Managing the environmental risk associated with livestock production is a significant challenge. Nitrogen and phosphorus are commonly implicated as the sources of ground and surface water quality problems associated with livestock production. The degree of imbalance between these nutrient inputs and the managed nutrient outputs for a livestock operation defines the magnitude of potential enviro...

Data on nutrient contents of 27 seagrass species at 30 locations were compiled from the literature. Mean (f SE) concentrations of carbon, nitrogen and phosphorus in seagrass leaves were 33.6 2 0.31, 1.92 f 0.05, and 0.23 2 0.011 % dry wt, respectively. The median C:N:P ratio was 474 :24: 1, which represents a C:P ratio more than 4 times, and a N:P ratio more than 1.5 times that of oceanic sesto...

Combinations of phosphorus, nitrogen, and carbon were added to several small lakes in northwestern Ontario, Canada, at rates similar to those in many culturally eutrophied lakes. Phosphate and nitrate caused rapid eutrophication. A similar result was obtained with phosphate, ammonia, and sucrose, but recovery was almost immediate when phosphate additions only were discontinued. When two basins ...

The beneficial uptake of nutrients by wetland plants is countered to some extent by nutrient release back into the aquatic environment due to vegetative die-back. This current study examined whether Leersia oryzoides, a common wetland plant, exhibits luxury uptake of nutrients from simulated farm runoff. The study also tested whether with subsequent decomposition, these nutrients are released b...

1. We have confirmed the results of previous workers on tetrachlorphthalein, fibrinogen, and lipase. 2. The total non-protein nitrogen, urea, and amino-acids of the blood serum show a definite and sometimes marked increase in phosphorus poisoning. These changes are not so evident in chloroform poisoning, although they sometimes occur. They are usually terminal phenomena. 3. The urinary nitrogen...

Anthropogenic activities have severely altered fluxes of nitrogen and phosphorus in ecosystems worldwide. In grasslands, subsequent negative effects are commonly attributed to competitive exclusion of plant species following increased above-ground biomass production. However, some studies have shown that this does not fully account for nutrient enrichment effects, questioning whether lowering c...

Excessive nutrient loads to the Chesapeake Bay cause violations of the new dissolved oxygen water quality standard established to protect the Bay’s living resources. Reducing nitrogen and phosphorus loads is necessary to achieve the dissolved oxygen standard. Based on a set of water quality model runs, we used a response surface method to establish a function of dissolved oxygen (DO) versus tot...

Major sedimentary nutrient cycles Phosphorus cycle Sulphur cycle Major gaseous cycles Nitrogen Cycle Carbon Cycle Ammonification Nitrification Nitrogen fixation Symbiotic nitrogen fixation Non-symbiotic nitrogen fixation Photosynthesis Light reaction Dark reaction Carbon dioxide cycle Micronutrients Plant uptake of trace elements (essential and non-essential) Factors influencing micronutrient u...

In the soil there exist cycles of biological oxidation and reduction for inorganic compounds of sulfur and nitrogen. We have been interested in the possibility that a similar cycle might exist for inorganic compounds of phosphorus. In particular, we have been interested in one step of such a cycle, that of biological oxidation of orthophosphite to orthophosphate. There are few reports in the li...