Influence of subsidiary energy on growth ofDunaliella viridis Teodoresco: the role of extra energy in algal growth

1994 ◽  
Vol 6 (3) ◽  
pp. 323-330 ◽  
Author(s):  
José Aguilera ◽  
Carlos Jiménez ◽  
J. M. Rodríguez-Maroto ◽  
F. X. Niell
Keyword(s):  
Algal Growth ◽  
Extra Energy ◽  
Subsidiary Energy

scholarly journals Effect of bicarbonate on growth of the oleaginous microalga Botryococcus braunii

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Giovanna Salbitani ◽  
Carmela M.A. Barone ◽  
Simona Carfagna
Keyword(s):  
Inorganic Carbon ◽  
Algal Growth ◽  
Botryococcus Braunii ◽  
Final Concentration ◽  
Time Intervals ◽  
Experimental Conditions ◽  
Co2 Gas ◽  
Inorganic Carbon Source ◽  
Doubling Times

The effect of bicarbonate, produced by the enzymatic hydration of CO2 from postcombustion fumes, was investigated on Botryococcus braunii growth. The NaHCO3, supplied to cultures in the role of inorganic carbon source is proposed as a more eco-sustainable alternative to gaseous CO2. The salt was provided to the cultures at the final concentration of 0.5-1.5-2.5 g L- 1. The growth rate was considered for specific time intervals (T0-T5, T5-T10 and T0- T10) showing values significantly higher in the culture supplemented with 2.5 g L-1 bicarbonate. The doubling times were also considered in all experimental cultures showing a faster doubling for the period T0÷T5. The increase in pH drives the increase in growth in the experimental conditions in which the salt was added. The results suggest that bicarbonate is able to promote the algal growth, therefore it can be considered a valid alternative to CO2 gas.

scholarly journals Feces from Piscivorous and Herbivorous Birds Stimulate Differentially Phytoplankton Growth

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2567 ◽  
Author(s):  
Jolita Petkuviene ◽  
Diana Vaiciute ◽  
Marija Katarzyte ◽  
Iveta Gecaite ◽  
Giorgio Rossato ◽  
...  
Keyword(s):  
Heterotrophic Bacteria ◽  
Algal Growth ◽  
Major Effect ◽  
Phytoplankton Growth ◽  
Curonian Lagoon ◽  
Phosphorus Concentration ◽  
Direct Role ◽  
Algal Groups ◽  
Reactive Phosphorus

Aquatic birds may impact shallow ecosystems via organic and nutrient enrichment with feces. Such input may alleviate nutrient limitation, unbalance their ecological stoichiometry, and stimulate primary production. Herbivorous and piscivorous birds may produce different effects on aquatic ecosystems due to different physiology, diet and feces elemental composition. We analyze the effects of droppings from swans (herbivorous) and cormorants (piscivorous) on phytoplankton growth via a laboratory experiment. These birds are well represented in the Curonian Lagoon, where they form large colonies. As this lagoon displays summer algal hyper-blooms, we hypothesize an active, direct role of birds via defecation on algal growth. Short-term incubations of phytoplankton under low and high feces addition produces different stimulation of algal growth, significantly higher with high inputs of cormorant feces. The latter produces a major effect on reactive phosphorus concentration that augments significantly, as compared to treatments with swan feces, and determines an unbalanced, N-limited stoichiometry along with the duration of the experiment. During the incubation period, the dominant algal groups switch from blue-green to green algae, but such switch is independent of the level of feces input and from their origin. Heterotrophic bacteria also are stimulated by feces addition, but their increase is transient.

scholarly journals Contribution of Internal Nutrients Loading on the Water Quality of a Reservoir

Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1409 ◽  
Author(s):  
Hye Won Lee ◽  
Yong Seok Lee ◽  
Jonggun Kim ◽  
Kyoung Jae Lim ◽  
Jung Hyun Choi
Keyword(s):  
Water Quality ◽  
Sediment Load ◽  
Transport Model ◽  
Three Dimensional ◽  
Algal Growth ◽  
Nutrient Concentrations ◽  
Internal Load ◽  
Phosphorus Flux

Sediment plays an important role in the water quality of a lake by acting as both a nutrient source and sink. The amount of phosphorus and nitrogen in the water depends on the internal load from the sediment as well as the external load. To estimate the effects of sediment load on the water quality of a reservoir, we applied a three-dimensional hydrodynamic and transport model based on the benthic chamber experimental results at Euiam Lake, South Korea. As shown in the sensitivity analysis results, the eutrophication period could be significantly extended by a change of phosphorus flux rates from the sediments. The increased phosphorus flux from the sediments intensifies the algal growth of Euiam Lake, which could cause serious algal bloom during spring and fall. This study provides information on nutrient concentrations in the sediment of Euiam Lake, verifies the role of the sediment as a source or sink of nutrients, and evaluates the effect of sediment release of nutrients and contaminants on water quality. This research is a useful tool in determining the effects of internal load in lakes and establishing the operation guideline for sediment management in order to maintain feasible water quality for beneficial use.

scholarly journals The potential role of sediment organic phosphorus in algal growth in a low nutrient lake

2019 ◽  
Vol 255 ◽  
pp. 113235 ◽  
Author(s):  
Zhaokui Ni ◽  
Shengrui Wang ◽  
Jingjing Cai ◽  
Hong Li ◽  
Alan Jenkins ◽  
...  
Keyword(s):  
Potential Role ◽  
Organic Phosphorus ◽  
Algal Growth

Role of residual biofilm in the recolonization of rocky intermittent streams by benthic algae

2000 ◽  
Vol 51 (7) ◽  
pp. 725 ◽  
Author(s):  
Belinda J. Robson
Keyword(s):  
Algal Growth ◽  
Benthic Algae ◽  
Algal Community ◽  
Transplant Experiment ◽  
Intermittent Streams ◽  
Naturally Occurring ◽  
Eastern Australia ◽  
Algal Biofilm ◽  
Stream Biota

Human use of stream flow for water supply may increase the duration and/or frequency of dry periods in intermittent streams, but there is little information on the effect of this change on in-stream flora or fauna. To predict the effects of dry periods on stream biota, it is necessary to understand the relative roles of various sources of recolonization. A transplant experiment was used to test the hypothesis that the dry residual algal biofilm on stones in intermittent streams is an important source of algal growth when the streams are re-wetted. Two sites were chosen, one on each of two intermittent streams in south-eastern Australia. Rocks at the sites differed in the amount of naturally occurring residual biofilm on them. Forty rocks were transplanted between the sites and counts of algal densities were made from samples taken one and five weeks after flow recommenced. At one of the sites, where the biofilm was dominated by Cyanobacteria, dry residual biofilm strongly influenced the developing algal community at both one and five weeks after flow recommenced. At the other site the influence of dry biofilm was limited after five weeks, implying that other sources of algal recolonization were influential there.

Standing stock variations, growth and CaCO3 production by the calcareous green alga Halimeda opuntia

2016 ◽  
Vol 98 (2) ◽  
pp. 401-409 ◽  
Author(s):  
Pedro Bastos De Macedo Carneiro ◽  
Jamile Ulisses Pereira ◽  
Helena Matthews-Cascon
Keyword(s):  
Standing Stock ◽  
Algal Growth ◽  
Exponential Model ◽  
Carbonate Sediments ◽  
Coverage Area ◽  
South West ◽  
Marine Carbonate ◽  
Specific Biomass ◽  
Average Biomass

The present paper investigates standing stock variations of Halimeda opuntia on a sandstone reef of the South-west Atlantic Ocean, in order to better understand the role of this seaweed as a CaCO3 producer. The study was conducted over two 3-month periods, using photo quadrats to analyse the coverage area, and destructive sampling to quantify area-specific biomass and CaCO3 percentage. The alga occupied 2.4% of the substrate (4464 m2), growing as clumps with an average biomass of 1.59 kg m−2, resulting in a standing stock of 7097.8 kg of alga. This standing stock varied with environmental conditions, particularly wind speed. Assuming an exponential model for these variations, H. opuntia produced at least 13,050.14 kg (54.37 g m−2 day−1) of carbonate sediments. There was a positive correlation between changes in standing stock and coverage, but not with area-specific biomass. This suggests that net algal growth results in the occupation of new spaces, with minimal increases in height or segment density. Therefore monitoring coverage should complement traditional individual-based methods for estimating Halimeda growth and production. Combined, these approaches should result in more accurate models of the role of this alga on marine carbonate budgets.

Barley straw as an inhibitor of algal growth III: the role of fungal decomposition

1992 ◽  
Vol 4 (4) ◽  
pp. 353-355 ◽  
Author(s):  
J. M. Pillinger ◽  
J. A. Cooper ◽  
I. Ridges ◽  
P. R. F. Barrett
Keyword(s):  
Algal Growth ◽  
Barley Straw ◽  
Fungal Decomposition

scholarly journals Examining the relationship between herbivores, corals and macroalgae on Singapore’s heavily disturbed reefs

2016 ◽  
Author(s):  
James R Guest ◽  
Adriana Vergés ◽  
Andrew G Bauman ◽  
Alexandra H Campbell ◽  
Loke Ming Chou ◽  
...  
Keyword(s):  
Anthropogenic Impacts ◽  
Coral Cover ◽  
Benthic Communities ◽  
Critical Role ◽  
Algal Growth ◽  
Phase Shifts ◽  
Human Disturbances ◽  
Species Specific ◽  
The Relationship

Background.Herbivores play a critical role in structuring benthic communities on tropical coral dominated reefs because they remove macro and microalgae, which might otherwise overgrow adult corals or prevent successful recruitment of juveniles. Reducing herbivory has been implicated in promoting phase shifts from coral dominance to other ecosystem states following acute disturbances. Turbidity and sedimentation are key physical processes that also structure coral reef communities because they limit light penetration and may interfere with biological processes such as heterotrophy. Singapore’s coral reefs have been heavily impacted by human activities for decades and experience very high levels of sedimentation and turbidity. Macroalgae, particularly Sargassum spp. are abundant on the reef flats, while adjacent reef slopes are dominated by diverse coral assemblages, yet nothing is known about the role of herbivory in structuring these heavily disturbed reefs. Methods. To gain a better understanding of the role of herbivore biomass and potential herbivory in structuring these disturbed reefs, we quantified benthic cover of corals and macroalgae, fish biomasses and urchin abundance at eight representative sites among Singapore’s southern islands during two seasons. In addition we filmed herbivory assays on replicate experimental macroalgal stands (4 separate macroalgal species) and natural EAM patches at three of these sites to estimate species-specific rates of herbivory. Using generalised linear mixed models we examine the relationship between herbivore abundances and benthic cover of corals and macroalgae. Results. Average coral cover at 3-4 m depth was surprisingly high (~40%) compared to other Indo-Pacific reefs, considering decades of chronic anthropogenic impacts. In contrast, the average biomass of herbivorous fishes (~4 g m-2) was more typical of degraded and overfished reefs, while urchin abundances were within the range found at other Indo-Pacific sites. Herbivorous fish were not observed feeding on macroalgal assays during 29 h of filming, with all bites counted on EAM carried out primarily by territorial damselfish. There was a significant but weak relationship between coral cover and herbivore biomass but none for macroalgae or between urchin abundance and benthic cover. Discussion. Relatively high coral cover and low macroalgal cover at 3-4 m depth has been maintained on these highly disturbed reefs, demonstrating possible resilience to coral-macroalgal phase shifts despite decades of chronic human disturbances. We suggest that low light levels at 3-4 m depth may limit algal growth rates so that only low levels of herbivory are necessary to prevent seaweeds from outcompeting corals on turbid reefs such as those in the present study.

scholarly journals Neuroanatomical Framework of the Metabolic Control of Reproduction

2018 ◽  
Vol 98 (4) ◽  
pp. 2349-2380 ◽  
Author(s):  
Jennifer W. Hill ◽  
Carol F. Elias
Keyword(s):  
Energy Homeostasis ◽  
Protein Biosynthesis ◽  
Pubertal Development ◽  
Metabolic Stress ◽  
Reproductive Function ◽  
Metabolic Dysfunction ◽  
Physiological Processes ◽  
Extra Energy ◽  
The Brain

A minimum amount of energy is required for basic physiological processes, such as protein biosynthesis, thermoregulation, locomotion, cardiovascular function, and digestion. However, for reproductive function and survival of the species, extra energy stores are necessary. Production of sex hormones and gametes, pubertal development, pregnancy, lactation, and parental care all require energy reserves. Thus the physiological systems that control energy homeostasis and reproductive function coevolved in mammals to support both individual health and species subsistence. In this review, we aim to gather scientific knowledge produced by laboratories around the world on the role of the brain in integrating metabolism and reproduction. We describe essential neuronal networks, highlighting key nodes and potential downstream targets. Novel animal models and genetic tools have produced substantial advances, but critical gaps remain. In times of soaring worldwide obesity and metabolic dysfunction, understanding the mechanisms by which metabolic stress alters reproductive physiology has become crucial for human health.

scholarly journals Role of the Plasma Activation Degree on Densification of Organosilicon Films

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 25 ◽  
Author(s):  
Rita C. C. Rangel ◽  
Nilson C. Cruz ◽  
Elidiane C. Rangel
Keyword(s):  
Electrochemical Impedance ◽  
Average Energy ◽  
Film Properties ◽  
Force Microscopy ◽  
Atomic Force ◽  
Plasma Activation ◽  
Extra Energy ◽  
Plasma Species ◽  
Oxidative Species

The possibility of controlling the density of organosilicon films was investigated by tuning the plasma activation degree without providing extra energy to the structure, as usually reported in the literature. For this purpose, thin films were deposited in plasmas fed with hexamethyldisiloxane/Ar mixtures at a total pressure of 9.5 Pa. The power of the radiofrequency excitation signal, P, ranged from 50 to 300 W to alter the average energy of the plasma species while the electrical configuration was chosen to avoid direct ion bombardment of the growing films. In this way, it was possible to evaluate the effect of P on the film properties. Thickness and deposition rate were derived from profilometry data. X-ray energy dispersive and infrared spectroscopies were, respectively, applied to analyze the chemical composition and molecular structure of the layers. Surface topography and roughness were determined by atomic force microscopy while nanoindentation was used to evaluate the mechanical properties of the films. From electrochemical impedance spectroscopy the total resistance to the flow of electrolyte species was derived. The main alteration observed in the structure with changing P is related to the proportion of the methyl functional which remains connected to the Si backbone. Chain crosslinking and film density are affected by this structural modification induced by homogeneous and heterogeneous plasma reactions. The density increase resulted in a film with hardness comparable to that of the silica and more resistant to the permeation of oxidative species, but preserving the organosilicon nature of the structure.

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