Masahiro Ochiai

Hydrocarbons generated by pyrolysis of insoluble kerogen-like materials isolated from microbially degraded plant residues

Abstract Leaves of trees, leaves and stems of fresh water- and seawater-submerged weeds and marine benthic macroalgae were incubated for long periods of time (2 months to 14.5 yr.) under subaquatic conditions either in fresh water or seawater. The incubation experiments provided light- to dark-brown colored plant residues, from which insoluble organic fractions comparable to kerogen in natural sediments were separated. The kerogen-like materials were isolated by using the same method as usually employed for isolation of natural kerogens. On pyrolysis, the kerogen-like materials produced a series of n -alk-1-enes and n -alkanes with little odd-even carbon-number preference, and various C 19 -C 20 acyclic isoprenoid hydrocarbons. These hydrocarbons, except for phytenes and phytadienes, are known to be the major pyrolysis products of natural kerogens. The elemental composition and the chromatographic profile of the pyrolysate hydrocarbons varied according to the type of source material, providing evidence for variation in the structural characteristics of natural kerogens from different depositional environments.

Chemical composition of labile fractions in DOM

Dissolved organic matter in natural water was classified into a labile and a refractory fraction according to the decomposition properties for microorganisms. In decomposition experiments of dissolved organic matter from an eutrophic small lake in Japan, dissolved amino acids and dissolved carbohydrates fractions could be confirmed to be the labile fractions of dissolved organic matter.

Behavior of particulate carbohydrates and amino acids in the estuary of the Tama river

Abstract Surface waters were sampled in the estuary of the Tama River, a typical highly eutrophic urban river, and the particulate matter was analyzed for carbohydrates, amino acids and chlorophyll pigments. Particulate carbohydrates (PCHO) and particulate amino acids (PAA) were found to be in two fractions: one transported from the upper reaches and another produced in situ. Arabinose was used as an index of terrestrial origin and chlorophyll pigments for in situ production. PCHO and PAA transported from the upper reaches of the river (PCHO-AL and PAA-AL) differed in behavior in estuarine water. PAA-AL decreased sharply with increase in Cl - concentration, while PCHO-AL decreased with dilution by seawater. This difference in behavior in the estuary may originate from the difference in charge characteristics of these compounds. It is suggested that particulate matter may undergo differential flocculation due to the different electric charge in the estuarine water.

Vertical distribution of monosaccharides in lake water

AbstractsThe concentrations of carbohydrates measured by gas chromatography in lakes of three different trophic levels have a tendancy to be lower than those measured by spectrophotometry. The concentrations of glucose and galactose were high in the euphotic zone of eutrophic lakes and the rhamnose was relatively high in the profundal zone. The ratio of the concentrations of each monosaccharide was relatively uniform from surface to bottom in a dystrophic lake. Glucose and galactose freshly produced in the euphotic zone might well be easily decomposed.

Spring red snow phenomenon ‘Akashibo’ in the Ozegahara mire, Central Japan, with special reference to the distribution of invertebrates in red snow

lt has been noted extensively from the earliest days that the surface of snow is frequendy colored red, pink, yellow, green o r b laek in the Arctic and Antarctic Zones or the high mountains, and also in glaciers. The colored snow patches usually contain many species of algae, bacteria and fungi (FUKUSHIMA 1963, KOL 1964, 1968). The comprehensive literature available on red snow idenrifies Chlamydomonas as the main alga in the Northern and Southern Hemispheres (NEWfON 1982, LING 1996, MULLER et al. 1998). The shade of red snow patches varies from mild pink to deep blood red (NEwrON 1982). Some invertebrates, a very low number of species of aquatic insects, crustaceans, rotifers, tardigrads and oligochaetes in red snow with algae are known as cryobionts, i.e. living in/on ice or snow and in pools of ice melt such as cryoconite-holes (TYNEN 1970, MAciNTYRE 1984, KoHSHIMA 1984, 1994, K:!KUCHI 1994). Red-colored snow patches, or so-called Akashibo (meaning red dirt or dark-red ooze), have been known in several parts in the Ozegahara mire, Central Japan by a few alpinists or skiers. They appear very briefly during 2 or 3 weeks when snow is rapidly melting under strong sunny conditions in late spring around May or June. In this season the Akashibo snow patches are colored deep red (from brown to black-red) and contain snow algae, and many species of small invertebrates at a high density on/in the snow or in small pools forming on the snow surface. lt was found that the dominant algae and invertebrates at high density in the Akashibo snow patches were different to those reported in other areas of typical red snow. Another distinctive character of the Akashibo compared to other red snow is that a redcolored substance remains on the peat even after the snow has disappeared entireJy. KOBAYASHI & FUKUSHIMA (1952a,b) speculated that the cause of the coloration of the Akashibo snow in the Ozegahara mire was not algal color but ferric oxides oozing out from the peat onro the snow surface. However, they had not conducted cryophytological studies when searching for the origin of the Akashibo phenomenon. This phenomenon in the Ozegahara mire have been investigated from many aspects chemical, biological, geographical, ecological and limnological since the research by KOBAYASHI & FuKUSHIMA (1952a). This srudy offers a preliminary description of the red snow phenomenon, the so-called Akashibo, in the Ozegahara mire in Central Japan with special reference to the invertebrates distributed in the Akashibo snow patches.

Alpha- and gamma-BHC in Tamagawa river water, Japan (September 1968 to September 1969)

Abstract The concentrations of BHC residues in Tamagawa river water in an urban region of Japan were determined at three sampling sites during the period September 1968 to September 1969. The concentrations of BHC residues ranged from 5 to 577 ng/litre (alpha-BHC) and from 5 to 234 ng/litre (gamma-BHC) and were highest in summer. The high summer concentrations of BHC residues were considered to reflect the period when BHC was used.

pH response in stream water and buffering capacity of forested soil affected by clear-cutting

Leaf litter supply to the forest floor i s m ue h reduced after clear-cutting, which may affect the budget o forganic matter as well as meta\ elements in the forest ecosystem. Acid rain attacks soi! surtàce directly, and metalleaching is accelerated after felling. Aluminum and manganese released from forest soi! results in harmful effects to biota in aquatic environments (CHRISTOPHERSEN et al. 1990). Long-term measurements of some metals and pH in stream water are useful for estimating the impacts from clear-cutting. We measured the concentrations o f so m e meta! s (Al, Fe and Ca2-) and pH in stream water before and after clear-cutting and carried out experiments of meta! leaching from soi! ofthe forest floor by artificial rain water.

Denitrification and nitrous oxide production in a stream

Increases in anthropogenie nitrogen loading to riverine systems eause nitrate inereases in river water. By 2050, anthropogenic input to rivers is estimated to inerease more than 2 fold eompared to the 1998 1evel (KROEZE & SEITZINGER 1998). This situation has attraeted attention to the nitrogen-loss funetion of riverine eeosystems. Studies of eonditions eontrolling the nitrogen metabolism in small streams are important beeause rapid uptake and transformation of inorganic nitrogen oeeur in these reaehes (ALEXANDER et al. 2000, PETERSON et al. 2001). Using undisturbed natural samples is the preferred method for measuring denitrifieation rate in situ (SHEIBLEY et al. 2003). Many previous studies have used the natural biofilm method (NAKAJIMA 1979, SORENSEN et al. 1988, TEISSIER & ToRRE 2002), intaet sediment eores (HILL & SANMUGADAS 1985, COOKE & WHITE 1987, CHRISTENSEN & SORENSEN 1988, CHRISTENSEN et al. 1989 KESTER et al. 1997, PATTINSON et al. 1998) or sediment perfusion eores (SHEIBLEY et al. 2003). However, few studies have been eondueted in a sandy stream sueh as the middle reaeh o f the Kizu River, Japan. Nitrous oxide, whieh is produeed by denitrifieation and nitrifieation, is one o f the greenhouse gases and a regulator of atrnospherie ozone. Nitrous oxide emissions derived from rivers area net souree ofN20 to the atrnosphere (McELROY et al. 1978, CoLE & CARACO 200 l). More than 30% o f the anthropogenie N20 produetion on land was estimated to derive from rivers in 1998 (SEITZINGER & KROEZE 1998). Between 1990 and 2050, nitrous oxide emissions from rivers, estuaries and eontinental shelves are predieted to inerease by 2.6 times, 2/3 ofwhieh will eome from rivers (KROEZE & SEITZINGER 1998). In the present study, laboratory experiments with intaet eores from the middle reaeh o f the Kizu River were eondueted to determine the spatial and temporai variation in respiration ( oxygen flux ), the flux N20 from sediment to the overlying water body, and denitrifieation (aeetylene inhibition).

Effects of forest cutting on stream water quality

The watershed o f Lake Biwa is u p to 60% eovered by forest, and the river warer flowing imo rhe lake through the foresred watershed may signifieandy affeet the lake warer qualiry. The Asou Experimemal Area (AEA) was established at rhe head water region of the Ado river, flowing imo Lake Biwa and rhe forese was eur in o ne drainage basin to srudy rhe effeets on the lake water qualiry. The environmemal eonditions in the AEA signifieandy differ from rhe Hubbard Brook Experimemal Forest (LIKENS at al. 1977) in meteorology, vegetation, soi! texture and reeovery of soi! aeriviry afi:er clearfelling, ete. The coneemration of Al inereased with deereases in pH, and below a pH of about 5.0 the speeiation of Al was dominared by inorganie Al whieh is toxie to aquarie biota (BAILEY er al. 1995). In the AEA region, most of rhe preeipitation is aeidified (pH < 4.0) whieh has rhe potemial for leaehing of meta! elemems sueh as Al and Mn. An aeid deposition to forest watersheds includes deplerion of eations and the mobilizarion o f elevared eoneentrarions of Al from soi! to drainage warers (CRONAN & SCHOFIELD 1990). Al erosion by aeid rain from rhe soi! of forested areas in rhe US and Germany is an imporcam problem (ULRICH er al. 1980, SHORTLE & SMITH 1988). A high eoneenrrarion of Mn has rhe poremial for fish deformation (FRASER & HARVEY 1982). In the presem srudy, stream water of a rype similar to rhat of neighboring drainage basins was analyzed for some meta! elements (Ca, Mg, Al, Mn, Cu, Zn and Fe) and rhe beforeand after-clearfelling meta! eoneemrations were eompared.

Secular variation of BHC in the paper of books

Abstract In order to consider the distribution, migration and accumulation of the organochlorine compounds in cities, hexachlorocyclohexane (BHC) levels were measured in the paper of books. BCH was always present in books published between 1927 and 1972; the highest concentration was observed in the books published in 1946 but it was not detected (below 1 ng/g) in the paper of books published in 1973. The secular variation of BHC content in the paper of books is considered as an indicator for the use of BHC in Japan.