The rhizosphere of an aquatic plant (Lemna minor)

1969 ◽  
Vol 15 (8) ◽  
pp. 964-966 ◽  
Author(s):  
R. A. Coler ◽  
H. B. Gunner
Keyword(s):  
Population Density ◽  
Carrying Capacity ◽  
Aquatic Plant ◽  
Lemna Minor ◽  
Fold Increase ◽  
Inert Surfaces

Dominant epiphytes colonizing the surface of Lemna minor were identified and enumerated. The distribution of these organisms compared to populations on inert surfaces at depths 0, [Formula: see text], 1, 2, 4 and 8 in. revealed greater than a 100-fold increase in population density. This enhanced carrying capacity of the plant diminished with depth.

scholarly journals Understanding drivers of wild oyster population persistence

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mickael Teixeira Alves ◽  
Nick G. H. Taylor ◽  
Hannah J. Tidbury
Keyword(s):  
Population Density ◽  
Carrying Capacity ◽  
Pacific Oyster ◽  
Wild Population ◽  
Population Persistence ◽  
Oyster Reefs ◽  
Oyster Population ◽  
Northern European ◽  
Age Structured ◽  
The Impact

AbstractPersistence of wild Pacific oyster, Magallana gigas, also known as Crassostrea gigas, has been increasingly reported across Northern European waters in recent years. While reproduction is inhibited by cold waters, recent warm summer temperature has increased the frequency of spawning events. Although correlation between the increasing abundance of Pacific oyster reefs in Northern European waters and climate change is documented, persistence of wild populations may also be influenced by external recruitment from farmed populations and other wild oyster populations, as well as on competition for resources with aquaculture sites. Our understanding of the combined impact of the spawning frequency, external recruitment, and competition on wild population persistence is limited. This study applied an age-structured model, based on ordinary differential equations, to describe an oyster population under discrete temperature-related dynamics. The impact of more frequent spawning events, external recruitment, and changes in carrying capacity on Pacific oyster density were simulated and compared under theoretical scenarios and two case studies in Southern England. Results indicate that long term persistence of wild oyster populations towards carrying capacity requires a high frequency of spawning events but that in the absence of spawning, external recruitment from farmed populations and other wild oyster populations may act to prevent extinction and increase population density. However, external recruitment sources may be in competition with the wild population so that external recruitment is associated with a reduction in wild population density. The implications of model results are discussed in the context of wild oyster population management.

scholarly journals Optimum Carrying Capacity for Bison in Theodore Roosevelt National Park

1982 ◽  
Vol 6 ◽  
pp. 95-97
Author(s):  
Clayton Marlow ◽  
Lynn Irby ◽  
Jack Norland
Keyword(s):  
Population Density ◽  
Carrying Capacity ◽  
Food Habits ◽  
National Park ◽  
Theodore Roosevelt ◽  
Secondary Use ◽  
Range Condition ◽  
Theodore Roosevelt National Park ◽  
Management Priorities ◽  
Capacity Estimates

This project was designed to determine the optimum population size for bison in the Theodore Roosevelt National Park (TRNP) by fulfilling the following objectives: 1. Delineate primary and secondary bison ranges; 2. Determine forage productivity for major range sites within primary and secondary use areas; 3. Determine the general seasonal food habits of bison in TRNP; 4. Determine range condition under present population density of bison and the maximum carrying capacity of primary use areas; and 5. Integrate range condition and carrying capacity estimates with management priorities for bison on the TRNP.

Iron oxide nanoparticle phytotoxicity to the aquatic plant Lemna minor: effect on reactive oxygen species (ROS) production and chlorophyll a/chlorophyll b ratio

2019 ◽  
Vol 26 (23) ◽  
pp. 24121-24131 ◽  
Author(s):  
Lilian Rodrigues Rosa Souza ◽  
Luís Eduardo Bernardes ◽  
Maike Felipe Santos Barbetta ◽  
Márcia Andreia Mesquita Silva da Veiga
Keyword(s):  
Reactive Oxygen Species ◽  
Iron Oxide ◽  
Aquatic Plant ◽  
Lemna Minor ◽  
Iron Oxide Nanoparticle ◽  
Minor Effect ◽  
Ros Production ◽  
Oxygen Species ◽  
Chlorophyll B ◽  
Oxide Nanoparticle

scholarly journals Evaluating the Toxic Impacts of Cadmium Selenide Nanoparticles on the Aquatic Plant Lemna minor

Molecules ◽  
2019 ◽  
Vol 24 (3) ◽  
pp. 410 ◽  
Author(s):  
Roshanak Tarrahi ◽  
Ali Movafeghi ◽  
Alireza Khataee ◽  
Farkhondeh Rezanejad ◽  
Gholamreza Gohari
Keyword(s):  
Reactive Oxygen Species ◽  
Cadmium Selenide ◽  
Aquatic Plant ◽  
Lemna Minor ◽  
Ionic Form ◽  
Morphological Parameters ◽  
Oxygen Species ◽  
Defense System ◽  
Simple Method ◽  
Cadmium Selenide Nanoparticles

Cadmium selenide nanoparticles (CdSe NPs) were synthesized by an easy and simple method and their properties were assessed by XRD, TEM and SEM techniques. The effects of CdSe NPs as well as Cd2+ ions on Lemna minor plants were investigated. The absorption of CdSe NPs by the plants had some adverse consequences that were assessed by a range of biological analyses. The results revealed that both CdSe NPs and the ionic form of cadmium noticeably caused toxicity in L. minor. Morphological parameters as well as peroxidase (POD) activity were deteriorated. In contrast, the activities of some other antioxidant enzymes (superoxide dismutase (SOD) and catalase (CAT)) as well as the contents of total phenol and flavonoids went up. Taken all together, it could be implied that CdSe NPs as well as Cd2+ were highly toxic to plants and stimulated the plant defense system in order to scavenge produced reactive oxygen species (ROS).

scholarly journals EFEKTIVITAS KOMBINASI MIKROORGANISME DAN TUMBUHAN AIR Lemna minor SEBAGAI BIOREMEDIATOR DALAM MEREDUKSI SENYAWA AMONIAK, NITRIT, DAN NITRAT PADA LIMBAH PENCUCIAN IKAN

2016 ◽  
Vol 5 (3) ◽  
pp. 80-90
Author(s):  
Alfian Dony Saputra ◽  
Haeruddin Haeruddin ◽  
Niniek Widyorini
Keyword(s):  
Waste Water ◽  
Aquatic Plant ◽  
Lemna Minor ◽  
Outer Part ◽  
Biological Method ◽  
Fish Processing ◽  
Processing Industry ◽  
Effectiveness Analysis ◽  
Main Variable ◽  
Negative Effect

ABSTRAK Limbah pencucian ikan bersumber dari kegiatan pencucian bagian luar dan dalam tubuh ikan. Limbah pencucian ikan memiliki kandungan senyawa amoniak, nitrit, dan nitrat yang tinggi sehingga kemungkinan mempunyai efek negatif bagi lingkungan. Sebagian besar industri pengolahan ikan belum melakukan pengolahan limbah cairnya dengan baik. Bioremediasi merupakan metode biologi dengan memanfaatkan mikroorganisme dan tumbuhan air Lemna minor dalam pengolahan air limbah. Penelitian ini bertujuan untuk mengetahui efektivitas dan pengaruhdari kombinasi mikroorganisme dan Lemna minor dalam mereduksi senyawa amoniak, nitrit, dan nitrat pada limbah pencucian ikan. Metode penelitian yang digunakan adalah eksperimen skala laboratorium dimana wadah percobaan berisi limbah pencucian ikan dengan volume 1 Liter. Desain penelitian yang digunakan yaitu percobaan faktorial 3 x 3 dengan 2 faktor, sehingga terdapat 9 kombinasi perlakuan M1L10, M1L50, M1L100, M5L10, M5L50, M5L100, M10L10, M10L50, dan M10L100, dimana “M” faktor konsentrasi mikroorganisme (1 mL/L, 5 mL/L, 10 mL/L), sedangkan “L” faktor bobot biomassaLemna minor (0,0255 gr/cm2, 0,1273 gr/cm2 , 0,2546 gr/cm2). Variabel utama penelitian adalah amoniak, nitrit, dan nitrat yang didukung oleh temperatur, pH, dan oksigen terlarut. Analisis data dengan menggunakan analisis efektivitas, uji two way Anova, dan uji Beda Nyata Jujur. Hasil penelitian menunjukkan bahwa nilai efektivitas berkisar antara 40,85% - 74,03% (amoniak), 42,21% - 74,10% (nitrit), dan 3,19% - 34,65% (nitrat). Pengaruh interaksi kombinasi mikroorganisme dan Lemna minor yaitu terdapat pengaruh yang nyata dan efektif dalam mereduksi senyawa amoniak, nitrit, dan nitrat pada limbah pencucian ikan. Kata Kunci: Amoniak; Bioremediasi; Lemna minor; Limbah Pencucian Ikan; Mikroorganisme; Nitrat; Nitrit ABSTRACT Fish washery waste derived from washing inner and outer part of fish body.Fish washery waste containshigh ammonia, nitrite, and nitrate which may have negative effect for the environment.Most of the fish processing industry are not doing the processing of waste water properly yet. Bioremediation is a biological method by using microorganisms and aquatic plant Lemna minor in wastewater treatment. The aims of study is to determine the effectiveness anda effect of the use of microorganism and Lemna minor combination in effort to reduce ammonia, nitrite, and nitrate compound in fish washery waste. The method used is laboratory-scale experiments where the experimental containers containing fish washery waste with a volume of 1 Liter. 3 x 3 factorial with 2 factor method design were used, so there are nine treatment combinations of M1L10, M1L50, M1L100, M5L10, M5L50, M5L100, M10L10, M10L50, and M10L100, where "M" forconcentrationof microorganisms factor (1 mL/L, 5mL/L, 10 mL/L), while the "L" for biomass weight of Lemna minorfactor (0,0255 gr/cm2, 0,1273 gr/cm2 , 0,2546 gr/cm2). The main variable of this study are ammonia, nitrite, and nitrate supported by temperature, pH, and Dissolved Oxygen. The data was analyzed using effectiveness analysis, two way Anova, and Least Signifficant Difference methode. The results show that the concentration of ammonia, nitrite, and nitrate decreased after 96 hours for all treatmentscombination. The effectiveness value, ranged between 40.85% - 74.03% (ammonia), 42.21% - 74.10% (nitrite), and 3.19% - 34.65% (nitrate). There is a signifficant influence and effective in combination of microorganisms and Lemna minor to reduce ammonia, nitrite, and nitrate compound in fish washery waste. Keywords: Ammonia; Bioremediation; Lemna minor; Fish Washery Waste; Microorganism; Nitrate;Nitrite

scholarly journals Intriguing density dependence but problematic birth rates in Greaver et al.’s study of a black-rhinoceros population

2016 ◽  
Author(s):  
Peter R Law ◽  
Wayne L. Linklater ◽  
Jay V. Gedir
Keyword(s):  
Population Density ◽  
Density Dependence ◽  
Carrying Capacity ◽  
Population Management ◽  
Demographic Parameters ◽  
Birth Rates ◽  
Black Rhinoceros ◽  
African Black ◽  
Birth Data ◽  
Important Evidence

AbstractGreaver et al. (2014) presented evidence for density dependence in the Ithala population of black rhinoceros. Finding that they did not place their regression-based evidence in a modelling context, we recast their result as an example of the ramp model of density dependence that underlies black rhinoceros meta-population management. Greaver et al. concluded that the Ithala population did not reach carrying capacity, a conclusion we consider unwarranted since they did not conduct any analyses of trends in demographic parameters with population density. Our interpretation implies that the Ithala population did indeed reach carrying capacity. Where relevant, we compared their results for the Ithala population with those for another southern African black-rhinoceros population in order to provide a broader basis for evaluating black rhinoceros demography. We detail inconsistent presentation of data in their paper that plagued our efforts to understand their results and also draw attention to possible errors in some analyses. In particular, we argue that the results on birth rates reported by Greaver et al. appear dubious. Greaver et al. have presented important evidence for density dependence in a population of black rhinoceros but we suggest they have underutilized their data in interpreting this density dependence while misanalysing birth data.

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