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Does energetic cost for leaf construction in Sonneratia change after introduce to another mangrove wetland and differ from native mangrove plants in South China?
2017
Li, Fenglan | Yang, Lei | Zan, Qi-Jie | Shin, Paul-K.S. | Cheung, Siu-Gin | Wong, Yuk-Shan | Tam, Nora Fung-Yee | Lei, An-Ping
Exotic species invasions are serious ecological problems. Leaf construction cost (CC) and growth traits of two Sonneratia (Sonneratia caseolaris and S. apetala) and four native species (Bruguiera gymnorrhiza, Kandelia obovata, Aegiceras corniculatum and Avicennia marina) in Hainan and Shenzhen mangrove wetlands were compared to evaluate invasive potentials of Sonneratia after introduced to Shenzhen, their new habitat. There were no significant differences in CC and growth traits between two wetlands, suggesting Sonneratia did not lose any advantage in the new habitat and were competitive in both wetlands. CC per unit mass (CCM), CC per unit area (CCA) and caloric values of Sonneratia were significantly lower than those of native mangrove species while specific leaf area (SLA) was just the opposite. CCM of S. caseolaris and S. apetala were 6.1% and 11.9% lower than those of natives, respectively. These findings indicated the invasive potential of Sonneratia in Shenzhen after their introduction.
Показать больше [+] Меньше [-]Biological effects of gold mine tailings on the intertidal marine environment in Nova Scotia, Canada
2017
Doe, K. | Mroz, R. | Tay, K.-L. | Burley, J. | Teh, S. | Chen, S.
From 1861 to the 1940s, gold was produced from 64 mining districts in Nova Scotia, where mercury amalgamation was the dominant method for the extraction of gold from ore until the 1880s. As a result, wastes (tailings) from the milling process were contaminated by mercury and were high in naturally occurring arsenic. In 2004 and 2005, sediments, water and mollusc tissues were collected from 29 sampling stations at nine former gold mining areas along the Atlantic coastline and were analysed for arsenic and mercury. The resulting data were compared with environmental quality guidelines. Samples indicated high potential risk of adverse effects in the intertidal environments of Seal Harbour, Wine Harbour and Harrigan Cove. Arsenic in Seal Harbour was bioavailable, resulting in high concentrations of arsenic in soft-shell clam tissues. Mercury concentrations in tissues were below guidelines. This paper presents results of the sampling programs and implications of these findings.
Показать больше [+] Меньше [-]Dramatic increase in mud distribution across a large sub-tropical embayment, Moreton Bay, Australia
2017
Lockington, James R. | Albert, Simon | Fisher, Paul L. | Gibbes, Badin R. | Maxwell, Paul S. | Grinham, Alistair R.
Major flood events can dramatically alter the coastal sediment environment. This study established the current sediment distribution in a large sub-tropical embayment, Moreton Bay, Australia, and examined the effect of three recent floods on modifying this distribution. In 2015, surface sediment samples were collected from 223 sites across the study area and analysed for particle size distribution with the resultant sediment distribution mapped. In addition, sampling of flood waters during two major events in 2011 and 2013 was undertaken and particle size distribution of suspended sediment was determined. Data was compared to the result of an earlier large-scale survey completed in 1970, with three large flood events occurring between the two surveys. The sediment environment has undergone a dramatic change with muddy sediments now covering an estimated area of over 860km2, more the double the area found in 1970. Mud is now the dominant sediment type within Moreton Bay.
Показать больше [+] Меньше [-]Geochemical partitioning of lead in biogenic carbonate sediments in a coral reef depositional environment
2017
Horta-Puga, Guillermo
The fate of trace elements in reef depositional environments has not been extensively investigated. The aim of this study was to determine the partitioning of Pb in sediments of the Veracruz Reef System, and its relation to local environmental sources. Lead was determined in four geochemical fractions: exchangeable (3.8±0.4μgg−1), carbonate (57.0±13.6μgg−1), organic matter (2.0±0.9μgg−1), and mineral (17.5±5.4μgg−1). For the mineral fraction, lead concentrations were higher in those reefs influenced by river discharge or by long-distance transport of terrigenous sediments. The bioavailable concentration of lead (range: 21.9–85.6μgg−1) indicates that the Veracruz Reef System is a moderately polluted area. As expected, the carbonate fraction contained the highest proportion of Pb (70%), and because the reef framework is largely made up of by biogenic carbonate sediments, hence, it is therefore the most important repository of Pb in coral reef depositional environments.
Показать больше [+] Меньше [-]A new method to calibrate Lagrangian model with ASAR images for oil slick trajectory
2017
Tian, Siyu | Huang, Xiaoxia | Li, Hongga
Since Lagrangian model coefficients vary with different conditions, it is necessary to calibrate the model to obtain optimal coefficient combination for special oil spill accident. This paper focuses on proposing a new method to calibrate Lagrangian model with time series of Envisat ASAR images. Oil slicks extracted from time series images form a detected trajectory of special oil slick. Lagrangian model is calibrated by minimizing the difference between simulated trajectory and detected trajectory. mean center position distance difference (MCPD) and rotation difference (RD) of Oil slicks' or particles' standard deviational ellipses (SDEs) are calculated as two evaluations. The two parameters are taken to evaluate the performance of Lagrangian transport model with different coefficient combinations. This method is applied to Penglai 19-3 oil spill accident. The simulation result with calibrated model agrees well with related satellite observations. It is suggested the new method is effective to calibrate Lagrangian model.
Показать больше [+] Меньше [-]Reliability and utility of citizen science reef monitoring data collected by Reef Check Australia, 2002–2015
2017
Done, Terence | Roelfsema, Chris | Harvey, Andrew | Schuller, Laura | Hill, Jocelyn | Schläppy, Marie-Lise | Lea, Alexandra | Bauer-Civiello, Anne | Loder, Jennifer
Reef Check Australia (RCA) has collected data on benthic composition and cover at >70 sites along >1000km of Australia's Queensland coast from 2002 to 2015. This paper quantifies the accuracy, precision and power of RCA benthic composition data, to guide its application and interpretation. A simulation study established that the inherent accuracy of the Reef Check point sampling protocol is high (<±7% error absolute), in the range of estimates of benthic cover from 1% to 50%. A field study at three reef sites indicated that, despite minor observer- and deployment-related biases, the protocol does reliably document moderate ecological changes in coral communities. The error analyses were then used to guide the interpretation of inter-annual variability and long term trends at three study sites in RCA's major 2002–2015 data series for the Queensland coast.
Показать больше [+] Меньше [-]Chlorination induced damage and recovery in marine diatoms: Assay by SYTOX® Green staining
2017
Venkatnarayanan, Srinivas | Sriyutha Murthy, P. | Nancharaiah, Yarlagadda V. | Kirubagaran, Ramalingam | Venugopalan, Vayalam P.
Phytoplankton entrained into cooling water systems of coastal power stations are subjected to acute chemical stress due to biocides (chlorine) used for biofouling control. They are subsequently released into the environment, where they may survive/recover or succumb. Experiments were conducted to evaluate the susceptibility of a centric (Chaetoceros lorenzianus) and pennate (Navicula sp.) diatom to in-plant administered concentrations of chlorine (0.2–0.5mg/L, TRO). Viability of cells exposed to chlorine was assessed by SYTOX® Green fluorimetry and was compared with other conventional end points like total cell counts, chlorophyll a content and cellular autofluorescence. Results showed a concentration-dependant reduction in viability, chlorophyll a and autofluorescence. C. lorenzianus cells were more susceptible to chlorine compared to Navicula sp. SYTOX® Green staining appears to be a sensitive method to assess chlorine-induced damages. The data show that in-use levels of chlorination can potentially impact entrained organisms; however, they can recover when returned to coastal waters.
Показать больше [+] Меньше [-]The Persistent Environmental Relevance of Soil Phosphorus Sorption Saturation
2017
Kleinman, Peter J. A.
Controlling phosphorus (P) loss from agricultural soils remains a priority pollution concern in much of the world. Dissolved forms of P loss are among the most difficult to manage. The concept of soil P sorption saturation, the extent to which a soil’s binding sites for P are occupied, emerged from the Netherlands in the 1990s and has broad appeal as both environmental indicator and management paradigm. For hydrologically active and connected soils, P sorption saturation is responsible for the stubborn problem of legacy P, resulting in long-term release of dissolved forms of P from soils. Short- and long-term mitigation options for elevated soil P sorption saturation do exist, all with trade-offs that require adoption of new mitigation and prevention strategies. Ultimately, better incorporation of soil P sorption saturation into both crop fertility and environmental management programs is needed to promote the sustainable management of P in agricultural production systems.
Показать больше [+] Меньше [-]Seasonal variation of polycyclic aromatic hydrocarbons in the surface sediments of the southern Caspian Sea
2017
Baniemam, Mehrnaz | Moradi, Ali Mashinchian | Bakhtiari, Alireza Riyahi | Fatemi, Mohammad Reza | Khanghah, Keivan Ejlali
The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) were determined in sediments from the southern Caspian Sea in fall 2015 and winter 2016. The sum of 16 PAH (ΣPAH) concentrations varied from 17.3±3.05 to 926.7±157.37ngg−1 dry weight and 14.3±0.58 to 85.8±4.41ngg−1 dry weight in fall and winter, respectively. There was no significant correlation between PAH and total organic carbon contents (p>0.05). PAH source identification showed that the PAHs in the sediments originated from petroleum and petroleum combustion. When classified according to the pollution levels, sediments from the southern Caspian Sea could be considered to be low to moderately polluted with PAHs.
Показать больше [+] Меньше [-]Concomitance of oligotrophy and low grazing pressure is essential for the resilience of Mediterranean subtidal forests
2017
Piazzi, Luigi | Ceccherelli, Giulia
The study aimed at investigating factors influencing the recovery of the canopy seaweed Cystoseira brachycarpa. A manipulative experiment was done to test if in barren patches the recovery of Cystoseira I) is enhanced by the removal of the urchins, II) is prevented by eutrophication, III) depends on the time of patch clearance and IV) decreases with the distance from Cystoseira bed edge within the barren patch. The effects of the same factors on the structure of the macroalgal assemblage were also tested. Cystoseira recovered abundantly only in clearings where nutrients were not added and urchins were removed. Furthermore, Cystoseira recovered irrespectively of the time the patches were cleared and the distance from the canopy edge. This study showed that the lack of sea urchins at oligotrophic conditions was essential for Cystoseira brachycarpa recruitment, providing evidence that interacting constraints are involved in the recovery of Cystoseira beds.
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