Modern lake sedimentary record of PAHs and OCPs in a typical karst wetland, south China: Response to human activities and environmental changes

2021 ◽  
pp. 118173
Author(s):  
Cheng Cheng ◽  
Tianpeng Hu ◽  
Weijie Liu ◽  
Yao Mao ◽  
Mingming Shi ◽  
...  
Geology ◽  
2006 ◽  
Vol 34 (1) ◽  
pp. e107-e108
Author(s):  
A. L. Weislogel ◽  
S. A. Graham ◽  
E. Z. Chang ◽  
J. L. Wooden ◽  
G. E. Gehrels ◽  
...  

2020 ◽  
Vol 26 (4) ◽  
pp. 2377-2389 ◽  
Author(s):  
Laibin Huang ◽  
Junhong Bai ◽  
Xiaojun Wen ◽  
Guangliang Zhang ◽  
Chengdong Zhang ◽  
...  

2014 ◽  
Vol 49 (2) ◽  
pp. 323-337 ◽  
Author(s):  
Wu Mei-Lin ◽  
Wang You-Shao ◽  
Wang Yu-Tu ◽  
Sun Fu-Lin ◽  
Sun Cui-Ci ◽  
...  

2020 ◽  
Vol 12 (2) ◽  
pp. 711 ◽  
Author(s):  
Wen Liu ◽  
Long Ma ◽  
Jilili Abuduwaili

A short lacustrine sediment core (41 cm) from Lake Bosten in arid central Asia was used to investigate the environmental changes that occurred in the past ≈150 years based on the superposition of climate and anthropogenic factors. Geochemical elements, total organic carbon (TOC) and nitrogen (TN), and stable isotope data (δ13Corg and δ15N) were used to identify abnormal environmental changes. The average C/N ratio in the sediments of Lake Bosten suggested that the organic matter in lake sediments was mainly from aquatic plants. The δ13Corg and δ15N in the lake sediments mainly reflect changes in the structure of the lake’s ecosystem. Before the 1960s, the primary productivity of the lake was relatively low with a relatively stable lake water environment. From the 1960s to the mid-1980s, the lake’s ecosystem was closely related to a significant decline in water levels caused by human activities and an increase in salinity. From the late 1980s to ≈2000, the aquatic plant structure of Lake Bosten did not change significantly. After 2000, the upper part of the sedimentary record suggested enhanced productivity due to urban and industrial development in the catchment area. However, sedimentary perspectives of the responses of different environmental proxies in sediments to human activities were anisochronous, and the increasing heavy metal (Pb and Cu) and P accumulations appeared in 1970, reflecting heightened human impacts. Through the comparison between the Aral Sea and Lake Bosten, it was inferred that, under the intervention of human activities, the lake experienced a completely different evolution trend. Humans, as geological agents, should protect our living environment while satisfying social development. The results will provide an important supplement to a large spatial scale study of the influences of human activities on the environment in Central Asia, which also has some significant implications for the protection of the ecological environment and the realization of sustainable development in arid regions.


2014 ◽  
Vol 11 (2) ◽  
pp. 269-280 ◽  
Author(s):  
S. L. Shang ◽  
Q. Dong ◽  
C. M. Hu ◽  
G. Lin ◽  
Y. H. Li ◽  
...  

Abstract. Chlorophyll a (Chl) concentrations derived from satellite measurements have been used in oceanographic research, for example to interpret eco-responses to environmental changes on global and regional scales. However, it is unclear how existing Chl products compare with each other in terms of accuracy and consistency in revealing temporal and spatial patterns, especially in the optically complex marginal seas. In this study, we examined three MODIS (Moderate Resolution Imaging Spectroradiometer) Chl data products that have been made available to the community by the US National Aeronautics and Space Administration (NASA) using community-accepted algorithms and default parameterization. These included the products derived from the OC3M (ocean chlorophyll three-band algorithm for MODIS), GSM (Garver–Siegel–Maritorena model) and GIOP (generalized inherent optical properties) algorithms. We compared their temporal variations and spatial distributions in the northern South China Sea. We found that the three products appeared to capture general features such as unique winter peaks at the Southeast Asian Time-series Study station (SEATS, 18° N, 116° E) and the Pearl River plume associated blooms in summer. Their absolute magnitudes, however, may be questionable in the coastal zones. Additional error statistics using field measured Chl as the truth demonstrated that the three MODIS Chl products may contain high degree of uncertainties in the study region. Root mean square error (RMSE) of the products from OC3M and GSM (on a log scale) was about 0.4 and average percentage error (ε) was ~ 115% (Chl between 0.05–10.41 mg m−3, n = 114). GIOP with default parameterization led to higher errors (ε = 329%). An attempt to tune the algorithms based on a local coastal-water bio-optical data set led to reduced errors for Chl retrievals, indicating the importance of local tuning of globally-optimized algorithms. Overall, this study points to the need of continuous improvements for algorithm development and parameterization for the coastal zones of the study region, where quantitative interpretation of the current Chl products requires extra caution.


2013 ◽  
Vol 23 (1) ◽  
pp. 333-353 ◽  
Author(s):  
Miyuki Tahata ◽  
Yuichiro Ueno ◽  
Tomoko Ishikawa ◽  
Yusuke Sawaki ◽  
Kazuki Murakami ◽  
...  

2014 ◽  
Vol 41 (4) ◽  
pp. 361-368 ◽  
Author(s):  
Danuta Dzieduszyńska ◽  
Joanna Petera-Zganiacz ◽  
Juliusz Twardy ◽  
Piotr Kittel ◽  
Piotr Moska ◽  
...  

AbstractResults of OSL dating and sedimentary studies from the profile of the low alluvial terrace of the middle Warta River are presented. The samples were dated using the single-aliquot regenera-tive method. Dating was used to establish a timing of the Weichselian Late Glacial events in the river valley environment. Stable conditions on the floodplain are expressed by the deposition of organic-rich series radiocarbon dated at 12 900-12 600 cal BP and 11 600-10 770 cal BP. Samples for OSL dating were collected from the mineral material deposited during the intensification of flood events during the Weichselian decline. The results obtained for the alluvia range from 12.78 ± 0.62 ka b2k to 14.33 ± 0.74 ka b2k. Sedimentological criteria allowed to distinguish between particular flood events. Overestimation of OSL ages is probably a result of rapidity of environmental changes in that time.


Chemosphere ◽  
2018 ◽  
Vol 207 ◽  
pp. 130-138 ◽  
Author(s):  
Yihong Xu ◽  
Shaoming Pan ◽  
Jianhua Gao ◽  
Xiaolin Hou ◽  
Yongfu Ma ◽  
...  

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