The effects of variations in nutrient cation levels on the growth and biochemistry of Chlorella were investigated. This study involved concentration-series experiments in which the levels of Mg(2+), K(+), and Ca(2+) varied from deficiency to toxicity levels for growth. The nutrient sufficiency concentrations of Mg(2+) and K(+) were 0.08 and 0.10 meq/1, respectively. Deficiencies of Mg(2+) or K(...

SHEPPARD L.J. 1996. How reproducible are the reactions of stress indicators for Sitka spruce treated with acid mist? Phyton (Horn, Austria) 36 (3): (23) (30). Results of previously published experiments based on open-top chambers and field exposure systems with seedlings, mature grafts and physiologically mature trees (<13m tall) of Sitka spruce exposed to pH 2.5 mist are discussed briefly for ...

A balanced nutrient supply is essential for the healthy growth of plants in hydroponic systems. However, the commonly used electrical conductivity (EC)-based nutrient control for plant cultivation can provide amounts of nutrients that are excessive or inadequate for proper plant growth. In this study, we investigated the kinetics of major and minor nutrient uptake in a nutrient solution during ...

In woodland streams, the decomposition of allochthonous organic matter constitutes a fundamental ecosystem process, where aquatic hyphomycetes play a pivotal role. It is therefore greatly affected by water temperature and nutrient concentrations. The individual effects of these factors on the decomposition of litter have been studied previously. However, in the climate warming scenario predicte...

Elemental concentrations in tree-rings from red and white oak trees at six sites across Southern Ontario, Canada, were assessed to determine whether they passively record changes in geochemical cycling in the presence of environmental stress. Periods of stress were defined as sustained periods with elevated delta(13)C values in tree-rings relative to atmospheric CO(2) during the same period. In...

The effects of nutrients on algal productivity are not transferred directly to production at higher trophic levels and can not be modelled as if they were. Rates of processes and time scales at different trophic levels require a modular approach to a comprehensive model of the Great Lakes. Predator growth is based ultimately on prey availability and life histories of predators. Factors that con...

Many models of phosphorus (P) transfer at the catchment scale rely on input from generic databases including, amongst others, soil and land use maps. Spatially detailed geochemical data sets have the potential to improve the accuracy of the input parameters of catchment-scale nutrient transfer models. Furthermore, they enable the assessment of the utility of available, generic spatial data sets...

An intense subsurface chlorophyll enhancement was found repeatedly within the core of a modewater eddy during a 2-month period. Two controls on chlorophyll concentrations in this deep chlorophyll maximum (DCM) layer are noted: chlorophyll concentration is controlled by nutrients at low nutrient concentrations and by light when nutrients are saturating. To synthesize these results, a simple one-...

It was hypothesized that nutrient removal from waste­ water could be achieved by using methane oxidizing bacteria (melhan­ otrophs). Because methane is inexpensive. it can be used as an energy source to encourage bacterial growth to assimilate nitrogen and phos­ phorus and other trace elements. This initial feasibility study used syn­ thetic nutrient mixtures and secondary sewage effluent as fe...

Plants absorb nutrients needed for plant type, growing season, depending on soil and yield. Absorb of nutrient 30-90 percent depends management practices in the use of fertilizer. Can be used fertilizers in most cases soil and for foliar feeding can be quickly absorbed into the plant at the proper levels of nutrition in cucumber. In this experiment, was used a split plot in a randomized complet...