Production of spirulina biomass: Effects of environmental factors and population density

Biomass ◽  
1982 ◽  
Vol 2 (3) ◽  
pp. 175-185 ◽  
Author(s):  
Avigad Vonshak ◽  
Aharon Abeliovich ◽  
Samy Boussiba ◽  
Shoshana Arad ◽  
Amos Richmond
Keyword(s):  
Environmental Factors ◽  
Population Density

Study on the Relationship between Population Density of Noctiluca scintillans and Environmental Factors in the Coastal Waters of Qinhuangdao

2014 ◽  
Vol 1010-1012 ◽  
pp. 635-638
Author(s):  
Yan Juan Xi ◽  
Zhen Liang Zhao ◽  
Chun Long Zhao ◽  
Yan Qin Xi ◽  
Li Yan ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Population Density ◽  
Correlation Analysis ◽  
Dissolved Oxygen ◽  
Linear Correlation ◽  
Coastal Waters ◽  
Ammonia Nitrogen ◽  
Noctiluca Scintillans ◽  
Nitrite Nitrate ◽  
The Relationship

Based on the environmental survey data in off-shore of Qin Huangdao from May to June 2011,correlation analysis was made between population density of Noctiluca scintillans and environmental factors. The results indicates that population density of Noctiluca scintillans does not exist linear correlation with nitrite, nitrate, ammonia, nitrogen, phosphate,dissolved oxygen and PH ,it is positive correlation with temperature and silicate noctiluca and negatively correlation with transparency and salinity.

scholarly journals Effects of environmental factors on Tigriopus fulvus, Fischer 1860, a Mediterranean harpacticoid copepod

2018 ◽  
Vol 91 (1) ◽  
Author(s):  
Guido Bonello ◽  
Cristiano Angelini ◽  
Luigi Pane
Keyword(s):  
Climate Change ◽  
Life Cycle ◽  
Environmental Factors ◽  
Population Density ◽  
Harpacticoid Copepod ◽  
Environmental Parameters ◽  
Chemical Parameters ◽  
Climate Change Effects ◽  
Physical Chemical ◽  
Extinction Event

Tigriopus fulvus (Fischer, 1860) is a benthic harpacticoid copepod of the Mediterranean supralittoral zone. The transitional characteristics of this environment forced this species to develop high resistance to changes of environmental parameters. Nevertheless, Tigriopus fulvus life-cycle is influenced from the splashpools physical-chemical parameters. In this paper, we present the results of a supralittoral monitoring performed in 2014, confirming the influence of some of these environmental parameters on population buildups. Because of recent worldwide climate change effects, a threat might have been posed on this particularly exposed organism, whose population density decreased of a sixfold value in the last 30 years. During the three pools (A, B, C) monitoring, the maximum copepod density recorded was 1456 Ind/l (September 2014, Pool C), alongside first records of extinction event for Tigriopus fulvus.

scholarly journals Enviromental factors as the elements determing the development of floating homes

2021 ◽  
pp. 41-51
Author(s):  
Emilia MISZEWSKA ◽  
Maciej NIEDOSTATKIEWICZ ◽  
Radosław WIŚNIEWSKI
Keyword(s):  
Climate Change ◽  
North America ◽  
Environmental Factors ◽  
Population Density ◽  
Significant Role ◽  
Western Europe ◽  
The State ◽  
Land Prices ◽  
The Impact

The popularity of Floating Homes in Western Europe and North America is noticeable. The interest in these facilities in Poland is also constantly growing. The popularity of Floating Homes is due to climate change, rising land prices and population density in city centers. However, environmental factors play a significant role in their development. The publication presents the results of research on the impact of environmental factors on the development of Floating Homes in Poland. As part of the research, the most important environmental factors were identified and then, using the State of the Surroundings Scenarios (SSS) method, an initial scenario of their development was developed. The most probable scenario was developed, the purpose of which was to identify the most favorable factors - strengths and unfavorable factors - weaknesses responsible for the development opportunities of Floating Homes in Poland. Additionally, a surprise scenario was prepared, which indicated factors that may unexpectedly accelerate the development of Floating Homes in Poland or slow it down.

scholarly journals Environmental and Socioeconomic Factors Associated with West Nile Virus

2018 ◽  
Author(s):  
E Hernandez ◽  
AL Joyce ◽  
R Torres
Keyword(s):  
Public Health ◽  
Logistic Regression ◽  
West Nile Virus ◽  
Environmental Factors ◽  
Population Density ◽  
Median Income ◽  
West Nile ◽  
Factors Associated ◽  
Socioeconomic Variables ◽  
Chi Squared

AbstractEnvironmental and socioeconomic risk factors associated with West Nile Virus cases were investigated in the Northern San Joaquin Valley region of California, a largely rural area. The study included human West Nile Virus (WNV) cases from the years 2011-2015 in the three county area of San Joaquin, Stanislaus and Merced Counties, and examined whether factors were associated with WNV using census tracts as the unit of analysis. Environmental factors included temperature, precipitation, mosquitoes positive for WNV, and habitat. Socioeconomic variables included age, education, housing age, home vacancies, median income, population density, ethnicity, and language spoken. Chi-squared independence tests were used to examine whether each variable was associated with WNV in each county, and then also used for the three counties combined. Logistic regression was used for a three-county combined analysis, to examine which environmental and socioeconomic variables were most likely associated with WNV cases. The chi-squared tests found that the variables associated with WNV varied in each of the three counties. The chi-squared tests for data combined from the three counties found that WNV cases were significantly associated with mosquitoes positive for WNV, urban habitat, higher home vacancies, higher population density, higher education, and ethnicity. Logistic regression analysis revealed that overall, the environmental factors precipitation, mean temperature, and WNV positive mosquitoes were the strongest predictors of WNV cases. Results support efforts of mosquito control districts, which aim for source reduction of mosquito breeding sites. In addition, findings suggest that residents with higher income and education may be more aware of WNV and its symptoms, and more likely to request testing from physicians. Lower income and education residents may not be aware of WNV. Public health education might increase its prevention messages about vector-borne disease in the various languages of the region, which would contribute overall to public health in the region.

scholarly journals Genomic basis of fishing-associated selection varies with population density

2021 ◽  
Vol 118 (51) ◽  
pp. e2020833118
Author(s):  
Amélie Crespel ◽  
Kevin Schneider ◽  
Toby Miller ◽  
Anita Rácz ◽  
Arne Jacobs ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Population Density ◽  
Brain Function ◽  
Natural Populations ◽  
Phenotypic Selection ◽  
Selective Pressures ◽  
Experimental Fish ◽  
Growth Metabolism ◽  
Evolutionary Consequences ◽  
Genomic Basis

Fisheries induce one of the strongest anthropogenic selective pressures on natural populations, but the genetic effects of fishing remain unclear. Crucially, we lack knowledge of how capture-associated selection and its interaction with reductions in population density caused by fishing can potentially shift which genes are under selection. Using experimental fish reared at two densities and repeatedly harvested by simulated trawling, we show consistent phenotypic selection on growth, metabolism, and social behavior regardless of density. However, the specific genes under selection—mainly related to brain function and neurogenesis—varied with the population density. This interaction between direct fishing selection and density could fundamentally alter the genomic responses to harvest. The evolutionary consequences of fishing are therefore likely context dependent, possibly varying as exploited populations decline. These results highlight the need to consider environmental factors when predicting effects of human-induced selection and evolution.

scholarly journals ANALISIS SPASIAL (TOPOGRAFI) TUBERKULOSIS PARU DI KOTA PARIAMAN, BUKITTINGGI, DAN DUMAI TAHUN 2010-2016

2020 ◽  
Vol 18 (3) ◽  
pp. 149-158
Author(s):  
Arinil Haq ◽  
Umar Fahmi Achmadi ◽  
Dewi Susanna
Keyword(s):  
Health Promotion ◽  
Spatial Analysis ◽  
Environmental Factors ◽  
Population Density ◽  
Strong Correlation ◽  
Ecological Study ◽  
District Health Office ◽  
District Health ◽  
Lower Altitude ◽  
Pulmonary Tb

ABSTRACT Tuberculosis (TB) is a disease that has become one of the global concerns. Various factors can increase the incidence of TB and facilitate transmission, one of which is environmental factors. This study aimed to understand the correlation between altitude, population density, and healthy home coverage with the proportion of smear-positive pulmonary TB in Pariaman, Bukittinggi and Dumai in 2010-2016. This study is an ecological study. The data of smear-positive pulmonary TB cases obtained from District Health Office were processed in aggregate at each sub-district in Pariaman, Bukittinggi and Dumai areas. Data were analyzed by correlation test and spatial analysis. The results of this study indicate that there is a strong correlation between altitude with the proportion of smear-positive pulmonary TB in Bukittinggi with direction of the correlation is negative, which mean that the higher the altitude the lower the pulmonary Tb case. It is suggested that area with lower altitude can focus more on promotion and prevention of pulmonary TB through health education or other health promotion measures. Keywords: Spatial analysis, pulmonary TB cases, altitude, population density, healthy home coverage   ABSTRAK Tuberkulosis (TB) adalah penyakit yang menjadi salah satu perhatian global. Berbagai faktor dapat meningkatkan kejadian TB dan mempermudah penularan, salah satunya adalah faktor lingkungan. Penelitian ini merupakan studi ekologis yang bertujuan untuk mengetahui korelasi antara ketinggian wilayah, kepadatan penduduk, dan cakupan rumah sehat dengan proporsi TB paru basil tahan asam (BTA) positif di Kota Pariaman, Bukittinggi, dan Dumai tahun 2010-2016. Data dianalisis dengan uji korelasi dan analisis spasial. Hasil penelitian ini menunjukkan bahwa diantara variabel yang diuji, hanya ketinggian wilayah yang berkorelasi kuat dengan proporsi TB paru BTA positif di Kota Bukittinggi.  Semakin tinggi wilayah maka semakin rendah kasus TB paru BTA positif di Kota Bukittinggi. Disarankan daerah dengan dataran yang lebih rendah dapat lebih fokus untuk melakukan upaya preventif dan promotif TB paru melalui kegiatan penyuluhan dan upaya promosi kesehatan lainnya. Kata kunci:Analisis spasial, angka kejadian TB paru, ketinggian wilayah, kepadatan penduduk, cakupan rumah sehat

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