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101.
Understanding the effect of various environmental factors on algal blooms is essential for proper management of water resources. Eight weirs were constructed on the Nakdong River in South Korea between 2010 and 2011 to manage water resources and deal with possible floods and droughts. In this study, water quality observation data were collected from eight representative monitoring sites in the Nakdong River between 2001 and 2016. Particularly, the effect of the weirs construction on water retention time was statistically analyzed in terms of algal growth and other important water quality parameters. While there was slight increase of water temperature (0.8 °C) over 16 years, the concentrations of total phosphorous (TP) and total nitrogen (TN) decreased by 62.3, and 12.9%, respectively, after the construction of weirs. This TP decrease was noticeable, but still high enough to maintain the eutrophic state of the river. Correlation statistical analysis suggests that the Chl-a concentration is positively affected by the changes of TP, TN and chemical oxygen demand. However, there was no direct correlation between Chl-a concentration and the increased water retention time from the weir construction. 相似文献
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A technique is developed to separate the incident and reflected waves propagating on a known current in a laboratory wave–current flume by analyzing wave records measured at two or more locations using a least squares method. It can be applied to both regular and irregular waves. To examine its performance, numerical tests are made for waves propagating on quiescent or flowing water. In some cases, to represent the signal noise and measurement error, white noise is superimposed on the numerically generated wave signal. For all the cases, good agreement is observed between target and estimation. 相似文献
104.
Pb on groundwater particles,Door County,Wisconsin 总被引:4,自引:0,他引:4
N. C. Woo 《Environmental Geology》1994,24(2):150-156
Pb was detected on groundwater particles larger than 0.45m. Pb concentration (micrograms per liter) showed positive correlations with particle concentration (milligrams per liter) at five sampled wells, although the slopes of the best-fit lines were different. X-ray fluorescence scans suggested that the particles primarily consist of K-Al silicate minerals, and that Pb is absorbed onto Fe oxyhydroxide coatings on Mg-rich silicates. Particle compositions varied at wells, but remained consistent at each well through the sampling period of a month. The particulate nature of Pb in groundwater could cause the spatial and temporal variations due to: (1) the unique composition of particles at wells, (2) the irregular pathways for groundwater particles, (3) the unpredictable amount of Pb-carrying particles entering the groundwater system during recharge events, and (4) the irregular sampling of groundwater particles subsequently dispersed along the advective flow path. 相似文献
105.
Ho Jung Song Jae Hyung Lee Gawn Woo Kim So Hyun Ahn Houng-Min Joo Jin Young Jeong Eun Jin Yang Sung-Ho Kang Sang Heon Lee 《Ocean Science Journal》2016,51(3):387-396
Recent changes in climate and environmental conditions have had great negative effects such as decreasing sea ice thickness and the extent of Arctic sea ice floes that support ice-related organisms. However, limited field observations hinder the understanding of the impacts of the current changes in the previously ice-covered regions on sea ice algae and other ice-related ecosystems. Our main objective in this study was to measure recent primary production of ice algae and their relative contribution to total primary production (ice plus pelagic primary production). In-situ primary productivity experiments with a new incubation system for ice algae were conducted in 3 sea ice cores at 2 different ice camps in the northern Chukchi Sea, 2014, using a 13C and 15N isotope tracer technique. A new incubation system was tested for conducting primary productivity experiments on ice algae that has several advantages over previous incubation methods, enabling stable carbon and nitrogen uptake experiments on ice algae under more natural environmental conditions. The vertical C-shaped distributions of the ice algal chl-a, with elevated concentrations at the top and bottom of the sea ice were observed in all cores, which is unusual for Arctic sea ice. The mean chl-a concentration (0.05 ± 0.03 mg chl-a m?3) and the daily carbon uptake rates (ranging from 0.55 to 2.23 mg C m?2 d?1) for the ice algae were much lower in this study than in previous studies in the Arctic Ocean. This is likely because of the late sampling periods and thus the substantial melting occurring. Ice algae contributed 1.5–5.7% of the total particulate organic carbon (POC) contents of the combined euphotic water columns and sea ice floes. In comparison, ice algae contributed 4.8–8.6% to the total primary production which is greater than previously reported in the Arctic Ocean. If all of the ice-associated productions were included, the contributions of the sea ice floes to the total primary production would be greater in the Arctic Ocean and their importance would be greater in the arctic marine ecosystems. 相似文献
106.
P.J. Baxter W.P. Aspinall A. Neri G. Zuccaro R.J.S. Spence R. Cioni G. Woo 《Journal of Volcanology and Geothermal Research》2008
Disasters from explosive volcanic eruptions are infrequent and experience in emergency planning and mitigation for such events remains limited. The need for urgently developing more robust methods for risk assessment and decision making in volcanic crises has become increasingly apparent as world populations continue to expand in areas of active explosive volcanism. Nowhere is this more challenging than at Vesuvius, Italy, with hundreds of thousands of people living on the flanks of one of the most dangerous volcanoes in the world. We describe how a new paradigm, evidence-based volcanology, has been applied in EXPLORIS to contribute to crisis planning and management for when the volcano enters its next state of unrest, as well as in long-term land-use planning. The analytical approach we adopted enumerates and quantifies all the processes and effects of the eruptive hazards of the volcano known to influence risk, a scientific challenge that combines field data on the vulnerability of the built environment and humans in past volcanic disasters with theoretical research on the state of the volcano, and including evidence from the field on previous eruptions as well as numerical simulation modelling of eruptive processes. Formal probabilistic reasoning under uncertainty and a decision analysis approach have provided the basis for the development of an event tree for a future range of eruption types with probability paths and hypothetical casualty outcomes for risk assessment. The most likely future eruption scenarios for emergency planning were derived from the event tree and elaborated upon from the geological and historical record. Modelling the impacts in these scenarios and quantifying the consequences for the circumvesuvian area provide realistic assessments for disaster planning and for showing the potential risk–benefit of mitigation measures, the main one being timely evacuation, but include for consideration protecting buildings against dilute, low dynamic pressure surges, and temporary roof supports in the most vulnerable buildings, as well as hardening infrastructure and lifelines. This innovative work suggests that risk-based methods could have an important role in crisis management at cities on volcanoes and small volcanic islands. 相似文献
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108.
Sojung Park Mansik Choi Dongjun Jang Dongjin Joe Kyunggue Park Hyojin Lee Junsik Woo Taeha Kim Jongkyu Park 《Ocean Science Journal》2020,55(1):69-84
In this study, we investigated the spatial and temporal distribution of heavy metals and nutrients in Gyeonggi Bay, Korea, to determine their present statu 相似文献
109.
110.
Shin Hyeon Ho Li Zhun Seo Min Ho Soh Ho Young Lim Weol Ae Park Jong Woo 《Ocean Science Journal》2019,54(4):685-691
Ocean Science Journal - There have been controversies regarding the taxonomy of Prorocentrum donghaiense, however Zhang et al. (2016) recently developed a probe with a quantitative real-time PCR... 相似文献