No abstract

Approximately 60 fungal isolates from Zijin Mountain (Nanjing, China) were screened to determine their algicidal ability. The results show that 8 fungi belonging to Ascomycota and 5 belonging to Basidiomycota have algicidal ability. Of these fungi, Irpex lacteus T2b, Trametes hirsuta T24, Trametes versicolor F21a, and Bjerkandera adusta T1 showed strong algicidal ability. The order of fungal chlorophyll-a removal efficiency was as follows: T. versicolor F21a > I. lacteus T2b > B. adusta T1 > T. hirsuta T24. In particular, T. versicolor F21a completely removed algal cells within 30 h, showing the strongest algicidal ability. The results also show that all 4 fungal species degraded algal cells through direct attack. In addition, most of the tested fungi from the order Polyporales of Basidiomycota exhibited strong algicidal activity, suggesting that most fungi that belong to this order have algicidal ability. The findings of this work could direct the search for terrestrial fungi for bloom control.

In this study, a quick method using a digital elevation model (DEM) to obtain real terrain points for generating tetrahedral mesh has been developed, based on TetGen. Then threedimensional (3-D) forward modeling and inversion, based on the patching method of electrical resistivity tomography (ERT) and which have been compared favorably with those obtained using other software, were used to study topography effect. Asystematic research of apparent resistivity features of different topographies with pole-pole array and Wenner array has been conducted in this study. Based on that, the solutions for removing topography effect are given to the two-dimensional (2-D) survey and the 3-D survey, respectively. Comparing to the inversion result, the solution for the 2-D survey can effectively remove topography influence. A 3-D inversion algorithm incorporating topography is proposed at the same time. Two synthetic models incorporating real topography with fault and ellipse anomalies were created to test the 3-D inversion algorithm, and the results show that the relative image error is less than 30 % and the correlation coefficient is more than 90 %.

In order to investigate the effectiveness of ERT in monitoring LNAPL migration and delineating its spatial distribution in unsaturated porous media, a LNAPL contaminant experiment was made with a sand box and ERT measurement was conducted to monitor the LNAPL contamination process. After the contamination test, the sand was excavated layer by layer and digital pictures were recorded. The results show that the spatial range and shape of the contaminated area obtained from the ERT coincide with that recorded very well, and the contamination process of LNAPL is clearly reflected from the temporal variations of the 3‐D resistivity relative variation rate. This means that it is possible to use the ERT to monitor the LNAPL migration and delineate its spatial distribution in the unsaturated porous media.

Understanding and characterizing subsurface structures is challenging, especially when the objective is to investigate sites for nuclear waste disposal. This paper presents a multi‐geophysical approach for subsurface experimental investigations in which seismic data are used to improve electrical resistivity tomography quality. Different synthetic models ranging from simple to complex were created to quantitatively demonstrate the improvements enabled by the use of this strategy. Moreover, the scheme was tested at Beishan, a candidate site for the disposal of high‐level radioactive waste in northwestern China. The results show that the combination of geophysical data sources improves the interpretation of the subsurface over a single source. The root‐mean‐square level and runtime were found to rapidly decrease when using the proposed scheme.