This site uses cookies.
Some of these cookies are essential to the operation of the site,
while others help to improve your experience by providing insights into how the site is being used.
For more information, please see the ProZ.com privacy policy.
This person has a SecurePRO™ card. Because this person is not a ProZ.com Plus subscriber, to view his or her SecurePRO™ card you must be a ProZ.com Business member or Plus subscriber.
Affiliations
This person is not affiliated with any business or Blue Board record at ProZ.com.
Services
Translation, Subtitling
Expertise
Specializes in:
Telecom(munications)
Art, Arts & Crafts, Painting
Rates
Portfolio
Sample translations submitted: 1
Chinese to English: The Study on pH Changes and Algal Growth Response Model in Alkaline Lakes under Water Transfer Conditions General field: Science
Translation - English The Study on pH Changes and Algal Growth Response Model in Alkaline Lakes under Water Transfer Conditions
Abstract
Under the stress of global change and impacted by anthropogenic disturbance, a class of naturally alkaline lakes located in arid-semi-arid regions are mostly faced with declining water levels and significant shrinkage of the lake surface. Therefore, water transfer from outer basins for water recharge is an important measure to maintain the lake ecosystem. However, the alkalinisation of alkaline lakes is actually a long-term process. Under the influence of transfer of water from external basins in such short time, the influx of neutral river water from the external will lead to a sudden drop in lake pH. pH is a key element in maintaining the structural stability of the special aquatic ecosystems of alkaline lakes, and it also plays a decisive role in the growth of algae and their community composition. A decrease in pH may have irreversible effects on the unique algal communities that have already adapted to their alkaline environment, which will lead to a series of unknown and uncertain ecological risks. Therefore, it is urgent to conduct investigations on the effects of the water transfer from outer basins on pH changes and algal ecological processes in alkaline lakes, so as to safeguard the ecological environment for alkaline lakes. Thus, the development of a coupled hydrodynamic-ecological model of algal growth in response to pH changes can provide an effective tool for such alkaline waters or similar waters when carrying out ecological management and development.
This paper hereafter takes the Chenghai Lake, one of typical alkaline lakes in the Yunnan-Guizhou plateau of China as an example, and systematically summarizes structural characteristics of algal communities, algal growth and extinction patterns as well as their influencing factors. By an indoor algal culture experiment, the influence of pH change on the growing pattern of algal communities in alkaline lakes was investigated, which laid the foundation for the limiting function of algal growing pattern in response to pH changes. Additionally, based on the carbonic acid equilibrium theory, a set of pH calculation model was proposed for the mixing of rivers and lakes. The final purpose is, the traditional algal ecological model was to be modified, by adding the limiting function and the pH calculation model of the growth of cyanobacteria and chlorophyta in response to pH changes, and a numerical model of alkaline lake water quality considering the influence of pH change on algal growth was established, so that the prediction of the evolution of pH changes and algae in the lake under the water transfer condition can be carried out. The main results are as follows.
(1) The population structure of planktonic algae in the Chenghai Lake and the patterns of algal growth, as well as their responses to various habitat factors, were grasped. The results of the historical ecological research of the Chenghai Lake and the monitored data of ecological environment from 2014-2019 were summarised, it was found that algal blooms in the Chenghai Lake were mainly spotted in the winters and springs from Decembers to Mays, additionally the blooms mostly scattered in the northern Chenghai Lake. Similar to other alkaline lakes, cyanobacteria were dominant in the structure of the algal communities in Chenghai Lake throughout the year, among them, herba houttuynia was the most common. In addition, correlation analysis with Spearman test revealed that the limiting effect of phosphorus salts was the key factor dominating the annual algal bloom pattern in the lake, with algal biomass increasing significantly when the TP concentration exceeded 0.04 mg/L. Among the other habitat factors, dissolved oxygen concentration and pH also emerged significant response relation with algal growth.
(2) The growth patterns of the dominant cyanobacteria, herba houttuyniae and the dominant chlorophyta, scenedesmus in alkaline lakes and their interspecific competition patterns were investigated in relation to pH. The results showed that both species are basophilic algae and that under the experimental pH conditions (9 pH gradients from pH 7 to 11), the growth of both the herba houttuyniae and the scenedesmuse was inhibited in low pH while promoted in high. The herba houttuyniae was more sensitive to pH changes than scenedesmus. In addition, pH also plays an important role in the interspecific competition between algae, with cyanobacteria and chlorophyta biomass ratios mostly greater than 1 at pH≥9, and according to the Lotka-Volterra competition model, herba houttuyniae eventually won in alkaline environments at pH≥9, drawing the conclusion that high pH is the vital element causing herba houttuyniae's dominance in alkaline waters.
(3) A mathematical model of alkaline lake pH turbulence is constructed. Based on the water ionization equilibrium and carbonic acid equilibrium laws in water chemistry, a precise, effective and applicable pH calculation method for rivers and lakes mixing was established using the thermodynamic equilibrium equation. On this basis, a three-dimensional prediction model of alkaline lake pH is developed by coupling the hydrodynamic mathematical model. And this model is validated by the field observation data of pH in the pumping test of another Chinese typical alkaline lake, Yamdrok Tso Lake. The validation also indicated that this model based on carbonic acid equilibrium laws in water chemistry can simulate preferably the spatial dynamic variation of alkaline lakes' pH during neutral river recharge.
(4) The effect of water transfer on the pH of Chenghai lake area and its cumulative evolution trend over the years were simulated and studied. Based on the simulation study with the alkaline lake pH turbulence model responding to pH changes in the Chenghai Lake under water transfer, the effect of water transfer on pH mainly focused in the northern parts of Chenghai Lake, where the water transfer with relatively long and uniformly distributed flow is smaller and shorter than that with high flow in a short period of time. In contrast, a windless condition would result in a dramatic increase in both the extent and duration of the impact on the lake pH. So, attention should be paid to wind changes off the lake surface during the transfer, and avoiding transfers in windless periods as much as possible. In addition, the cumulative effect of the transfer on lake pH over the years is evident, with a total reduction of 2.2% after the five-year water level upgrade compared to the pre-transfer pH.
(5) Based on the experimental results, the limiting function equation of the growth of cyanobacteria and chlorophyta on the pH in alkaline lakes was constructed. And it was added to classical algal ecological dynamics model to improve the model growth equation. A coupled hydrodynamic-water quality ecological mathematical model of alkaline lakes with cyanobacteria and chlorophyta as the dominant algal species was also constructed by adding the improved algal growth equation and pH calculation model to the traditional ecological one. The model was then deployed in numerically simulating the algal growth process and water quality in Chenghai Lake from 2014 to 2016, when the water transfer was not conducted. After validation by the measured data, it was concluded that this model can preferably show the spatial and temporal changes of water temperature, chlorophyll a, pH and various nutrients in Chenghai Lake, and can grasp the overall trend pattern of algal biomass, as well as capture the algal growth process in the lake. The model can also effectively predict the algal ecology and evolution of the kind of alkaline lakes studied in this paper, and can provide a useful tool for subsequent ecological management of similar waters.
(6) The algal evolution trend of Chenghai Lake under the outer basin water transfer scenario was simulated and predicted, with the constructed coupled alkaline lake hydrodynamic-water quality ecological mathematical model. The simulated results show that the massive influx of neutral high-quality river water will lead to a decrease in the algal biomass level and cyanobacterial biomass proportion in the whole lake area, which will drop by about 32.3%-57.1% and 42.2%-69.2% respectively after the completion of the multi-year water level upgrade. The transfer also effectively reduced the extent of algae bloom and the extent where chlorophyta is not the dominant algae. Short-term intra-annual transfers can result in reductions of 4.9% to 17.6% and 26.4% to 36.8%, respectively. In addition, the cumulative effect of the water transfer over many years has led to a change in the intra-annual variation of algal biomass from a 'multi-peak' pattern with peaks in Marchs, Mays and Augusts before the transfer, to a 'single-peak' pattern with a peak in Mays only. The intra-annual variation in the proportion of cyanobacteria and chlorophyta also changed from a 'double-peak' pattern with peaks in Mays and Septembers to a 'single-peak' pattern with peaks in Mays only after the transfer. In addition, the effect on algae is less pronounced when the flow is evenly distributed over a long period than when the flow is high over a short period. The reduction in pH caused by the transfer also exacerbates the decline in algal biomass and cyanobacterial proportion in the lake, with the contribution up to 13.8% and 17.6% respectively under windy condition. While under extreme windless conditions, the reduction in pH caused by the transfer may cause chlorophyta to replace cyanobacteria as the dominant algae on a large extent in the northern parts of the lake. It is clear from the above that although water transfer reduces the risk of alga bloom outbreaks in alkaline lakes, it also leads to a reduction in the proportion of cyanobacterial biomass, which in turn threatens the absolute dominance of cyanobacteria in alkaline waters.
Keywords: water transfer, alkaline lakes, pH, planktonic algae, ecological model, algal community structure
More
Less
New! Video portfolio:
More
Less
Translation education
Other - NetEase Youdao Translation College
Experience
Years of experience: 4. Registered at ProZ.com: Jul 2021.
Portfolio