Use of protein to carbohydrate ratios to analyse for nutrient deficiency in phytoplankton

1986 ◽  
Vol 37 (2) ◽  
pp. 183 ◽  
Author(s):  
GG Ganf ◽  
SJL Stone ◽  
RL Oliver
Keyword(s):  
Growth Rate ◽  
Laboratory Experiments ◽  
Nutrient Deficiency ◽  
Nutrient Status ◽  
Photon Flux ◽  
Diurnal Changes ◽  
Nutrient Additions ◽  
Nitrogen Phosphorus ◽  
Saturated Medium

A series of laboratory experiments was designed to investigate the influence of nitrogen, phosphorus and photon irradiance on the protein to carbohydrate ratio and growth rate of Scenedesmus quadricauda. These parameters responded to nutrient additions and depletions in a predictable manner. As nutrients were added the ratio rose to a maximum of 5, but as nutrients were depleted from the medium the ratio fell to < 1 during long-term experiments. The ratio also showed that diurnal fluctuations in cultures grown under a 12 h light : 12 h dark cycle were similar in magnitude to the long-term changes. The extent of these diurnal changes was dependent upon the nutrient status of the cells. In nutrient-saturated medium the ratio showed maximum change (4.2 to 1.1), but in nutrient-depleted medium the change was small (0.98 to 0.81). In addition to these responses to nutrients, the ratio was also influenced by photon flux. At high photon fluxes the ratio showed a marked diurnal change (0.91 to 4.05), but this change decreased with decreasing photon fluxes. A general relationship existed between growth rate and the protein to carbohydrate ratio for ratios >2. Below this value, however, growth rate was independent of the protein to carbohydrate ratio. Criteria based upon these laboratory experiments were derived to determine the nutrient status of field populations of phytoplankton. Using these criteria, the phytoplankton of Mount Bold Reservoir were shown to pass from a condition indicating nutrient sufficiency in November to a condition that implied varying degrees of nutrient deficiency for the period December to March. This pattern of nutrient sufficiency based upon protein to carbohydrate ratios agreed well with the results of nutrient-enrichment trials. This pattern would not have been discernible by the rigid application of previously determined critical protein to carbohydrate ratios.

Relationship of the ratio of chlorophyll a to chlorophyll b and Douglas-fir seedling nutrient status

1993 ◽  
Vol 23 (8) ◽  
pp. 1655-1662 ◽  
Author(s):  
Grant A. Bracher ◽  
Peter A. Murtha
Keyword(s):  
Chlorophyll A ◽  
Nutrient Deficiency ◽  
Nutrient Status ◽  
Douglas Fir ◽  
Chlorophyll B ◽  
Nutrient Deficiencies ◽  
One Year ◽  
Relationship Of ◽  
Nitrogen Phosphorus ◽  
Nutrient Solutions

One–year-old Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) seedlings were treated with 24 nutrient solutions containing nitrogen, phosphorus, and sulphur levels ranging from 1 to 400 mg/L. After one growing season, newly matured needles were harvested, and foliar samples analyzed for nutrient and chlorophyll concentrations. Several nutrient deficiencies were diagnosed. A consistent and statistically significant relationship between the ratio of chlorophyll a to b and the severity of nutrient deficiency was not found; consequently, it appears ineffectual as an index of nutrient stress.

scholarly journals Effect of N and P fertilisation and aeration on biodegradation of crude oil in aged hydrocarbon contaminated soils

2010 ◽  
Vol 56 (No. 4) ◽  
pp. 149-155 ◽  
Author(s):  
S. Syafruddin ◽  
G. Wieshammer ◽  
M. Puschenreiter ◽  
I. Langer ◽  
M. Wieshammer-Zivkovic ◽  
...  
Keyword(s):  
Crude Oil ◽  
Contaminated Soils ◽  
Laboratory Experiments ◽  
Crude Oil Degradation ◽  
Substrate Induced Respiration ◽  
The Impact ◽  
Nitrogen Phosphorus ◽  
Different Levels ◽  
Limited Oxygen

We conducted two laboratory experiments to examine the effects of fertilisation and agitation (aeration) on crude oil degradation in two soils with differential nutrient (nitrogen, phosphorus) availability. Two soils that had been spiked with crude oil two years before were mixed with nitrogen and/or phosphorus at three different levels and subsequently incubated 28 days (Exp. 1). In experiment 2 we investigated the effect of repeated agitation (manual mixing) on hydrocarbon degradation with and without fertilisation. One of the soils was also freshly spiked to assess the impact of ageing. Heptane-extractable hydrocarbon concentrations were determined in both experiments and substrate-induced respiration in Exp. 2. The generally small changes of hydrocarbon concentrations during 28 days of incubation in Exp. 1 are likely attributed to low bio-accessibility of hydrocarbons as a consequence of long-term ageing. Fertilization of nitrogen, phosphorus or combinations thereof was ineffective in most treatments of Exp. 1, which may be explained by limited oxygen supply due to the high proportions of clay and silt. However, agitation enhanced HC biodegradation in the sandy-loamy soil by about 15% (Exp. 2) compared to non-agitated treatments. In contrast, we observed no effect of agitation in the sandy soil. &nbsp;

scholarly journals LED Illumination Spectrum Manipulation for Increasing the Yield of Sweet Basil (Ocimum basilicum L.)

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 344
Author(s):  
Md Momtazur Rahman ◽  
Mikhail Vasiliev ◽  
Kamal Alameh
Keyword(s):  
Growth Rate ◽  
Fold Increase ◽  
Photosynthetic Photon Flux Density ◽  
Ocimum Basilicum ◽  
Photon Flux ◽  
Photon Flux Density ◽  
White Led ◽  
Experimental Conditions ◽  
Sweet Basil ◽  
Optimal Illumination

Manipulation of the LED illumination spectrum can enhance plant growth rate and development in grow tents. We report on the identification of the illumination spectrum required to significantly enhance the growth rate of sweet basil (Ocimum basilicum L.) plants in grow tent environments by controlling the LED wavebands illuminating the plants. Since the optimal illumination spectrum depends on the plant type, this work focuses on identifying the illumination spectrum that achieves significant basil biomass improvement compared to improvements reported in prior studies. To be able to optimize the illumination spectrum, several steps must be achieved, namely, understanding plant biology, conducting several trial-and-error experiments, iteratively refining experimental conditions, and undertaking accurate statistical analyses. In this study, basil plants are grown in three grow tents with three LED illumination treatments, namely, only white LED illumination (denoted W*), the combination of red (R) and blue (B) LED illumination (denoted BR*) (relative red (R) and blue (B) intensities are 84% and 16%, respectively) and a combination of red (R), blue (B) and far-red (F) LED illumination (denoted BRF*) (relative red (R), blue (B) and far-red (F) intensities are 79%, 11%, and 10%, respectively). The photosynthetic photon flux density (PPFD) was set at 155 µmol m−2 s−1 for all illumination treatments, and the photoperiod was 20 h per day. Experimental results show that a combination of blue (B), red (R), and far-red (F) LED illumination leads to a one-fold increase in the yield of a sweet basil plant in comparison with only white LED illumination (W*). On the other hand, the use of blue (B) and red (R) LED illumination results in a half-fold increase in plant yield. Understanding the effects of LED illumination spectrum on the growth of plant sweet basil plants through basic horticulture research enables farmers to significantly improve their production yield, thus food security and profitability.

ON THE CONSUMPTION/DISTRIBUTION THEOREM UNDER THE LONG-RUN GROWTH CRITERION SUBJECT TO A DRAWDOWN CONSTRAINT

2010 ◽  
Vol 13 (06) ◽  
pp. 931-957 ◽  
Author(s):  
MICHAEL J. KLASS ◽  
KRZYSZTOF NOWICKI
Keyword(s):  
Growth Rate ◽  
Short Term ◽  
Long Run ◽  
Time Period ◽  
Total Capital ◽  
Growth Criterion ◽  
Drawdown Constraint ◽  
Riskless Asset ◽  
Distribution Theorem

Consider any discrete time sequence of investment fortunes Fn which has a finite long-run growth rate [Formula: see text] when subject to the present value capital drawdown constraint Fne-rn ≥ λ* max 0≤k≤nFke-rk, where 0 ≤ λ* < 1, in the presence of a riskless asset affording a return of er dollars per time period per dollar invested. We show that money can be withdrawn for consumption from the invested capital without either reducing the long-run growth rate of such capital or violating the drawdown constraint for our capital sequence, while simultaneously increasing the amount of capital withdrawn for consumption at the identical long-term rate of V(r, λ*). We extend this result to an exponentially increasing number of consumption categories and discuss how additional yearly contributions can temporarily augment the total capital under management. In addition, we assess the short-term practicality of creating such an endowment/consumption/distribution program.

The Effects of Reduced Salinity on the Shell Growth of Small Mytilus Edulis

1984 ◽  
Vol 64 (1) ◽  
pp. 171-182 ◽  
Author(s):  
Patricia C. Almada-Villela
Keyword(s):  
Growth Rate ◽  
Mytilus Edulis ◽  
High Salinity ◽  
Shell Growth ◽  
Experimental Period ◽  
Gradual Decline ◽  
Poor Growth ◽  
Term Response ◽  
Better Than

The shell growth of small coastal Mytilus edulis L. was measured at three different constant low salinities over short periods of time. Growth was significantly depressed in 6·4 and 16‰ S but not in 22·4‰ S. Fluctuating salinities between 0 and 32‰ S depressed growth whether the fluctuations were of sinusoidal or abrupt form. After 1 week of preconditioning to constant 32‰ S the growth of coastal (Bangor) mussels was better than estuarine (Conwy) mussels. However, after two weeks’ preconditioning to 32‰ S the estuarine mussels displayed the best growth. In the fluctuating regime, both coastal and estuarine mussels exhibited poor growth rates. The long-term response of the shell growth of coastal M. edulis was followed over a period of 44 days. Salinities in the range 1·8–9·6‰ S were lethal to the mussels within 10 days. In 12·8 and 16‰ S growth was initially delayed but recovered eventually. There was a gradual decline in the growth rate of the mussels exposed to the higher salinities (19·2–32‰) and an improvement in the growth of the mussels living in lower salinities (12·8 and 16‰) to levels nearly matching that of the high salinity animals by day 37. This suggests that acclimation of the shell growth of M. edulis to salinities in the 12·8–28·8‰ S range was achieved by the mussels during the experimental period.

Walleye (Stizostedion vitreum vitreum) and Yellow Perch (Perca flavescens) Populations and Fisheries of the Red Lakes, Minnesota, 1930–75

1977 ◽  
Vol 34 (10) ◽  
pp. 1774-1783 ◽  
Author(s):  
Lloyd L. Smith Jr.
Keyword(s):  
Growth Rate ◽  
Yellow Perch ◽  
Climatic Factors ◽  
Perca Flavescens ◽  
Growing Season ◽  
Commercial Fishery ◽  
Class Strength ◽  
Parent Stock ◽  
Catch Statistics

In an investigation of the commercial fishery of Red Lakes, Minnesota, for the 46-yr period 1930–75, catch statistics were analyzed, and the dynamics of the perch and walleye populations were examined. Mean annual yields of walleye for two statistical periods, 1930–53 and 1954–75, were 309,900 and 245,100 kg, respectively for walleyes, and 96,400 and 109,500 kg for perch. Annual abundance (CPE based on average catches per day per 5-net units of gill nets) varied from 3.8 to 64.6 kg for walleye, and from 2.5 to 34.4 kg for perch. Causes of fluctuations in harvestable stock were directly related to strength of year-classes and to growth rate during the season of capture. Year-class strength was not related to the abundance of parent stock or of potential predators. The respective strengths of year-classes of perch and walleye in the same year were positively correlated (r = 0.859, P < 0.01), and are directly related to climatic factors. Growth rate of walleye in different calendar years varied from +30.7 to −42.2% of mean growth, and that of perch from +13.4 to −8.6% (1941–56). Growing season began in mid-June and was almost over by September 1. Walleye yield could be enhanced by starting harvest July 1 instead of early June. Perch yield could be improved by harvesting small perch. Key words: Percidae, Perca, population dynamics, Stizostedion, long-term yield

EFFECTS OF NITROGEN, PHOSPHORUS, POTASSIUM, AND MANURE FACTORIALLY APPLIED TO POTATOES IN A LONG-TERM STUDY

1973 ◽  
Vol 53 (2) ◽  
pp. 205-211 ◽  
Author(s):  
W. N. BLACK ◽  
R. P. WHITE
Keyword(s):  
Solanum Tuberosum L ◽  
Starch Content ◽  
Leaf Tissue ◽  
Soil Test ◽  
Term Study ◽  
Long Term Study ◽  
Soil Test P ◽  
Yield Responses ◽  
Nitrogen Phosphorus

The effects of N, P, K, and manure factorially applied to potato (Solanum tuberosum L.) yields, starch content, and soil and tissue nutrient levels were evaluated on continuous plots over 12 yr in a 4-yr potato, grain, hay, hay rotation. Although yield responses were observed with N, P, and K applications, manure application substantially increased yields above yield levels due to applied N, P, and K. Increasing rates of KCl strongly depressed tuber starch contents. Soil test P and K levels increased with repeated fertility applications, and leaf tissue levels were increased with N, P, and K treatments.

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