Understanding the relationship between land use and surface water quality is necessary for effective water management. We estimated the impacts of catchment-wide land use on water quality during the dry and rainy seasons in the Dongjiang River basin, using remote sensing, geographic information systems and multivariate statistical techniques. The results showed that the 83 sites can be divided ...

Ammonia volatilisation has generally been reported as, or assumed to be, the main nitrogen removal mechanism in waste stabilisation ponds (WSP). Nitrogen removal via ammonia volatilisation is based on two observations: (a) in-pond pH values can reach high values (>9, even >10), so increasing the proportion of the total ammonia present as the un-ionized form or free ammonia (NH(3)); and (b) in-p...

Lava caves are an understudied ecosystem in the subterranean world, particularly in regard to nitrogen cycling. The diversity of ammonia oxidation (amoA) and nitrogen fixation (nifH) genes in bacterial mats collected from lava cave walls on the island of Terceira (Azores, Portugal) was investigated using denaturing gradient gel electrophoresis (DGGE). A total of 55 samples were collected from 1...

1. In focal and diffuse necroses of the liver due to haemotoxic sera there occurs an increased elimination of total nitrogen with a corresponding augmented output of urea. The ammonia excretion becomes slightly diminished at first, but later rises somewhat above normal. The undetermined nitrogen is markedly increased. 2. In diffuse degeneration with no necrosis on the other hand only a slightly...

Deposition of nitrogen forms one of the largest threats to the vitality and biodiversity of Dutch nature areas. Of the two nitrogen compounds contributing to the total nitrogen deposition, Dutch sources of reduced nitrogen are estimated to contribute 47% to the total nitrogen deposition, whereas for oxidised nitrogen this is only 15%. For Dutch policy, it is therefore most effective to decrease...

Most birds are uricotelic. An exception to this rule may be nectar-feeding birds, which excrete significant amounts of ammonia under certain conditions. Although ammonia is toxic, because it is highly water soluble its excretion may be facilitated in animals that ingest and excrete large amounts of water. Bird-pollinated plants secrete carbohydrate- and water-rich floral nectars that contain ex...

rumen is a persistent and specific ecosystem consists of bacteria, protozoa and fungus where feed fermentation takes place in it. produced hydrogen in rumen can be used in the synthesis of the volatile fatty acids and the microbial protein and its excess would be eliminated through the production of methane by methanogenesis. nutritionists have tried to find ways to decrease loss and energy and...

In previous work with the chlorate method (1, 2) for determining nitrogen in plant tissues, materials were used in which the amounts of ammonia and amide nitrogen were either absent or negligible in relation to the total nitrogen present. In working with samples containling significant amounts of ammonia compounds or amide nitrogen, it is necessary to accomiipany the determination with a Nessle...

The rate of protein synthesis in the whole body was measured in one fed subject with seven 15N-labelled amino acids (intravenous and oral doses) and two 15N protein mixtures (oral doses only). The rates were determined individually from the urinary excretion of ammonia and total urea over a 12 h experimental period. Except with oral glycine and alanine, the synthesis rates given by ammonia and ...

A submerged biofilter (SBF) with 0.1 m of filter medium was maintained without backwash at four different water temperatures (14°C, 18°C, 22°C and 26°C) in four different recirculating systems stocked with green tiger shrimp (Penaeus semisulcatus). The ammonia removal profile and nitrification performance of the SBF was evaluated at feed loading rates of 2.65 g day at 14°C, 5.52 g day at 18°C, ...