GROWTH RATE RELATIONSHIPS TO PHYSIOLOGICAL INDICES OF NUTRIENT STATUS IN MARINE DIATOMS

2001 ◽  
Vol 37 (2) ◽  
pp. 249-256 ◽  
Author(s):  
Darren R. Clark
Keyword(s):  
Growth Rate ◽  
Nutrient Status ◽  
Marine Diatoms ◽  
Physiological Indices

The effect of cell size on cellular Zn and Cd and Zn‐Cd‐CO 2 colimitation of growth rate in marine diatoms

2020 ◽  
Vol 65 (12) ◽  
pp. 2896-2911
Author(s):  
Weiying Li ◽  
William G. Sunda ◽  
Wenfang Lin ◽  
Haizheng Hong ◽  
Dalin Shi
Keyword(s):  
Growth Rate ◽  
Cell Size ◽  
Marine Diatoms

Investigation of a nutrient-growth model using a continuous culture of natural phytoplankton

1978 ◽  
Vol 58 (4) ◽  
pp. 923-941 ◽  
Author(s):  
K. J. Jones ◽  
P. Tett ◽  
A. C. Wallis ◽  
B. J. B. Wood
Keyword(s):  
Growth Rate ◽  
Continuous Culture ◽  
Algal Growth ◽  
Nutrient Status ◽  
Inorganic Phosphorus ◽  
Particulate Phosphorus ◽  
Particulate Carbon ◽  
Particulate Nitrogen ◽  
Rate Of Increase ◽  
Dominance Pattern

Phytoplankton from Loch Creran, Argyll was maintained in continuous culture for 41 days. During most of this time the mixture of species retained the diversity and dominance pattern typical of summer phytoplankton in the loch, notwithstanding the manipulation of algal nutrient status to bring about phosphorus control of growth. Results suggest that most detritus was washed out early in the experiment.The aim of the experiment was to test the applicability to natural multispecies phytoplankton of part of Droop's (1974, 1975) model of nutrient-limited algal growth. ‘Quasi-steady states’ with respect to concentration of chlorophyll, particulate carbon (PC), particulate phosphorus (PP) and particulate nitrogen (PN), wereobserved at two levels of input of dissolved inorganic phosphorus. At other times the algal phosphorus quota (estimated from the ratio of PP to PC) varied from about 0·002 to 0·015 atoms P per atom C. Specific growth rate was estimated from the rate of increase of PC. During part of the experiment, growth rate was linearly related to reciprocal phosphorus quota, thus confirming the applicability of the model.

scholarly journals Physiological indices and driving performance of drivers at tunnel entrances and exits: A simulated driving study

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0243931
Author(s):  
Jinliang Xu ◽  
Xiaodong Zhang ◽  
Huan Liu ◽  
Kaige Yang ◽  
Fangchen Ma ◽  
...  
Keyword(s):  
Heart Rate ◽  
Growth Rate ◽  
Pupil Diameter ◽  
Driving Performance ◽  
Simulation Software ◽  
Motion Platform ◽  
Tunnel Length ◽  
Simulated Driving ◽  
Physiological Indices ◽  
Tunnel Entrance

The entrance and exit sections of a tunnel are the accident black-spots in an expressway. For a safe operation of road tunnels, it is necessary to understand a driver’s physiological indices and driving performance when driving through tunnels. In this study, the UC-Win/Road simulation software was used to build 12 tunnel models of different lengths. A simulated driving experiment was carried out in a 6-DoF motion platform. The lateral position of vehicles characterizing the driving performance was measured using the motion platform. Electrocardiogram and eye movement data of 25 recruited drivers were collected simultaneously through the experiment. The spatial changes in a driver’s heart rate (HR) growth rate, RMSSD, pupil diameter growth rate and vehicle lateral deviation within 300 m before and after the tunnel entrance and exit were analyzed to determine the variation rules in the different tunnels. The study identified the length range in the tunnel entrance and exit sections that influences the drivers. A quantitative analysis was further carried out to analyze the relationship between the physiological indices and the driving performance indicator. The results showed that a driver’s heart rate fluctuates significantly 250 m before the tunnel entrance and 50 m before the exit. In this region, the pupil diameter increases gradually, and drivers tend to shift the vehicle to the left. At the tunnel exit, the HR and RMSSD are affected significantly by the tunnel length, and the variation is higher in longer tunnels. In comparison, the tunnel length has no significant effect on the physiological indicators and driving performance of the drivers at the entrance and exit.

scholarly journals Effects of an iron-light co-limitation on the elemental composition (Si, C, N) of the marine diatoms <I>Thalassiosira oceanica</I> and <I>Ditylum brightwellii</I>

2010 ◽  
Vol 7 (2) ◽  
pp. 657-669 ◽  
Author(s):  
E. Bucciarelli ◽  
P. Pondaven ◽  
G. Sarthou
Keyword(s):  
Growth Rate ◽  
Cell Volume ◽  
Growth Conditions ◽  
Marine Diatoms ◽  
Ditylum Brightwellii ◽  
Interspecific Differences ◽  
Coastal Species ◽  
Global Trend ◽  
C And N ◽  
First Time

Abstract. We examined the effect of iron (Fe) and Fe-light (Fe-L) co-limitation on cellular silica (BSi), carbon (C) and nitrogen (N) in two marine diatoms, the small oceanic diatom Thalassiosira oceanica and the large coastal species Ditylum brightwellii. We showed that C and N per cell tend to decrease with increasing Fe limitation (i.e. decreasing growth rate), both under high light (HL) and low light (LL). We observed an increase (T. oceanica, LL), no change (T. oceanica, HL) and a decrease (D. brightwellii, HL and LL) in BSi per cell with increasing degree of limitation. The comparison with literature data showed that the trend in C and N per cell for other Fe limited diatoms was similar to ours. Interspecific differences in C and N quotas of Fe limited diatoms observed in the literature seem thus to be mostly due to variations in cell volume. On the contrary, there was no global trend in BSi per cell or per cell volume, which suggests that other interspecific differences than Fe-induced variations in cell volume influence the degree of silicification. The relative variations in C:N, Si:C and Si:N versus the relative variation in specific growth rate (i.e. μ:μmax) followed the same patterns for T. oceanica and D. brightwellii, whatever the irradiance level. However, the variations of C:N under Fe limitation reported in the literature for other diatoms are contrasted, which may thus be more related to growth conditions than to interspecific differences. As observed in other studies, Si:C and Si:N ratios increased by more than 2-fold between 100% and 40% of μmax. Under more severe limitation (HL and LL), we observed for the first time a decrease in these ratios. These results may have important biogeochemical implications on the understanding and the modelling of the oceanic biogeochemical cycles, e.g. carbon and silica export.

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.

scholarly journals Nutrient sufficiency levels for haskap (Lonicera caeruleaL.) using the boundary-line approach

2019 ◽  
Vol 99 (2) ◽  
pp. 268-280 ◽  
Author(s):  
Ekene Mark-Anthony Iheshiulo ◽  
Lord Abbey ◽  
Andrew M. Hammermeister
Keyword(s):  
Growth Rate ◽  
Nova Scotia ◽  
Leaf Tissue ◽  
Principal Component ◽  
Leaf Size ◽  
Nutrient Status ◽  
Boundary Line ◽  
Tissue Samples ◽  
Leaf Tissues ◽  
Representative Farms

Adequate supply of plant nutrients is crucial for haskap plant growth and increased productivity. A study was carried out to determine the variability in haskap (Lonicera caerulea L. cv. Indigo Gem) plant characteristics in relation to soil and leaf tissue nutrient status. A total of 19 composite soil samples and corresponding plant leaf tissue samples were collected in 2016 from 12 locations in Nova Scotia. Plant parameters measured include growth rate, leaf size, leaf chlorophyll content, and visual observations. A boundary-line approach was used to determine nutrient sufficiency ranges in leaf tissues of 2.23%–2.96% for N, 0.22%–0.28% for P, 0.84%–1.32% for K, 1.63%–2.10% for Ca, and 0.14%–0.50% for Mg. Principal component and correlation analysis suggested a possible antagonistic interaction between leaf K and Mg. Negative associations were observed most frequently between Ca and Mg and other nutrients, especially K. Plant parameters such as bush volume, leaf size, and growth rate were closely related to soil and leaf K. Deficiencies in leaf tissue K and P were identified as potentially important factors limiting growth. Therefore, there is a need to adjust or balance the application of these nutrients. In conclusion, the sufficiency ranges derived can be used as a guiding principle in diagnosing the nutritional status of haskap cv. Indigo Gem on representative farms in Nova Scotia.

Assessment of Microcystis growth rate potential and nutrient status across a trophic gradient in western Lake Erie

2011 ◽  
Vol 37 (1) ◽  
pp. 92-100 ◽  
Author(s):  
Justin D. Chaffin ◽  
Thomas B. Bridgeman ◽  
Scott A. Heckathorn ◽  
Sasmita Mishra
Keyword(s):  
Growth Rate ◽  
Lake Erie ◽  
Nutrient Status ◽  
Trophic Gradient ◽  
Western Lake ◽  
Western Lake Erie

Influence of Nitrogen Status on the Sensitivity of Glyphosate-Resistant and -Susceptible Tall Waterhemp (Amaranthus tuberculatus) and Palmer Amaranth (Amaranthus palmeri)

Weed Science ◽  
2016 ◽  
Vol 64 (4) ◽  
pp. 735-742 ◽  
Author(s):  
Jonathon R. Kohrt ◽  
Julie M. Young ◽  
Joseph L. Matthews ◽  
Bryan G. Young
Keyword(s):  
Growth Rate ◽  
Crop Production ◽  
Field Experiments ◽  
Nutrient Status ◽  
Palmer Amaranth ◽  
Fertilizer Treatment ◽  
Weed Species ◽  
Corn Production ◽  
Volume Number ◽  
Amaranthus Tuberculatus

Anecdotal observations of improved glyphosate efficacy on glyphosate-resistant (GR) tall waterhemp populations in corn production compared with soybean suggested the presence of nitrogen (N) fertilizer may influence the expression of glyphosate resistance. Greenhouse and field experiments were conducted to determine the influence of soil-applied nitrogen fertilizer on the growth rate and sensitivity of glyphosate-susceptible (GS) and GR tall waterhemp and Palmer amaranth. The addition of supplemental fertilizer increased the relative growth rate (plant height and shoot volume), number of nodes, and percentage of shoot nodes with axillary branches on GS and GR biotypes of both weed species. The axillary bud activity was increased 52 and 8% with increasing N for the GR and GS biotypes of tall waterhemp and Palmer amaranth, respectively. The GS populations of tall waterhemp and Palmer amaranth were more sensitive to glyphosate in the greenhouse under increased fertilizer levels compared with no fertilizer. Additionally, GR tall waterhemp was more sensitive to glyphosate under the higher fertilizer treatments, which resulted in a reduction in the calculated resistance factor (RF) from 27.8 under no fertilizer to 4.7 for the high fertilizer treatment. The RF for GR Palmer amaranth was not influenced by the fertilizer treatments in the greenhouse. Field experiments demonstrated that glyphosate efficacy may be greater on GR populations of tall waterhemp and Palmer amaranth under high N conditions, but these results were not consistent and most likely were influenced by soil moisture in 2012, which was more limiting than N supply. This research implies that soil fertility can influence the sensitivity of some GR weed species to glyphosate and the RF. Therefore, the evolution and management of GR weed species in commercial crop production may be influenced by the nutrient status of the soil and the use of supplemental fertilizers.

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