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The spatial and temporal variations in the activity of six microbial enzymes (invertase, urease, alkaline phosphatase, protease, peroxidase, and polyphenoloxidase) present in the sediment of Erhai Lake, China were investigated. Enzyme activities peaked in summer. This phenomenon can be attributed to high temperature and sediment organic matter accumulation, which could be traced to the breakdown of algal bloom. In addition, sediment enzyme activities exhibited apparent spatial heterogeneity across the lake, but individual enzymes showed similar spatial patterns of activity. Moreover, sediment enzyme activities were found to be closely related to the water quality of Erhai Lake. Enzyme activities were also significantly correlated with sediment total nitrogen and organic matter, implying that the sediment enzyme can be used as a biological indicator that reflects the sediment status. The investigation of sediment enzyme activities can facilitate a comprehensive understanding of the process of nutrient cycling and the mechanisms underlying lake eutrophication.

High concentrations of nitrate have been detected in streams flowing from nitrogen-saturated forests; however, the spatial variations of nitrate leaching within those forests and its causes remain poorly explored. The aim of this study is to evaluate the influences of catchment topography and coniferous coverage on stream nitrate concentrations in a nitrogen-saturated forest. We measured nitrate concentrations in the baseflow of headwater streams at 40 montane forest catchments on Mount Tsukuba in central Japan, at three-month intervals for 1 year, and investigated their relationship with catchment topography and with coniferous coverage. Although stream nitrate concentrations varied from 0.5 to 3.0 mgN L-1, those in 31 catchments consistently exceeded 1 mgN L-1, indicating that this forest had experienced nitrogen saturation. A classification and regression tree analysis with multiple environmental factors showed that the mean slope gradient and coniferous coverage were the best and second best, respectively, at explaining inter-catchment variance of stream nitrate concentrations. This analysis suggested that the catchments with steep topography and high coniferous coverage tend to have high nitrate concentrations. Moreover, in the three-year observation period for five adjacent catchments, the two catchments with relatively higher coniferous coverage consistently had higher stream nitrate concentrations. Thus, the spatial variations in stream nitrate concentrations were primarily regulated by catchment steepness and, to a lesser extent, coniferous coverage in this nitrogen-saturated forest. Our results suggest that a decrease in coniferous coverage could potentially contribute to a reduction in nitrate leaching from this nitrogen-saturated forest, and consequently reduce the risk of nitrogen overload for the downstream ecosystems. This information will allow land managers and researchers to develop improved management plans for this and similar forests in Japan and elsewhere.

A marine container terminal operator may have a situation with excessive calling requests to be served especially when some new service contracts are under consideration. For this situation, we propose a strategic berth template problem (BTPS) that selects the ships among the requesting ones to be served and arrange their berth-windows within a limited planning horizon. The BTPS employs the subgradient optimization procedure, which is an improved version of the procedure that the authors developed for the operational berth allocation problem. A wide variety of numerical experiments indicate the improved subgradient procedure works well for the BTPS.

Stable nitrogen isotope ratios (δ 15 N) in sediment cores recovered from two Siberian lakes (Baikal and Hovsgol) are determined in order to evaluate the biologically mediated nitrogen cycle from the Last Glacial period to the postglacial period. The ranges of δ 15 N values from the two lakes are similar, varying from +2.8‰ to +6.7‰. The high values of δ 15 N (around +6‰) during the Last Glacial Maximum (LGM, 26.5–19 cal ka BP) indicate that a larger fraction of the available nitrate in both lakes was utilised by phytoplankton. A cool and dry climate during the LGM may have limited the input of terrestrial nitrate, resulting in the use of a large fraction of the nitrate, and low productivity, in both lakes. The use of a smaller fraction of the nitrate by phytoplankton in both lakes after the LGM (19–12 cal ka BP) is reflected in the lower δ 15 N values (down to +3.0‰). The increase in summer insolation after the LGM caused increased vertical mixing of the lake water column, which transported nitrate upwards from the deeper waters and into the photic zone. The reduced rate of nitrogen consumption after the LGM indicates that nitrate was more readily available to phytoplankton at this time and did not limit their activities. This change suggests that other factors limited phytoplankton activity during this period. At the climatic transition between Oxygen Isotope Stages 2 and 1 (around 11.5 cal ka BP), the rapid increase in δ 15 N (from +3.0‰ to +6.0‰) reflected a rapid increase in nitrate utilization. At this transition, increases in precipitation and lake levels, which were associated with the increased intensity of the East Asian Monsoon, may have brought a large influx of nutrients required by the phytoplankton into the lakes from the watershed. This hydrological change led to increased phytoplankton activity in both lakes, resulting in increased nitrate consumption. The δ 15 N data obtained here from the sediments of lakes Baikal and Hovsgol suggest that the nitrogen cycle in the Siberian region is strongly linked to hydrological changes across the Asian continent, which are related to global climate change.

The paleoclimatic changes in the southern region on the Tibetan Plateau (TP) after the LGM were studied by multi-proxy analysis, including pollen, Ca-carbonates, TOC, δ 13 C TOC , plant macrofossils and sands with sediment cores from Lake Pumoyum Co, close to the east end of the Himalayas. The following paleoclimatic changes characteristic of the southern TP were suggested by comparing with the paleoclimatic records from various regions within the Southwest (SW) monsoon domain on the TP. Soon after the LGM, deglaciation in the southern TP had already started at 18.5 ka BP, and more actively increased after ca. 16.5 ka BP, with the hydrological circulation oscillating in ca. 1200-, 2000- and 4000-year periods. An abrupt increase in humidity under the reduced SW monsoon intensity occurred at 15.0 ka BP as part of further deglaciation processes. Subsequently, the climate amelioration in the southern region started from 15.0 ka BP a few centuries earlier than other regions of the TP and then was further intensified by synchronizing with the Bolling/Allored (B/A) event. Over the B/A period, the SW monsoon intensity in the southern region almost continuously and sharply increased. Unlike many regions on the TP, the southern region experienced almost no or substantially small impact of the Younger Dryas (YD) event and also other major dry/cold reversals, such as Heinrich 1 event, the 8.2 kyr event, and an abrupt spell occurring between 5 and 4 ka BP. The monsoon intensity in the southern region after the YD event started to rapidly increase from 11.4 ka BP and reached a maximum between 10.8 and 10.0 ka BP after the LGM which lagged about 1200 years behind the maximum insolation in the northern hemisphere. From ca. 9.6 ka BP, the gradual decrease in humidity in the southern TP started and continued until 4.2 ka BP. It's aridification trend was characterized by three-stepwise transition observed at 9.6, 7.7 and 5.5 ka BP. However, the aridification in the southern TP was rather weak, and the climatic conditions were sustained fairly humid and comparably stable. The humidity between 4.2 and 2.5 ka BP essentially increased despite the weakened SW monsoon intensity at that time, whereas from 2.5 ka BP to the present, the climatic conditions became most arid and instable during the Holocene. As a consequence, the Holocene climate optimum in the southern region lasted from 11.4 ka BP until 2.5 ka BP and was marked by the earliest start and the latest end timings within the SW monsoon domain on the TP. The comparison of the start timings from various paleoclimatic records indicated that the first SW monsoon on the TP after the YD event generated at 11.4 ka BP in the southern region. Subsequently, according to the degree of the recovery of positive vegetation-albedo feedback system in each region, the monsoon probably extended from the southern TP over the entire TP taking 3000–4000 years. Based on these results, the possible key factors and mechanisms responsible for the paleoclimatic changes in the southern region and also the possible processes as to the evolution of the SW monsoon over the TP are discussed.

This paper addresses two innovative design alternatives of marine container terminals for efficient ship handling service in the mega-containership era. They serve a mega-ship from two sides at dedicated berths. One of the key issues for higher utilization is how the dedicated berths serve other ships efficiently when they are idle. For this, we develop efficient heuristics for the berth allocation of the two terminals to identify a more productive terminal among them in terms of the total service time of both ordinary and mega-ships. A wide variety of experiments show the channel terminal is the most preferred.

We tested the hypothesis that in shallow, eutrophic Lake Kasumigaura, the concentration of particulate phosphorus (PP) is controlled by biogenic P (P in living or dead phytoplankton and bacterial cells), rather than by resuspension of inorganic P in sediment. Increases in wind velocity and turbidity were associated with bottom shear stress exceeding the critical value for the lake (τc=0.15Nm(-2)); this increased turbidity was due to sediment resuspension. However, concentrations of PP; HCl-extractable, reactive P in PP (P-rP); and HCl-extractable, non-reactive P in PP (P-nrP) were not correlated with wind velocity (PP vs. wind velocity: r=0.40, p>0.05). Rather, the P-nrP concentration accounted for approximately 79% of PP, and the concentrations of PP, P-rP, and P-nrP were correlated with the particulate organic carbon (POC) concentration (POC vs. PP: r=0.90, p

Differences in biogenic phosphorus (P) compounds between sediment and suspended particles in aquatic environments are important for understanding the mechanisms of internal P loading, but these differences are still unknown. We used solution-state (31)P-nuclear magnetic resonance spectroscopy ((31)P NMR) with NaOH-ethylenediaminetetraacetic extraction to detect the multiple P compounds in suspended particles and sediment in the eutrophic Lake Kasumigaura, including orthophosphate monoesters, orthophosphate diesters, pyrophosphate, and polyphosphate. We tested the hypothesis that there is a significant difference between these groups in suspended particles and sediment. Biogenic P other than orthophosphate was found in significantly higher proportions in suspended particles (74.3% of total P) than in sediment (25.6%). Orthophosphate monoesters were comparatively more abundant in suspended particles, as indicated by the ratio of orthophosphate diesters to monoesters (average, 0.31 for suspended particles; 1.05 for sediment). The compounds identified as orthophosphate monoesters by (31)P NMR spectroscopy originated mainly from phospholipids (α-glycerophosphate and β-glycerophosphate) and ribonucleic acid (RNA-P), whereas the orthophosphate diesters included mostly DNA (DNA-P). These results suggest that the dynamics of orthophosphate diesters, the production of DNA-P, or the degradation of phospholipids, play an important role in P cycling in Lake Kasumigaura.

Summary The free-living, cosmopolitan, freshwater betaproteobacterial bacterioplankton genus Polynucleobacter was detected in different years in 11 lakes of varying types and a river using the size-exclusion assay method (SEAM). Of the 350 strains isolated, 228 (65.1%) were affiliated with the Polynucleobacter subclusters PnecC (30.0%) and PnecD (35.1%). Significant positive correlations between fluorescence in situ hybridization and SEAM data were observed in the relative abundance of PnecC and PnecD bacteria to Polynucleobacter communities (PnecC + PnecD). Isolates were mainly PnecC bacteria in the samples with a high specific UV absorbance at 254 nm (SUVA254), and a low total hydrolysable neutral carbohydrate and amino acid (THneutralCH + THAA) content of the dissolved organic matter (DOM) fraction, which is known to be correlated with a high humic content. In contrast, the PnecD bacteria were abundant in samples with high chlorophyll a and/or THneutralCH + THAA concentrations, indicative of primary productivity. With few exceptions, differences in the relative abundance of PnecC and PnecD in each sample, determined using a high-sensitivity cultivation-based approach, were due to DOM quality. These results suggest that the major DOM component in the field, which is allochthonously or autochthonously derived, is a key factor for ecological niche separation between PnecC and PnecD subclusters.

Human activities have created high nutrient surpluses in agricultural lands due to the increasing rate of chemical fertilizer application and the increase in livestock production. To analyse the nutrient characteristics and estimate the nutrient load in streams, we conducted extensive field survey and water quality experiments from 2007 to 2008 in Koise River, a major river of the Lake Kasumigaura watershed, Japan. Water quality indicators of total nitrogen (TN), total phosphorus (TP) and total organic carbon (TOC) were investigated. The nutrient loads of TN, TP and TOC, as well as dissolved total nitrogen, dissolved inorganic nitrogen, dissolved organic nitrogen, particle organic nitrogen, dissolved total phosphorus, dissolved organic carbon and particle organic carbon were also estimated for the Koise River. Seasonal variation of the nutrient concentration from 2007 to 2008 was analysed considering the river discharge variation and agricultural activities. The results showed that the irrigation...

The chlorophyll a-specific absorption coefficient (\( a_{\text{ph}}^{*} \left( \lambda \right) \)) in a highly eutrophic lake can show characteristics distinct from that in the ocean due to the differences in the structure and composition of phytoplankton. In this study, investigated the variation of \( a_{\text{ph}}^{*} \left( \lambda \right) \) in Lake Kasumigaura, a highly eutrophic lake in Japan, in association with the package effect and the effect of accessory pigments, and carried out the parameterization of \( a_{\text{ph}}^{*} \left( \lambda \right) \). Although \( a_{\text{ph}}^{*} \left( \lambda \right) \) did not vary spatially, it did show significant temporal variation, with a particularly high value after spring-bloom. This high \( a_{\text{ph}}^{*} \left( \lambda \right) \) in spring was attributed to a lower package effect and a higher proportion of carotenoid than the other samples. Although the value of \( a_{\text{ph}}^{*} \left( \lambda \right) \) was correlated with the concentration of chlorophyll-a (Chl-a), the correlation coefficient was lower than those reported in the ocean. Some lake-water samples showed variations of the package effect and the effect of accessory pigments that were independent of the concentration of Chl-a, and these independent variations resulted in the weak correlation between \( a_{\text{ph}}^{*} \left( \lambda \right) \) and the concentration of Chl-a. Together, these results suggest that the factors controlling \( a_{\text{ph}}^{*} \left( \lambda \right) \) in highly eutrophic lakes are distinct from that in ocean samples.

Light environment variability was investigated in the two Japanese lakes Biwa and Kasumigaura, which offer a broad range of optical conditions in the water bodies due to their diverse morphometries and limnological characteristics. To elucidate their light environments, Secchi depths (SDs) were related to long-term monitored datasets of concentrations of optically active substances (OASs) using two approaches based on statistical and mechanistic models. A good estimate for the nonphytoplanktonic suspended solids (NPSS) concentration gained using a monthly factor δ (which represents the phytoplanktonic portion in total suspended solids) from a long-term analysis was utilized to develop robust models. Using the mechanistic model, the contribution of each OAS to the SD can be understood and investigated in more detail than possible with a statistical approach, but the statistical model yields better results in terms of SD prediction. Based on the results of an analysis of the contribution of each OAS to the SD, it was clear that NPSS was the component that exerted the most influence on the light environments in the two lakes; in this respect, this study agrees with other studies that show the importance of suspended inorganic particles as the main contributor to the SD in inland waters. Using ANOVA, we analyzed how specific inherent optical properties may have changed spatially and temporally, and the results indicated that the temporal (monthly) effect was primarily responsible for the loss of accuracy in the models. In addition, the ANOVA analysis suggested that grouping the data improved the predictive performances of the statistical models. Finally, we concluded that combining the two models yields the most reliable results in terms of SD prediction and determining the contribution of each OAS to the SD at present.

This article analyses the way in which foldable containers could potentially lower the costs of container fleet management in liner shipping networks. An integer programming model is used to obtain an optimal fleet mix of foldable and standard containers. It emerges that savings could be realised in the management costs of container fleets by applying a proper combination of the two. It also emerges that the economic viability of foldable containers depends on the level of trade imbalances and the exploitation costs of the containers.

A new type of high-performance liquid chromatography (HPLC)-size exclusion chromatography (SEC) system with ultraviolet (UV) absorbance detection and non-dispersive infrared (NDIR) detection of total organic carbon is described. The introduction of an online degassing tube and a low-volume HPLC column helped to reduce the analytical time and increase the sensitivity of the SEC system. This study is the first in which linear calibration curves (R(2)>0.99) were obtained for both UV absorbance and NDIR data for polystyrene sulfonate standards, which are the most suitable standards for molecular size analysis of aquatic humic substances as well as dissolved organic matter (DOM). Using the calibration curves, the molecular size distribution of DOM in water collected from Lake Kasumigaura and in pore water from lake sediments was estimated. Most of the DOM had a molecular weight less than 4000 Daltons (Da), and the amount of low-molecular-weight DOM (∼ 2000 Da) with low UV absorbance increased with depth in the sediment pore water. This result shows the importance of combining quantitative analysis by NDIR detection with qualitative analysis by UV detection to determine the chemical and physical properties of DOM. The possible sources and reactivity of DOM in Lake Kasumigaura and its sediment pore water are also discussed.

Microcystis aeruginosa causes surface blooms in eutrophic lakes in the tropical and temperate zones. We investigated which factors suppressed blooms of M. aeruginosa in Lake Kasumigaura, a shallow hypereutrophic lake in the temperate zone of Japan, from 1999 to 2007 by quantifying the 16S rRNA gene of M. aeruginosa using real-time PCR. These results showed that M. aeruginosa existed in the lake water throughout the year. The abundance of M. aeruginosa usually increased from March to July and decreased from August to February. The factors determining the maximum density of the year were the overwintering population and the growth rate in summer (in June and July). The overwintering population was affected by abundance during the previous summer. The growth rates of M. aeruginosa in summer were correlated significantly with the extinction coefficient and mean daily photosynthetically active radiation irradiance. The mean daily irradiance in summer from 1999 to 2007 was 77% of that from 1983 to 1986, when blooms of M. aeruginosa occurred. Therefore, the most important factor controlling the growth of M. aeruginosa in Lake Kasumigaura after 1999 appears to be the amount of light supplied to the water column.

Sediment core samples from the center of Lake Kasumigaura, Japan, were collected from 1979 to 2007 at intervals of 1 month to 5 yr. We evaluated the degree of modification in N isotope composition during sedimentation and diagenesis. We estimated the degree of isotope discrimination during diagenesis by comparing historical changes in N isotope composition of the surface sediment (top 2 cm) against the vertical profile of the isotope composition of sediment core samples (15 cm depth). The degree of 15 N enrichment during sedimentation appeared to be significant under the preferential N decomposition that occurred in the periods with low C/N ratio values of suspended particulate organic matter. We documented 15 N depletion in sediment deeper than approximately 3 cm during diagenesis. The contrasting directions of N isotope discrimination during sedimentation and diagenesis suggest changing mechanisms of isotopic shift across an oxidation–reduction boundary.

近年，海上コンテナ輸送でも燃料油価格の高騰が問題となっている．今後しばらくは燃料油価格の大幅な回復は見込めないことから，船社は燃料油費削減のために航海日数を増加して減速運航を行っている．そこで本研究では，単独の船社による単一航路の運航を仮定した航路計画モデルを用いて，減速運航の費用削減(利益増加)効果を検証する．さらに，港での荷役時間の短縮は，減速運航や費用低減効果をもたらす可能性があるので，それに関しても検討する．アジア－北米航路を対象とした数値実験の結果，航海日数の増加による減速運航がある一定の範囲で有効であることが明らかとなった．また，港での荷役時間の短縮により，航海日数をさほど増加させることなしに減速運航が可能となることも確認できた．

硝酸イオンの窒素・酸素安定同位体比(δ15N，δ18O)はその高い起源推定能から海洋，湖沼，河川，地下水での物質循環の研究に用いられてきた。1990年代半ばに開発された脱窒菌法により，硝酸イオンのδ15N，δ18Oを微量で同時に測定できるようになった。脱窒菌法で多量のサンプルを短時間に精度よく測定するには前処理ライン(N2Oガスを質量分析計に導入するための前処理)が必要不可欠である。しかしながら，こうした前処理ラインの分析機器は高額(数千万円程度)である。著者らは多くの研究室に設置されている通常の固体粉末試料の同位体測定ライン(質量分析計と元素分析計がConflo IIIで連結された測定システム)を活用し，測定精度や処理速度を落とすことなく，安価に自動前処理できるラインを開発することに成功したのでここに報告する。

In 2003 and 2004, we conducted field investigations of a canal during the summer algal bloom to estimate the in-situ growth rate of Microcystis spp. and its limiting factors. Cellular RNA content (RNA/cell), determined by the real-time PCR method with a primer specific for amplification of Microcystis rRNA, was used as an index of in-situ growth rate. A Microcystis bloom was found in the canal in summer 2004 but not in summer 2003, because of its coldness. Corresponding to this, the average value of RNA/cell in 2004 was significantly higher than that in 2003. Water temperature, light intensity, and NO3 and PO4 concentrations were regarded as the factors limiting the in-situ growth rate of Microcystis in the canal, and their effects were quantified on the basis of laboratory experimental data. Effects of temperature and light intensity (photoinhibition by excessive photon flux density) were found to be important in limiting the growth rate, and more severe limitation was suggested in 2003. We then estimated the in-situ growth rate from the combined effect of these limiting factors. The estimated in-situ growth rates correlated significantly with RNA/cell in each year and in the combined (2003 + 2004) data. This agreement between our two different methods for estimation of in-situ growth rate suggests the validity of our approaches. This study was first field application of cellular RNA content as an index of algal growth rate in natural water samples.

Changes in sulfur cycles in Lake Hovsgol (northwest Mongolia) are discussed on the basis of total organic carbon (TOC), total sulfur (TS) concentrations and stable sulfur isotope ratios (δ 34 S) in two sediment cores (X104 and X106) covering the last glacial to the present. Correlation plots of TOC and TS (C–S plots) of the sediment cores indicate dissolved sulfate enrichment in sediment pore water and high sulfate reducing bacteria (SRB) activity during the climate transition from the last glacial to postglacial period (LG–PG transition, from ca. 21 to 11.6 cal ka BP). In addition, positive shifts of δ 34 S values (from + 3.7‰ to + 32.6‰) were observed during the LG–PG transition. These results suggest a large influx of 34 S-rich dissolved sulfate into the lake during this period. The 34 S-rich dissolved sulfate may have accumulated on the shore (wetlands and marshes) of Lake Hovsgol during the last glacial period. Owing to the increase in atmospheric precipitation and lake level rise during the LG–PG transition, the 34 S-rich dissolved sulfate may have been supplied from the shore to the lake. Increased sulfate influx during the LG–PG transition has also been observed in a Lake Baikal sediment core. Our new sulfur geochemical data shows past-environmental changes, particularly moisture changes, within continental Asia during the climate transition.

This paper analyzes the possibility to save container fleet management costs in repositioning empty containers through the use of foldable containers. We model this entire empty container flow as an integer programming problem with different strategies in empty container flow itinerary. The model is used to carry out numerical experiments that optimize the empty container repositioning in the hinterland, where there are serious empty container repositioning problems caused by extremely imbalanced trades. The study finds that foldable containers can substantially save on repositioning costs compared to the use of standard containers.

In order to elucidate the nutrient dynamics in lakes with special reference to sediments, the changes in vertical distributions of sediment nutrients over 20 years were analyzed with the aid of sediment dating at the centers of two shallow, eutrophic lakes in Japan, i.e. Lakes Kasumigaura and Suwa. Peaks of 137 Cs and apparent density gave estimated sedimentation rates of around 1 and 2 kg m -2 y -1 in Lakes Kasumigaura and Suwa, respectively. Slight decreases of TP and TN contents (0.07 and 0.63 mg g -1 for TP and TN, respectively, in Lake Kasumigaura and 0.90 mg g -1 for TN in Lake Suwa) were observed by comparison between the cores obtained around 1980 and those of recent years except for a considerable decrease in TP in Lake Suwa (1.0 mg g -1 ). This decrease probably came from the higher percentage of easily releasable phosphorus in the past sediments of Lake Suwa. Using the TP and TN increases in lake waters during summer, the averaged nutrient release rates were estimated to be within the ranges of those observed by laboratory core experiments and by measuring the vertical profiles of interstitial concentrations except for a smaller estimation of TN in Lake Kasumigaura. On the other hand, the nutrient release rates were also determined using the long-term changes in sediment nutrient contents. The estimated rates were a little lower than the rates determined by the method using the increase in lake nutrient concentrations other than the higher ones for TP in Lake Suwa, which were originally based on the higher percentage of easily releasable phosphorus as mentioned above. Net sedimentation rates for 24 years in Lake Kasumigaura and those for 26 years in Lake Suwa calculated as the sum of new sedimentation and changes in old sediments during these periods were compared with the net input loads based on the per capita/exporting method. In the case ofTP, we observed a fairly good agreement because of its conservation, whereas the residuals were larger for TN due to denitrification in the overlying waters of sediments. The rates estimated from the imbalances in TN were in the ranges of the measured denitrification rates in laboratory tests with the sediments. Thus, the information on the long-term changes in sediment nutrients could provide the average rates of these fundamental processes in lake environments.

In an attempt to better characterize dissolved organic carbon (DOC) in several specific sources to Lake Kasumigaura, such as sewage-treatment-plant effluent (STPE), domestic sewage (DS) and forest stream (FS), we analyzed radiocarbon (14C) and stable carbon isotopic compositions (13C) of the DOCs. The measurements of 14C for DOC were performed by an accelerator mass spectrometer (AMS) at the National Institute for Environmental Studies (NIES-TERRA) in Japan. The Δ14C and δ13C values of the DOCs in several sources to Lake Kasumigaura, have low carbon isotopic values, ranging from −470‰ to −79‰ and from −27.9‰ to −24.2‰, respectively. These carbon isotopic values are substantially different from those of Lake Kasumigaura. These results imply different origins for the DOC in Lake Kasumigaura. The 14C and 13C analyses of DOC led to a useful classification for DOCs in Lake Kasumigaura, Japan.

The spectral decomposition algorithm (SDA), which is a new approach for the simultaneous estimation of chlorophyll-a (Chl-a) and non-phytoplankton suspended solid (NPSS) concentrations in Case 2 waters using satellite data, was proposed by our previous study. Here, we investigated the effect of phytoplankton composition on the SDA based on the tank experiments using cultured samples for five phytoplankton species (three cyanobacteria, one green algae and one diatom) and lake water samples collected from Lake Kasumigaura from September 2004 to August 2005 except for April 2005. The results showed that the SDA-based models obtained from the cultured samples (culture-based models) showed high accuracies for Chl-a and NPSS estimations in all phytoplankton species (root mean square error [RMSE] about 16.2 μg l-1 for Chl-a and about 11.0 mg l-1 for NPSS). However, the Landsat Thematic Mapper (TM) band combinations, which gave the smallest RMSE of the Chl-a and NPSS estimations, differed among the species. In addition, the culture-based models could apply to lake water samples with similar accuracies if the optimal standard reflectance spectra (SRS) of end-members in the water body could be determined. This implies the potential of the SDA-based model as follows: (1) it is less site-and time-specific compared with conventional empirical methods (single band, band ratio, and arithmetic band calculation); (2) it can be proposed by a tank experiment or by a simulation using bio-optical modelling.

Speciation of aluminum (Al), including inorganic monomeric Al (Ali, the sum of aquo, hydroxy, and inorganically complexed forms), organic monomeric Al (Alo, the organically complexed form), and colloidal mineral Al (Alc, the fine particulate form that passes through a 0.4-μm pore size membrane filter), was investigated in circumneutral (pH 7–9) eutrophic Lake Kasumigaura, Japan. The mean concentrations calculated from the result of monthly observations during the period from January to December 2003 were compared among ten stations. Ali decreased downstream from the mouth of the influent rivers (0.07–0.10 μM) to the mouth of the effluent river (0.03 μM). Alc, which also decreased downstream (from 0.11 to 0.06 μM), was the major fraction (>50%) of total dissolved Al at all stations. Alo remained around 0.02 μM at all stations. In Lake Kasumigaura, a high concentration of Si (average 0.23 mM) seems to be involved in the removal of Ali and formation of Alc. Also, a high concentration of Ca (ave. 0.43 mM) seems to be acting as a competitive cation for complexation with a high concentration of dissolved organic carbon (ave. 0.26 mM), and inhibit the formation of Alo.

A sediment core (VER99G12; core length, 4.66 m) was taken from the Buguldeika Saddle of Lake Baikal in 1999. Radiocarbon measurements of total organic carbon (TOC) and pollen concentrate fractions from the VER99G12 core were performed by a Tandetron accelerator mass spectrometry (AMS) system (Model-4130, HVEE) at Nagoya University. The AMS 14C ages showed that the VER99G12 core spans the past ∼30 cal ka BP (from the MIS 3 to present), and the average sedimentation rate of this core was calculated to be 13.6 cm/kyr based on the calibrated ages. This means that the time resolution of VER99G12 sediment samples in this study is better than ∼70–80 yr/cm. Stable carbon isotope ratios of TOC (δ13CTOC) in the VER99G12 core varied widely from about 26.6‰ to 31.3‰ during the last glacial/post-glacial transition period (about 17–12 cal ka BP). Therefore, a rapid change in the carbon sources in Lake Baikal occurred in the last glacial/post-glacial transition period is concluded.

We estimated the runoff loadings of nutrients and organic carbon to the Koise River from its catchment area, a major river emptying into Lake Kasumigaura. The catchment was divided into several subwatersheds on the basis of digital elevation data, and extensive surveys of water quality and quantity were conducted in those defined subwatersheds. The runoff loadings were estimated for each subwatershed by multiple regression analysis using land-cover use distributions derived from high-resolution satellite (Quickbird) imagery and the measured loadings. The stepwise method, which cases a nonlinear model requiring no initial values, was introduced in the regression analysis to improve reliability in the estimation of the loadings.During the nonirrigated period, the unit loading factor from crop lands was highest for nitrogen, phosphorus, and organic carbon in the dissolved phase. The loading factor in the particulate phase from deciduous forests was constant for nitrogen and organic carbon, while that from crop lands was constant for phosphorus. The dominant unit loading factors of total nitrogen, total phosphorus, and total organic carbon were found to differ between the irrigated and nonirrigated periods.

Carbon isotopes (14C and 13C) of dissolved organic carbon (DOC) in a Japanese oligotrophic lake (Lake Towada) were measured to study the origin and cycling of dissolved organic matter (DOM) in Lake Towada. Lake water samples were collected at 3 depths (0, 30, and 80 or 85 m) during 4 months (April, June, August, and October) in 2006. 14C measurements of DOC were performed by accelerator mass spectrometry (AMS) at the National Institute for Environmental Studies (NIES-TERRA) in Japan. Δ14C and δ13C values of DOC in Lake Towada showed light carbon isotopic values ranging from –750 to −514‰ and –29.0 to –27.8‰, respectively. These values are similar to those of humic substances reported. The very low carbon isotopic values of DOC in Lake Towada suggest a very small contribution of DOC derived from fresh phytoplankton to the lake DOC. There is an extremely high linear relationship between the Δ14C and δ13C of DOC in Lake Towada when all data points are plotted (r2 =0.818, p < 0.01), suggesting that the DOC in Lake Towada has 2 specific sources contributing heavy and light carbon isotopes. Although the freshly produced DOC of phytoplankton origin can be decomposed easily, the variation in the autochthonous DOC should influence the carbon isotopic values of DOC in Lake Towada.

The halogenation of 3-arylimidazo[1,5-a]pyridines was carried out with iodine, bromine, N-chlorosuccinimide, and 1-fluoro-2,4,6-trimethylpyridinium tetrafluoroborate as halogenating agents to give selectively halogenated products 1-halo-3-arylimidazo[1,5-a]pyridines in good to excellent yields. Kumada–Tamao–Corriu cross-coupling of the obtained 1-iodo-3-arylimidazo[1,5-a]pyridines and aryl Grignard reagents led to 1,3-diarylated imidazo[1,5-a]pyridines in good to excellent yields. Suzuki–Miyaura cross-coupling of the 1-bromo-3-phenylimidazo[1,5-a]pyridine and p- or m-methoxycarbonylphenylboronic acids furnished the coupling product in respective yields of 91% and 61%. The obtained 1,3-diarylated imidazo[1,5-a]pyridines showed a wide variety of fluorescent emissions in a wavelength range of 449–533 nm with improved quantum yields compared to monoarylated ones.

A series of ansa-cyclopentadienyl-phenoxy titanium complexes (PHENICS: phenoxy-induced complex of Sumitomo) (1a−e), [{Me2CCp(OC6H2-3-R-5-R′)}TiCl2] (1a, R = R′ = H; 1b, R = tBu, R′ = Me) and [{Me2Si(C5Me4)(OC6H2-3-R′′-5-Me)}TiCl2] (1c, R′′ = iPr; 1d, R′′ = tBu; 1e, R′′ = Adm), have been synthesized and characterized. It is noteworthy that the dihedral angles of the cyclopentadienyl and phenoxy moieties of the complexes 1b and 1d, revealed by X-ray crystal structure analysis, are 63.0° (1b) and 68.2° (1d), indicating a distortion from a mutual perpendicular arrangement, whereas the symmetrical patterns of the 1H NMR spectra indicate a dynamic behavior in solution. The PHENICS-type complexes exhibit good to excellent catalytic activities for copolymerization of ethylene and 1-hexene upon activation with AliBu3/[Ph3C][B(C6F5)4] cocatalyst. Particularly, the complexes with a bulky substituent at the ortho position of the phenoxy moiety showed excellent catalytic features (1d, 27 200 kg mol−1 h−1 at 80 °C, 600...

The remote sensing of Case 2 water has been far less successful than that of Case 1 water, due mainly to the complex interactions among optically active substances (e.g., phytoplankton, suspended sediments, colored dissolved organic matter, and water) in the former. To address this problem, we developed a spectral decomposition algorithm (SDA), based on a spectral linear mixture modeling approach. Through a tank experiment, we found that the SDA-based models were superior to conventional empirical models (e.g. using single band, band ratio, or arithmetic calculation of band) for accurate estimates of water quality parameters. In this paper, we develop a method for applying the SDA to Landsat-5 TM data on Lake Kasumigaura, a eutrophic lake in Japan characterized by high concentrations of suspended sediment, for mapping chlorophyll-a (Chl-a) and non-phytoplankton suspended sediment (NPSS) distributions. The results show that the SDA-based estimation model can be obtained by a tank experiment. Moreover, by combining this estimation model with satellite-SRSs (standard reflectance spectra: i.e., spectral end-members) derived from bio-optical modeling, we can directly apply the model to a satellite image. The same SDA-based estimation model for Chl-a concentration was applied to two Landsat-5 TM images, one acquired in April 1994 and the other in February 2006. The average Chl-a estimation error between the two was 9.9%, a result that indicates the potential robustness of the SDA-based estimation model. The average estimation error of NPSS concentration from the 2006 Landsat-5 TM image was 15.9%. The key point for successfully applying the SDA-based estimation model to satellite data is the method used to obtain a suitable satellite-SRS for each end-member.

This paper addresses efficient berth and crane allocation scheduling at a multi-user container terminal. First, we introduce a formulation for the simultaneous berth and crane allocation problem. Next, by employing genetic algorithm we develop a heuristic to find an approximate solution for the problem. The fitness value of a chromosome is obtained by crane transfer scheduling across berths, which is determined by a maximum flow problem-based algorithm based on a berth allocation problem solution defined by the chromosome. The results of numerical experiments show that the proposed heuristic is applicable to solve this difficult but essential terminal operation problem.

We conducted field investigations in a canal connected to Lake Kasumigaura (Japan) twice weekly during a summer algal bloom to understand the temporal variations in dissolved iron and its speciation, and the controlling factors. Dissolved iron (D-Fe), which is operationally defined as that passing through a 0.2-μm pore filter, acid-labile particulate iron (LP-Fe), and chemical speciation of dissolved iron were analyzed. LP-Fe was extracted from the suspended solids (SS) on 0.2-μm pore-size filters after a 2 h soak in 25% (4.5 M) acetic acid. The chemical speciation of dissolved iron was determined using cathodic stripping voltammetry. The concentration of D-Fe ranged from 72 to 1354 nM and that of filterable labile iron (FL-Fe) from 5 to 881 nM, and both increased markedly after two heavy rains. The increased D-Fe and FL-Fe appeared to be removed within a few days. The concentrations of LP-Fe ranged from 4.1 to 16.1 μM, were much higher than those of D-Fe, and did not increase after the rains. There was a significant correlation (|r| = 0.88, P < 0.01) between ln[D-Fe] and pH. This suggests that the dynamics of D-Fe in the canal depend upon the cycle of adsorptive removal onto the surface of SS at high pH and desorptive supply from the surface of SS at low pH. Moreover, D-Fe concentration would also be controlled by the formation of iron oxyhydroxides amorphous particles at high pH and dissolution at low pH. The percentage of organically complexed iron ranged from 35% to 99% and varied markedly at time scales of days to weeks. There was a significant correlation (|r| = 0.60, P < 0.01) between the percentage of organically complexed iron and the log of the cell density of Microcystis spp.. This suggests that the growth of specific algal species affects iron speciation in the canal.

A simple extraction method and real-time PCR with SYBR-Green I were combined to monitor Microcystis 16S rRNA gene (16S rDNA) concentrations over a wide range. A Fast DNA SPIN Kit (MP Biomedicals) was used to extract rDNA quantitatively. Real-time PCR amplified Microcystis rDNA for quantification with the forward primer Micro229f, which was newly designed by us and was highly specific for Microcystis, and the reverse universal primer 342r. The method developed here can detect Microcystis at concentrations as low as 3 cells mL(-1). The rDNA concentration and cell count were highly correlated in the range from 1.2×10(4) to 1.1×10(6) copies mL(-1) and from 9.5×10(2) to 1.0×10(5) cells mL(-1), respectively, in a canal where Microcystis algal blooms occur annually. The Microcystis rDNA concentration in Lake Kasumigaura was measured by the application of our method to water samples collected monthly from April 2004 to March 2006. Microcystis was not detected by microscopy from January to June 2005, except in May, but our method detected 1.0×10(3) to 1.0×10(4) copies mL(-1) of Microcystis rDNA during this period. This result clearly showed that our method is useful for clarifying the annual fluctuation in Microcystis concentration, especially when concentrations are low.

Three-dimensional excitation-emission matrix (EEM) fluorescence spectra were used to evaluate and compare the characteristics of dissolved organic matter (DOM) in lake and river waters as well as effluent from several sewage treatment plants. Our comparisons of the EEMs indicated a substantial difference in the peak profiles among the samples. For example, five peaks (i.e. Ex/Em = 225/280, Ex/Em = 225/340, Ex/Em = 240/420, Ex/Em = 340/430, and Ex/Em = 480/520nm) were observed on the EEM of the sewage treatment plant effluent, but only two peaks (i.e. Ex/Em = 240/420 and Ex/Em = 340/430nm) were observed in the case of the lake and river waters. Furthermore, one of the peaks (i.e. Ex/Em = 340/430), which has been used as an indicator of the humic-like groups of DOM, was actually found in the EEMs of both humic and non-humic fractions prepared by the XAD-8 resin fractionation method. The non-humic fraction consistently accounted for 30-50% of the peak intensity of the DOM . This result suggests that the peak at Ex/Em = 340/430 is not appropriate as an indicator of humic-like groups in DOM.

We determined the monosaccharide composition of dissolved organic matter (DOM) to evaluate the origin of DOM in Lake Kasumigaura. We applied high-performance liquid chromatography coupled with pulsed amperometric detection (HPLC-PAD) for the analysis of monosaccharides. We collected water samples from Lake Kasumigaura in 2004 and prepared samples from culture medium used for growing blue-green algae that are typically found in Lake Kasumigaura. The dissolved total saccharides (DTS) content of the lake water ranged from 1.8 to 3.0 μM. The DTS content of the DOM from lake water ranged from 3 to 6%. The monosaccharide composition in the lake water was uniform all year round. The main monosaccharides were fucose, rhamnose, arabinose, galactose, glucose, mannose, xylose and ribose. The algae released a large amount of DTS during the stationary phase. The concentration and composition of the released DTS differed substantially among the algal species. The released DTS was 43.2 to 126 μM. Glucose was the most predominant among the monosaccharides of the DTS. The DTS content of the algal DOM ranged from 11 to 33% depending on the type of algae. The monosaccharide composition was very different between the lake-water-derived and algal-derived DOMs.

This paper addresses a variation of the berth allocation problem at multi-user terminals, as ships which would normally be served at the terminal but their expected wait time exceeds the time limit, are assigned to an external terminal. The objective of the problem is to minimize the total service time of ships at the external terminal. A genetic algorithm based heuristic is developed and a wide variety of numerical experiments showed that the heuristic developed performed well in reducing external terminal usage and thus may be helpful in the efficient management of busy ports during extreme peaking conditions.

This study addresses a two-objective berth allocation problem: ship service quality expressed by the minimisation of delay in ships' departure and berth utilisation expressed by the minimisation of the total service time. In this problem, noninferior solutions are expected to be identified. Two heuristics, which are implemented based on two existing procedures of the subgradient optimisation and genetic algorithm, are proposed for solving this problem. Through numerical experiments, it was found that in most cases the genetic algorithm outperformed the subgradient optimisation. Also the tight time window yielded noninferior solutions. Maritime Economics & Logistics (2007) 9, 269–290. doi:10.1057/palgrave.mel.9100186