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Volume 49, Issue 1
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Tatemasa HIRATA, Kohji MURAOKA1988 Volume 49 Issue 1 Pages 1-9
Published: January 30, 1988
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSThis paper describes the seasonal changes of the streamsolute concentration for two years in the Tsukuba Experimental Forest with 67.5 ha. NO3--N concentration shows the clear seasonal change according to which it is elevated in summer, but declines in winter. Runoffs of K+ and Ca2+ seem to have a pattern similar to NO3--N behavior. On the other hand, SiO2 concentration declines occasionally due to the effect of the rainfall runoff, as does Na+ concentration.
Two types of runoff can be found in time-dependent changes of the streamsolute concentration during the rainfall runoff event. Most of the solute concentrations decrease in the rising limb, and increase in the recession limb. In the end stage of the recession limb, the solute concentration classified into Type I recovers approximately the baseflow level prior to the rainfall runoff, while that into Type II overshoots the baseflow level. SiO2 and Na+ belong to Type I, and NO3--N, K+ and Ca2+ to Type II. This proves that (1) concentration of Type I remains lowered due to the effect of the rainfall runoff, compared to the baseflow level, and (2) when a new rainfall runoff event occurs, concentration of Type II is raised still more than the older one. Thus, there is a concentration increase of NO3--N in summer due to successive rainfall. These runoff features are reliable for interpreting the seasonal changes mentioned above.View full abstractDownload PDF (1315K) -
Yu ISHITOBI, Mitsuo KAWATSU, Hiroshi KAMIYA, Kyoichiro HAYASHI, Hidero ...1988 Volume 49 Issue 1 Pages 11-17
Published: January 30, 1988
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSSemi-daily sampling was carried out from July 1983 to June 1984 to evaluate nutrient loads in the Hii River. The variation of concentration was synchronized with the variation of flow for all examined substances. The strong increase in concentration of suspended substance (SS), ignition loss (IL) and total phosphorus (TP) was found at the flush stage of flooding. Statistical analysis on the variation of concentration was conducted for all examined substances except for ammonium-nitrogen (NH4-N). Using the concentration-flow data collected during the first half interval, log load-log flow relationships were obtained. All relationships were significant and linearity as to total nitrogen (TN) and TP was ensured. There was little difference between the predicted and observed value for TN and TP load during the last half period. Annual load from July 1983 to June 1984 was estimated to be 857 and 95.6 t for TN and TP, respectively.View full abstractDownload PDF (1007K) -
Masahiro UCHIYAMA, Yuh NAKAJIMA, Tuneo TOMIZAWA, Hideo AKAIWA1988 Volume 49 Issue 1 Pages 19-25
Published: January 30, 1988
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSAn easy and useful back-extraction method for measuring copper (II) complexing capacity (CuCC) was established (AKAIWA et al, 1986; AKAIWA et al., in contribution), was used to study the CuCC of Lake Haruna water. Using the ultrafiltration technique, it was found that dissolved organic materials having high CuCC were distributed in less than the 10, 000 molecular weight range, and CuCC/DOC (Dissolved Organic Carbon) was the highest in the 1, 000-10, 000 molecular weight range. The CuCC/DOC of Lake Haruna water was 0.06-0.08, which was almost similar to the values of other lakes previously reported.
As far as the relation between the molecular weight distribution and the CuCC value, similar tendencies were observed for metabolic products in the growth of Chlorella sp. This consistency might indicate that the algal products are very important in evaluating the CuCC of such as Lake Haruna into which artificial pollutants do not flow.
A positive relationship was observed between E260 (absorbance at 260 nm) and CuCC in both Lake Haruna waters and Chlorella sp. experiment.View full abstractDownload PDF (885K) -
A Case Study on River Akashi of Hyogo Pref.Yoshinari KOBUKE1988 Volume 49 Issue 1 Pages 27-36
Published: January 30, 1988
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSThe behavior of LAS in river waters was investigated in a medium-size river of Hyogo Pref. in November 1985 and March 1986. The LAS concentration was high in lower streams traversing urbanized areas and also relatively high in upper streams passing through newly developed housing districts. The distribution of LAS-assimilable bacteria was similar to that of LAS, and the correlation between the two concentrations was significant.
Four LAS homologues with C10 to C13 alkyl chain were detected in river waters. The relative abundance of LAS homologues is governed by “the distance principle” (SWISHER, 1963), according to which biodegradation of LAS is facilitated by increasing the distance between a sulfonate group and the most remote end of the alkyl chain.
The change of the relative abundance of LAS homologues was closely related with the increase of SS concentration in the middle reaches of the river. A laboratory experiment showed that the relative abundance of LAS homologues with longer alkyl chain decreased with as adsorption of total LAS onto SS took place. These results suggest that both adsorption on SS and biodegradation play an important role in the change of LAS composition in the river water.View full abstractDownload PDF (1454K) -
Takayuki HANAZATO, Masayuki YASUNO1988 Volume 49 Issue 1 Pages 37-41
Published: January 30, 1988
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSAssimilation rates of Diaphanosoma brachyurum and Moina macrocopa on Microcystis were measured using a stable isotope 13C. When D. brachyurum and M. macrocopa fed on Chlorella sp. or Chlamydomonas reinhardtii, the animals increased their assimilation rate proportionally with food density up to a certain food level, and showed a constant assimilation rate above it. However, when the animals fed on M. aeruginosa, the assimilation rate declined at the highest algal density in the present study, and the decline in the rate was greater for D. brachyurum than for M. macrocopa. D. brachyurum seemed to be more susceptible to the M. aeruginosa toxin than M. macrocopa. D, brachyurum assimilated M. aeruginosa as much as Chlorella sp. when the animal fed on the mixture of both algal species, although the animal assimilated M. aeruginosamuch less than Chlorella sp. when fed on the single algal species. Chlorella sp. probably masked the toxic effect of M. aeruginosa.View full abstractDownload PDF (642K) -
Muneoki YOH, Hisayoshi TERAI, Yatsuka SAIJO1988 Volume 49 Issue 1 Pages 43-46
Published: January 30, 1988
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSIn the hypolimnion of Lake Kizaki, an increase of N2O concentration was observed with time, concomitant with an increase of NO3- concentration and a decrease of oxygen concentration. In addition, the amount of apparent N2O production (ΔN2O) was found to be linearly correlated with that of apparent oxygen consumption (-ΔO2). These facts suggest that N2O was produced during the process of nitrification in the hypolimnion of Lake Kizaki. The mole fraction of ΔN2O/-ΔO2was found to be 2.7×10-4, consistent with the value of 1.0×10-4, obtained by YOSHINARI (1976) in the western North Atlantic Ocean.View full abstractDownload PDF (397K) -
Michiro MATSUYAMA1988 Volume 49 Issue 1 Pages 47-51
Published: January 30, 1988
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSLight-limited growth was compared in two phototrophic bacteria, a large-celled one which was densely populating the dissolved O2-H2S interface of Lake Kaiike, and a Chromatium buderi strain DSM 176 obtained from the German Collection of Microorganism. C. buderi could grow fast at a high light intensity, but in a light-limited condition similar to that at the dissolved O2-H2S interface of Lake Kaiike C. buderi could not form a dense population. The intrinsic low growth rate of a large-celled phototrophic bacterium isolated from Lake Kaiike was considered to be its means of survival under light-limited conditions.View full abstractDownload PDF (751K)
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