scholarly journals Factors governing phytoplankton community in the Can Gio mangrove biosphere reserve, Vietnam

2019 ◽  
Vol 19 (1) ◽  
pp. 67-78
Author(s):  
Thanh-Luu Pham
Keyword(s):  
Biosphere Reserve ◽  
Environmental Parameters ◽  
Temporal Variations ◽  
Wet Season ◽  
Physico Chemical ◽  
Phytoplankton Communities ◽  
Significant Difference ◽  
Can Gio Mangrove ◽  
Set Up ◽  
Chemical Water

This paper covers spatial and temporal variations in phytoplankton communities and physico-chemical water properties in the Can Gio Mangrove Biosphere Reserve (CGMBR), Vietnam based on field measurement conducted in dry and wet seasons of 2010. Phytoplankton samples and water parameter data were collected from nine stations in the CGMBR. A total of 86 species were recorded with clear dominance of Bacillariophyceae, which formed above 90% of the total phytoplankton abundance with average of 48,000 cell/l in dry season and 35,000 cell/l in wet season. Although Chaetoceros and Coscinodiscus were the two most diverse genera, Skeletonema showed high abundance during the studied period. Among the ten environmental parameters tested in this study, salinity, turbidity, nitrate, ammonium and silicon dioxide were found to be significantly different between seasons. On the other hand, no significant difference was found between stations for the studied physico-chemical parameters. Results of CCA indicated that the phytoplankton assemblage in CGMBR was influenced by salinity, turbidity, nitrate, ammonium and phosphate concentration. This is the first study simultaneously investigating the phytoplankton communities and their environment in this area and it is essential to set up the baseline of future studies.

scholarly journals Microbial population dynamics during traditional production of Mabisi, a spontaneous fermented milk product from Zambia: a field trial

2020 ◽  
Vol 36 (12) ◽  
Author(s):  
Anneloes E. Groenenboom ◽  
John Shindano ◽  
Nachimuka Cheepa ◽  
Eddy J. Smid ◽  
Sijmen E. Schoustra
Keyword(s):  
Fermented Milk ◽  
Shannon Index ◽  
Lag Phase ◽  
Milk Product ◽  
Physico Chemical ◽  
Significant Difference ◽  
Set Up ◽  
Rural Zambia ◽  
Fermented Milk Product ◽  
Over Time

AbstractMabisi is a fermented milk product, traditionally produced in a calabash by uncontrolled fermentation. Due to high costs and a reduced availability of calabashes, nowadays plastic containers are also used for Mabisi production. However, the effect of this change in production practice on the properties of the product has not been documented. Therefore, we aimed at determining the effect of fermentation vessels and types of back-slopping on acidification and microbial communities during fermentation. A series of fifteen experiments using two types of fermentation vessels (plastic buckets and calabashes) in combination with different types of back-slopping (no back-slopping, passive back-slopping, and active back-slopping) were set up at a field site in rural Zambia. In each of the fifteen fermentations we analysed acidification rate of traditional Mabisi fermentation and bacterial diversity over time. No significant difference was found in terms of microbial diversity during and at the end of fermentation between fermentations performed in buckets or previously used calabashes. Bacterial communities in general decreased in diversity over time, where the drop in pH correlated with a decrease in Shannon Index. In case of active back-slopping, the pH drop started right after inoculation while in the no back-slopping and passive back-slopping fermentations, there was a clear lag phase before acidification started. All experimental series resulted in a microbial community dominated by Lactococcus lactis and a Shannon Index, as a measure for diversity, between 0.6 and 2.0. The use of plastic buckets for Mabisi fermentation can be a valuable alternative to the use of calabashes as this study showed no biological and physico-chemical differences between Mabisi resulting from both fermentation vessels, although the reason for perceived differences should be further investigated.

Seasonal changes in the abundance of benthic macroinvertebrates & physico-chemical condition of Moussa Stream Bida, Nigeria

2020 ◽  
Vol 29 (1) ◽  
pp. 57-70
Author(s):  
Y.M. Mohammed ◽  
F.O. Arimoro ◽  
A.V. Ayanwale ◽  
B.S. Adama ◽  
U.N. Keke ◽  
...  
Keyword(s):  
Flow Velocity ◽  
Benthic Macroinvertebrates ◽  
Seasonal Changes ◽  
Anthropogenic Activities ◽  
Oxygen Demand ◽  
Chemical Condition ◽  
Wet Season ◽  
Physico Chemical ◽  
Significant Difference ◽  
Number Of Individuals

Seasonal changes in the abundance of benthic macroinvertebrates and physico-chemical condition of Moussa Stream, Bida Nigeria, were studied monthly from January to August 2017. Macroinvertebrates were sampled using modified kick sampling techniques. Three different sampling stations were selected along the course of the Stream. The results from the stream showed that water temperature (24.9-27.50C), Depth  (14.7-45.8cm), Flow velocity (0.14-0.23m/s), Biochemical oxygen demand (2.0-7.0mg/L), pH (6.33-8.6), Conductivity (20-63μ/cm), Alkalinity  (8-30mg/L), Turbidity (61-285NTU), Nitrate (0.87-3.85mg/L) and Phosphate (0.31-1.01mg/L) were within the maximum permissible limit (WHO, SON) except Dissolved oxygen (3.1-10mg/L). Most of the parameters investigated with the exception of depth and flow velocity showed no significant difference (p>0.05) among all the sampling stations. Temperature, depth and flow velocity showed no significant differences with season. pH, DO, BOD5, Turbidity, Conductivity, Alkalinity, Nitrate, and Phosphate were significantly higher during wet season. A total of 471 individuals from 30 species and 20 families of invertebrates were recorded. The overall macroinvertebrates recorded from station 1, 2 and 3 were 166(35.24%), 149(31.63%) and 156(33.12%). Overall, there was significant difference (P<0.05) in number of individuals among the sampling stations. The abundance according to the Orders revealed that Coleopterans, Odonata and Hemipterans were the most common groups encountered. Ephemeroptera Diptera, Mollusca and Oligochaeta were sparingly found in all stations. The percentage and total number of individuals of macroinvertebrates recorded during the study period shows 67.09% (316 individuals) in dry season and the remaining 32.90% (155 individuals) were recorded in rainy season. CCA result correlated positively between species abundances and measured environmental variables. Low density of pollution sensitive macro invertebrates groups and the deteriorating water quality were implications of pollution stress caused by anthropogenic activities. Key words: seasonal changes, macroinvertebrates, stream, Bida.

scholarly journals Productivity of winter rye in organic vs. Conventional cropping system

2010 ◽  
Vol 55 (2) ◽  
pp. 123-129 ◽  
Author(s):  
Snezana Oljaca ◽  
Zeljko Dolijanovic ◽  
Djordje Glamoclija ◽  
Snezana Djordjevic ◽  
Jasmina Oljaca
Keyword(s):  
Cropping System ◽  
Special Kind ◽  
Winter Rye ◽  
Wet Season ◽  
Mean Values ◽  
Growing Period ◽  
Hilly Region ◽  
Significant Difference ◽  
Cropping Seasons ◽  
Set Up

Rye is a cereal which is very much demanded at the market, for making a special kind of bread, but it is little grown in Serbia. The aim of this paper is to investigate possibilities of organic growing of winter rye, comparing with the conventional one, in agroecological conditions of Valjevo hilly region during 2008/2009 and 2009/2010 cropping seasons. The trial was set up in a village of Kotesica, on soil which had not been used for agriculture for 7 years. In organic cropping system three combinations of microbiological fertiliser baktofil with zeolite and hydrogel were used prior to sowing. Half of each plot was treated with foliar microbiological fertiliser Slavol during crop growing period. In conventional cropping system three variants with mineral fertilisers were included: NPK, NPK+zeolite, NPK+hydrogel. Results of the yield obtained in the experiment showed a significant difference between two seasons, 2008/2009 and 2009/2010. In comparison with the control, the treatments in an organic cropping system resulted with statistically insignificant differences for mean values in both years, while the mean in conventional cropping system has significantly higher yield of winter rye. Organic cropping system under conditions of Valjevo hilly region did not give significantly lower rye yield compared with the conventional one in a moderate growing season such was 2008/2009. The combination of soil microbiological fertiliser (Baktofil) with foliar fertiliser (Slavol) and zeolite gave the highest winter rye grain yield in all other treatments in the second year of investigation. In a very wet season (2009/2010) mineral fertiliser NPK showed an advantage, especially in combinations with zeolite, and this treatment can be recommended.

scholarly journals Nutrient and Phytoplankton Dynamics along the Ocean Road Sewage Discharge Channel, Dar es Salaam, Tanzania

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Mariam I. Hamisi ◽  
Florence A. Mamboya
Keyword(s):  
Phytoplankton Biomass ◽  
Environmental Parameters ◽  
Water Clarity ◽  
Temporal Variations ◽  
Dar Es Salaam ◽  
Northeast Monsoon ◽  
Sewage Discharge ◽  
Dissolved Inorganic Nutrients ◽  
Significant Difference ◽  
Nitrite Nitrate

Ocean Road shoreline is situated close to Dar es Salaam largest fish market and is subjected to sewage discharge. In this study, temporal and spatial variations of physicochemical parameters and phytoplankton were studied in five stations along the Ocean Road Coast. Phytoplankton composition, temperature, dissolved oxygen (DO), salinity, water clarity, pH, and dissolved inorganic nutrients (DIN) including nitrite, nitrate, and phosphate were measured. Results revealed that DIN were significantly higher in the station close to the discharge point than other stations (P<0.0001). There were no significant temporal variations in DIN except nitrate that was significantly higher during Northeast Monsoon than Southeast Monsoon (P<0.001). Other environmental parameters showed no significant differences except clarity, conductivity, and DO. Occurrence of potential harmful species such as Trichodesmium, Microcystis, and Pseudo-nitzschia was observed. The phytoplankton biomass (chlorophyll a) ranged from 3.2 to 56.5 mg m−3 and 18 to 113 mg m−3 for Mjimwema (MJ) and Ocean Road (OR) stations, respectively. There was significant difference (P=0.0033) in chlorophyll a among the stations being higher in OR II. The phytoplankton biomass was positively correlated with nutrient concentration in all stations except OR I. This study suggests an alarming level of DIN at OR that may alter phytoplankton biomass, abundance, and composition.

Size structure and pigment composition of phytoplankton communities in different hydrographic zones in Hong Kong's coastal seas

2015 ◽  
Vol 95 (5) ◽  
pp. 885-896 ◽  
Author(s):  
Chi Hung Tang ◽  
Chong Kim Wong ◽  
Alle An Ying Lie ◽  
Ying Kit Yung
Keyword(s):  
High Performance ◽  
Size Structure ◽  
Principal Component ◽  
Environmental Parameters ◽  
Temporal Variations ◽  
High Concentration ◽  
Estuarine Zone ◽  
Phytoplankton Communities ◽  
Temporal And Spatial ◽  
Deep Bay

The abundance and community composition of phytoplankton are influenced by a suite of interacting environmental factors. Hong Kong's marine environment features a hydrographic gradient from an estuarine zone in the west to a transition zone in the middle and an oceanic zone in the east. Size fractionation combined with high performance liquid chromatography (HPLC) pigment analyses were used to investigate the phytoplankton communities in different hydrographic zones during summer (July–August 2009) and winter (December 2009–January 2010). Clear temporal and spatial variations in environmental parameters occurred among hydrographic zones. Results of principal component analysis (PCA) revealed that the major deviating factors among hydrographic zones were turbidity and salinity in summer and nitrate and phosphate in winter. Phytoplankton abundance showed significant temporal variations, but no zonal variations. Phytoplankton communities in all hydrographic zones were dominated by cells >5 µm in both summer and winter. Chlorophyll a concentrations for most size fractions correlated significantly with temperature. The high concentration of fucoxanthin indicated that the phytoplankton community was dominated by diatoms in both summer and winter, while dinoflagellates, cryptophytes, cyanobacteria and other minor groups occurred sporadically in low abundance. The spatial pattern of phytoplankton in Hong Kong's coastal seas did not reflect the hydrographic zonation, but the phytoplankton in the semi-enclosed Tolo Harbour and Deep Bay were different from those in the other zones.

scholarly journals Temporal variations in abundance and species richness of phytoplankton with emphasis on diatoms in the subtidal waters of Umm Al-Namil Island, north-western Arabian Gulf of the ROPME Sea Area

2020 ◽  
Vol 41 (6) ◽  
pp. 1470-1485
Author(s):  
Matrah Al-Mutairi ◽  
◽  
M.N.V. Subrahmanyam ◽  
Mohammad Ali ◽  
Sasini Isath ◽  
...  
Keyword(s):  
Species Richness ◽  
Intertidal Zone ◽  
Species Abundance ◽  
Negative Relationship ◽  
Subtidal Zone ◽  
Phytoplankton Species ◽  
Kuwait Bay ◽  
Physico Chemical ◽  
Phytoplankton Communities ◽  
Significant Difference

Aim: The present study aimed to understand the physico-chemical factors affecting the abundance and species richness of phytoplankton communities, with emphasis on diatoms at the end of the intertidal zone and start of subtidal zone. Methodology: Water quality and phytoplankton community species richness and abundance were measured in the subtidal waters of Umm Al-Namil Island, Kuwait Bay. Kruskal-Wallis statistical approach was used to measure the effect of various environmental parameters on abundance and species richness as well as abundance-species richness relationships using R statistical software. Results: The physico-chemical parameters showed variations at each sampling event as well as within the same season. Total phytoplankton mean abundance values in summer (22.26 ± 0.66 ind. 5l-1) and winter (21.63 ± 0.52 ind. 5l-1) did not significantly vary and the lowest mean abundance was observed during spring (26.36 ± 0.33 ind. 5l-1). Species abundance showed clear pattern with the events, resulting in somehow a negative relationship. Mean species richness was highest during autumn (24.59 ± 1.51), while no significant difference was observed between spring (11.09 ± 0.33), winter (10.47 ± 0.51) and summer (10.11 ± 0.66). The results indicate that phytoplankton species richness and species abundance in Umm Al-Namil Island varied temporally in response to fluctuations in environmental conditions. Interpretation: The end of intertidal zone and beginning of subtidal zone is affluent in diverse forms of phytoplankton species, specifically diatoms since Kuwait Bay is a eutrophic area mainly due to sewage and urbanization. Therefore, a temporal monitoring is required in order to observe any changes in either physico-chemical or biological factors with time and that will help in future conservation and restoration programs. Conservation approaches should be considered seriously since some diatoms like Melosira moniliformis, Gyrosigma diminutum, Fragilaria martyi, Hemidiscus cuneiformis, Planktoniella sol and Amphiprora plicata have been observed only at one event despite abundance and season.

Physico-chemical water properties and flora diversity under the old mining load influence (Rudnansky creek, Slovakia)

2015 ◽  
Vol 10 (2) ◽  
pp. 123-131
Author(s):  
Lenka Angelovičová ◽  
Zuzana Boguská ◽  
Danica Fazekašová
Keyword(s):  
Water Properties ◽  
Physico Chemical ◽  
Flora Diversity ◽  
Chemical Water

Aerosol generation through pars plana vitrectomy

2020 ◽  
pp. bjophthalmol-2020-317214
Author(s):  
Hasan Naveed ◽  
Fong May Chew ◽  
Hanbin Lee ◽  
Edward Hughes ◽  
Mayank A Nanavaty
Keyword(s):  
Pars Plana Vitrectomy ◽  
Ex Vivo ◽  
Dynamic Changes ◽  
Aerosol Generation ◽  
Significant Difference ◽  
Optical Particle Counter ◽  
Pars Plana ◽  
23 Gauge ◽  
Set Up ◽  
Ex Vivo Study

PurposeTo assess whether pars plana vitrectomy (PPV) is an aerosol-generating procedure (AGP) in an ex vivo experimental model.MethodsIn this ex vivo study on 10 porcine eyes, optical particle counter was used to measure particles ≤10 μm using cumulative mode in the six in-built channels: 0.3 μm, 0.5 μm, 1 μm, 2.5 μm, 5 μm and 10 μm aerosols during PPV. Two parts of the study were as follows: (1) to assess the pre-experimental baseline aerosol count in the theatre environment where there are dynamic changes in temperature and humidity and (2) to measure aerosol generation with 23-gauge and 25-gauge set-up. For each porcine eye, five measurements were taken for each consecutive step in the experiment including pre-PPV, during PPV, fluid–air exchange (FAX) and venting using a flute with 23-gauge set-up and a chimney with 25-gauge set-up. Therefore, a total of 200 measurements were recorded.ResultsWith 23-gauge and 25-gauge PPV, there was no significant difference in aerosol generation in all six channels comparing pre-PPV versus PPV or pre-PPV versus FAX. Venting using flute with 23-gauge PPV showed significant reduction of aerosol ≤1 μm. Air venting using chimney with 25-gauge set-up showed no significant difference in aerosol of ≤1 μm. For cumulative aerosol counts of all particles measuring ≤5 μm, compared with pre-PPV, PPV or FAX, flute venting in 23-gauge set-up showed significant reduction unlike the same comparison for chimney venting in 25-gauge set-up.ConclusionPPV and its associate steps do not generate aerosols ≤10 μm with 23-gauge and 25-gauge set-ups.

scholarly journals Responses of Bat Communities (Mammalia: Chiroptera) to Forest Loss and Habitat Conversion in Southern Cameroon

2021 ◽  
Vol 14 ◽  
pp. 194008292110103
Author(s):  
Patrick Jules Atagana ◽  
Eric Moïse Bakwo Fils ◽  
Sevilor Kekeunou
Keyword(s):  
Secondary Forest ◽  
Biosphere Reserve ◽  
Abundant Species ◽  
Primary Forest ◽  
Habitat Types ◽  
Habitat Transformation ◽  
Significant Difference ◽  
Southern Cameroon ◽  
Habitat Conversion ◽  
Species Specific

We aimed to assess how bats are affected by habitat transformation by comparing bat assemblages in four habitat types: primary forest, secondary forest, cocoa plantations and human habitations in the Dja Biosphere Reserve of southern Cameroon. Bats were sampled in the four habitat types using mist nets. During 126 nights, a total of 413 bats were captured, belonging to four families, 16 genera and 24 species. Ninety three individuals (17 species) were captured in the primary forest, followed by plantations (105 individuals, 14 species), human habitations (159 individuals, 10 species), and secondary forest (55 individuals, eight species). Megaloglossus woermanni was recorded in all the four habitats, and was the most abundant species (105 individuals). The analysis of bat assemblage between habitat types showed a statistically significant difference in species composition. The distribution of the six most abundant species ( Epomops franqueti, Megaloglossus woermanni, Rousettus aegyptiacus, Dohyrina cyclops, Hipposideros cf. caffer and Hipposideros cf. ruber) was influenced by habitat types. Our results suggest that the decrease in species richness observed in disturbed habitats may be due to habitat perturbations of primary forest habitats. Therefore, it is important to examine the effects of habitat conversion at species level, as responses are often species-specific.

scholarly journals Implementation of a deep learning model for automated classification of Aedes aegypti (Linnaeus) and Aedes albopictus (Skuse) in real time

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Song-Quan Ong ◽  
Hamdan Ahmad ◽  
Gomesh Nair ◽  
Pradeep Isawasan ◽  
Abdul Hafiz Ab Majid
Keyword(s):  
Deep Learning ◽  
Aedes Aegypti ◽  
Real Time ◽  
Aedes Albopictus ◽  
Automated Classification ◽  
Expert Performance ◽  
Deep Convolutional Neural Networks ◽  
Significant Difference ◽  
Set Up

AbstractClassification of Aedes aegypti (Linnaeus) and Aedes albopictus (Skuse) by humans remains challenging. We proposed a highly accessible method to develop a deep learning (DL) model and implement the model for mosquito image classification by using hardware that could regulate the development process. In particular, we constructed a dataset with 4120 images of Aedes mosquitoes that were older than 12 days old and had common morphological features that disappeared, and we illustrated how to set up supervised deep convolutional neural networks (DCNNs) with hyperparameter adjustment. The model application was first conducted by deploying the model externally in real time on three different generations of mosquitoes, and the accuracy was compared with human expert performance. Our results showed that both the learning rate and epochs significantly affected the accuracy, and the best-performing hyperparameters achieved an accuracy of more than 98% at classifying mosquitoes, which showed no significant difference from human-level performance. We demonstrated the feasibility of the method to construct a model with the DCNN when deployed externally on mosquitoes in real time.

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