The research on nutrients release during the decomposition of Chaetomorpha sp.

通过室内模拟,研究了不同环境条件下绿潮硬毛藻的分解速率,以及死亡藻体内营养盐的释放规律,以阐明硬毛藻大量衰亡对天鹅湖水质的潜在影响。结果显示,温度对硬毛藻分解速率的影响显著(P沉积物>营养盐水平;N释放为:沉积物>温度>营养盐水平。高温条件下,死亡藻..

Effects of the Decomposition of Chaetomorpha sp. on Nitrogen and Phosphorus Levels in Water from Swan Lake

Macroalgal blooms,which can dramatically modify nitrogen (N) and phosphorus (P) cycle in water column and sediments, have frequently occurred in coastal areas in recent decades. Rongcheng Swan Lake,a natural coastal lagoon in the eastern Shandong Peninsula in China,has suffered from extensive macroalgal blooms dominated by Chaetomorpha sp. over the past ten years. In the present study,Chaetomorpha sp. and the sediments from different areas of Swan Lake were collected to study the influence of algal decomposition on N and P levels in the overlying water. In addition,the changes of physio-chemical parameters in water were detected during the algal decomposition,and the release potential of N and P from sediments in different lake areas was estimated. The results showed that the concentrations of total nitrogen (TN) and NH_4 ~+ -N in water increased obviously during the first 16 days due to the decomposition of Chaetomorpha sp.,and reached 12.40 mg /L and 7.98 mg /L,respectively. However,the concentrations of total phosphorous (TP) and soluble reactive phosphorous (SRP) changed slightly at the early stage,and increased significantly after 19 days. During the experiment, the concentrations of TP and SRP ranged from 0.02-1.14 mg /L and 0.01-0.40 mg /L, respectively. After 16 days of the incubation experiment,N and P concentrations in water at different sediment treatments both followed the order of: treatment with sediments and algae > treatment with only algae > treatment with only sediments. There were great differences in the release ability of N and P from the sediments among different lake regions. Under the condition of algal decomposition,the order of the release amount of N and P from the sediments was: center > northwest > south and northwest > center > south. During the degradation phase of green tide,the concentrations of TN,NH_4 ~+ -N,TP and SRP in water all increased significantly due to the nutrient release from the decomposing Chaetomorpha sp. and the indirect effect on promoting nutrient release from the sediments,which aggravated the level of water eutrophication in Swan Lake,China. Therefore,the massive decomposing Chaetomorpha sp. should be salvaged quickly to avoid the deterioration of water quality in Swan Lake

绿潮硬毛藻衰亡分解过程中营养盐的释放规律

通过室内模拟,研究了不同环境条件下绿潮硬毛藻的分解速率,以及死亡藻体内营养盐的释放规律,以阐明硬毛藻大量衰亡对天鹅湖水质的潜在影响。结果显示,温度对硬毛藻分解速率的影响显著(P沉积物>营养盐水平;N释放为:沉积物>温度>营养盐水平。高温条件下,死亡藻..

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel

JUNO sensitivity on proton decay p → ν K + searches*

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this study, the potential of searching for proton decay in the $p\to \bar{\nu} K^+$ mode with JUNO is investigated. The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar{\nu} K^+$ is 36.9% ± 4.9% with a background level of $0.2\pm 0.05({\rm syst})\pm$$0.2({\rm stat})$ events after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure is $9.6 \times 10^{33}$ years, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies