Environmental change based on diatom assemblages from Lake Yamanaka at the northern foot of Mt, Fuji, Central Japan

Environmental history in Lake Yamanaka was investigated based on diatom assemblages obtained from the 17.5m length borehole core in the lake center. Lake Yamanaka (surface area 6.89km²; maximun depth 14.3m; mean depth 9.4m; altitude above sea level 978m) is one of the Fuji Five Lakes and located at the northern foot of Mt.Fuji. Although this lake had been considered formed by the lava flow from Mt.Fuji about 1850 years ago, results of this research suggested that the formation age more old stage on account of the presence of planktonic diatoms mentioned below. The borehole core sample has mainly consists of unconsolidated silts and scoria fall deposits associated with sandstone layers. According to the composition of diatoms contained in silts, the geohistory of this lake was divided into 4 periods;i.e., 1) The 1'st swamp or river period (11.4-9.2m borehole core in depth); Epiphytic or benthic diatomes such as Flagiralia spp. or Epithemia sp. were dominant in these samples. 2) The 1'st lake period(9.2-6.0m borehole core in depth): Planktonic diatoms such as Aulacoseira sp. or Cyclotella sp. were dominant in these samples. 3) The 2'nd swamp or very shallow lake period(6.0-2.5m borehole core in depth): Epiphytic or benthic diatoms became dominant again. 4) The 2'nd lake period (2.5m-surface borehole core): Planktonic diatoms were dominant again.Article信州大学山地水環境教育研究センター研究報告 2: 105-110(2004)departmental bulletin pape

Horizontal distribution of benthic macroinvertebrates in Lake Kawaguchi, Japan

Article信州大学理学部附属諏訪臨湖実験所報告 9: 121-129(1995)departmental bulletin pape

Bathymetric distribution of benthic macroinvertebrates in deep lake Motosu, Fuji Five Lakes, Japan

The distribution of benthic macroinvertebrates was studied in deep Lake Motosu (oligotrophic lake), Japan. Bathymetrical sampling surveys were carried out using a standard Ekman grab at each of 16 stations in the lake on 8 March 2013. The average densities of the benthic community for all the stations were 2185 ind./m2, comprised principally of Tubifex tubifex (Muller) 23.4%, Asellus hilgendorfi Bovallius 4.9% and chironomids 65.8%. T. tubifex and chironomids inhabited the entire lake bottom, with higher densities in the shallower region (25 m>) than in the deeper region (ca. 120 m). On the other hand, the density of A. hilgendorfi increased with water depth and was highest in the deeper regions (>70 m). The densities of chironomid larvae were lower in the deeper region, with fewer chironomid larvae located in the center of the lake (637 ind./m2). The most abundant species, Micropsectra yunoprima Sasa, exhibited the widest distribution from 10.0 m to 121.0 m (mean density 926 ind./m2), followed by Procladius choreusi (Meigen) from 10 m to 74.1 m (mean density 365 ind./m2). The results of this study were compared to previous data by Kitagawa (1973) on chironomid larvae. The densities of these chironomid larvae increased throughout the whole lake in 2013. The water quality has not undergone a major change since the 1970’s. In this study, the number of M. yunoprima larvae has shown a tendency to increase, especially in shallower regions; where they are widely distributed, suggesting the continuation of favorable bottom condition for larvae since the 1970’s.ArticleEuropian Journal of Environmental Science. 5(1):35-40 (2015)journal articl

A long-term eutrophication process observed from the changes in the horizontal distribution of profundal oligochaete fauna in mesotrophic-eutrophic Lake Kawaguchi, Japan

The purpose of this study was to record the oligochaete fauna in Lake Kawaguchi and clarify their horizontal distribution. In addition, annual changes in the lake were recorded. Samples were collected between 5 March 1993 and 7 March 2006 by using a standard Ekman-Birge sampler at 22 stations, and multipoint sampling surveys were carried out. As a result of the study, a total of 8 species belonging to 6 genera and 3 subfamilies were identified. The average density of oligochaetes for the entire lake was 5247 +/- 3873 ind m(-2) and the average wet weight of oligochaetes was 25.5 +/- 23.4 g m(-2) in 1993, compared to 1075 +/- 676 ind m(-2) and 2.7 +/- 1.7 g m(-2), respectively, in 2006. Tubifex tubifex had inhabited the entire lake bottom in 1993, but Limnodrilus spp. inhabited only the center of the lake in 2006. In recent years, the total number of oligochaetes has shown a tendency to increase, compared with the past record from the 1970s, suggesting that eutrophication is an ongoing process.ArticleTURKISH JOURNAL OF ZOOLOGY. 36(1):39-46 (2012)journal articl

Bathymetric distribution of benthic macroinvertebrates in deep Lake Motosu, Fuji Five Lakes, Japan

The distribution of benthic macroinvertebrates was studied in deep Lake Motosu (oligotrophic lake), Japan. Bathymetrical sampling surveys were carried out using a standard Ekman grab at each of 16 stations in the lake on 8 March 2013. The average densities of the benthic community for all the stations were 2185 ind./m2, comprised principally of Tubifex tubifex (Muller) 23.4%, Asellus hilgendorfi Bovallius 4.9% and chironomids 65.8%. T. tubifex and chironomids inhabited the entire lake bottom, with higher densities in the shallower region (25 m>) than in the deeper region (ca. 120 m). On the other hand, the density of A. hilgendorfi increased with water depth and was highest in the deeper regions (>70 m). The densities of chironomid larvae were lower in the deeper region, with fewer chironomid larvae located in the center of the lake (637 ind./m2). The most abundant species, Micropsectra yunoprima Sasa, exhibited the widest distribution from 10.0 m to 121.0 m (mean density 926 ind./m2), followed by Procladius choreusi (Meigen) from 10 m to 74.1 m (mean density 365 ind./m2). The results of this study were compared to previous data by Kitagawa (1973) on chironomid larvae. The densities of these chironomid larvae increased throughout the whole lake in 2013. The water quality has not undergone a major change since the 1970’s. In this study, the number of M. yunoprima larvae has shown a tendency to increase, especially in shallower regions; where they are widely distributed, suggesting the continuation of favorable bottom condition for larvae since the 1970’s.ArticleEuropian Journal of Environmental Science. 5(1):35-40 (2015)journal articl

Technical Note: Solid Wood Properties of Eucalyptus Camaldulensis Planted for Pulpwood Production in Thailand

Solid wood properties of two Eucalyptus camaldulensis clones (clone A and clone B), derived from different pulp and paper companies and planted in Thailand for pulpwood production, were investigated to evaluate the possibility for lumber production. Clone A had significantly higher Young's modulus, greater density, and straighter grain compared with clone B. These results suggest that some clones may have more favorable properties for lumber production than others. Thus, wood properties should be included in clonal trials and early testing of this species

Wood Property Variation in Acacia Auriculiformis Growing in Bangladesh

This study examined the radial variations of wood properties in 11-yr-old Acacia auriculiformis grown in Bangladesh having diameters of 222 ± 38 mm. The basic density, fiber length, and fiber length increment increased up to about 80 mm radial distance from the pith and then were almost constant toward the bark. The compressive strength (CS) increased from the pith to 50 mm and then became nearly constant to the bark. Conversely, the specific compressive strength, the ratio of CS to air-dried density, was almost constant from pith to bark, indicating positive relationships. However, the air-dried density explained only 50% variation of the CS. On the basis of radial variation of basic density, the core wood and outer wood boundary can be delineated at 70 - 90 mm from the pith. Similarly, the fiber length and fiber length increment curves showed that this boundary could be marked at 60 - 90 mm from the pith. The selected wood properties except CS varied significantly among the trees, which indicated the potential of tree selection for wood quality improvement through tree breeding

Effect of mediastinal lymph nodes sampling in patients with clinical stage I non-small cell lung cancer

Objective : Systematic nodal dissection has been recommended for patients with resectable non-small cell lung cancer because of its staging accuracy. However, in patients with clinical stage I non-small cell lung cancer whether systematic nodal dissection provides more benefits than mediastinal lymph node sampling or not is controversial. In this retrospective study, we evaluated the effect of mediastinal lymph node sampling in patients with clinical stage I NSCLC. Methods : One hundred and nineteen consecutive patients with clinical stage I NSCLC, who underwent curative operation between January 1994 and December 2000, were retrospectively reviewed (dissection group = 58 : sampling group= 61). Systematic nodal dissection was defined as complete removal of mediastinal lymph node, and mediastinal lymph node sampling was defined as removal of lymph node levels 3, 4, and 7 for right-sided tumors and levels 5, 6, and 7 for left-sided tumors. Results : The total number of removed mediastinal lymph nodes in patients who underwent systematic nodal dissection was 22.1±9.7, which was significantly higher than that in patients who underwent mediastinal lymph node sampling of 11.4±7.0 (p<0.001). Postoperatively N2 disease was detected in 8 patients (13.8%) in the dissection group and 7 (11.5%) in the sampling group. After the median follow up of 79 months, the cancer specific survival rate at 5 year was 78.0% in the dissection group and 76.2% in the sampling group (p = 0.60). Conclusions : Mediastinal lymph node sampling showed the similar effect to systematic nodal dissection in patients with clinical stage I non-small cell lung cancer