Dynamics of shoreline and land reclamation from 1985 to 2015 in the Bohai Sea,China

Journal of Geographical Sciences - Extraction and analysis of the shoreline and land reclamation patterns are important for studies on topics such as the dynamics of coastal wetland ecological...     

Legitimacy of Different Knowledge Types in Natural Resource Governance and Their Functions in Inter-Institutional Gaps

Abstract

This study expands the Inter-Institutional Gaps (IIGs) framework to conceptualize the legitimacy associated with different types of ecological knowledge (e.g., scientific, traditional and local) used in natural resource governance. We draw on primary qualitative data, and document analysis to examine a case of inland fisheries management in the north-eastern floodplain of Bangladesh. We posit that the pragmatic, moral, cognitive, and regulative legitimacy for different types of ecological knowledge are repeatedly reevaluated by rule-makers and resource users in the process of rule-devising. Results show that inter-institutional gaps may be perpetuated when formal rules do not sufficiently consider traditional and local ecological knowledge. While it is widely proposed that systematically incorporating different knowledge types can better address local-national policy problems, this study underscores that the source of legitimacies for different knowledge types often differs across formal and informal institutional actors. Recognizing the differences is critical to fishers’ resource management.     

Seasonal Shift in Community Structure of Periphytic Ciliates in Estuarine Waters in the Northern Bay of Bengal,Bangladesh

To investigate the seasonal heterogeneity of the periphytic ciliate communities, a 1-year baseline survey was conducted in the Karnaphuli River estuary, northern Bay of Bengal, Bangladesh. A total of 54 ciliate species were recorded, including seven common and 14 dominant species. Maximum species number was in autumn whereas maximum abundance was in winter; the minimum for both occurred in summer. Multivariate analyses, i.e., canonical analysis of principal coordinates (CAP) and principal co-ordinates analysis (PCoA), revealed a clear seasonal heterogeneity of community structure and environmental variables. Multivariate correlation analysis (RELATE) demonstrated that the community structure of the periphytic ciliate communities was significantly correlated with environmental variables, and best matching analysis (BIOENV) indicated that heterogeneity of community patterns was mainly driven by water temperature, pH, dissolved oxygen, total dissolved solids and nutrients. Species richness and diversity peaked in autumn whereas species evenness peaked in summer. These results suggest that environmental conditions shape periphytic ciliate community structure, which is a potentially useful bio-indicator of estuarine water quality.     

利用Landsat TM和IRS P6 LISS III卫星影像及GIS对耕地和耕种模式的时空动态分析(英文)

The study of the spatial patterns and temporal changes of cropland is important to understand the underlying factors and the functional effects of the agricultural landscape. On the other hand, crop dynamics mapping is essential to know the overall agro-spatial diversity of the area. Therefore, this paper addressed a spatio-temporal analysis of cropland and cropping pattern change in the Bogra district of Bangladesh over the last 16 years (between 1988/89 and 2004/05). In this paper, crop mapping from multi-temporal and multi-sensor satellite images was described. Landsat TM and IRS P6 LISS III satellite images were used with GIS for spatial dynamics of cropland and cropping pattern change analysis. First, seasonal cropland maps were derived from object-based classification of satellite images, then two-date classified image differencing with GIS overlay technique and decision rules were applied. Cropping pattern change was analyzed in a spatial and quantitative way for the 16 years and for this, Integrated Land and Water Information System (ILWIS) and Land Change Modular (LCM) of IDRISI Andes were used. The results showed that in the area, mono crop cultivation was found in summer, but in winter, areas under different crop cultivation had changed dramatically. Change analysis showed that the changes mainly occurred in the north northwest and southwest of the areas, and during the time the highest change area was found under the rice-potato pattern.      

Petrology, geochemistry and remote sensing data of island arc assemblage along Wadi Abu Marawat, Central Eastern Desert, Egypt

The basement rocks of Abu Marawat area comprise serpentinites (oldest), metavolcanics and their equivalent pyroclastics, intrusive metagabbro–diorite complex, synkinematic granitoids, Hammamat sediments and basic intrusion (youngest). Remote sensing ETM+ data of Abu Marawat area were analyzed, and band ratios technique was applied to discriminate between different varieties of these basement rocks. Serpentinites are represented by lensoidal bodies tectonically incorporated in the metavolcanics. On band ratio 5/7 image, they are characterized by very bright image signature. The metavolcanics comprise basalts, andesite and subordinate dacites together with their equivalent pyroclastics. They were regionally metamorphosed up to the greenschist facies and exhibit dark grey image signatures on band ratio 5/7 image. The metagabbro–diorite complex is made up of metagabbros, diorites and quartz diorites, whereas the synkinematic granitoids are formed of tonalites and granodiorites. The band ratio 5/7 image illustrates tonalites with dark image signature, whereas metagabbro–diorites and granodiorites exhibit grey image signature. The metavolcanic suites are of island arc setting, where metabasalts are of tholeiitic affinity, while the meta-andesites and metadacites are of calc-alkaline character. The metagabbroic and granitoid rocks are of I-type, calc-alkaline affinity and were formed in arc tectonic setting. They are enriched in LIL elements and depleted in Nb and HFS elements, a characteristic feature of subduction-related magmatism. The regular variation trends among the major and trace elements as well as the coincidence of the plotted samples favor the assumption that they are comagmatic and formed by processes such as fractional crystallization.     

Halocarbon emissions from marine phytoplankton and climate change

Long-lived and short-lived halocarbons have long been known for their adverse effects on atmospheric chemistry, especially ozone depletion that may be directly or indirectly influenced by global climate change. Marine organisms including phytoplankton contribute shorter-lived halocarbon compounds to the atmosphere. Oceans cover more than 70% of the Earth’s surface making the marine phytoplankton a significant presence. Changes in the environment will inevitably affect this widely distributed group of organisms. Various predictions have been made about how phytoplankton will respond to climate change, but as yet little is known about the interactions between phytoplankton, climate change and halocarbon emissions. We provide a summary of studies on halocarbon emissions by marine phytoplankton isolated from different climatic zones that includes data from our recent studies on tropical marine phytoplankton. It is important to determine and characterize the contribution of the phytoplankton to the halocarbon load in the atmosphere to allow their interaction with the changing global climate to be understood. Using these data, we compare the range of halocarbons emitted by phytoplankton with halocarbon emission data for seaweeds, a well-known biogenic contributor of short-lived halocarbons. Sørensen’s coefficient of similarity of 0.50 was calculated, which suggests that half of the detected halocarbon species present in seaweeds are also present in phytoplankton.     

Trend analysis of maximum,minimum, and average temperatures in Bangladesh: 1961–2008

The present study is about the analysis of mean maximum and mean minimum temperatures carried out on annual, seasonal, and monthly timescales examining the data from 15 meteorological stations in Bangladesh for the period 1961–2008. Various spatial and statistical tools were used to display and analyze trends in temperature data. ArcGIS was used to produce the spatially distributed temperature data by using Thiessen polygon method. The nonparametric Mann–Kendall test was used to determine whether there is a positive or negative trend in data with their statistical significance. Sen’s method was also used to determine the magnitude of the trends. The results reveal positive trends in annual mean and mean maximum temperatures with 95 % significance. Trend test reveals that the significant positive trend is found in June to November in case of mean maximum temperature, but according to the mean minimum temperature, the situation is different and a significant positive trend was found from November to February. The analysis of the whole record reveals a tendency toward warmer years, with significantly warmer summer periods and slightly colder winters. These warming patterns may have important impacts on energy consumption, water supply, human health, and natural environment in Bangladesh.