High nutrient concentration and temperature alleviated formation of large colonies of Microcystis: Evidence from field investigations and laboratory experiments

2016 ◽  
Vol 101 ◽  
pp. 167-175 ◽  
Author(s):  
Wei Zhu ◽  
Xiaohua Zhou ◽  
Huaimin Chen ◽  
Li Gao ◽  
Man Xiao ◽  
...  
Author(s):  
Richard Mayne ◽  
David Patton ◽  
Ben de Lacy Costello ◽  
Andrew Adamatzky ◽  
Rosemary Camilla Patton

The plasmodium of Physarum polycephalum is a large single cell visible with the naked eye. When inoculated on a substrate with attractants and repellents the plasmodium develops optimal networks of protoplasmic tubes which span sites of attractants (i.e. nutrients) yet avoid domains with a high nutrient concentration. It should therefore be possible to program the plasmodium towards deterministic adaptive transformation of internalised nano- and micro-scale materials. In laboratory experiments with magnetite nanoparticles and glass micro-spheres coated with silver metal the authors demonstrate that the plasmodium of P. polycephalum can propagate the nano-scale objects using a number of distinct mechanisms including endocytosis, transcytosis and dragging. The results of the authors’ experiments could be used in the development of novel techniques targeted towards the growth of metallised biological wires and hybrid nano- and micro-circuits.


1978 ◽  
Vol 58 (2) ◽  
pp. 233-243 ◽  
Author(s):  
E. T. MORAN Jr.

Commercial source, medium-type male poults were either placed in floor pens with food and water within 6 h after hatching or delayed a subsequent 24 h. Starting feed offered in each case was either of a normal (28% crude protein and 2,850 kcal ME/kg) or high (30% and 3,040 kcal) nutrient concentration. During the initial 2 wk, birds that had been fasted gained less weight but had a better feed conversion than those placed early. Poults which received a ration having a high nutrient concentration gained more weight and had a better feed conversion than those offered the normal diet. Mortality at this time was greater with birds subjected to a fast than those placed early. Having access to the higher nutrient concentration ration led to a greater mortaility than if the normal diet was employed. Body weight differences established during the first 2 wk remained throughout the experiment. Feed conversions of rations common to all groups during the subsequent 2- to 6-, 6-to 10- and 10- to 14-wk periods were not influenced by the early treatments after 6 wk of age. Slaughter at 14 wk did not reveal any differences in apparent carcass yield, conformation or finish grade. Degree of fleshing was reduced when poults were subjected to a post-hatch fast and partially improved when the high nutrient starting diet was fed. Effects of fasting and early nutrition on mortality and carcass changes are explained in terms of biochemical events occurring with the neonate.


1986 ◽  
Vol 26 (4) ◽  
pp. 405 ◽  
Author(s):  
AS Pell ◽  
RW Polkinghorne

Hens of 2 laying strains were fed ad libitum from 20 to 72 weeks of age on 3 diets of different nutrient concentration. The start of lay coincided with the onset of the hot summer. During summer, birds on the diet with high nutrient concentration (HNC, 19% protein, 12.6 MJ metabolisable energy (ME)/kg) had significantly higher intakes of ME (3% higher) and other nutrients than did those on the diets of medium (MNC, 18% protein, 11.7 MJ ME/kg) and low (LNC, 16% protein, 11.4 MJ ME/kg) nutrient concentration. Egg weight. egg mass and feed efficiency were greater on the HNC diet than on the MNC and LNC diets. Birds on the HNC diet produced more eggs (10% more) than those on the LNC diet. Over the cooler periods, feed intakes were inversely related to energy level, with no dietary effects on egg production. It is concluded that grain- and meat meal-based diets of low nutrient concentrations are unlikely to support maximum performance in early lay in hot conditions and that increased dietary nutrient concentrations can improve performance via increased nutrient intake.


2016 ◽  
Vol 72 (4) ◽  
pp. 955-964 ◽  
Author(s):  
Reetta Penttinen ◽  
Hanna Kinnula ◽  
Anssi Lipponen ◽  
Jaana K. H. Bamford ◽  
Lotta-Riina Sundberg

HortScience ◽  
1991 ◽  
Vol 26 (10) ◽  
pp. 1299-1300 ◽  
Author(s):  
W.C. Lin ◽  
D.L. Ehret

Long English cucumber (Cucumis sativus L.) plants were treated with one of three nutrient concentrations in combination with two fruit thinning treatments forming a 3 × 2 factorial greenhouse experiment. High nutrient concentration enhanced fruit color at harvest and prolonged shelf life but reduced marketable fruit per plant. Thinning of one-third of the fruit from the main stem and laterals had a similar effect. Cucumbers harvested from the upper canopy generally had longer shelf life than those from the lower canopy. Shelf life was correlated with fruit color at harvest.


1979 ◽  
Vol 36 (8) ◽  
pp. 883-890 ◽  
Author(s):  
Per-Edvin Persson

The study area was a shallow, extremely eutrophic, somewhat brackish water bay on the south coast of Finland. Muddy odor in bream (Abramis brama) was significantly correlated with the amount of the blue-green alga Oscillatoria agardhii occurring in the phytoplankton. Cultures dominated by this alga contained the muddy odor compound geosmin. The high concentrations of O. agardhii in the study area were caused by several interacting factors, of which the high nutrient concentration and the temperature of the water seemed to be especially important. Odoriferous actinomycetes isolated from the water produced the muddy odor compounds geosmin and 2-methylisoborneol, but there seemed to be a lag time of several weeks between maximal concentrations of actinomycetes and development of off-flavors in the fish. Key words: geosmin, 2-methylisoborneol, Oscillatoria agardhii, actinomycetes, flavor, fish, eutrophication


2013 ◽  
Vol 4 (2) ◽  
pp. 77-89 ◽  
Author(s):  
Matthijs Bonte ◽  
Boris M. Van Breukelen ◽  
Pieter J. Stuyfzand

Aquifer thermal energy storage (ATES) uses groundwater to store energy for heating or cooling purposes in the built environment. This paper presents field and laboratory results aiming to elucidate the effects that ATES operation may have on chemical groundwater quality. Field data from an ATES site in the south of the Netherlands show that ATES results in chemical quality perturbations due to homogenisation of the initially present vertical water quality gradient. We tested this hypothesis by numerical modelling of groundwater flow and coupled SO4 transport during extraction and injection of groundwater by the ATES system. The modelling results confirm that extracting groundwater from an aquifer with a natural quality stratification, mixing this water in the ATES system, and subsequent injection in the second ATES well can adequately describe the observation data. This mixing effect masks any potential temperature effects in typical low temperature ATES systems (<25 °C) which was the reason to complement the field investigations with laboratory experiments focusing on temperature effects. The laboratory experiments indicated that temperature effects until 25 °C are limited; most interestingly was an increase in arsenic concentration. At 60 °C, carbonate precipitation, mobilisation of dissolved oxygen concentration, K and Li, and desorption of trace metals like As can occur.


1964 ◽  
Vol 96 (11) ◽  
pp. 1450-1457 ◽  
Author(s):  
J. G. Pilon ◽  
H. A. Tripp ◽  
J. M. McLeod ◽  
S. L. Ilnitzky

AbstractLaboratory experiments at various constant temperatures indicate a theoretical threshold of about 40°F. for spinning of cocoons by eonymphal larvae of Neodiprion swainei Midd. As temperatures fall below 52.5°F. the increase in mortality and time required to spin is pronounced. The optimum temperature is estimated to be around 60°F. Field investigations for three consecutive years show a close correlation between rate of spinning and temperature. Temperature is considered as a prime factor influencing the spinning of cocoons and is possibly one of the more important factors governing the population dynamics of N. swainei in the Province of Quebec.


Zootaxa ◽  
2011 ◽  
Vol 3102 (1) ◽  
pp. 50 ◽  
Author(s):  
JEANCLAUDE VALA ◽  
LOUIS GHÉLUS GBEDJISSI

All studies during the last six decades have stated that sciomyzid larvae are strictly malacophagous. However, the Afrotropical sciomyzid Sepedonella nana species was found in this study to feed only on the small freshwater oligochaete, Aulophorus furcatus. The divergent oligophagous feeding behaviour of this species was investigated. The physical attributes of the egg, first-, secondand third-instar larvae, and the puparium are described. Four types of sensilla—coeloconicum, trichodeum, chaeticum, and styloconicum—are present with a characteristic distribution on each tagma. Each thoracic segment is distinguished by presence of a pair of Keilin’s organ on ventral surface. Each abdominal segment has eleven pairs of the same sensilla types; their variable locations are presented. Population dynamics of the adults are shown from our field investigations in permanent and temporary freshwater biotopes during 1996–2008. The life cycle of the species is presented from our field observations and laboratory experiments. Among the 62 species of Afrotropical Sciomyzidae, this is the eighth species for which life-cycle is entirely resolved.


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