Influence Of Physicochemical Parameters Research Articles

Visible light responsive heterophase Titania monoliths for the fast and efficient photocatalytic decontamination of organic pollutants

The article reports the synthesis of an ordered mesoporous network of heterophase TiO2 monoliths as a visible light-responsive photocatalyst using tri-block copolymers of Pluronic F108, P123 and F127 as structure-directing agents (SDAs) and temperature-controlled calcination (450–650 °C) has been carried out by direct templating-assisted hydrothermal approach. The structural/surface morphology and topographical properties of the photocatalyst are characterized using FE-SEM-EDAX, HR-TEM-SAED, p-XRD, VB-XPS, PLS, TG/DTA, UV-Vis-DRS, BET/BJH and zeta potential analysis. The undoped heterophase mesoporous TiO2 monoliths with in-built lattice/surface defects exhibit visible light photocatalytic properties, successfully dissipating Reactive Brown 10 (RB-10) dye. The influence of physicochemical parameters, such as SDAs, temperature, pH, dye concentration, catalyst dosage, photosensitizers and light intensities, are optimized for maximum photocatalytic performance at a shorter timespan. The F127-assisted mesoporous TiO2 monolith (550 °C) exhibits superior degradation kinetics (15 min) for RB-10 dye solution (20 ppm) at pH 2.0–3.0 using a photocatalyst dosage of 50 mg and 2 mM of KBrO3, irradiated with 150 W/cm2 tungsten lamp. The photocatalysts are fabricated without complicated chemical modifications and display topmost efficiency in quickly decontaminating persistent pollutants. The photoproducts from RB-10 photocatalytic degradation are investigated using HR-MS analysis. The photocatalyst can be reused efficiently for six cycles, even under extreme conditions.

Assessment of Removal Methylene Blue and Green Dye in Water by Adsorption in Aqueous Solution by the Pan Bottom from a Mining Waste from Betaré-Oya

This work focuses on the study of the adsorption of methylene blue (BM) and a green dye (CV) in aqueous solution by the pan bottom from a mining waste from Betaré-Oya. The aim is to recover mining waste as an adsorbent. The influence of physico-chemical parameters on the kinetics and isotherm of adsorption of these dyes on the pan bottom was determined. The UV/Visible spectroscopy technique was used for the analyses. The green dye was study at spectral wavelength 570 nm. Green. Adsorption equilibrium times are 15 minutes for these dyes. Experiments show that when the bottom mass of the pan increases, the quantities adsorbed decrease. In fact, it is the adsorption yields that increase from 60 to 80% for BM and from 30 to more than 90% for CV. Variations in pH showed greater adsorption of dyes in basic medium (pH ≥ 10) which indicates that the dyes are cationic. It was also observed that the amounts of BM and CV per unit of pan bottom increase with increasing initial concentration. The experimental data was analyzed by isotherm models. The value of the constant n of the Freundlich model for BM is 1.53, indicating that adsorption is unfavorable, whereas in the case of CV, adsorption is moderate. Langmuir and Temkin models better describe MB adsorption. The mechanism of adsorption of BM and CV is of chemical type. Pseudo-first-order, pseudo-second-order, Elovich and intra-particle kinetic models have been applied on data and the most suitable is the pseudo-second-order kinetic model.

Influence of physicochemical parameters on the biodiversity indices of fresh water snails in selected rivers of Osun State, Nigeria

Studies have investigated the influence of environmental factors on distribution of vectors of parasites of public health importance but little is known on the role of these factors on the biodiversity indices of the vectors. This study is therefore set to assess the role of physicochemical parameters on biodiversity indices of fresh water snails. The study was carried out in three randomly selected communities across the three senatorial regions of Osun state namely Ere Ijesha, Ede and Erin-Osun. Through reports from community members, a mostly visited river from each community was selected. Three contact points with evident human water contact were identified for snail and water sampling. Morphological identification of snails was done. Physicochemical parameters of water were measured while snail biodiversity indices were determined using Shannon index, snail richness and abundance. Relationship between continuous variables was determined using Spearman’s correlation. There is a significant difference between pH values of Ere Ijesa and Erin Osun while Ede and Erin Osun also show a significant difference in their chloride concentration. A significant positive correlation was observed between pH and diversity (correlation coefficient (rho)= 0.64, P<0.05), pH and Bulinus abundance (rho= 0.68, P< 0.05), chloride and snail richness (rho= -0.65, P< 0.05), chloride and diversity (rho= -0.88, P< 0.01), BOD and snail richness (rho= -0.78, P < 0.05), BOD and diversity (rho= -0.64, P<0.05) COD and snail richness (rho= -0.61, P< 0.05). Ede had highest diversity index while Ere Ijesa had highest Bulinus abundance. Erin Osun was the least in terms of snail richness, diversity and Bulinus abundance. Snail diversity, snail richness and Bulinus abundance significantly differ across the sampling locations (P< 0.01). Physicochemical parameters such as pH, chloride content, BOD and COD have significant role to play in fresh water snail richness, snail diversity and Bulinus abundance.

Influence of physico-chemical parameters on the settlement of competent larvae of cultured sea urchin, Paracentrotus lividus

Achieving efficient metamorphosis and settlement of larvae is a major bottleneck in the culture of sea urchins; therefore, in order for culture operations to be economically viable, it is urgent to optimize this crucial step under captive conditions. This study aimed to investigate how various parameters, including temperature, salinity, light cycle, and inducer type, affect the settlement of competent P. lividus larvae. Three different salinities (35, 30, 25‰), three temperatures (25, 20, 15 °C), four light conditions (16/8, 12/12, 24/0 and 0/24) and five types of biofilms (three of “natural” origin and the other two from monospecific collection cultures) were tested. The results suggest a relationship between low salinity and decreased survival and settlement rates. Conversely, the photoperiod appears not to have significant influence over survival and settlement rates. It appears that specific temperatures did not affect rates of survival and settlement, rather it was the deviation from initial culture temperature that is responsible for these rates. Finally, the multispecific inoculum of benthic diatoms showed a higher survival and settlement rate and lower mortality rate compared to monospecific inoculum.

Influence of physico-chemical parameters on natural radionuclides in the coastal belt of Kollam district, South west coast of India

Influence of physico-chemical parameters on natural radionuclides in the coastal belt of Kollam district, South west coast of India

Influence of Physicochemical Parameters on Abundance, Distribution and Diversity of Freshwater Snails in Bakolori Reservoir

Influence of Physicochemical Parameters on Abundance, Distribution and Diversity of Freshwater Snails in Bakolori Reservoir

Physical aspects of the fire and explosion hazard of combustible dust. Part 2. Self-wave modes of combustion

In present review, based on the authors' long-term research, generalized ideas about the ignition patterns andmetal dust wave burning are given. The first part discusses patterns of ignition as a result of the action of non-linearthermokinetic type factors (Arrhenius dependence). The second part analyzes the flame propagation patterns in dust caused by the presence of hydrodynamic nonlinearities in the active system, which lead to the existence of laminar, vibrational, and turbulent flames. The influence of physico-chemical parameters (type, dispersion, concentration of fuel) andflame propagation hydrodynamic conditions (reaction pipes of different diameters and lengths, dust clouds with a volume of 10 ÷ 40 m3) on theindicated modes implementation and their characteristics are discussed.
 For laminar flames, the main focus is on the problem of normal flame speed and flame propagation concentration limits. For a vibrating flame (reaction tubes were ignited at the open end of a semi-closed tube), the regularities of cascade transitions are analyzed – laminar flame ↔ vibrational type I ↔ vibrational type II ↔ turbulent flame.

Insights into the influence of physicochemical parameters on the microbial community and volatile compounds during the ultra-long fermentation of compound-flavor Baijiu.

While the variation in physicochemical parameters, microbial communities, metabolism, composition, and the proportion of volatile components in fermented grains (FG) affect final Baijiu quality, their complex interactions during the ultra-long fermentation of compound-flavor Baijiu (CFB) are still poorly understood. In this study, amplicon sequencing was used to analyze the microbial community, and headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) was used to analyze the volatile components in FG during ultra-long fermentation of CFB. The relationships between the dominant microbial communities, physicochemical parameters, and volatile components were analyzed using redundancy analysis and network analysis. During ultra-long fermentation, bacterial diversity was initially higher than during the mid and late stages. Fungal diversity in the mid stages was higher than that initially and later in the process. A total of 88 volatile components, including six alcohols, 43 esters, eight aldehydes and ketones, 13 acids, and 18 other compounds were detected in FG. Starch and reducing sugars in FG strongly affected the composition and function of bacterial and fungal communities. However, acidity had little effect on the composition and function of the bacterial flora. Lactobacillus, Bacillus, Weissella, and Pichia were the core microbial genera involved in metabolizing the volatile components of FG. We provide insights into the relationships and influences among the dominant microbial communities, physicochemical parameters, and volatile components during ultra-long fermentation of CFB. These insights help clarify the fermentation mechanisms of solid-state fermentation Baijiu (SFB) and control and improve the aroma quality of CFB.

Studies on Limnological Parameters and their Impact on the Distribution and Diversity of Zooplankton in Anchar Lake, Kashmir

The transfer of energy from producers to consumers, such as fish, fish larvae, and invertebrates, is facilitated by zooplankton. Consequently, zooplankton play a crucial part in the productivity and functioning of aquatic ecosystems, and they are also involved in the application of several emerging environmental management concepts, such as Environmental Impact Assessment (EIA), bioindication of pollution, and biomonitoring. To analyse the present condition of the Anchar Lake, this research was conducted to investigate the zooplankton association, their abundance, richness, diversity (Cladocera and Rotifera), and their seasonal fluctuations in connection to limnological factors. Four sampling sites were used to examine thirteen physicochemical parameters along with the abundance of zooplankton from January 2019 to December 2020. During the present investigation, significant variation (p < 0.05) was observed in transparency (trans), dissolved oxygen (DO), pH, electrical conductivity (EC), total alkalinity (TA), nitrate-nitrogen (NO3-N), total hardness (TH), and total phosphorus (TP) between the different sites of Anchar Lake, whereas non-significant variation was observed in air temperature (AT), water temperature (WT), free carbon dioxide (FCO2), chloride (Cl-), and nitrite-nitrogen (NO2-N). The results further revealed a total of 44 zooplankton species, belonging to two: Rotifera (27 species) and Cladocera (17 species). The zooplankton diversity was found to vary on spatiotemporal scales showing maximum values for the Shannon diversity index in the case of Cladocera during spring (2.63±0.25) and for Rotifera during summer (2.53±0.25) whereas, minimum diversity values were recorded during winter for both Cladocera and Rotifera (1.54±0.44 & 1.47±0.54 respectively). On the spatial scale, site-A2 showed maximum diversity of Cladocera (2.3±0.21), while site-A4 showed maximum diversity of Rotifera (1.99±0.03). The influence of physicochemical parameters on zooplankton distribution and diversity provides a detailed picture of the impact of pollution load in Anchar Lake.

Examining the applicability of polar organic chemical integrative sampler for long-term monitoring of groundwater contamination caused by currently used pesticides

The possibilities of expanding a groundwater quality monitoring scheme by passive sampling using polar organic chemical integrative sampler (POCIS) comprising HLB sorbent as the receiving phase were explored. Passive sampling and grab sampling were carried out simultaneously in the regions with vulnerable groundwater resources in Slovakia, between 2013 and 2021. For 27 pesticides and degradation products detected both in POCIS and the grab samples, in situ sampling rates were calculated and statistically evaluated. The limited effectiveness of the receiving phase in POCIS for sampling polar or ionized compounds was confirmed through a comparison of the medians of compound-specific sampling rates. For the majority of the monitored compounds the median sampling rates varied between 0.01 and 0.035 L/day. In some cases, the actual in situ values could be confirmed by parallel exposure of POCIS and silicone rubber sheet employed to obtain a benchmark for maximum attainable sampling rate. Sampling site and sampling period appear to have also some influence on the sampling rates, which was attributed in part to the groundwater velocity varying in both space and time. The influence of physico-chemical parameters (temperature, pH, electrolytic conductivity) remains mostly questionable due to the naturally limited ranges of recorded values over the entire duration of the study. Concentrations of pollutants in POCIS could be used for predicting time weighed average concentrations in water, provided the sampling rates were known and relatively constant. Generally, the compound-specific sampling rate cannot be considered constant due to a combination of naturally varying environmental factors that influence the actual in situ sampling rate. The relative standard deviation of concentration data from POCIS exposed in triplicates varied between approx. 5 %–50 %. Utilizing exploratory data analysis approach and tools enabled us to obtain a relatively complex picture of the situation and progress regarding pesticide pollution of groundwater in the monitored areas.

Characterization and spatiotemporal dynamics of the ichthyofauna of two tidal containment zones on the Brazilian Amazon coast

This study aimed to characterize spatiotemporal variations in the ichthyofauna of two tidal containment zones in Maranhão state, Brazil. Monthly, collections were carried out in the containment zones of São Luís and São José de Ribamar, with samplings performed after the peak of the lowest tide (transition between low tide and high tide).Physicochemical parameters such as water salinity, temperature, transparency, and precipitation were measured monthly. A gill net (25-mm mesh) was used to capture fish. A total of 169 ichthyic individuals were captured and identified in the coastal containment areas of São Luís and São José de Ribamar. The orders Perciformes (41%) and Siluriformes (13.6%) were the most representative in terms of number of species. According to analysis of the t-test, there were significant seasonal and spatial variations in the number of organisms (p < 0.05), with the highest catches in rainy and transitional months. It was possible to identify a variation in niches in both study areas, the influence of physicochemical parameters on ichthyofaunal communities of São Luís and São José de Ribamar, and the effects of the containment structures on fish biomass and diversity, mainly in São Luís.

Mechanisms controlling the transport and evaporation of human exhaled respiratory droplets containing the severe acute respiratory syndromecoronavirus: a review.

Transmission of the coronavirus disease 2019 is still ongoing despite mass vaccination, lockdowns, and other drastic measures to control the pandemic. This is due partly to our lack of understanding on the multiphase flow mechanics that control droplet transport and viral transmission dynamics. Various models of droplet evaporation have been reported, yet there is still limited knowledge about the influence of physicochemical parameters on the transport of respiratory droplets carrying the severe acute respiratory syndromecoronavirus 2. Here we review the effects of initial droplet size, environmental conditions, virus mutation, and non-volatile components on droplet evaporation and dispersion, and on virus stability. We present experimental and computational methods to analyze droplet transport, and factors controlling transport and evaporation. Methods include thermal manikins, flow techniques, aerosol-generating techniques, nucleic acid-based assays, antibody-based assays, polymerase chain reaction, loop-mediated isothermal amplification, field-effect transistor-based assay, and discrete and gas-phase modeling. Controlling factors include environmental conditions, turbulence, ventilation, ambient temperature, relative humidity, droplet size distribution, non-volatile components, evaporation and mutation. Current results show that medium-sized droplets, e.g., 50µm, are sensitive to relative humidity. Medium-sized droplets experience delayed evaporation at high relative humidity, and increase airborne lifetime and travel distance. By contrast, at low relative humidity, medium-sized droplets quickly shrink to droplet nuclei and follow the cough jet. Virus inactivation within a few hours generally occurs at temperatures above 40°C, and the presence of viral particles in aerosols impedes droplet evaporation.

Water Quality, Heavy Metals, and Antifungal Susceptibility to Fluconazole of Yeasts from Water Systems.

Aquatic environments could be reservoirs of pathogenic yeasts with acquired antifungal resistance. The susceptibility to antifungal agents of yeasts present in the wastewater and natural waters of the city of Cali was evaluated. Samples were taken from two types of water: drinking water (Meléndez River, drinking water treatment plant "Puerto Mallarino" in the Cauca River) and wastewater (South Channel of the Cauca River, "Cañaveralejo-PTAR" wastewater treatment plant). Physico-chemical parameters, heavy metal concentration, and yeast levels were determined using standard procedures. Yeasts were identified using API 20 C AUX (BioMérieux) and sequence analysis of the ITS1-5.8S-ITS2 and D1/D2 regions of the large subunit of the ribosome. Susceptibility assays against fluconazole and amphotericin B using the minimum inhibitory concentration (MIC) test were determined using the microdilution method. The influence of physico-chemical parameters and heavy metals was established using principal component analysis (PCA). Yeast counts were higher at WWTP "PTAR" and lower at Melendez River, as expected. A total of 14 genera and 21 yeast species was identified, and the genus Candida was present at all locations. Susceptibility tests showed a 32.7% resistance profile to fluconazole in the order DWTP "Puerto Mallarino = WWTP "PTAR" > South Channel "Navarro". There were significant differences (p < 0.05) in the physico-chemical parameters/concentration of heavy metals and yeast levels between the aquatic systems under study. A positive association was observed between yeast levels and total dissolved solids, nitrate levels, and Cr at the "PTAR" WWTP; conductivity, Zn, and Cu in the South Channel; and the presence of Pb in the "Puerto Mallarino" DWTP. Rhodotorula mucilaginosa, Candida albicans, and Candida sp. 1 were influenced by Cr and Cd, and Diutina catelunata was influenced by Fe (p < 0.05). The water systems explored in this study showed different yeast levels and susceptibility profiles, and, therefore, possible genetic differences among populations of the same species, and different physico-chemical and heavy metals concentrations, which were probably modulating the antifungal-resistant yeasts. All these aquatic systems discharge their content into the Cauca River. We highlight the importance to further investigate if these resistant communities continue to other locations in the second largest river of Colombia and to determine the risk posed to humans and animals.

Aerosolization Behaviour of Fungi and Its Potential Health Effects during the Composting of Animal Manure

Compost is an important source of airborne fungi that can adversely affect occupational health. However, the aerosol behavior of fungi and their underlying factors in composting facilities are poorly understood. We collected samples from compost piles and the surrounding air during the composting of animal manure and analyzed the aerosolization behavior of fungi and its potential health effects based on the fungal composition and abundance in two media using high-throughput sequencing and ddPCR. There were differences in fungal diversity and richness between the air and composting piles. Ascomycota and Basidiomycota were the two primary fungal phyla in both media. The dominant fungal genera in composting piles were Aspergillus, Thermomyces, and Alternaria, while the dominant airborne fungal genes were Alternaria, Cladosporium, and Sporobolomyces. Although the communities of total fungal genera and pathogenic/allergenic genera were different in the two media, fungal abundance in composting piles was significantly correlated with abundance in air. According to the analysis on fungal composition, a total of 69.10% of the fungal genera and 91.30% of pathogenic/allergenic genera might escape from composting pile into the air. A total of 77 (26.64%) of the fungal genera and six (20%) of pathogenic/allergenic genera were likely to aerosolize. The influence of physicochemical parameters and heavy metals on the aerosol behavior of fungal genera, including pathogenic/allergenic genera, varied among the fungal genera. These results increase our understanding of fungal escape during composting and highlight the importance of aerosolization behavior for predicting the airborne fungal composition and corresponding human health risks in compost facilities.

Cyanobacterium Raphidiopsis raciborskii and its toxin in Buon Phong reservoir, Dak Lak province, Vietnam

This study investigated the variation of the cyanobacterium Raphidiopsis raciborskii population under the influence of physicochemical parameters from May 2019 to April 2020 in the Buon Phong reservoir. The correlations between these parameters were explored by using Principal Component Analysis (PCA) and Pearson correlation analysis. The cylindrospermopsin (CYN) toxin in isolated strains from the reservoir was confirmed by using High-performance liquid chromatography (HPLC) analyses. R. raciborskii presented throughout the year in the reservoir with a biovolume from 0.12 to 9.14 mm3 L-1. Four R. raciborskii strains (CBP2, CBP3, CBP4, and CBP5) were successfully isolated and confirmed to produce CYN by the HPLC results. The highest concentration in isolated strains was 0.345 μg g-1 DW in the CBP4 strain. The PCR results of genes responsible for CYN biosynthesis showed that the PCR amplicons of cyrB and CyrC were amplified in two toxic strains (CBP2 and CBP3), while the amplicons of both cyrB and cyrC were not observed in two remaining toxic strains. In addition, such abiotic factors as temperature and nutrients played major roles in the abundance of R. raciborskii. Moreover, the biovolume of R. raciborskii positively correlated with the CYN concentrations in the Buon Phong reservoir.

Impact of Physico-Chemical Parameters on distribution and diversity of Euglenophyceae in Saroornagar Lake, Hyderabad

Saroornagar Lake is one of the major fresh water-bodies of Hyderabad. The study deals with the influence of physico-chemical parameters on the distribution and diversity of Euglenophyceae. Samples were collected from four sampling stations for a period of two years and comprehensive physico-chemical analysis was carried out. Linear multiple regression analysis (MRA) has been carried out with SPSS software to evaluate the importance of various physico-chemical variables on the growth and development of Euglenophyceae. The physico-chemical parameters played an important role in distribution and diversity of algae. The growth of Euglenophyceae was positively influenced by sulphates, Free CO2, calcium, total hardness, COD and bicarbonates. Negative influence on euglenoids was exerted by temperature, organic matter, total solids, total dissolved solids, magnesium and chlorides. Euglenoid flagellates exhibited higher peaks in winter and found very low in summer. Diversified species of Euglena, Lipocinclis, Phacus and Trachelomonas were reported. Euglena acus, E. gracillis, E. oxyuris, Lipocinclis ovum and Trachelomonas volvocina represent high organic pollution of the lake and indicate high degree of organic pollution.

Total nitrogen influence bacterial community structure of active layer permafrost across summer and winter seasons in Ny-Ålesund, Svalbard.

The permafrost in the polar regions is vital for maintaining the status quo of the earth's climate by limiting greenhouse gas emissions. The present study aims to investigate the seasonal variations and the influence of physicochemical parameters on the bacterial diversity and community structure of active layer permafrost (AL) around Ny-Ålesund, Svalbard. The AL soil samples were collected from four different geographical locations around Ny-Ålesund during the winter and summer seasons. The 16S rDNA amplicon sequencing was carried out to investigate the diversity and distribution profiles of bacterial communities among the collected AL samples. Physico-chemical parameters including soil pH, moisture content, total carbon (TC), total nitrogen (TN), and trace metals concentrations were measured. Bacterial phyla, Proteobacteria (15.4%-26%) and Chloroflexi (9.6%-22.5%) were predominantly distributed across both seasons. In the winter samples, Verrucomicrobiota (14.12%-23.39%) phylum, consisting of genera Chthoniobacter and Opitutus were highly abundant (Lefse, p < 0.05), whereas in summer bacterial genera belonging to Gemmatimonadota (3.3%-13.74%) and Acidobacteriota (18.02%-28.52%) phyla were highly abundant. The bacterial richness and diversity index were not significantly different between the winter and summer seasons. Principal coordinate analysis (PCoA) has revealed a distinct grouping between two seasons (PERMANOVA, p < 0.05). Bacterial community structure was significantly varied between winter and summer seasons, whereas the physico-chemical variable, TN, influenced the community structure. About 37.8% of the total operational taxonomic units (OTUs) were shared between seasons, whereas 25.4% and 36.8% of OTUs were unique to the summer and winter seasons. The present study revealed that the conditions prevailing during winter and summer has shaped bacterial community structure in AL samples albeit the stable diversity and most of the variation was explained by TN, indicating its critical role in oligotrophic permafrost.

Dry Chemo-Mechanical Pretreatment of Chickpea Straw: Influence of Physicochemical Parameters on the Release of Reducing Sugars by a Fractional Factorial Design Approach

Dry Chemo-Mechanical Pretreatment of Chickpea Straw: Influence of Physicochemical Parameters on the Release of Reducing Sugars by a Fractional Factorial Design Approach

Dry Chemo-Mechanical Pretreatment of Chickpea Straw: Influence of Physicochemical Parameters on the Release of Reducing Sugars by a Fractional Factorial Design Approach

Dry Chemo-Mechanical Pretreatment of Chickpea Straw: Influence of Physicochemical Parameters on the Release of Reducing Sugars by a Fractional Factorial Design Approach

Nutrient ratios driven by vertical stratification regulate phytoplankton community structure in the oligotrophic western Pacific Ocean

Abstract. The stratification of the upper oligotrophic ocean has a direct impact on biogeochemistry by regulating the components of the upper-ocean environment that are critical to biological productivity, such as light availability for photosynthesis and nutrient supply from the deep ocean. We investigated the spatial distribution pattern and diversity of phytoplankton communities in the western Pacific Ocean (WPO) in the autumn of 2016, 2017, and 2018. Our results showed the phytoplankton community structure mainly consisted of cyanobacteria, diatoms, and dinoflagellates, while the abundance of Chrysophyceae was negligible. Phytoplankton abundance was high from the equatorial region to 10∘ N and decreased with increasing latitude in spatial distribution. Phytoplankton also showed a strong variation in the vertical distribution. The potential influences of physicochemical parameters on phytoplankton abundance were analyzed by a structural equation model (SEM) to determine nutrient ratios driven by vertical stratification to regulate phytoplankton community structure in the typical oligotrophic ocean. Regions with strong vertical stratification were more favorable for cyanobacteria, whereas weak vertical stratification was more conducive to diatoms and dinoflagellates. Our study shows that stratification is a major determinant of phytoplankton community structure and highlights that physical processes in the ocean control phytoplankton community structure by driving the balance of chemical elements, providing a database to better predict models of changes in phytoplankton community structure under future ocean scenarios.