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Reef-forming polychaetes outcompetes ecosystem engineering mussels
2013
In order to understand changes in the functioning and the community structure of intertidal ecosystem in sewage-impacted sites, a long-term monitoring coverage study (2004–2011) was carried out on abrasion platforms of the SW Atlantic. The intertidal zone is characterized by the mytilid Brachidontes rodriguezii, an ecosystem engineer. Since the austral spring of 2008, a demographic explosion of an invader polychaetes, Boccardia proboscidea, has produced massive biogenic structures around the sewage discharge outfall. Cover percentage of this polychaete reached almost 100% in sewage-impacted sites but low or no coverage at all in Reference Sites. The density of B. rodriguezii declined due to the biogenic reefs stifles these mytilids. The massive settlement of B. proboscidea among mussels, the rapid growth and the tube construction smothers the mussels in sewage-impacted sites.
Show more [+] Less [-]The incidence of plastic ingestion by fishes: From the prey’s perspective
2013
One of the primary threats to ocean ecosystems from plastic pollution is ingestion by marine organisms. Well-documented in seabirds, turtles, and marine mammals, ingestion by fish and sharks has received less attention until recently. We suggest that fishes of a variety of sizes attack drifting plastic with high frequency, as evidenced by the apparent bite marks commonly left behind. We examined 5518 plastic items from random plots on Kamilo Point, Hawai’i Island, and found 15.8% to have obvious signs of attack. Extrapolated to the entire amount of debris removed from the 15km area, over 1.3tons of plastic is attacked each year. Items with a bottle shape, or those blue or yellow in color, were attacked with a higher frequency. The triangular edges or punctures left by teeth ranged from 1 to 20mm in width suggesting a variety of species attack plastic items. More research is needed to document the specific fishes and rates of plastic ingestion.
Show more [+] Less [-]Investigation of priorities in water quality management based on correlations and variations
2013
Boyacıoğlu, Hülya | Gündogdu, Vildan | Boyacıoğlu, Hayal
The development of water quality assessment strategies investigating spatial and temporal changes caused by natural and anthropogenic phenomena is an important tool in management practices. This paper used cluster analysis, water quality index method, sensitivity analysis and canonical correlation analysis to investigate priorities in pollution control activities. Data sets representing 22 surface water quality parameters were subject to analysis. Results revealed that organic pollution was serious threat for overall water quality in the region. Besides, oil and grease, lead and mercury were the critical variables violating the standard. In contrast to inorganic variables, organic and physical-inorganic chemical parameters were influenced by variations in physical conditions (discharge, temperature). This study showed that information produced based on the variations and correlations in water quality data sets can be helpful to investigate priorities in water management activities. Moreover statistical techniques and index methods are useful tools in data – information transformation process.
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 [-]Spatial variations in polycyclic aromatic hydrocarbons concentrations at surface sediments from the Cyprus (Eastern Mediterranean): Relation to ecological risk assessment
2013
Darılmaz, Enis | Kontaş, Aynur | Uluturhan, Esin | Akçalı, İdil | Altay, Oya
The objective of the present study was to evaluate the distribution, sources, origins, and environmental risk assessment of polycyclic aromatic hydrocarbons (16 US EPA priority pollutants) pollution in 23 surface sediments from Cyprus coast. The mean total polycyclic aromatic hydrocarbons (PAHs) concentrations in the sediments from Gemi Konagi, Girne and Gazi Magusa areas were found 47, 52 and 50ng/g, respectively. Molecular ratios and principle component analysis indicated that PAH pollution originated mainly from fossil sources, with higher pyrolytic contributions. The 2–3 ring PAHs were dominant in Cyprus sediments. Concentrations of PAHs observed in this study were compared with available soil quality guidelines and the concentrations were lower than the guideline values. The guideline values suggested that the Cyprus sediments were likely to be not contaminated by toxic PAH compounds.
Show more [+] Less [-]Characteristics of visibility and particulate matter (PM) in an urban area of Northeast China
2013
Zhao, Hujia | Che, Huizheng | Zhang, Xiaoye | Ma, Yanjun | Wang, Yangfeng | Wang, Hong | Wang, Yaqiang
The visibility data from 2010 to 2012 were obtained at Shenyang in Northeast China and the relations between visibility, PM mass concentration and meteorological variables were statistically analyzed. These results demonstrate that the monthly–averaged visibility over Shenyang was higher in March and September with values of approximately 19.0±4.3 km and 17.1±4.3 km, respectively. Low visibility over Shenyang occurred in January at approximately 11.0±4.7 km. Among the meteorological variables considered, wind speed was the main meteorological factor that influenced visibility and PM mass concentrations. The relation between visibility and PM indicates that fine particles are already a main source of pollutants, the existence of which is the most important factor in the deterioration of visibility in an urban area of Northeast China. The study also shows an obvious diurnal variation and weekend effects of visibility and PM, which are mainly caused by human activities. Results of this study highlight the significant impact of fine particles on air pollution and visibility in an urban area of Northeast China.
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 [-]Improving a prediction system for oil spills in the Yellow Sea: Effect of tides on subtidal flow
2013
Kim, Chang-Sin | Cho, Yang-Ki | Choi, Byoung-Ju | Jung, Kyung Tae | You, Sung Hyup
A multi-nested prediction system for the Yellow Sea using drifter trajectory simulations was developed to predict the movements of an oil spill after the MV Hebei Spirit accident. The speeds of the oil spill trajectories predicted by the model without tidal forcing were substantially faster than the observations; however, predictions taking into account the tides, including both tidal cycle and subtidal periods, were satisfactorily improved. Subtidal flow in the simulation without tides was stronger than in that with tides because of reduced frictional effects. Friction induced by tidal stress decelerated the southward subtidal flows driven by northwesterly winter winds along the Korean coast of the Yellow Sea. These results strongly suggest that in order to produce accurate predictions of oil spill trajectories, simulations must include tidal effects, such as variations within a tidal cycle and advections over longer time scales in tide-dominated areas.
Show more [+] Less [-]Is the distribution of the lancelet Branchiostoma caribaeum affected by sewage discharges? An analysis at multiple scales of variability
2013
Barboza, Carlos Alberto de Moura | Hadlich, Heliatrice Louise | Sandrini-Neto, Leonardo | Martins, César de Castro | Lana, Paulo da Cunha
Spatial variation in the density and biomass of Branchiostoma caribaeum was analyzed along a sewage contamination gradient identified by fecal steroids in a subtropical estuary, southern Brazil. Sampling, repeated in the austral winter and summer, followed a hierarchical design nested at four spatial scales (sector>1km; area>100m; site>10m; replicate<1m). Density and biomass were significantly lower at sites characterized by high concentrations of fecal steroids. The best combinations of variables that explained the biological similarities among sites involved contamination indicators. Most of the variation of biological data was found at the smallest scales and could be related with the sediment texture. Our study highlighted the usefulness of a multi-scale perspective to evaluate distribution patterns of benthic invertebrates as a biological indication of environmental pollution. Gradient analyses at larger spatial scales may be invalidated by the patchy distribution of benthic fauna if they do not account for such small scale variability.
Show more [+] Less [-]Distribution of the genus Alexandrium (Halim) and paralytic shellfish toxins along the coastline of New South Wales, Australia
2013
Farrell, Hazel | Brett, Steve | Ajani, Penelope | Murray, Shauna
Blooms of Alexandrium species, in particular the species Alexandrium catenella, accounted for more than 50% of algal related, shellfish aquaculture harvest zone closures in New South Wales (NSW) Australia since 2005. While there are indications that species of Alexandrium are more abundant than they were formerly, there is little data available on the spatial and temporal distribution and abundance of the genus in NSW. A six and a half year dataset comprising a total of 8649 fortnightly samples from 31 estuaries spread over 2000km of NSW coastline was analysed. The greatest abundances of Alexandrium spp. were observed during the austral Spring and Summer, in estuaries in the mid and southern latitudes of the state. In identifying these high risk zones, we propose variables such as season, temperature, rainfall and estuarine flushing to be targeted in intensive site specific studies, to support the development of predictive tools for resource managers.
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