The Biological Sources of the Organic Matter in Poyang Lake Sediments

2013 ◽  
Vol 724-725 ◽  
pp. 431-436
Author(s):  
Ming Sheng Yang

We conducts a systematic study on the biological sources of the sediment organic matter through the analysis of the organic carbon and nitrogen content in the sediments of Poyang Lake, the n-alkanes as biomarker and the characteristics of the compound-specific isotope of n-alkanes. It is found that the C/N ratio of organic matter is less than 10 in Poyang Lake and that the organic matter mainly originates from lacustrine aquatic organism. The short-chain hydrocarbon takes absolute advantage in the n-alkanes. The value of C21-/C22+is greater than 1, which shows that the biomass of bacteria and algae is greater than the sum of the aquatic submerged plants and terrigenous organisms biomass. The value of (nC15+nC17)/(nC23+nC25) of n-alkanes is greater than 2, which reveals that bacteria and algae have an absolute predominance in aquatic organism. The high carbon n-alkanes come from terrigenous plants and their compound-specific carbon isotope demonstrates that C3plant is the main biological source.

2004 ◽  
Vol 4 (4) ◽  
pp. 175-182 ◽  
Author(s):  
K. Rojek ◽  
F.A. Roddick ◽  
A. Parkinson

Phanerochaete chrysosporium was shown to rapidly decolorise a solution of natural organic matter (NOM). The effect of various parameters such as carbon and nitrogen content, pH, ionic strength, NOM concentration and addition of Mn2+ on the colour removal process was investigated. The rapid decolorisation was related to fungal growth and biosorption rather than biodegradation as neither carbon nor nitrogen limitation, nor Mn2+ addition, triggered the decolorisation process. Low pH (pH 3) and increased ionic strength (up to 50 g L‒1 added NaCl) led to greater specific removal (NOM/unit biomass), probably due to increased electrostatic bonding between the humic material and the biomass. Adsorption of NOM with viable and inactivated (autoclaved or by sodium azide) fungal pellets occurred within 24 hours and the colour removal depended on the viability, method of inactivation and pH. Colour removal by viable pellets was higher under the same conditions, and this, combined with desorption data, confirmed that fungal metabolic activity was important in the decolorisation process. Overall, removals of up to 40–50% NOM from solution were obtained. Of this, removal by adsorption was estimated as 60–70%, half of which was physicochemical, the other half metabolically-dependent biosorption and bioaccumulation. The remainder was considered to be removed by biodegradation, although some of this may be ascribed to bioaccumulation and metabolically-dependent biosorption.


1981 ◽  
Vol 32 (2) ◽  
pp. 245 ◽  
Author(s):  
DJW Moriarty ◽  
MC Barclay

The food of seven species of penaeid prawns from the Gulf of Carpentaria consists predominantly of Foraminifera, small molluscs, crustaceans and polychaetes. Measurements of organic and inorganic carbon, organic nitrogen and bacterial biomass were made. Foregut contents of adult prawns contained between 72 and 223 mg organic carbon/g dry wt. Protein constituted between 43 and 64% of the organic matter. Approximate assimilation efficiencies of food in prawns caught in the gulf, determined for four species, varied from 48 to 77% of organic carbon and from 42 to 77% of organic nitrogen. The food of juvenile Penaeus merguiensis was examined for two growing seasons. In the 1976-1977 season the foregut contents contained a mean of 41 mg organic nitrogen /g dry wt and 181 mg organic carbon /g dry wt. In the 1977-1978 season, significantly lower proportions of organic nitrogen and carbon were eaten, viz, 21 mg organic nitrogenlg dry wt and 101 mg organic carbon /g dry wt. Improved assay procedures for muramic acid have shown that bacteria are less important in the food of prawns than previously reported. Bacteria constituted less than 2% of the organic matter in the adults of all species, but in many juvenile P. merguiensis bacteria were more important, constituting up to 14% of organic matter.


1924 ◽  
Vol 14 (4) ◽  
pp. 555-562 ◽  
Author(s):  
Selman A. Waksman

Various investigations on the decomposition of organic matter in the soil have brought out the fact that there exists a more or less constant ratio between the carbon and nitrogen content of the soil, whatever the ratio between these elements in the organic matter originally added to the soil. This ratio varies from 8: 1 to 12: 1, i.e. for every 8 to 12 parts of carbon, there exists in the soil one part of nitrogen; the average ratio is about 10 to 1. Brown and O'Neal (1923), for example, found that the ratio of the carbon to the nitrogen in a Carrington loam is 12: 1 to 13: 1, while, in the case of a Tama silt loam, the ratio may go down to 10: 1. According to Sievers (1923), the ratio of carbon to nitrogen in the soil is about 11·6: 1. Russell (1923) stated that, although there is about 40 times as much carbon as nitrogen in the original plant residues, the ratio will drop down to 10 to 1, before these residues have been very long in the soil. This ratio seemed to be in a stable position, for which no explanation could be suggested. Fraps (1922) found the ratio of carbon to nitrogen in the surface soil to be 9·2: 1 and in the subsoil 8·3: 1; he suggested, therefore, to judge the percentage of organic carbon in the soil from the percentage of nitrogen present.


1963 ◽  
Vol 14 (2) ◽  
pp. 155 ◽  
Author(s):  
Pont G Dal ◽  
B Newell

Samples of particulate material were collected down to 4500 m at a station in the Tasman Sea. The material was analysed for its carbon and nitrogen content. Determinations of total organic phosphorus were also made on water samples collected at the same depths. Some 400 g of carbon were found under 1 m² of sea surface, and the vertical distribution of particulate carbon, nitrogen, and organic phosphorus was closely related to the hydrological structure.


Author(s):  
D. Davoult ◽  
N. Degros ◽  
M. A. Janquín ◽  
B. Soyez

Relationships between size, wet weight, dry weight, carbon and nitrogen content were determined in Ophiothrix fragilis (Echinodermata: Ophiuroidea). Such relationships appeared very useful when studying dynamic processes such as nutrition, growth, excretion or reproduction, considered as fluxes of carbon and nitrogen in the ecosystem.Relationships between size, wet weight, dry weight, ash free dry weight, carbon and nitrogen content of organisms are of fundamental interest in ecological studies of ecosystems. They allow us to understand and quantify the role of a species as it stores, consumes or produces organic matter during its life cycle. Determination of conversion factors are time-consuming but very useful for estimating flows in the ecosystem (Brey et al., 1988). Some compilations of conversion factors have been published (Båmstedt, 1981; Rumohr et al., 1987).Ophiothrix fragilis (Abildgaard) is the dominant species of the ‘pebbles with sessile epifaunal community’ (Davoult, 1990), located in the Dover Strait (eastern Channel), where tidal currents are very strong. It is considered as an efficient suspension feeder (Roushdy & Hansen, 1960; Warner, 1971) and lives in dense populations (1000–2000 individuals m-2; Davoult, 1989) which are assumed to have a significant effect on the fluxes of organic matter from the pelagic to the benthic system and on the fluxes of ammonium to the water column (Davoult et al., 1991).Individuals were sampled in May and June 1991 off the Cape Gris-Nez (50°55′N 1°35′E). Two-hundred individuals were measured (diameter ±01 mm, after Guille, 1964), dried at 60°C for 48 h, weighed (±0·1 mg), burnt at 520°C for 6 h (Anonymous, 1986), and the ash weighed (±0·1 mg). Total organic carbon and nitrogen content were determined with a CHN element analyser (Carlo Erba 1106): after a flash combustion in a helium stream temporarily enriched with pure oxygen, quantitative combustion was achieved by passing gases over Cr2O3 after a transfer through a reduction reactor to eliminate the excess of oxygen; components were separated in a chromato-graphic column, eluted, then measured by a thermal conductivity detector. Thirty-eight dried ophiuroids were ground with a micro-grinder, then two sub-samples (except for individuals <2 mm) were weighed at ±1 μg (76 measurements).


Alloy Digest ◽  
2018 ◽  
Vol 67 (1) ◽  

Abstract UGI 4116N is a martensitic stainless steel with high carbon and nitrogen for hardness and corrosion resistance. This datasheet provides information on composition, physical properties, hardness, and elasticity as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-1275. Producer or source: Schmolz + Bickenbach USA Inc..


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