Background:The cold winter weather in northern China influences the dietary habits of its residents,contributing to a heightened risk of cardiovascular disorders,such as hypertension and coronary heart disease.Key fac...Background:The cold winter weather in northern China influences the dietary habits of its residents,contributing to a heightened risk of cardiovascular disorders,such as hypertension and coronary heart disease.Key factors include low vegetable consumption and high salt and fat intakes.This study aims to investigate the relationships between northern dietary nutrient intake in northern China and cardiovascular disorders during the winter season.Methods:A food frequency questionnaire tailored to the actual eating habits in northern China was designed.Retrospective data from 955 Chinese adults were collected from November to March between 2014 to 2023.Logistic regression was employed to analyze the relationship between dietary nutrients and cardiovascular diseases,with model performance assessed using receiver operating characteristic(ROC)curves.Results:Adjusted for gender,age,and body mass index(BMI),an inverse association was observed between vitamin A(OR=0.706,95%CI:0.550,0.907),nicotinic acid(OR=0.584,95%CI:0.447,0.762),phosphorus(OR=0.777,95%CI:0.608,0.994),selenium(OR=0.719,95%CI:0.560,0.923),zinc(OR=0.683,95%CI:0.531,0.880),methionine(OR=0.730,95%CI:0.569,0.936),arginine(OR=0.753,95%CI:0.588,0.964),lysine(OR=0.706,95%CI:0.550,0.907),aspartic acid(OR=0.730,95%CI:0.569,0.936)and hypertension.Additionally,a negative association was found between niacin(OR=0.752,95%CI:0.597,0.946)and coronary heart disease.Conversely,a positive association was identified between iodine and hypertension(OR=1.305,95%CI:1.020,1.669)and coronary heart disease(OR=1.301,95%CI:1.037,1.634).Conclusion:Our study suggests that maintaining a balanced dietary intake of vitamin A,niacin,phosphorus,selenium,zinc,methionine,arginine,lysine,and aspartic acid can be beneficial in preventing hypertension.Adequate niacin intake is associated with a lower risk of coronary heart disease.However,excessive iodine intake may contribute to hypertension and coronary heart disease.展开更多
The necessity to saline and sodic waters is sometimes used for irrigating agricultural activities under certain circumstances, but it is important to note that the use of these waters comes with specific consideration...The necessity to saline and sodic waters is sometimes used for irrigating agricultural activities under certain circumstances, but it is important to note that the use of these waters comes with specific considerations and limitations. One way to decrease undesirable effects of sodic waters on the physical and chemical properties of soils is to apply organic and chemical amendments within the soil. This study aimed to assess the effectiveness of saline water on soil acidity, alkalinity and nutrients leaching in sandy loamy soil at Bella flower farm, in Rwamagana District, Rwanda. The water used was from the Muhazi Lake which is classified as Class I (Saline water quality). Column leaching experiments using treated soils were then conducted under saturated conditions. The soil under experimental was first analyzed for its textural classification, soil properties and is classified as sandy loamy soil. The t-test was taken at 1%, 5% and 10% levels of statistical significance compared to control soil. The results indicated that the application of saline water to soils caused an increase in some soil nutrients like increase of Phosphorus (P), Potassium (K<sup>+</sup>), Magnesium (Mg2<sup>+</sup>), Sulphur (S), CN ratio and Sodium (Na<sup>+</sup>) and decreased soil texture, physical and chemical properties and remained soil nutrients. Consequently, the intensive addition of saline water leachates to soil in PVC pipes led to decreased of soil EC through leaching and a raiser Soluble Sodium Percentage (SSP). The rate of saline water application affected the increase accumulation of SAR and Na% in the top soil layers. The study indicated that saline water is an inefficient amendment for sandy soil with saline water irrigation. The study recommends further studies with similar topic with saline water irrigation, as it accentuated the alkalinity levels.展开更多
BACKGROUND Dietary methyl donors might influence DNA methylation during carcinogenesis of colorectal cancer(CRC).However,whether the influence of methyl donor intake is modified by polymorphisms in such epigenetic reg...BACKGROUND Dietary methyl donors might influence DNA methylation during carcinogenesis of colorectal cancer(CRC).However,whether the influence of methyl donor intake is modified by polymorphisms in such epigenetic regulators is still unclear.AIM To improve the current understanding of the molecular basis of CRC.METHODS A literature search in the Medline database,Reference Citation Analysis(https://www.referencecitationanalysis.com/),and manual reference screening were performed to identify observational studies published from inception to May 2022.RESULTS A total of fourteen case-control studies and five cohort studies were identified.These studies included information on dietary methyl donors,dietary components that potentially modulate the bioavailability of methyl groups,genetic variants of methyl metabolizing enzymes,and/or markers of CpG island methylator phenotype and/or microsatellite instability,and their possible interactions on CRC risk.CONCLUSION Several studies have suggested interactions between methylenetetrahydrofolate reductase polymorphisms,methyl donor nutrients(such as folate)and alcohol on CRC risk.Moreover,vitamin B6,niacin,and alcohol may affect CRC risk through not only genetic but also epigenetic regulation.Identification of specific mechanisms in these interactions associated with CRC may assist in developing targeted prevention strategies for individuals at the highest risk of developing CRC.展开更多
Subterranean estuaries(STE)are important seawater-groundwater mixing zones with complex biogeochemical processes,which play a vital role in the migration and transformation of dissolved materials.In this study,we firs...Subterranean estuaries(STE)are important seawater-groundwater mixing zones with complex biogeochemical processes,which play a vital role in the migration and transformation of dissolved materials.In this study,we first investigated the spatial distributions of dissolved inorganic nitrogen(DIN),dissolved inorganic phosphorous(DIP),dissolved inorganic silicon(DSi)and metal elements(As,Ba,Cr,Cu,Fe,Mn,Ni,Pb,and Zn)in STE including upper intertidal,seepage face and subtidal zones.We then estimated submarine groundwater discharge(SGD)and associated nutrient and metal element fluxes.From the generalized Darcy’s law method,SGD was estimated to be 30.13 cm/d,which was about 7 times larger than the inflow(4.16 cm/d).The nutrient and metal fluxes from SGD were estimated to be(5.33±4.99)mmol/(m^(2)·d)for DIN,(0.22±0.03)mmol/(m^(2)·d)for DIP,(16.20±2.05)mmol/(m^(2)·d)for DSi,(1325.06±99.10)μmol/(m^(2)·d)for Fe,(143.41±25.13)μmol/(m^(2)·d)for Mn,(304.06±81.07)μmol/(m^(2)·d)for Zn,(140.21±13.33)μmol/(m^(2)·d)for Cu,(84.49±2.94)μmol/(m^(2)·d)for Pb,(37.38±5.51)μmol/(m^(2)·d)for Ba,(27.88±3.89)μmol/(m^(2)·d)for Cr,(10.10±6.33)μmol/(m^(2)·d)for Ni,and(6.25±3.45)μmol/(m^(2)·d)for As.The nutrient and metal fluxes from SGD were relatively higher than those from the inflow,suggesting that nearshore groundwater acted as the sources of nutrients and metal elements discharging into the sea.The environmental potential pollution of coastal seawater was evaluated by pollution factor index(Pi),comprehensive water quality index(CWQI),and ecological risk index(ERI).Pb mainly caused potential danger of nearshore environment with considerable contamination(Pi=5.78±0.19),heavy pollution(CWQI=4.09)and high ecological risk(ERI=18.00).This study contributed to better understanding the behavior of nutrients and metal elements and improving the sustainable management of STE under the pressure of anthropogenic activities and climate change.展开更多
To investigate the role of nutrients intake during pregnancy with longitudinal development of rhinitis,asthma,eczema,wheeze,and food allergy in offspring.The PubMed,Embase,and Cochrane library were searched for articl...To investigate the role of nutrients intake during pregnancy with longitudinal development of rhinitis,asthma,eczema,wheeze,and food allergy in offspring.The PubMed,Embase,and Cochrane library were searched for articles published throughout May 2022.The pooled effect estimate were presented using relative risk and calculated by the random-effects model.Twenty-three prospective cohort studies enrolling 210817 individuals were included.The risk of wheeze in offspring were lowered when high vitamin D,vitamin E,zinc,and milk intakes during pregnancy,whereas high meat intake during pregnancy could induce additional risk of wheeze in offspring.Moreover,highβ-carotene and magnesium intakes during pregnancy were related to lower eczema risk in offspring,whereas eczema risk in offspring was increased for pregnant women with high intake of butter and margarine.Finally,the asthma risk in offspring could protect against for pregnant women with high intake of vitamin D and apple,whereas high folic acid during pregnancy could produce excess asthma risk in offspring.This study provides the summary evidences regarding the role of nutrients intake during pregnancy and subsequent risk of rhinitis,asthma,eczema,wheeze,and food allergy,and further effective intervention strategies should be employed to improve childhood allergic diseases.展开更多
How coral reefs with high productivity and biodiversity can flourish in oligotrophic tropical oceans has inspired substantial research on coral reef ecosystems.Increasing evidence shows that similar to water in an oas...How coral reefs with high productivity and biodiversity can flourish in oligotrophic tropical oceans has inspired substantial research on coral reef ecosystems.Increasing evidence shows that similar to water in an oasis in the desert,there are stable nutrient supplies to coral reefs in oligotrophic oceans.Here,with emphasis on the fluxes of organic matter,we summarize at the ecosystem level(1)the multiple input pathways of external nutrients,(2)the storage of nutrients in reef organisms,(3)the efficient retaining and recycling of dissolved and particulate organic matter within coral reef ecosystems,(4)the distinctly high phytoplankton productivity and biomass inside and near oceanic coral reefs,and(5)the export of reef-related organic carbon to adjacent open oceans.These properties enable coral reefs to function as ecological“pumps”for gathering nutrients across ecosystems and space,retaining and recycling nutrients within the ecosystem,supporting high phytoplankton productivity,and exporting organic carbon to adjacent open oceans.Particularly,the high phytoplankton productivity and biomass make waters around coral reefs potential hotspots of carbon export to ocean depths via the biological pump.We demonstrate that organic carbon influx is vital for coral reef ecosystems’carbon budget and carbon export.The concept of the coral reef ecological pump provides a framework to improve the understanding of the functioning of the coral reef ecosystem and its responses to disturbance.Prospects of the coral reef ecological pump in coral reef studies are discussed in changing oceans driven by human activities and global change in the Anthropocene.展开更多
Artemisia argyi is a traditional Chinese herb,which is widely distributed in various areas in China.In recent years,due to the development of A.argyi related industries and the continuous improvement of people’s heal...Artemisia argyi is a traditional Chinese herb,which is widely distributed in various areas in China.In recent years,due to the development of A.argyi related industries and the continuous improvement of people’s health awareness,experts and scholars are concerned about the nutrients and effects of A.argyi.A.argyi is rich in carbohydrates,proteins,essential amino acids,fatty acids,minerals,vitamins,dietary fibers,flavonoids and other nutrients.It has the effects of antioxidant,anti-tumor,antibacterial,antiinflammatory,neuroprotection and immune regulations,and has been widely applied in the fields of COVID-19 prevention,food health care,food preservation and feed breeding,and has good development potential.This review summarized the research and application of A.argyi nutrients,in order to provide reference and application for further study.展开更多
The implementation of appropriate tillage practices is of great significance for agricultural production. However, the effects of different tillage depths on soil nutrients content and microbial communities in tobacco...The implementation of appropriate tillage practices is of great significance for agricultural production. However, the effects of different tillage depths on soil nutrients content and microbial communities in tobacco-planting soils are still lacking systematic research. In this study, three different tillage depths of 15 cm (T1), 20 cm (T2), and 30 cm (T3) were set up for field experiments in Liupanshui, Guizhou Province, to explore the effects of tillage depth on tobacco-planting soil nutrients and bacterial and fungal communities based on 16S rRNA and ITS sequencing and figure out the key factors affecting soil microbial communities. The results showed that T2 and T3 increased the contents of organic matter, total nitrogen, total phosphorus, available phosphorus, and available potassium in tobacco-planting soil, and increased the diversity of bacterial communities compared with T1. There was no significant difference in the structure of bacterial and fungal communities in different tillage depth treatments, but some dominant genera were significantly enriched in T2 and T3. Desulfobacter, Setophoma, Humicola, and Acremonium were significantly enriched in T2. Chthonomonas and Fusarium were significantly enriched in T3. These genera favor the decomposition of organic matter and the cycling of nutrients, and control soil pests and diseases. Redundancy analysis indicated that TP and AK were the key factors influencing the dominant genera of bacteria and fungi. This study provides a scientific basis for the selection of soil tillage depth for tobacco production in this region.展开更多
The incidence rate of breast cancer is the second highest of all cancers.Alterations to one's epigenome are among the most critical factors in breast cancer control.In breast cancer,nutrients can influence epigene...The incidence rate of breast cancer is the second highest of all cancers.Alterations to one's epigenome are among the most critical factors in breast cancer control.In breast cancer,nutrients can influence epigenetic pathways and homocysteine(Hcy)levels.Hcy has been related to cognitive decline,Alzheimer's disease,and cancer.Similar to how altered Hcy metabolism is strongly influenced by genetic,epigenetic,and environmental factors,it is significantly linked to cancer.This review aims to discuss the relationship between the levels of Hcy in breast cancer and the effects of nutrients on epigenetic processes.Dietary interventions have the ability to control epigenetic processes,and the Hcy levels are associated with both epigenetic mechanisms and nutritional supplements in breast cancer.Certain nutrients have been discovered to have an impact on these processes.Altered Hcy metabolism is influenced by genetic,epigenetic,and environmental factors and has a substantial link to the emergence of cancer.Nutrients,such as folic acid,vitamin B12 and many phytonutrients that have been found to affect the epigenetic processes in breast cancer may alter DNA methylation and histone modification,which in turn may affect how cancer cells behave.The review emphasizes the need for additional studies to fully comprehend nutrition's potential for the epigenetic mechanism and the relation between Hcy metabolism in breast cancer.展开更多
Constructing multispecies submerged vegetation systems and maintaining stable seasonal succession is crucial for restoring shallow eutrophic lakes.However,little is known about the interactions between successional an...Constructing multispecies submerged vegetation systems and maintaining stable seasonal succession is crucial for restoring shallow eutrophic lakes.However,little is known about the interactions between successional and existing species of different growth forms,particularly under the low light and high nutrient conditions of eutrophic lakes.We measured the functional traits of mature Vallisneria natans(Lour.)Hara plants and Potamogeton crispus L.shoots in monoculture and mosaic patterns under different light and nutrient conditions.The effect of light on functional traits of the submerged macrophyte species was more significant than that of nutrients,but the reverse was true for P.crispus biomass allocation.Moreover,interspecific interactions affected only the submerged macrophytes under the low light condition and varied with species.Specifically,the interaction of P.crispus to V.natans was biased towards competition,while the interaction of V.natans to P.crispus was converted from facilitation to competition by eutrophication,particularly in the homogenous mosaic growth pattern.This study demonstrates that sufficient light is a prerequisite and patch planting is an effective means to form a multispecies submerged vegetation system.In addition,we emphasize that the coexistence of eutrophication and low light will likely result in a competition between submerged macrophytes thus simplifying the vegetation,even if their growth forms and growing seasons are different.These findings help explain the collapse of multispecies submerged vegetation and guide the restoration of aquatic plants in eutrophic lakes.展开更多
A field experiment was conducted to evaluate the integrated nutrients effect on growth, yield and quality of maize (Zea mays L.) during spring, 2009, at the Agronomic Research Area, University of Agriculture, Faisalab...A field experiment was conducted to evaluate the integrated nutrients effect on growth, yield and quality of maize (Zea mays L.) during spring, 2009, at the Agronomic Research Area, University of Agriculture, Faisalabad. The ex-periment was laid out in Randomized Complete Block Design (RCBD) having three replications with following treat-ments: T1 (control), T2(recommended NPK @ 200-120-125 kg ha-1), T3 [single spray of multinutrient (a solution mixture of micronutrients i.e;Zn = 2%, Fe = 1%, B = 1%, Mn = 1%, Cu = 0.2% and macronutrients N = 1%, K2O = 2%, S = 2%) @ 1.25Lha-1], T4 (recommended NPK @ 200-120-125 kg ha-1 + single spray of multinutrient @ 1.25L ha-1), T5 (recom-mended NPK @ 200-120-125 kg ha-1 + two spray of multinutrient @1.25Lha-1) and T6 (recommended NPK @ 200-120-125 kg ha-1+ three spray of multinutrient @ 1.25Lha-1).The recommended dose of NPK in addition with single spray of Multi-nutrients substationally improved all growth parameters, ear characteristics and also enhanced macronutrients use efficiency up to 11.5% which induced significant increase in grain yield as compared to control and also in the treatment where recommended dose of NPK was applied alone. The quality parameter of maize (oil contents) significantly improved by foliar application of multinutrients solution but recommended dose of fertilizer in addition to single spray of Multi-nutrients was economical.展开更多
Tomato is an important field crop,and nutritional imbalances frequently reduce its yield.Diagnosis and Recommendation Integrated System(DRIS),uses ratios for nutrient deficiency diagnosis instead of absolute concentra...Tomato is an important field crop,and nutritional imbalances frequently reduce its yield.Diagnosis and Recommendation Integrated System(DRIS),uses ratios for nutrient deficiency diagnosis instead of absolute concentration in plant tests.In this study,local DRIS norms for the field tomatoes were established and the nutrient(s)limiting tomatoes yield were determined.Tomato leaves were analyzed for nutrients,to identify nutritional status using the DRIS approach.One hundred tomatoes fields were selected from Chatter Plain Khyber Pakhtunkhwa and the Sheikupura Punjab Pakistan.The first fully matured leaf was sampled,rinsed,dried and ground for analyzing P,K,Ca,Mg,Cu,Fe,Mn and Zn using an Inductively Coupled Plasma Atomic Emission Spectrophotometer(ICP AES).Plant tissue N and S were measured by the combustion method.The tomatoes yields were recorded at each location.The data were divided into high-yielding(≥3.79 kg/10 plant)and low-yielding(<3.79 kg/10 plant)populations and norms were computed using standard DRIS procedures.High-yielding plant population had a statistically greater mean S and Fe than the low-yielding population.The average balance index,the sum of functions,for S and Fe were−11.04 and−5.17 which reflected deficiency of S and Fe.Plant nutrients norms established may optimize plant nutrition in field tomatoes for high yield.展开更多
Recent research has demonstrated that critically ill patients with coronavirus disease 2019(COVID-19)show significant immune system dysregulation.Due to that,some nutrients that influence immunomodulation have been su...Recent research has demonstrated that critically ill patients with coronavirus disease 2019(COVID-19)show significant immune system dysregulation.Due to that,some nutrients that influence immunomodulation have been suggested as a form of treatment against the infection.This review collected the information on the impact of vitamins on the prognosis of COVID-19,with the intention of facilitating treatment and prevention of the disease risk status in patients.The collected information was obtained using the PubMed electronic database by searching for articles that relate COVID-19 and the mechanisms/effects of the nutrients:Proteins,glucose,lipids,vitamin B12,vitamin D,calcium,iron,copper,zinc,and magnesium,including prospective,retrospective,and support articles.The findings reveal an optimal response related mainly to omega-3,eicosapentaenoic acid,docosahexaenoic acid,calcium,and iron that might represent benefits in the treatment of critically ill patients.However,nutrient supplementation should be done with caution due to the limited availability of randomized controlled studies.展开更多
The nutrients contents and distributions are discussed briefly, based on the data obtained in 1998～1999. Besides explanation of the results,a 20 a time series data of nutrients and biological parameters for central B...The nutrients contents and distributions are discussed briefly, based on the data obtained in 1998～1999. Besides explanation of the results,a 20 a time series data of nutrients and biological parameters for central Bohai Sea are reviewed. It is found that both concentration and relative content of nutrients have been changed dramatically. The increase of nitrogen and decrease of phosphate and silicate led to the dramatically increase of N/P ratio and the decrease of Si/N ratio. The situation of nitrogen limiting in central Bohai Sea is gradually changing to that of relative lack of phosphate and silicate. The decrease of the Huanghe River input to the Bohai Sea may be responsible for this change. These in turn may limit the growth of diatom and thus promote the development of pyrrophyta if other conditions (e.g. temperature and hydrodynamics) are suitable. We conclude that this may be the major inducement factor of pyrrophyta red tide in the Bohai Sea.展开更多
Investigations from August, 1985 to July , 1986 showed that the high concentration area of PO4-P , SiO3-Si and NO3-N gradually reduced with the reduction of the area of the Changjiang River diluted water from summer, ...Investigations from August, 1985 to July , 1986 showed that the high concentration area of PO4-P , SiO3-Si and NO3-N gradually reduced with the reduction of the area of the Changjiang River diluted water from summer, autumn to winter , and that the seasonal distributions and variations of the nutrients concentrations were mainly controlled by the river flow and were also related to the growth and decline of phytoplankton . The conservation of SiO3-Si and NO3-N in the estuary in the flood season was poorer than that in the dry season .. The behaviour of PO4-P in the estuary shows that aside from -biological removal, buffering of PCU-P is possible in the estuary . The highest monthly average concentrations and annual average concentrations in the river mouth were respectively 0.88 and 0.57 umol/L for PO4-P,191.5 and 96.2 umol/L for SiO3-Si, and 81.6 and 58.6 umol/L for NOs-N . The Changjiang’s annual transports of PO4-P , SiO3-Si and NO3-N to the sea were about 1.4×104tons , 204.4×104 tons and 63.展开更多
Effects of iron and silicon nutrients and of orthogonal combinations of nitrogen, phosphorus, iron and silicon on the growth rate of three benthic diatoms were studied by using an in situ OD measurement method. The re...Effects of iron and silicon nutrients and of orthogonal combinations of nitrogen, phosphorus, iron and silicon on the growth rate of three benthic diatoms were studied by using an in situ OD measurement method. The results of monofactor tests of ironand silicon shawed that Fe-EDTA was bettef than ferric citrate in the culture of these diatoms;that the favourable concentration of Fe-EDTA was about 0.5 mg/L of Fe and that of silicate was 2.5 mg/L of Si or more.The orthogonal test showed that the optimal concentration ratios(mg/L)of nitrogen, phosphorus, iron and silicon were: 5. 0: 0. 25: 0.5: 2. 0 for Cocconeis scutellum var. parva; 2.5: 1.0: 1.0: 2.0 for Amphora coffeaeformis; and 5.0: 0. 15: 0.5: 2.0 for N. mollis.展开更多
The distribution of nutrients and the effect of side transport of nutrients on anchovy spawning ground to the southern waters of Shandong Peninsula are discussed based on the data collected in June 2000, May and June ...The distribution of nutrients and the effect of side transport of nutrients on anchovy spawning ground to the southern waters of Shandong Peninsula are discussed based on the data collected in June 2000, May and June 2001. The coastal current and upwelling are the main physical processes of nutrient transport to the southern waters of Shandong Peninsula. The concentrations of nutrients, Chl-a, the density of anchovy eggs, larva and juvenile fish increase obviously where they are greatly affected by these processes, while the contents of nutrients and Chl-a, the density of anchovy eggs, larva and juvenile fish decrease significantly where these processes diminish or disappear. The investigation suggest that the side transport of nutrients by Lubei (North Shandong) coastal current in the northern area causes the Chl-a content to be high and dense anchovy eggs, larva and juvenile fish to be dense in the coastal area of the Chengshan Cape.In the southern area, the riverine input from Subei irrigation ditch with high content of nutrients inshore and upwelling in the western edge of the Huanghai Sea Cold Water offshore should be responsible for high Chl-a concentration and dense anchovy eggs, larva and juvenile fish. It is possible that these processes of nutrient transport have controlled the anchovy spawning ground to the southern waters of Shandong Peninsula.展开更多
-The enrichment of nutrients (NOa-, NOa-, PO43-), suspended particles, organic matter (POC, PON,DOC) , and trace metals (Cu, Ni, Cd) was determined in the sea surface microlayer of Xiamen Bay and Jiulong Estuary. The ...-The enrichment of nutrients (NOa-, NOa-, PO43-), suspended particles, organic matter (POC, PON,DOC) , and trace metals (Cu, Ni, Cd) was determined in the sea surface microlayer of Xiamen Bay and Jiulong Estuary. The mean enrichment factors ([Xi]microlayer/[Xi ]15cm in depth) mostly ranged between 1 . 0 and 2. 0. The dissolved forms were the major forms of the components measured, the enrichment of dissolved organic matter and suspended particles could lead to the changes in the total amount and speciation of nutrients and trace metals. No correlation was observed between sample concentrations, speciation, enrichment factors and sample locations. However, some evidence shows that these parameters are correlated with sea state, indicating the complexity and dynamic nature of the sea surface microlayer.展开更多
Sinoe vertical transport of nutrients and dissolved oxygen are quite important in the water col-umn and have drawn serious attention these recent years, a one-dmension numerical model is tried to simulate the vertical...Sinoe vertical transport of nutrients and dissolved oxygen are quite important in the water col-umn and have drawn serious attention these recent years, a one-dmension numerical model is tried to simulate the vertical distribution of nutrients and dissolved oxygen in June at two research sites in the southemTaiwan Strait. Physical transport parameters are calibrated by temperature simulation, and thenare used to simulate the profiles of NO<sub>3</sub>, PO<sub>4</sub> and dissolved oxygen. The simulation was generally success-ful for both stations. The importance of various factors, such as upwelling tidal current andbiogeochemical activities, which influence the vertical distribution of nutrients and dissolved oxygen, is revealed by analysis of the modeling results. Some important rates, fluxes and ratios are also estimated anddiscussed on the basis of simulation.展开更多
This study on the distribution of phosphate and its relation to phytoplankton biomass in Western Xiamen Harbor using marine ecosystem enclosures to isolate the culture water from the tidal currents and salinity change...This study on the distribution of phosphate and its relation to phytoplankton biomass in Western Xiamen Harbor using marine ecosystem enclosures to isolate the culture water from the tidal currents and salinity changes outside indicated that the phytoplankton biomass variation closely related to dissolved inorganic phosphorus (DIP) in the seawater as described by the equation: [Chl a]=A×e -B[PO4] . The biomass changes lagged by about two days the corresponding DIP. The research also dealt with the minimal DIP concentration for stopping diatom bloom and the possible maximal diatom biomass was estimated from the DIP external concentration in the seawater. The threshold of DIP initiating Skeletonema costatum red tide was calculated for use as an index to forecast its red tides. In addition, the relationships between a dinoflagellate red tide and nutrients are discussed. The results showed that the multiplication of dinoflagellate was not entirely dependent on the nutrients in the seawater.展开更多
基金This research was supported by the National Natural Science Foundation of China(82273613)Heilongjiang Provincial Natural Science Foundation of China(LC2016032).
文摘Background:The cold winter weather in northern China influences the dietary habits of its residents,contributing to a heightened risk of cardiovascular disorders,such as hypertension and coronary heart disease.Key factors include low vegetable consumption and high salt and fat intakes.This study aims to investigate the relationships between northern dietary nutrient intake in northern China and cardiovascular disorders during the winter season.Methods:A food frequency questionnaire tailored to the actual eating habits in northern China was designed.Retrospective data from 955 Chinese adults were collected from November to March between 2014 to 2023.Logistic regression was employed to analyze the relationship between dietary nutrients and cardiovascular diseases,with model performance assessed using receiver operating characteristic(ROC)curves.Results:Adjusted for gender,age,and body mass index(BMI),an inverse association was observed between vitamin A(OR=0.706,95%CI:0.550,0.907),nicotinic acid(OR=0.584,95%CI:0.447,0.762),phosphorus(OR=0.777,95%CI:0.608,0.994),selenium(OR=0.719,95%CI:0.560,0.923),zinc(OR=0.683,95%CI:0.531,0.880),methionine(OR=0.730,95%CI:0.569,0.936),arginine(OR=0.753,95%CI:0.588,0.964),lysine(OR=0.706,95%CI:0.550,0.907),aspartic acid(OR=0.730,95%CI:0.569,0.936)and hypertension.Additionally,a negative association was found between niacin(OR=0.752,95%CI:0.597,0.946)and coronary heart disease.Conversely,a positive association was identified between iodine and hypertension(OR=1.305,95%CI:1.020,1.669)and coronary heart disease(OR=1.301,95%CI:1.037,1.634).Conclusion:Our study suggests that maintaining a balanced dietary intake of vitamin A,niacin,phosphorus,selenium,zinc,methionine,arginine,lysine,and aspartic acid can be beneficial in preventing hypertension.Adequate niacin intake is associated with a lower risk of coronary heart disease.However,excessive iodine intake may contribute to hypertension and coronary heart disease.
文摘The necessity to saline and sodic waters is sometimes used for irrigating agricultural activities under certain circumstances, but it is important to note that the use of these waters comes with specific considerations and limitations. One way to decrease undesirable effects of sodic waters on the physical and chemical properties of soils is to apply organic and chemical amendments within the soil. This study aimed to assess the effectiveness of saline water on soil acidity, alkalinity and nutrients leaching in sandy loamy soil at Bella flower farm, in Rwamagana District, Rwanda. The water used was from the Muhazi Lake which is classified as Class I (Saline water quality). Column leaching experiments using treated soils were then conducted under saturated conditions. The soil under experimental was first analyzed for its textural classification, soil properties and is classified as sandy loamy soil. The t-test was taken at 1%, 5% and 10% levels of statistical significance compared to control soil. The results indicated that the application of saline water to soils caused an increase in some soil nutrients like increase of Phosphorus (P), Potassium (K<sup>+</sup>), Magnesium (Mg2<sup>+</sup>), Sulphur (S), CN ratio and Sodium (Na<sup>+</sup>) and decreased soil texture, physical and chemical properties and remained soil nutrients. Consequently, the intensive addition of saline water leachates to soil in PVC pipes led to decreased of soil EC through leaching and a raiser Soluble Sodium Percentage (SSP). The rate of saline water application affected the increase accumulation of SAR and Na% in the top soil layers. The study indicated that saline water is an inefficient amendment for sandy soil with saline water irrigation. The study recommends further studies with similar topic with saline water irrigation, as it accentuated the alkalinity levels.
基金The Basque Government(BIOMICs Research Group,MICROFLUIDICs&BIOMICs Cluster of the University of the Basque Country UPV/EHU),No.IT1633-22.
文摘BACKGROUND Dietary methyl donors might influence DNA methylation during carcinogenesis of colorectal cancer(CRC).However,whether the influence of methyl donor intake is modified by polymorphisms in such epigenetic regulators is still unclear.AIM To improve the current understanding of the molecular basis of CRC.METHODS A literature search in the Medline database,Reference Citation Analysis(https://www.referencecitationanalysis.com/),and manual reference screening were performed to identify observational studies published from inception to May 2022.RESULTS A total of fourteen case-control studies and five cohort studies were identified.These studies included information on dietary methyl donors,dietary components that potentially modulate the bioavailability of methyl groups,genetic variants of methyl metabolizing enzymes,and/or markers of CpG island methylator phenotype and/or microsatellite instability,and their possible interactions on CRC risk.CONCLUSION Several studies have suggested interactions between methylenetetrahydrofolate reductase polymorphisms,methyl donor nutrients(such as folate)and alcohol on CRC risk.Moreover,vitamin B6,niacin,and alcohol may affect CRC risk through not only genetic but also epigenetic regulation.Identification of specific mechanisms in these interactions associated with CRC may assist in developing targeted prevention strategies for individuals at the highest risk of developing CRC.
基金The National Key R&D Program of China under contract No.2021YFC3200501the National Natural Science Foundation of China under contract Nos 42107055 and 42130703the Fund of Shenzhen Science and Technology Innovation Committee under contract No.20200925174525002.
文摘Subterranean estuaries(STE)are important seawater-groundwater mixing zones with complex biogeochemical processes,which play a vital role in the migration and transformation of dissolved materials.In this study,we first investigated the spatial distributions of dissolved inorganic nitrogen(DIN),dissolved inorganic phosphorous(DIP),dissolved inorganic silicon(DSi)and metal elements(As,Ba,Cr,Cu,Fe,Mn,Ni,Pb,and Zn)in STE including upper intertidal,seepage face and subtidal zones.We then estimated submarine groundwater discharge(SGD)and associated nutrient and metal element fluxes.From the generalized Darcy’s law method,SGD was estimated to be 30.13 cm/d,which was about 7 times larger than the inflow(4.16 cm/d).The nutrient and metal fluxes from SGD were estimated to be(5.33±4.99)mmol/(m^(2)·d)for DIN,(0.22±0.03)mmol/(m^(2)·d)for DIP,(16.20±2.05)mmol/(m^(2)·d)for DSi,(1325.06±99.10)μmol/(m^(2)·d)for Fe,(143.41±25.13)μmol/(m^(2)·d)for Mn,(304.06±81.07)μmol/(m^(2)·d)for Zn,(140.21±13.33)μmol/(m^(2)·d)for Cu,(84.49±2.94)μmol/(m^(2)·d)for Pb,(37.38±5.51)μmol/(m^(2)·d)for Ba,(27.88±3.89)μmol/(m^(2)·d)for Cr,(10.10±6.33)μmol/(m^(2)·d)for Ni,and(6.25±3.45)μmol/(m^(2)·d)for As.The nutrient and metal fluxes from SGD were relatively higher than those from the inflow,suggesting that nearshore groundwater acted as the sources of nutrients and metal elements discharging into the sea.The environmental potential pollution of coastal seawater was evaluated by pollution factor index(Pi),comprehensive water quality index(CWQI),and ecological risk index(ERI).Pb mainly caused potential danger of nearshore environment with considerable contamination(Pi=5.78±0.19),heavy pollution(CWQI=4.09)and high ecological risk(ERI=18.00).This study contributed to better understanding the behavior of nutrients and metal elements and improving the sustainable management of STE under the pressure of anthropogenic activities and climate change.
基金supported by CAMS Innovation Fund for Medical Science(CIFMS 2019-I2M-5-024)。
文摘To investigate the role of nutrients intake during pregnancy with longitudinal development of rhinitis,asthma,eczema,wheeze,and food allergy in offspring.The PubMed,Embase,and Cochrane library were searched for articles published throughout May 2022.The pooled effect estimate were presented using relative risk and calculated by the random-effects model.Twenty-three prospective cohort studies enrolling 210817 individuals were included.The risk of wheeze in offspring were lowered when high vitamin D,vitamin E,zinc,and milk intakes during pregnancy,whereas high meat intake during pregnancy could induce additional risk of wheeze in offspring.Moreover,highβ-carotene and magnesium intakes during pregnancy were related to lower eczema risk in offspring,whereas eczema risk in offspring was increased for pregnant women with high intake of butter and margarine.Finally,the asthma risk in offspring could protect against for pregnant women with high intake of vitamin D and apple,whereas high folic acid during pregnancy could produce excess asthma risk in offspring.This study provides the summary evidences regarding the role of nutrients intake during pregnancy and subsequent risk of rhinitis,asthma,eczema,wheeze,and food allergy,and further effective intervention strategies should be employed to improve childhood allergic diseases.
基金The Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou) under contract No.GML2019ZD0405the National Natural Science Foundation of China under contract Nos41506150 and 41130855+3 种基金the Guangdong Basic and Applied Basic Research Foundation under contract No.2019A1515011645the National Science and Technology Basic Work Program of the Ministry of Science and Technology of China under contract No.2015FY110600the Science and Technology Planning Project of Guangdong Province,China under contract No.2020B1212060058the Development Fund of South China Sea Institute of Oceanology of the Chinese Academy of Sciences under contract No.SCSIO202204。
文摘How coral reefs with high productivity and biodiversity can flourish in oligotrophic tropical oceans has inspired substantial research on coral reef ecosystems.Increasing evidence shows that similar to water in an oasis in the desert,there are stable nutrient supplies to coral reefs in oligotrophic oceans.Here,with emphasis on the fluxes of organic matter,we summarize at the ecosystem level(1)the multiple input pathways of external nutrients,(2)the storage of nutrients in reef organisms,(3)the efficient retaining and recycling of dissolved and particulate organic matter within coral reef ecosystems,(4)the distinctly high phytoplankton productivity and biomass inside and near oceanic coral reefs,and(5)the export of reef-related organic carbon to adjacent open oceans.These properties enable coral reefs to function as ecological“pumps”for gathering nutrients across ecosystems and space,retaining and recycling nutrients within the ecosystem,supporting high phytoplankton productivity,and exporting organic carbon to adjacent open oceans.Particularly,the high phytoplankton productivity and biomass make waters around coral reefs potential hotspots of carbon export to ocean depths via the biological pump.We demonstrate that organic carbon influx is vital for coral reef ecosystems’carbon budget and carbon export.The concept of the coral reef ecological pump provides a framework to improve the understanding of the functioning of the coral reef ecosystem and its responses to disturbance.Prospects of the coral reef ecological pump in coral reef studies are discussed in changing oceans driven by human activities and global change in the Anthropocene.
基金Supported by the Research on Scientific and Technological Innovation of Beef Cattle in Northeast Cold Region by Ministry of Education(002020010)。
文摘Artemisia argyi is a traditional Chinese herb,which is widely distributed in various areas in China.In recent years,due to the development of A.argyi related industries and the continuous improvement of people’s health awareness,experts and scholars are concerned about the nutrients and effects of A.argyi.A.argyi is rich in carbohydrates,proteins,essential amino acids,fatty acids,minerals,vitamins,dietary fibers,flavonoids and other nutrients.It has the effects of antioxidant,anti-tumor,antibacterial,antiinflammatory,neuroprotection and immune regulations,and has been widely applied in the fields of COVID-19 prevention,food health care,food preservation and feed breeding,and has good development potential.This review summarized the research and application of A.argyi nutrients,in order to provide reference and application for further study.
文摘The implementation of appropriate tillage practices is of great significance for agricultural production. However, the effects of different tillage depths on soil nutrients content and microbial communities in tobacco-planting soils are still lacking systematic research. In this study, three different tillage depths of 15 cm (T1), 20 cm (T2), and 30 cm (T3) were set up for field experiments in Liupanshui, Guizhou Province, to explore the effects of tillage depth on tobacco-planting soil nutrients and bacterial and fungal communities based on 16S rRNA and ITS sequencing and figure out the key factors affecting soil microbial communities. The results showed that T2 and T3 increased the contents of organic matter, total nitrogen, total phosphorus, available phosphorus, and available potassium in tobacco-planting soil, and increased the diversity of bacterial communities compared with T1. There was no significant difference in the structure of bacterial and fungal communities in different tillage depth treatments, but some dominant genera were significantly enriched in T2 and T3. Desulfobacter, Setophoma, Humicola, and Acremonium were significantly enriched in T2. Chthonomonas and Fusarium were significantly enriched in T3. These genera favor the decomposition of organic matter and the cycling of nutrients, and control soil pests and diseases. Redundancy analysis indicated that TP and AK were the key factors influencing the dominant genera of bacteria and fungi. This study provides a scientific basis for the selection of soil tillage depth for tobacco production in this region.
文摘The incidence rate of breast cancer is the second highest of all cancers.Alterations to one's epigenome are among the most critical factors in breast cancer control.In breast cancer,nutrients can influence epigenetic pathways and homocysteine(Hcy)levels.Hcy has been related to cognitive decline,Alzheimer's disease,and cancer.Similar to how altered Hcy metabolism is strongly influenced by genetic,epigenetic,and environmental factors,it is significantly linked to cancer.This review aims to discuss the relationship between the levels of Hcy in breast cancer and the effects of nutrients on epigenetic processes.Dietary interventions have the ability to control epigenetic processes,and the Hcy levels are associated with both epigenetic mechanisms and nutritional supplements in breast cancer.Certain nutrients have been discovered to have an impact on these processes.Altered Hcy metabolism is influenced by genetic,epigenetic,and environmental factors and has a substantial link to the emergence of cancer.Nutrients,such as folic acid,vitamin B12 and many phytonutrients that have been found to affect the epigenetic processes in breast cancer may alter DNA methylation and histone modification,which in turn may affect how cancer cells behave.The review emphasizes the need for additional studies to fully comprehend nutrition's potential for the epigenetic mechanism and the relation between Hcy metabolism in breast cancer.
基金Supported by the National Natural Science Foundation of China (Nos.U2240207,41971043,51809178)the Guangxi Key Research and Development Program of China (No.2018AB36010)。
文摘Constructing multispecies submerged vegetation systems and maintaining stable seasonal succession is crucial for restoring shallow eutrophic lakes.However,little is known about the interactions between successional and existing species of different growth forms,particularly under the low light and high nutrient conditions of eutrophic lakes.We measured the functional traits of mature Vallisneria natans(Lour.)Hara plants and Potamogeton crispus L.shoots in monoculture and mosaic patterns under different light and nutrient conditions.The effect of light on functional traits of the submerged macrophyte species was more significant than that of nutrients,but the reverse was true for P.crispus biomass allocation.Moreover,interspecific interactions affected only the submerged macrophytes under the low light condition and varied with species.Specifically,the interaction of P.crispus to V.natans was biased towards competition,while the interaction of V.natans to P.crispus was converted from facilitation to competition by eutrophication,particularly in the homogenous mosaic growth pattern.This study demonstrates that sufficient light is a prerequisite and patch planting is an effective means to form a multispecies submerged vegetation system.In addition,we emphasize that the coexistence of eutrophication and low light will likely result in a competition between submerged macrophytes thus simplifying the vegetation,even if their growth forms and growing seasons are different.These findings help explain the collapse of multispecies submerged vegetation and guide the restoration of aquatic plants in eutrophic lakes.
文摘A field experiment was conducted to evaluate the integrated nutrients effect on growth, yield and quality of maize (Zea mays L.) during spring, 2009, at the Agronomic Research Area, University of Agriculture, Faisalabad. The ex-periment was laid out in Randomized Complete Block Design (RCBD) having three replications with following treat-ments: T1 (control), T2(recommended NPK @ 200-120-125 kg ha-1), T3 [single spray of multinutrient (a solution mixture of micronutrients i.e;Zn = 2%, Fe = 1%, B = 1%, Mn = 1%, Cu = 0.2% and macronutrients N = 1%, K2O = 2%, S = 2%) @ 1.25Lha-1], T4 (recommended NPK @ 200-120-125 kg ha-1 + single spray of multinutrient @ 1.25L ha-1), T5 (recom-mended NPK @ 200-120-125 kg ha-1 + two spray of multinutrient @1.25Lha-1) and T6 (recommended NPK @ 200-120-125 kg ha-1+ three spray of multinutrient @ 1.25Lha-1).The recommended dose of NPK in addition with single spray of Multi-nutrients substationally improved all growth parameters, ear characteristics and also enhanced macronutrients use efficiency up to 11.5% which induced significant increase in grain yield as compared to control and also in the treatment where recommended dose of NPK was applied alone. The quality parameter of maize (oil contents) significantly improved by foliar application of multinutrients solution but recommended dose of fertilizer in addition to single spray of Multi-nutrients was economical.
基金supporting current work by Taif University Researchers Supporting Project No.(TURSP–2020/288),Taif University,Taif,Saudi Arabia.
文摘Tomato is an important field crop,and nutritional imbalances frequently reduce its yield.Diagnosis and Recommendation Integrated System(DRIS),uses ratios for nutrient deficiency diagnosis instead of absolute concentration in plant tests.In this study,local DRIS norms for the field tomatoes were established and the nutrient(s)limiting tomatoes yield were determined.Tomato leaves were analyzed for nutrients,to identify nutritional status using the DRIS approach.One hundred tomatoes fields were selected from Chatter Plain Khyber Pakhtunkhwa and the Sheikupura Punjab Pakistan.The first fully matured leaf was sampled,rinsed,dried and ground for analyzing P,K,Ca,Mg,Cu,Fe,Mn and Zn using an Inductively Coupled Plasma Atomic Emission Spectrophotometer(ICP AES).Plant tissue N and S were measured by the combustion method.The tomatoes yields were recorded at each location.The data were divided into high-yielding(≥3.79 kg/10 plant)and low-yielding(<3.79 kg/10 plant)populations and norms were computed using standard DRIS procedures.High-yielding plant population had a statistically greater mean S and Fe than the low-yielding population.The average balance index,the sum of functions,for S and Fe were−11.04 and−5.17 which reflected deficiency of S and Fe.Plant nutrients norms established may optimize plant nutrition in field tomatoes for high yield.
文摘Recent research has demonstrated that critically ill patients with coronavirus disease 2019(COVID-19)show significant immune system dysregulation.Due to that,some nutrients that influence immunomodulation have been suggested as a form of treatment against the infection.This review collected the information on the impact of vitamins on the prognosis of COVID-19,with the intention of facilitating treatment and prevention of the disease risk status in patients.The collected information was obtained using the PubMed electronic database by searching for articles that relate COVID-19 and the mechanisms/effects of the nutrients:Proteins,glucose,lipids,vitamin B12,vitamin D,calcium,iron,copper,zinc,and magnesium,including prospective,retrospective,and support articles.The findings reveal an optimal response related mainly to omega-3,eicosapentaenoic acid,docosahexaenoic acid,calcium,and iron that might represent benefits in the treatment of critically ill patients.However,nutrient supplementation should be done with caution due to the limited availability of randomized controlled studies.
文摘The nutrients contents and distributions are discussed briefly, based on the data obtained in 1998～1999. Besides explanation of the results,a 20 a time series data of nutrients and biological parameters for central Bohai Sea are reviewed. It is found that both concentration and relative content of nutrients have been changed dramatically. The increase of nitrogen and decrease of phosphate and silicate led to the dramatically increase of N/P ratio and the decrease of Si/N ratio. The situation of nitrogen limiting in central Bohai Sea is gradually changing to that of relative lack of phosphate and silicate. The decrease of the Huanghe River input to the Bohai Sea may be responsible for this change. These in turn may limit the growth of diatom and thus promote the development of pyrrophyta if other conditions (e.g. temperature and hydrodynamics) are suitable. We conclude that this may be the major inducement factor of pyrrophyta red tide in the Bohai Sea.
文摘Investigations from August, 1985 to July , 1986 showed that the high concentration area of PO4-P , SiO3-Si and NO3-N gradually reduced with the reduction of the area of the Changjiang River diluted water from summer, autumn to winter , and that the seasonal distributions and variations of the nutrients concentrations were mainly controlled by the river flow and were also related to the growth and decline of phytoplankton . The conservation of SiO3-Si and NO3-N in the estuary in the flood season was poorer than that in the dry season .. The behaviour of PO4-P in the estuary shows that aside from -biological removal, buffering of PCU-P is possible in the estuary . The highest monthly average concentrations and annual average concentrations in the river mouth were respectively 0.88 and 0.57 umol/L for PO4-P,191.5 and 96.2 umol/L for SiO3-Si, and 81.6 and 58.6 umol/L for NOs-N . The Changjiang’s annual transports of PO4-P , SiO3-Si and NO3-N to the sea were about 1.4×104tons , 204.4×104 tons and 63.
文摘Effects of iron and silicon nutrients and of orthogonal combinations of nitrogen, phosphorus, iron and silicon on the growth rate of three benthic diatoms were studied by using an in situ OD measurement method. The results of monofactor tests of ironand silicon shawed that Fe-EDTA was bettef than ferric citrate in the culture of these diatoms;that the favourable concentration of Fe-EDTA was about 0.5 mg/L of Fe and that of silicate was 2.5 mg/L of Si or more.The orthogonal test showed that the optimal concentration ratios(mg/L)of nitrogen, phosphorus, iron and silicon were: 5. 0: 0. 25: 0.5: 2. 0 for Cocconeis scutellum var. parva; 2.5: 1.0: 1.0: 2.0 for Amphora coffeaeformis; and 5.0: 0. 15: 0.5: 2.0 for N. mollis.
文摘The distribution of nutrients and the effect of side transport of nutrients on anchovy spawning ground to the southern waters of Shandong Peninsula are discussed based on the data collected in June 2000, May and June 2001. The coastal current and upwelling are the main physical processes of nutrient transport to the southern waters of Shandong Peninsula. The concentrations of nutrients, Chl-a, the density of anchovy eggs, larva and juvenile fish increase obviously where they are greatly affected by these processes, while the contents of nutrients and Chl-a, the density of anchovy eggs, larva and juvenile fish decrease significantly where these processes diminish or disappear. The investigation suggest that the side transport of nutrients by Lubei (North Shandong) coastal current in the northern area causes the Chl-a content to be high and dense anchovy eggs, larva and juvenile fish to be dense in the coastal area of the Chengshan Cape.In the southern area, the riverine input from Subei irrigation ditch with high content of nutrients inshore and upwelling in the western edge of the Huanghai Sea Cold Water offshore should be responsible for high Chl-a concentration and dense anchovy eggs, larva and juvenile fish. It is possible that these processes of nutrient transport have controlled the anchovy spawning ground to the southern waters of Shandong Peninsula.
文摘-The enrichment of nutrients (NOa-, NOa-, PO43-), suspended particles, organic matter (POC, PON,DOC) , and trace metals (Cu, Ni, Cd) was determined in the sea surface microlayer of Xiamen Bay and Jiulong Estuary. The mean enrichment factors ([Xi]microlayer/[Xi ]15cm in depth) mostly ranged between 1 . 0 and 2. 0. The dissolved forms were the major forms of the components measured, the enrichment of dissolved organic matter and suspended particles could lead to the changes in the total amount and speciation of nutrients and trace metals. No correlation was observed between sample concentrations, speciation, enrichment factors and sample locations. However, some evidence shows that these parameters are correlated with sea state, indicating the complexity and dynamic nature of the sea surface microlayer.
文摘Sinoe vertical transport of nutrients and dissolved oxygen are quite important in the water col-umn and have drawn serious attention these recent years, a one-dmension numerical model is tried to simulate the vertical distribution of nutrients and dissolved oxygen in June at two research sites in the southemTaiwan Strait. Physical transport parameters are calibrated by temperature simulation, and thenare used to simulate the profiles of NO<sub>3</sub>, PO<sub>4</sub> and dissolved oxygen. The simulation was generally success-ful for both stations. The importance of various factors, such as upwelling tidal current andbiogeochemical activities, which influence the vertical distribution of nutrients and dissolved oxygen, is revealed by analysis of the modeling results. Some important rates, fluxes and ratios are also estimated anddiscussed on the basis of simulation.
文摘This study on the distribution of phosphate and its relation to phytoplankton biomass in Western Xiamen Harbor using marine ecosystem enclosures to isolate the culture water from the tidal currents and salinity changes outside indicated that the phytoplankton biomass variation closely related to dissolved inorganic phosphorus (DIP) in the seawater as described by the equation: [Chl a]=A×e -B[PO4] . The biomass changes lagged by about two days the corresponding DIP. The research also dealt with the minimal DIP concentration for stopping diatom bloom and the possible maximal diatom biomass was estimated from the DIP external concentration in the seawater. The threshold of DIP initiating Skeletonema costatum red tide was calculated for use as an index to forecast its red tides. In addition, the relationships between a dinoflagellate red tide and nutrients are discussed. The results showed that the multiplication of dinoflagellate was not entirely dependent on the nutrients in the seawater.
