Environmental Geography Seminar10/30

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Human & Ecol. Sys.
Human & Ecol. Sys. : Environmental Geography Seminar10/30
投稿者 : kigaku 投稿日時: 2019-10-29 10:21:37 (45 ヒット)
Dear all,

Good afternoon.

This is an announcement of the upcoming Environmental Geography Seminar.

Since PhD students will attend Chang Liang's PhD defense on 30/Oct (14:45-16:15), so the seminar will be postponed to 17:00.

Please see all the details carefully below.

【Date】30 October. Wed. (Time: 17:00~)

【Place】 D201

【Content】

Presenters

(1). Xiao Juan (Paper review)

Title: Four decades of winter wetland changes in Poyang Lake based on Landsat observations between 1973 and 2013
Author: Xingxing Han, Xiaoling Chen, Lian Feng
Journal: Remote Sensing of Environment, Vol. 156, October 2014, Pages 426-437
Abstract: Poyang Lake, the largest freshwater lake of China, is well known for its ecological importance as a dynamic wetland system. However, due to the significant seasonality of the lake's inundation area, no systematic study has assessed the wetland changes over the past few decades. We addressed this challenge by using four decades of Landsat observations ranging from1973 to 2013. The images were acquired in the same season to ensure similar phenological and hydrological conditions during each year. Extensive training and validation samples were collected from high-resolution Quickbird imagery to develop a Support Vector Machines (SVM) method for wet- land classification of Poyang Lake. To obtain consistent results from different Landsat instruments, an empirical line correction approach was introduced to adjust the sensor-associated differences in band configurations and spectral responses. Significant changes in the major wetland cover types in Poyang Lake were revealed from long-term classification maps. The vegetation coverage of Poyang wetland showed a statistically significant increasing trend during the overall period (15.9 km2 year−1), and the vegetation tended to spread into the lake center in the Nanjishan Wetland National Nature Reserve (NWNNR) in recent years. At the same time, out-of-phase variability was observed for the mudflats since 1984, with a significant shrinking trend of −12.1 km2 year−1 (p b 0.05). Although sand coverage experienced a rapid decrease from 1973 to 1990 (from 544.3 km2 to 62.9 km2), it remained at a relative stable low level (b100 km2) in the following period. The two national reserves in Poyang Lake shared change patterns similar to those of the entire lake. Although ~70% of the long-term changes in the wetland vegetation area appeared to be explained by local temperature, there was rapid increase after 2002 possibly could be due to the impoundment of the Three Gorges Dam (TGD) in 2003. The large sand area in 1973 was potentially linked to previous human activities in China between the 1950s and the 1970s. The method used in this study could be easily extended to other places in the world to assess the decadal wetland changes, and the information provided in this work is critical for future restoration efforts of the Poyang Lake wetland ecosystem.

(2). Selatni Khadidja (Paper review)

Title: Soil metal pollution from former Zn–Pb mining assessed by geochemical and magnetic investigations: case study of the Boucaid area (Tissemsilt, Algeria)
Author: Lynda Attoucheik , Neli Jordanova , Boualem Bayou, France Lagroix, Diana Jordanova, Said Maouche, Bernard Henry, Abdelhak Boutaleb
Journal: Environmental Earth Sciences (2017) 76:298
Abstract: Former zinc and lead mines that have been operating for half a century are located in the massif of Bou Caid (Tissemsilt, Algeria). Hazardous heavy metals emitted from the mines are abundant in the surrounding soil and cause strong metal pollution in the region. This paper investigates the extent of lead and zinc mine activity derived pollution by characterizing both magnetic and geochemical properties of samples collected in the vicinity of the mines. The results of the magnetic study show the coexistence of magnetic minerals such as magnetite, hematite and goethite. Analyses on surface soils and weathered rocks suggest that hematite and goethite have ore-related lithogenic origins. Magnetic susceptibility shows a positive correlation with lead content when present in low-to-medium concentrations (< ~500 mg/kg). At higher lead concentrations, there is no correlation with magnetic susceptibility. The relationship between magnetic susceptibility and zinc content is not straightforward. These observations are explained by the higher affinity of Pb to iron oxides at lower pollution levels and their preferential bonding to carbonates when Pb and Zn contents are extremely high, as demonstrated by Iavazzo et al. (J Geochem Explor 113:56–67, 2012) in a study of former Zn–Pb mine in Morocco. Based on the general features of the spatial maps of field-measured magnetic susceptibility, mass-specific magnetic susceptibility, Pb and Zn contents, it is concluded that field magnetic measurements provide a good qualitative proxy of pollution spread out of the mining galleries, while laboratory measurements afford a more detailed investigation of the links between iron oxides and the main heavy metals in the ore.


2. Note this:

Please send me detailed information about your presentation at least 5 days before your turn.

For a paper review: title and author of the paper, journal name, which volume, pages, also the link (if possible) should be provided.

If a paper written in Japanese is going to be presented, please kindly send me the information both in Japanese and English.

【Notice】

※ In case you are absent from the seminar or late for the seminar, please contact Professors or me in advance. Any absence without permission is not allowed;

※ Please be punctual (very important);

※ Please do your full preparation for the seminar;

※ Your active participation is always appreciated;

※ Please feel free to contact me if you have any questions or comments.

Best Wishes & Regards.

Sun


Graduate School of Environmental Sceince, Hokkaido University