Freshwater fisheries are central to food security in China and this remains one of the most important priorities for the growing human population. Thus, combining ecosystem restoration with economics is pivotal in setting successful conservation in China. Here, we have developed a practical management model that combines fishery improvement with conservation. For six years, a ban on fertilizer ...

Longitudinal gradients in streamwater nutrient concentrations in Walker Branch are generated as a result of instream nutrient uptake and spatially confined groundwater inputs during the period from November to May. The response of the stream periphyton community to these longitudinal nutrient reductions was determined by measuring periphyton biomass, productivity, species composition, and phosp...

The Llanquihue lake is included in the called Araucanian or Nord Patagonian lakes located between 38-41° S. These lakes are characterized by their oligo-mesotrophic status due to human intervention which takes to the increase in nutrients inputs from industries and towns. Effects on zooplankton assemblages are observed with marked increase of daphnids abundance. The aim of the present study is ...

It is well-known that nutrients shape phytoplankton communities in marine systems, but in coastal waters allochthonous dissolved organic matter (ADOM) may also be of central importance. We studied how humic substances (proxy of ADOM) and other variables influenced the nutritional strategies, size structure and pigment content of the phytoplankton community along a south-north gradient in the Ba...

Nutrient pollution and associated eutrophication of freshwaters threaten the ecological integrity and the services provided to humans by lakes. We examined how human residential development influenced the level of lake eutrophication in the Seattle, WA, USA, region. We surveyed 30 lakes and measured 3 indicators of eutrophication: concentrations of chlorophyll-a and phosphorus, and the proporti...

The main reasons for the fixation of some elements and consequently nutrient deficiencies, especially phosphorus, iron and zinc, are high levels of calcium (calcareous soils) and soil pH. Two sulfur fertilizers (sulfur alone and sulfur + organic material + Thiobacillus spp.) with two rates (2 and 4 kg sulfur/tree) were used to decrease soil pH and availability of P, Fe and Zn in apple trees dur...

Four nutrient enrichment bioassay experiments were conducted in Sycamore Creek, Arizona, during summer and autumn 1983. In two experiments, nitrogen and phosphorus were added alone and in combination while in the other experiments nitrogen was added singly. In experiments involving enrichment of both nutrient-diffusing substrates (clay flowerpots) and streamwater overlying tileigravel artificia...

The biological variables consist of a single population each of phytoplankton and grazers, which are denominated in phosphorus units (mmol m23) in the constant (Redfield) ratio model (CRM) and are given the symbols Pp and Pz. In the variable ratio model (VRM), there are separate state variables for phytoplankton carbon (Cp), nitrogen (Np), phosphorus (Pp), and chlorophyll (M). Grazer biomass is...

Changes in the concentrations of selected trophic state parameters in Lake Griffi n were examined over a 22-year period. Parameters included chlorophyll-a, total nitrogen and total phosphorus. Additional information was obtained for phytoplankton composition and nutrient limitation status of phytoplankton growth over a shorter period of time, from 2000 to 2002. The central goal of the study was...