Matter Weight Research Articles

Manipulação do Corte do Sorgo (Sorghum bicolor, L. Moench) para Confecção de Silagem, Visando a Produção do Novilho Superprecoce

O experimento foi conduzido com o objetivo de estudar os parâmetros relativos ao consumo de alimentos, ganho de peso, conversão alimentar e eficiência energética de bezerros de corte em confinamento, alimentados com duas dietas, com inclusão de silagem de sorgo AG-2006 colhida em duas alturas de corte: corte baixo (14 cm) e corte alto (45 cm). Foram utilizados 12 bezerros Braford com idade média de sete meses e peso médio inicial de 208 kg. O período de confinamento foi de 126 dias, subdividido em dois períodos de 63 dias, em que a relação volumoso:concentrado, para ambas as dietas testadas, foi de 60:40 e 50:50, respectivamente, para o primeiro e segundo períodos. A silagem produzida pelo corte alto apresentou menor teor de FDN (42,57 contra 52,24%) e maior DIVMO (63,67 contra 53,59%). Não houve interação entre altura de corte e período de avaliação em confinamento para os parâmetros relativos aos consumos diários de matéria seca (CMS) e de energia digestível (CED), expressos nas diferentes formas, ao ganho de peso médio diário (GMD) e à eficiência energética (CE). A elevação da altura de corte de 14 para 45 cm das plantas de sorgo para produção de silagem não afetou o CMS (7,60 contra 7,70 kg/dia), o CED (21,62 contra 23,83 Mcal/dia), o GMD (1,233 contra 1,375 kg) e a eficiência energética (17,53 contra 17,31 Mcal/kg de PV), respectivamente. Animais que tiveram a silagem de sorgo colhida a 45 cm incluída na dieta alimentar foram mais eficientes na transformação da matéria seca consumida em ganho de peso em relação à dieta com silagem de sorgo colhida a 14 cm de altura (5,60 contra 6,17 kg de MS/kg de PV).

Genetic Relations between Reproduction, Chick Weight and Maternal Egg Composition in a White Leghorn Line

Selection is a viable way to increase egg dry matter, an important trait for the egg processing industry, but simultaneously a change in the embryonic environment takes place. The main purpose of this study was to estimate genetic parameters for the percentage of fertile eggs of eggs set (FERT), percentage of eggs hatched of fertile eggs (HATCH), percentage of live chicks 2 weeks post-hatch of hatched eggs (SURV/h) and of fertile eggs (SURV), and their genetic correlations with egg weight, albumen weight, yolk weight, yolk proportion, albumen dry matter and mean chick weight in a White Leghorn selection line. Direct and maternal heritabilities were low for FERT, HATCH and SURV, and non-existent for SURV/h. All direct-direct genetic correlations between reproduction traits and egg composition traits were not significant. Maternal-direct genetic correlations between HATCH and egg weight, albumen weight, yolk weight, yolk proportion and albumen dry matter were - 0.22, - 0.30, 0.28, 0.52 and 0.26, respectively. Similar correlations were found between SURV and egg composition traits. No significant genetic relationship was found between chick weight and post-hatch survival. In conclusion, within the range of values for egg composition in this study, selection for an increased egg dry matter should not impair reproduction.

Effect of Nitrogen Fertilization on Photosynthetic Characters and Dry Matter Production in F1 Hybrids of Rice (Oryza sativa L.)

This study was carried out to determine heterosis in different photosynthetic and morphological characters, and to observe photosynthetic ability and dry matter production potentiality of two F1 hybrids of rice grown in pots supplied with N fertilizer in the normal or double dose. Photosynthetic rate in terms of CO2 exchange rate (CER), leaf N concentration, SPAD value, soluble protein content and ribulose-l,5-bisphosphate carboxylase (Rubisco) activity was increased significantly by doubling the dose of fertilizer in most parental cultivars and F1 hybrids, but the rate of increase was higher in F1 hybrids than in their parents. Several morphological parameters were also increased significantly by doubling the dose of fertilizer, but not the percentage of dead leaf blades. The rates of increase of plant height, leaf area and dry matter production were higher in F1 hybrids. In particular, the rates of increase of total dry matter and root weight were very high in one of the F1 hybrids. The percentage of dead leaf blades decreased significantly in plants grown with a high dose of fertilizer as a result of higher leaf N concentration. At a normal fertilizer dose, both F1 hybrids failed to show positive heterosis in most photosynthetic characters. However, positive heterosis was found at a high fertilizer dose. Both F1 hybrids showed positive heterosis over mid-parent in dry matter production per plant at both fertilizer doses. One of the F1 hybrids also showed positive heterosis over the better parent. Heterosis in most photosynthetic and morphological characters was increased by increasing the dose of fertilizer. The sufficient supply by doubling the dose of fertilizer increased the leaf N concentration, chlorophyll content, soluble protein content and Rubisco activity in F1 hybrids, which led to higher positive heterosis in CER. A larger leaf area plus higher CER, especially at a high fertilizer dose, contributed to higher dry matter production in F1 hybrids of rice.

Effects of maize silage supplementation before lucerne grazing on the occurrence of bloat in cattle

The effects of maize silage supplementation, before lucerne grazing, on the occurrence of pasture bloat were studied under the hypothesis that this treatment could reduce the severity of this digestive disorder. The experiment was divided into two trials. Six ruminally fistulated heifers were used for the study of ruminal parameters, and in vitro measurements and 36 heifers were used for the study of bloat score. Treatments were: Tl, no supplement; T2, 0.5% body weight of maize silage dry matter animal‐1 day‐1; and T3, 1.0% of the same supplement. Lucerne was grazed ad libitum in the vegetative to pre‐bloom stage using a daily rotational grazing system. Visual bloat score in non‐supplemented animals was higher (P < 0.01) than in the treated groups but it did not differ (P > 0.01) between the different supplementation levels. When lucerne leaflets were mixed in vitro with inoculum from Tl, T2, and T3 animals, differences in microbial gas production were detected (P < 0.01) between Tl and T3 from the fourth hour of incubation, and between Tl and T2 from the twelfth hour of incubation. Soluble protein concentrations in the liquid phase of these in vitro incubates were lower (P < (1.05) for Tl than for T2 and T3, but soluble carbohydrate concentrations did not differ. In the ruminal fluid from the fistulated heifers, proteolytic activity, pH, and total N‐NH 3 and N‐NH 4 + concentrations did not differ (P > 0.05) among treatments. When sampled at the first (0800 h) and second (1200 h) sampling times, N‐NH3 concentrations were higher (P < 0.05) for T1 at both sampling times. Thus, maize silage supplementation at 0.5% and 1.0% of body weight before lucerne grazing reduced bloat occurrence and severity. Although the mechanisms involved in the control of this digestive disorder could not be clearly demonstrated, it is suggested that the lower fermentative capacity of the ruminal fluid from supplemented animals would reflect a reduction of the rumen‐free microbial population, which is the one available to attack bloating legumes immediately after the legumes reach the rumen. A reduced free rumen microbial population would lead to a slower release of soluble nutrients from lucerne leaflets and, consequently, to a reduction in bloat development.

Avaliação da Silagem de Diferentes Híbridos de Sorgo (Sorghum bicolor, L. Moench) por meio do Desempenho de Novilhos de Corte Confinados

Este experimento foi conduzido com o objetivo de estudar os parâmetros relativos ao consumo de alimentos, ganho de peso, conversão alimentar e eficiência energética de novilhos de corte em confinamento, alimentados com quatro dietas contendo silagem de híbridos de sorgo de comportamento agronômico diferenciado: AGX-213 e AG-2002 (forrageiro), AGX-217 e AG-2005E (duplo propósito). Foram utilizados 48 novilhos com idade média de 19 meses e peso médio inicial de 316 kg. A relação volumoso:concentrado foi de 63:37, para todas as dietas testadas. Não houve interação entre fonte de volumoso e período de avaliação em confinamento. A silagem do híbrido AG-2005E propiciou maior consumo de matéria seca e energia digestível, ganho de peso médio diário e melhor conversão alimentar frente aos demais genótipos testados. A análise de contraste mostrou que a inclusão de silagens de sorgo forrageiro (AGX-213 e AG-2002) à dieta alimentar causou redução significativa de 8,84 e 12,11% no consumo voluntário de matéria seca e energia digestível, respectivamente, frente às silagens de sorgo de duplo propósito (AGX-217 e AG-2005E). Animais alimentados com silagem de sorgo com características de duplo propósito apresentaram maior ganho de peso médio diário (1,163 contra 0,943 kg) e foram mais eficientes na transformação de matéria seca e energia digestível consumida em ganho de peso vivo (PV) (7,65 contra 8,73 kg de MS/kg de PV e 19,76 contra 21,84 Mcal/kg de PV).

Insights into the formation of tomato quality during fruit development

SummaryInfluence of the source-sink balance on the final quality of tomato was investigated in spring greenhouse production. Four treatments were compared differing by the fruit/leaf number ratio manipulated during either the cell division or the cell elongation periods of the sixth truss. At maturity, quality was assessed through fruit colour, firmness, fresh weight, titratable acidity, refractive index, and contents of dry matter, reducing sugars, (3-carotene, lycopene and C vitamin. (3-carotene and lycopene contents were correlated positively to each other, and negatively to fruit firmness. The refractive index, dry-matter and sugar contents were also positively correlated, but less under low competition during cell division. Fruit fresh weight was correlated with none of the qualitative parameters, and significantly differed among fruits within the sixth truss; however this relied only on the difference between the first fruit and the following ones. Fruit composition did not vary among basal and tip fruits, but significantly depended on the fruit/leaf ratio. Low competition during the whole fruit development promoted sugar, acid and carotenoid contents, indicating a general increase in fruit metabolism, though fruits were not significantly bigger. Decreasing the competition during the cell elongation period tended to decrease the fruit dry-matter content and increase the acid content, whereas affecting the competition only during the cell division period hardly influenced the fruit composition. On the whole, results indicated that drastic removal of fruits may have inhibited the source activity at a period of low sink demand. In contrast to fruit composition and fruit size, other physical quality traits (firmness and colour) were only slightly affected by the source-sink ratio.

Nutritive Value and Aversion of Honey Mesquite Leaves to Sheep

Honey mesquite (Prosopis glandulosa Torr.) is an invasive native plant that is abundant in Mexico and the Southwestern United States. We initiated 2 studies to determine if: 1) mesquite could provide valuable forage for domestic herbivores; and 2) if mesquite causes conditioned flavor aversions in ruminants. An in vivo digestion trial was completed with 15 lambs assigned to diets of 0, 5, 10, 15, or 20% dried mesquite leaves mixed with alfalfa hay to measure effects of mesquite on intake and digestion. Proportions of mesquite leaves > 5% of the diet negatively affected dry matter (DM) intake, nitrogen (N) balance, energy balance and weight gain. Mesquite intake was highest at the 5% level averaging 1.81 g kg-1 body weight (BW), mesquite intake of the other mesquite-containing diets averaged 0.78 g kg-1 BW. Apparent digestibility was not affected by the level of mesquite in the diet. An in situ digestion trial did however, reveal that pure alfalfa was more digestible than mesquite leaves. A conditioned flavor aversion (CFA) trial tested the effect of post-ingestive feedback from mesquite on the intake of a novel food (rye). Lambs were offered rye and then ground mesquite was infused into their rumens by esophageal tube. Twenty one lambs were assigned to 3 dosing treatments: 0 (control), 3.0 (low), or 4.5 (high) g of mesquite per kg BW. Two days after dosing, lambs that received mesquite infusions ate less rye than controls indicating the formation of a CFA. The aversion to rye persisted for at least 2 days. The high dose of mesquite also decreased intake of the alfalfa basal ration for at least 3 days and resulted in persistent diarrhea in lambs. Chemical analysis of mesquite leaves revealed similar nutritive quality (crude protein, gross energy, and fiber) as mature alfalfa. However, to exploit the forage value of mesquite, the allelochemicals that cause flavor aversions and other negative digestive consequences need to be identified and overcome. DOI:10.2458/azu_jrm_v54i1_baptista

Effect of rice bran on the production of different king oyster mushroom strains during bottle cultivation.

The effect of rice bran supplementation on the production of two king oyster mushroom strains was investigated in order to recommend the optimum and economic amount of rice bran for growing the mushroom to Pleurotus mushroom growers in Taiwan. The average yield, biological efficiency (B.E.) and production efficiency (P.E.) of the strain ATCC 36047 increased significantly with the supplementation of rice bran to substrate from 0 to 47.95% by weight of dry matter. The B.E. and P.E. of the strain Holland 150 reached the highest level when the rice bran was added up to 38.08%, but decreased significantly when the supplementation was up to 47.95%. These results show that different king oyster mushroom Strains response differently to the supplementation amount of rice bran and might indicate that the strain ATCC 36047 necessitate a great supply of some ingredients in rice bran to increase its B.E. and P.E. In consideration of the capacity of cropping room, productivity of cultivation spawn and mushroom production cost the most optimum and economic amout of rice bran in substrate would be about 48% and 38% for the strains ATCC 36047 and Holland 150 respectively..

Effect of Cottony Snow Mold on Mortality and Biomass of Calamagrostis canadensis under Controlled-Environment Conditions

Abstract A low-temperature basidiomycete (LTB), the causal agent of cottony snow mold, was evaluated as a potential biological control agent for marsh reed grass (Calamagrostis canadensis [Michx.] P. Beauv.), a native grass of the North American boreal forest. Marsh reed grass and 2-year-old white spruce trees (Picea glauca [Moench] Voss) were inoculated with LTB and incubated for 12 weeks in a cold chamber to determine whether the fungus was pathogenic to these species. The fungus was not pathogenic to white spruce but was to marsh reed grass, causing 15% mortality and 64% reduction in dry weight of aboveground plant matter. In a second experiment, two clones of marsh reed grass were inoculated with an isolate of LTB and incubated for 8, 14, and 20 weeks in a cold chamber. Maximum response in the grass to the LTB treatment occurred after 20 weeks of incubation, with decreases of 97, 97, and 63%, respectively, in tiller number, dry weight of aboveground plant matter, and plant height. The LTB is a potential biological control agent of marsh reed grass.

Aspectos da estrutura da raiz e do desenvolvimento de plantas de soja em solos compactados

O objetivo deste trabalho foi avaliar o efeito da compactação do solo na anatomia da raiz e no desenvolvimento de duas cultivares de soja (Glycine max (L.) Merrill), IAC-8 e IAC-14, em vasos. O solo utilizado foi um Latossolo Roxo, tirado da camada superficial (0-200 mm). Os níveis de compactação consistiram de 0,95 (controle), 1,20, 1,35 e 1,50 kg L-1, e foram obtidos pela compactação de determinada massa de solo por prensa hidráulica, em cilindros de ferro. A compactação do solo não afetou a estrutura anatômica da raiz, em nenhuma das duas cultivares. Na cultivar IAC-8, o número de folhas, a altura das plantas e o peso da matéria seca da raiz e do caule diminuíram com o aumento da densidade do solo, e o comprimento da raiz aumentou. Na cultivar IAC-14, o número de folhas, a área foliar, o número de vagens, a altura das plantas, o peso da matéria seca da raiz, do caule e das folhas foram diminuindo à medida que aumentava a densidade do solo, embora nas densidades intermediárias (1,20 e 1,35) se tenha notado uma tendência de aumento naquelas variáveis. A produção de soja não foi afetada pela compactação do solo, com exceção do número de vagens da cultivar IAC-14, que apresentou diferenças em razão do tratamento. Os resultados sugerem que as duas cultivares podem ser bem adaptadas a solos compactados, nos níveis analisados.

In-Situ High Temperature Neutron Diffraction Study of Bi,Pb(2223) Phase Formation in Ag-Sheathed Monofilamentary Tapes

High temperature neutron diffraction measurements were performed on Bi(2223)/Ag-sheathed monofilamentary tapes at the ILL high-flux reactor in Grenoble. Reactions leading to the conversion from Bi(2212) to Bi,Pb(2223), as well as other transformations involving secondary phases, were directly observed during the reaction heat treatment. The heating ramp and annealing conditions were exactly the same as those used for standard high-performance tapes processing. A quantitative analysis was carried out by means of a full-pattern profile refinement technique: up to 7 phases were simultaneously detected and successfully refined. An increase of the Bi(2212) phase during a slow cooling was found not to be related to a decomposition of Bi,Pb(2223), which remained stable during cooling. The role of secondary cuprates, in particular (Ca,Sr) 14 Cu 24 O 41, was investigated. Since neutron diffraction allows for an absolute measurement of the weight of crystalline matter inside the sample, it was possible to measure the total crystalline matter amount as a function of temperature and time during processing. Evidence of partial melting at high temperature was found strongly supporting the Bi,Pb(2223) formation via a nucleation-and-growth mechanism at the early stage of the process.

The ability of the nematode-trapping fungus Duddingtonia flagrans to reduce the transmission of

The ability of two isolates of the nematode-trapping fungusDuddingtonia flagransto reduce the numbers of gastrointestinal nematode larvae on herbage was tested in three plot studies. Artificially prepared cow pats containingOstertagia ostertagieggs, with and without fungal spores, were deposited on pasture plots two or three times during the grazing season in 1995, 1996 and 1997. The herbage around each pat was sampled fortnightly over a period of 2 months and the number of infective larvae was recorded. At the end of the sampling period, the remainder of the faecal pats was collected to determine the wet weight, dry weight, and content of organic matter. The infective larvae remaining in the pats were extracted. Faecal cultures showed that both fungal isolates significantly reduced the number of infective larvae. Significantly fewer larvae were recovered from herbage surrounding fungus-treated pats compared with control pats in all three experiments, reflecting the ability of the fungus to destroy free-living larval stages in the faecal pat environment. After 8 weeks on pasture there were no differences between control and fungus-treated pats with respect to wet weight, dry weight, and organic matter content. This indicates that the degradation of faeces was not negatively affected by the presence of the fungus.

The Second War and Postmodern Memory

We never discussed the Second World War much when I was growing up. I don't feel much like discussing it now. It seems presumptuous to interpret, much less give literary interpretations of, the Systematic Extermination Process or the dropping of the H-Bomb, the two poles of the Second War. When Stanley Diamond asked me to speak on "Poetry after the Holocaust," my first reaction was to wonder what qualifications I had to speak?as if the topic of the war made me question my standing, made me wonder what I might say that could bear the weight of this subject matter. Diamond reassured me that the audience would be small: "For many, the Holocaust is too far in the past to matter; for most of the rest, it's too painful to bring to mind." My father-in-law, who left Berlin as a teenager on a youth ally ah and spent the war in Palestine, had a different reaction: all these Holocaust conferences are a fad. This reaction is as disturbing as it is right. The Holocaust has come to stand for a kind of Secular Satanism?everyone's against it, anyone can work up a feverish moral fervor denouncing the Nazi Monster. Yet I've been struck by just the opposite: that the psychological effects of the Second War are still largely repressed and that we are

Physical and Chemical Treatment of a Nitrified Leachate from a Municipal Landfill

Leachate from a Swedish municipal landfill in the methanogenic phase was nitrified and then treated by various physical and chemical methods: oxidation with Fenton's reagent and with ozone, precipitation with ferric chloride and with aluminum sulphate and adsorption onto activated carbon. The leachate was analyzed by measuring the COD (chemical oxygen demand), the BOD7 (biochemical oxygen demand) and the TOC (total organic carbon). Specific organic compounds were analyzed by GC/MS (gas chromatography and mass spectrometry) while the molecular weight of the organic matter was determined by ultrafiltration. The nitrification process resulted in 20–30% of the COD being removed. The maximum COD removed after nitrification and oxidation was 80% using Fenton's reagent and 54% using ozone. The combination of nitrification and precipitation gave a maximum COD removal of 68% using ferric chloride and 54% using aluminum sulphate, while nitrification and adsorption onto activated carbon gave a maximum COD removal of 76%. A combination of nitrification, precipitation with ferric chloride and adsorption on activated carbon gave a TOC removal of 96%. The ultrafiltrations showed that nitrification and adsorption onto activated carbon were the most efficient processes for the removal of low molecular weight compounds. The GC/MS analyses showed that, for instance, C3-substituted benzenes and C2-C4 substituted phenol isomers were degraded during the nitrification process, while phthalates were unaffected even after treatment with Fenton's reagent or by adsorption onto activated carbon.

Slip casting of SiC-SiAlON composites

SiC-SiAlON composites were prepared by the reaction sintering of SiC, kaolin and silicon mixtures in a nitrogen atmosphere. To form complex shapes, slip casting was used, with water preferred as an economic dispersion medium. The methodology to obtain a highly concentrated, well-dispersed, slurry (73% by weight of dry matter) is described. Zeta potential and complementary redox potential measurements revealed the nature of the surface species as a function of pH and indicated compatible conditions for the three constituents (kaolin, SiC, Si). Sodium metasilicate was used as deflocculant and CMC as organic binder.

Response of two potato clones (S. tuberosum L.) to contrasting temperature regimes in the field

Two potato clones (S. tuberosum L.) were grown in the field under contrasting temperature regimes during the crop cycle. Differential growth and yield was observed in the clones studied. Differences in yield were due to the decreased proportion of tubers larger than 3.5 cm in length as well as to the differences in dry weight and percent of dry matter in tubers. Yield reductions per plant were 52 and 94% for Alfa and Herta, respectively, in the warmer regime compared with the cooler regime. Apparent photosynthesis rates measured in Herta were maximum (45 umol.m−2.s−1) during tuber filling. Stomatal resistance and apparent photosynthesis rate were reduced by high temperature, indicating mesophyllic inhibition of photosynthesis. Dark respiration was promoted by moderately high temperature and differed significantly between clones, with Herta showing the higher rates.

Effects of shading on vegetative, reproductive and fruit maturity aspects of 'Hayward' kiwifruit

Kiwifruit vines (cv. Hayward) were grown under 0, 25 and 50% sunlight conditions for four continuous years. Both vegetative growth (canes per vine, fruiting shoots per cane) and crop load gradually decreased with a higher rate at 50% shade. Vine productivity on the fourth year decreased by about 40 and 70% under 25 and 50% shading, respectively. Fruit growth and final size varied from year to year depending on the interaction with the reduced crop load. Shading significantly delayed fruit harvest (minimum Soluble Solids Content of 6.5%) and decreased firmness compared to the control. practice to avoid damage caused by hail, sunburn or wind. The reduction of photosynthetically active ra- diation caused by shading, is a factor which limits productivity. Shading has also been found to reduce flower bud initiation, crop load, fruit size and quality, number of new shoots, shoot diameter, fresh and dry weights of vines, dry matter and specific leaf weight.

A Method for Measuring Growth in Living Barnacles (Crustacea: Cirripedia)

A buoyant-weight method is described for the non-destructive estimation of fresh weight, total dry weight, shell weight and dry weight of organic matter in living barnacles Balanus amphitrite amphitrite Darwin. The method involves developing regression equations relating weight in air of these parameters to the buoyant weight of living barnacles in sea water. Buoyant weights of barnacles can then be used with the regression equations to obtain the weight in air of these consitituents, making possible the measurement of rates of shell growth and growth in dry weight without disturbance to the living animal. The method has been developed for the analysis of groups of juvenile barnacles cultured on coverslips, ranging in total dry weight from 1 to 60 mg, and for single mature individuals from 75 to 800 mg total dry weight. The buoyant-weight method has been used to measure shell growth of 2–3 mg d-1 in barnacles of 48 mg mean initial total dry weight cultured at 28°C.

Fertilisation soufrée du soja

The effect of S (60, 120 and 240 kg ha−1) and N (45 and 90 kg ha−1) fertilization on the yield and quality of soybean (Glycine max L. Merrill ’Maple Amber’), grown on a Kamouraska silty clay loam, was studied under greenhouse conditions, and in the field over a period of 2 yr. In the greenhouse, soybean (dry matter and pod weights) was responsive to N and S, and an excess of sulfate reduced P and K levels in the upper leaves. In the field, small or nonsignificant differences between fertilizer treatments were found for yield parameters in 1988 and 1989. However, as compared to the 45-kg ha−1 application rate, application of 90 kg N ha−1 decreased methionine concentration in the grain in 1989, when yield was low. Thus, excessive N reduced the nutritive value of soybean without affecting yield.Key words: Protein, oil, amino acids, nutritive value of soybean

Denitrification, Nitrificastion and Nitrogen Fixation in Sublittoral Sediments of the South China Sea

Measurements of denitrification, nitrification and nitrogen fixation rates were made alongside with measuring of chemical and physical properties in sublittoral sediments of the South China Sea near the coast of Vietnam. Studied sediments were suboxic (Eh was positive as a rule), had 0.18–1.5 % of organic carbon, 0.004–0.135 % of total nitrogen and 3-12 % of total iron. The numbers of denitrifying and nitrate-reducing bacteria were as high as millions and hundreds of millions cells per gram wet weight of sediment matter, respectively. The processes of nitrification and denitrification were not spearated spacely. The nitrification was measured in both superficial layer and in a 10-cm sediment column. There were indirect evidences suggesting possibility of anaerobic ammonium oxidation. Denitrification was detectable in the sediments from two sites of sampling; maximal value was 86.2 μmoles N m−2h−1. The denitrification potential determined at 1 mM nitrate decreased regularly from the upper to lower layers. Its values in the different sediments ranged from 134 to 532 μmoles N m−2h−1. Nitrogen fixation (from 4.8 to 86μmoles N m−2h−1) was close to that found in similar sediments in temperate waters in summer, and was not a significant source of nitrogen. It was comparable with diffusion of ammonium from sedimnts.