The Spatial Dispersion of Spiders in a Cotton Ecosystem.

1981 ◽  
Vol 29 (1) ◽  
pp. 15 ◽  
Author(s):  
AL Bishop
Keyword(s):  
Vertical Distribution ◽  
Spatial Dispersion ◽  
Cotton Field ◽  
Distribution Characteristics ◽  
Sequential Decision ◽  
Crop Canopy ◽  
Spider Species ◽  
Cotton Pests ◽  
The Mean ◽  
Western Side

In a cotton field in south-eastern Queensland, the spider species Cheiracanthium mordax L. Koch (diversum L. Koch), Archaearanea veruculata (Urquhart) and Lycosa sp. were equally distributed in the outer, middle and inner portions. However, A. veruculata was more abundant in the western side of the field late in the season, apparently in response to a more favourable habitat. In sampling, the variance was greater than the mean and overdispersion was apparent. C. mordax and A. veruculata were most abundant in the top one-third of plants, and Oxyopes mundulus L. Koch was evenly distributed over plants. The consistency with which these spiders were recorded in levels of vertical strata was enhanced by the formation of the crop canopy, and the eventual vertical distribution of C. mordax was apparently influenced by rainfall. Among crop spacings, most spiders of 4 species preferred the highest density (12 plants/m). The ecological consequences of the distribution characteristics are discussed in relation to current sequential decision plans for the management of cotton pests and beneficial species in the region.

scholarly journals Continuous borehole optical televiewing reveals variable englacial debris concentrations at Khumbu Glacier, Nepal

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Katie E. Miles ◽  
Bryn Hubbard ◽  
Evan S. Miles ◽  
Duncan J. Quincey ◽  
Ann V. Rowan ◽  
...  
Keyword(s):  
Vertical Distribution ◽  
Water Supply ◽  
Depth Profile ◽  
Variable Thickness ◽  
Surface Melting ◽  
High Mountain ◽  
Ablation Area ◽  
The Mean ◽  
Surface Melt ◽  
The Vertical Distribution

AbstractSurface melting of High Mountain Asian debris-covered glaciers shapes the seasonal water supply to millions of people. This melt is strongly influenced by the spatially variable thickness of the supraglacial debris layer, which is itself partially controlled by englacial debris concentration and melt-out. Here, we present measurements of deep englacial debris concentrations from debris-covered Khumbu Glacier, Nepal, based on four borehole optical televiewer logs, each up to 150 m long. The mean borehole englacial debris content is ≤ 0.7% by volume in the glacier’s mid-to-upper ablation area, and increases to 6.4% by volume near the terminus. These concentrations are higher than those reported for other valley glaciers, although those measurements relate to discrete samples while our approach yields a continuous depth profile. The vertical distribution of englacial debris increases with depth, but is also highly variable, which will complicate predictions of future rates of surface melt and debris exhumation at such glaciers.

Vertical distribution characteristics of aerosol particles over the Guanzhong Plain

2021 ◽  
Vol 255 ◽  
pp. 118444
Author(s):  
Yuanping He ◽  
Xinqi Xu ◽  
Zhaolin Gu ◽  
Xinhao Chen ◽  
Yuman Li ◽  
...  
Keyword(s):  
Vertical Distribution ◽  
Aerosol Particles ◽  
Distribution Characteristics

scholarly journals Phytoplankton Increase Along the Kuroshio Due to the Large Meander

2021 ◽  
Vol 8 ◽  
Author(s):  
Daniel Andres Lizarbe Barreto ◽  
Ricardo Chevarria Saravia ◽  
Takeyoshi Nagai ◽  
Takafumi Hirata
Keyword(s):  
Chlorophyll A ◽  
Mixed Layer Depth ◽  
Local Environment ◽  
Trophic Levels ◽  
Large Meander ◽  
The Mean ◽  
Western Side ◽  
The Kuroshio ◽  
Cold Core ◽  
Kuroshio Region

The Kuroshio Large Meander (LM) is known to be highly aperiodic and can last from 1 to 10 years. Since a stationary cold core formed between the Kuroshio and the southern coast of Japan off Enshu-Nada and approaching warm saltier water on the eastern side of the LM changes the local environment drastically, many commercially valuable fish species distribute differently from the non-LM period, impacting local fisheries. Despite this importance of the LM, the influences of the LM on the low trophic levels such as phytoplankton and zooplankton have still been unclear. In this study, satellite daily sea surface chlorophyll data are analyzed in relation to the LM. The results show positive anomalies of the chlorophyll-a concentration along the Kuroshio path during the LM periods, 2004–2005 and 2017–2019, from the upstream off Shikoku to the downstream (140°E). These positive anomalies are started by the triggering meander generated off south of Kyushu, which then slowly propagates to the downstream LM region in both the LM periods. Even though the detailed patterns along the Kuroshio region in the two LM periods were different, similar formations of the positive anomalies on the western side of the LM with shallower mixed layer depth are observed. Furthermore, we found clear relationships between the minimum distance from several stations along the coast to the Kuroshio axis and the mean chlorophyll-a anomaly, with significant correlations with the distance from different stations.

scholarly journals A Comparison of Equatorial Electrojet in Peru and East Brazil

2013 ◽  
Vol 7 (1) ◽  
pp. 29-36 ◽  
Author(s):  
R.G. Rastogi ◽  
H. Chandra ◽  
Rahul Shah ◽  
N.B. Trivedi ◽  
S.L. Fontes
Keyword(s):  
South America ◽  
Geomagnetic Field ◽  
Daily Variation ◽  
Equatorial Electrojet ◽  
Horizontal Component ◽  
Low Latitude ◽  
Vertical Field ◽  
The Mean ◽  
Western Side ◽  
The Magnetic Field

The paper describes the characteristics of the equatorial electrojet at Huancayo (HUA, 12.1oS, 75.3oW, inclination 1.5oN, declination 1.0oE) in western side of South America, where the geomagnetic field is aligned almost along the geographic meridian, and at Itinga (ITI, 4.3oS, 47.oW, inclination 1.4oN, declination 19.3oW) in eastern part of South America, where the geomagnetic field is aligned about 19o west of the geographic meridian; although the mean intensity of the magnetic field in the two regions are almost of the same order. Further comparisons are made of the current at Itinga and at Tatuoca (TTB, 1.2oS, 48.5oW, inclination 7.8o N, declination 18.7oW), a low latitude station in the same longitude sector. The daily range of horizontal component of the geomagnetic field, H, is shown to be almost 16% higher at HUA compared to that at ITI. The daily variation of the eastward field, Y, showed a strong minimum of -40 nT around 13-14 hr LT at ITI whereas very low values were observed at HUA with a positive peak of about 4 nT around 11- 12 hr LT. The vertical field, Z, showed abnormally large negative values of -70 nT at TTB around 13 hr LT. The day-today fluctuations of midday and midnight values of X field were positively correlated between HUA and ITI with a high correlation coefficient of 0.78 and 0.88 respectively. Values of Y field were also significantly positively correlated between HUA and ITI for midnight hours (0.72), while no correlation was observed for the midday hours. The midnight values of X field at HUA, ITI and TTB showed significant (0.90 or greater) correlation with Dst index. Correlation values of about 0.7 were observed between Dst and midday values of X at ITI and TTB and to a lesser degree (0.4) at HUA.

Aerosol Vertical Distribution Characteristics in Northwest China

2017 ◽  
Vol 37 (3) ◽  
pp. 0301001
Author(s):  
秦武斌 Qin Wubin ◽  
李学彬 Li Xuebin ◽  
鲁先洋 Lu Xianyang ◽  
陈小威 Chen Xiaowei ◽  
崔生成 Cui Shengcheng ◽  
...  
Keyword(s):  
Vertical Distribution ◽  
Northwest China ◽  
Distribution Characteristics

scholarly journals Distribution Characteristics and Pollution Assessment of Soil Heavy Metals under Different Land-Use Types in Xuzhou City, China

2019 ◽  
Vol 11 (7) ◽  
pp. 1832 ◽  
Author(s):  
Aman Fang ◽  
Jihong Dong ◽  
Yingli An
Keyword(s):  
Heavy Metals ◽  
Land Use ◽  
Organic Carbon ◽  
Mining Area ◽  
Distribution Characteristics ◽  
Grassland Soils ◽  
Risk Levels ◽  
Land Use Types ◽  
The Mean ◽  
Mean Concentration

Xuzhou, as a mining city in China, has been experiencing 130 years of coal mining and processing. To explore the spatial distribution characteristics and pollution status of soil heavy metals (Cr, Cd, As, Hg, Zn, and Pb) under different land-use types, a total of 2697 topsoil samples were collected in all of the areas (except for water) of Xuzhou in 2016. Overall, the mean concentrations of Cr (70.266 mg/kg), Cd (0.141 mg/kg), As (10.375 mg/kg), Hg (0.036 mg/kg), Zn (64.788 mg/kg), and Pb (24.84 mg/kg) in Xuzhou soils were lower than the environmental quality standard for soils (GB15618-1995). However, the mean concentrations of Cr, Hg, and Pb exceeded their corresponding background values, with the mean concentration of Hg being almost three times its background value. For different land-use types, the highest mean concentration of Cr was concentrated in grassland soils. The mean concentrations of Cd, As, Zn, and Pb in mining area soils were higher than those in the other soils. The mean concentration of Hg was the highest in the built-up area soils. Based on the potential ecological risk assessment, the forestland, garden land, grassland, and others were at low and moderate risk levels, the farmland and mining area were at low, moderate, and high risk levels, and the built-up area was at various risk levels in Xuzhou. There was a significant positive correlation between Cr, Pb, and Hg concentrations and the corresponding organic carbon contents in the farmland, built-up area, garden land, forestland, and other soils ( p < 0.01 ). A high degree of correlation was found between Cr and Hg concentrations, as well as organic carbon contents in grassland soils, with values of p < 0.05 and p < 0.01 , respectively. An obvious correlation could be seen between Hg concentrations and organic carbon contents in mining area soils ( p < 0.01 ).

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