIS and MERIS data for detecting cyanobacterial blooms in the southern Caspian Sea Полный текст
2014
Moradi, Masoud
Medium Resolution Imaging Spectrometer (MERIS) data, Moderate Resolution Imaging Spectroradiometer (MODIS) data, and hydro-biological measurements were used to detect two very severe blooms in the southern Caspian Sea in 2005 and 2010. The MERIS Cyanobacteria Index (CIMERIS) was more reliable for detecting cyanobacterial blooms. The CIMERIS and MODIS cyanobacteria indices (CIMODIS) were compared in an effort to find a reliable method for detecting future blooms, as MERIS data were not available after April 2012. The CIMODIS had a linear relationship with and similar spatial patterns to the CIMERIS. On the CIMODIS images, extremely high biomass cyanobacteria patches were masked. A comparison of classified in situ data with the CIMODIS and Floating Algal Index (FAI) from four images of a severe bloom event in 2005 showed that the FAI is a reliable index for bloom detection over extremely dense patches. The corrected CIMODIS, the MODIS FAI and in situ data are adequate tools for cyanobacterial bloom monitoring in the southern Caspian Sea.
Показать больше [+] Меньше [-]The invasive kelp Undaria pinnatifida (Laminariales, Ochrophyta) along the north coast of Portugal: Distribution model versus field observations Полный текст
2014
Veiga, P. | Torres, A.C. | Rubal, M. | Troncoso, J. | Sousa-Pinto, I.
After the first report of Undaria pinnatifida in north Portugal (between 1999 and 2007), a rapid spread of this species could be expected due to the presence of a stable population and the favourable environmental conditions proposed by distribution models. However, field surveys showed that U. pinnatifida was not present in most of the rocky shores in north Portugal. It seems that U. pinnatifida cannot outcompete native species outside of marinas in north Portugal. The only population in natural rocky shores was found in Buarcos, where this species was frequent. This study provides density data of U. pinnatifida that will be useful in the future to monitor changes on its abundance and distribution in the centre and south of Portugal.
Показать больше [+] Меньше [-]Community responses of intertidal soft-bottom macrozoobenthos to oil pollution in a tropical mangrove ecosystem, Niger Delta, Nigeria Полный текст
2014
Zabbey, Nenibarini | Uyi, Hanson
Preliminary impact assessment of two large oil spill incidents at Bodo Creek, in the Niger Delta, was undertaken, focusing on intertidal macrozoobenthos. Post-spill number of species and abundance were measured against recent pre-spill baseline data from the same study area. Results show that surface and infauna communities suffered severe reduction in abundance and number of species reduced by 81% after the spills, with two of the resampled sites having no taxa at all. Capitella capitata populations increased several-fold over pre-spill numbers. The impact of the oil spills is discussed in relation to local livelihoods and ecosystem integrity. The Niger Delta endemic lucinid, Keletistes rhizoecus, is proposed as a potential bioindicator for monitoring hydrocarbon contamination in Niger Delta estuaries.
Показать больше [+] Меньше [-]The effects of river run-off on water clarity across the central Great Barrier Reef Полный текст
2014
Fabricius, K.E. | Logan, M. | Weeks, S. | Brodie, J.
Changes in water clarity across the shallow continental shelf of the central Great Barrier Reef were investigated from ten years of daily river load, oceanographic and MODIS-Aqua data. Mean photic depth (i.e., the depth of 10% of surface irradiance) was related to river loads after statistical removal of wave and tidal effects. Across the ∼25,000 km2 area, photic depth was strongly related to river freshwater and phosphorus loads (R2=0.65 and 0.51, respectively). In the six wetter years, photic depth was reduced by 19.8% and below water quality guidelines for 156days, compared to 9days in the drier years. After onset of the seasonal river floods, photic depth was reduced for on average 6–8months, gradually returning to clearer baseline values. Relationships were strongest inshore and midshelf (∼12–80km from the coast), and weaker near the chronically turbid coast. The data show that reductions in river loads would measurably improve shelf water clarity, with significant ecosystem health benefits.
Показать больше [+] Меньше [-]Assessment of pollution in the Bizerte lagoon (Tunisia) by the combined use of chemical and biochemical markers in mussels, Mytilus galloprovincialis Полный текст
2014
Barhoumi, Badreddine | Menach, Karyn Le | Clérandeau, Christelle | Ameur, Walid Ben | Budzinski, Hélène | Driss, Mohamed Ridha | Cachot, Jérôme
In order to assess the environmental quality of the Bizerte lagoon (Tunisia), biomarker and contaminant levels were measured in Mediterranean mussels (Mytilus galloprovincialis) from five selected sites. Persistent organic pollutants (POPs) were quantified in whole body and enzyme activities such as acetylcholinesterase (AChE), catalase (CAT) and glutathione S-transferase (GST) in gills. Despite the relatively low levels of organic contaminants, the selected biomarkers responded differently according to the pollution level at the different sites. GST and AChE activities were correlated with the amount of DDTs in mussel tissues. These two enzymatic activities were also correlated to temperature and pH. No significant difference was observed for CAT activity. Principal component analysis showed a clear separation of sampling sites in three different assemblages which is consistent with POP body burden in mussels. Our results confirmed the usefulness of combining biomarker and chemical analyses in mussels to assess chemical pollution in the Bizerte lagoon.
Показать больше [+] Меньше [-]Monitoring ship noise to assess the impact of coastal developments on marine mammals Полный текст
2014
Merchant, Nathan D. | Pirotta, Enrico | Barton, Tim R. | Thompson, Paul M.
The potential impacts of underwater noise on marine mammals are widely recognised, but uncertainty over variability in baseline noise levels often constrains efforts to manage these impacts. This paper characterises natural and anthropogenic contributors to underwater noise at two sites in the Moray Firth Special Area of Conservation, an important marine mammal habitat that may be exposed to increased shipping activity from proposed offshore energy developments. We aimed to establish a pre-development baseline, and to develop ship noise monitoring methods using Automatic Identification System (AIS) and time-lapse video to record trends in noise levels and shipping activity. Our results detail the noise levels currently experienced by a locally protected bottlenose dolphin population, explore the relationship between broadband sound exposure levels and the indicators proposed in response to the EU Marine Strategy Framework Directive, and provide a ship noise assessment toolkit which can be applied in other coastal marine environments.
Показать больше [+] Меньше [-]Environmentally relevant exposure of 17α-ethinylestradiol impairs spawning and reproductive behavior in the brackish medaka Oryzias melastigma Полный текст
2014
Lee, Po-Yen | Lin, Chun-Yao | Chen, Te-Hao
We assessed the effects of 17α-ethinylestradiol (EE2) on spawning and reproductive behavior of the brackish medaka Oryzias melastigma at environmental concentrations. Breeding pairs were exposed to EE2 at either lower concentrations (0, 1, and 10ng/L) or higher concentrations (0, 50, and 100ng/L) for 14days. Swimming performance and reproductive behavior (following, dancing, and copulation) of the males were analyzed at the end of exposure. Additionally, gonad histology was conducted in the males in the higher EE2 experiment. We found that spawning was significantly inhibited in the 50–100ng/L EE2 groups. Swimming performance was not affected in all groups. Dancing and copulation were significantly suppressed in the 50–100ng/L groups. No effect was observed in testis histology in the 50–100ng/L groups. Our data suggests that reproductive behavior of O. melastigma can be utilized as a behavioral endpoint for ecotoxicology studies of endocrine disruptors in estuarine/marine environments.
Показать больше [+] Меньше [-]iTRAQ-based proteomic profiling of the marine medaka (Oryzias melastigma) gonad exposed to BDE-47 Полный текст
2014
Fong, C.C. | Shi, Y.F. | Yu, W.K. | Wei, F. | van de Merwe, J.P. | Chan, Alice K.Y. | Ye, R. | Au, Doris W.T. | Wu, Rudolf S.S. | Yang, M.S.
A recent study demonstrated that 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) may have an adverse effect on the reproduction in marine medaka (Oryzias melastigma), but the molecular mechanisms remain largely unknown. In this study, we investigated the protein expression profiles of male and female gonads of O. melastigma exposed to dietary BDE-47 at two dosages (0.65 and 1.30μg/g/day, respectively) for 21days. Extracted proteins were labeled with iTRAQ and analyzed on a MALDI TOF/TOF analyzer, as results, 133 and 144 unique proteins were identified in testis and ovary, respective, and they exerted dose- and sex-dependent expression patterns. In testis, among the 42 differentially expressed proteins; down-regulation of histone variants and parvalbumins implicated BDE-47 may disrupt the spermatogenesis and induce sterility in fishes. In ovary, 38 proteins were differentially expressed; the elevation of vitellogenins and apolipoprotein A–I expression indicated BDE-47 acts as an estrogen-mimicking compound and led to reproductive impairment in O. melastigma.
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