Growth Of Algal Blooms Research Articles

The role of zooplankton in the growth of algal bloom: a mathematical study

Here a nonlinear mathematical model for an aquatic ecosystem containing both non-toxic and toxin-producing algal blooms is formulated and analyzed. The presence of harmful algae impacts the aquatic population, subsequently affecting the human population that relies on zooplankton (fish, crabs, etc.). It also deteriorates the water quality, and it is advisable not to use water from lakes containing harmful algae. Here, our focus is to understand the dynamics of aquatic ecosystems when we have both types of algae, one that is non-toxic and acts as food to zooplankton, and another that is toxin-producing algae that causes death to zooplankton. The predation of zooplankton on algae influences the growth of the algae population. First, we consider a deterministic model, and later, this model is extended to stochastic model to check whether it has any impact on the dynamics of the populations under consideration. Various equilibria of the proposed model are derived, and the local stability of these equilibria is thoroughly examined. The existence of Hopf-bifurcation is also demonstrated for a suitable set of parameters. The results of deterministic and stochastic models are compared using numerical simulation. Upon examining our results and simulation data, it is evident that modifying specific key parameters, such as the growth rate of non-toxic algae due to nutrient intake and the parameter associated with the predation of non-toxic algae by zooplankton, has a substantial impact on algal bloom dynamics. Minor adjustments to these parameters can result in an augmented presence of non-toxic algae and a simultaneous decrease in toxin-producing algae, aligning with the primary objectives set by policymakers.

Harmful algal blooms (HAB) open issues: A review of ecological data challenges, factor analysis and prediction approaches using data-driven method

Ongoing research on the temporal and spatial distribution of algae ecological data has caused intricacies entailing incomprehensible data, model overfit, and inaccurate algal bloom prediction. Relevant scholars have integrated past historical data with machine learning (ML) and deep learning (DL) approaches to forecast the advent of harmful algal blooms (HAB) following successful data-driven techniques. As potential HAB outbreaks could be predicted through time-series forecasting (TSF) to gauge future events of interest, this research aimed to holistically review field-based complexities, influencing factors, and algal growth prediction trends and analyses with or without the time-series approach. It is deemed pivotal to examine algal growth factors for useful insights into the growth of algal blooms. Multiple open issues concerning indicator types and numbers, feature selection (FS) methods, ML and DL forms, and the time series-DL integration were duly highlighted. This algal growth prediction review corresponded to various (chronologically-sequenced) past studies with the algal ecology domain established as a reference directory. As a valuable resource for beginners to internalize the algae ecological informatics research patterns and scholars to optimize current prediction techniques, this study outlined the (i) aforementioned open issues with an end-to-end (E2E) evaluation process ranging from FS to predictive model performance and (ii) potential alternatives to bridge the literature gaps.

A Mathematical Study on Rising Pressures of Carbon Emissions and Acidity in Aquatic Bodies

Contamination of water bodies is one of the alarming concerns of today’s times calling for immediate attention and action. Accelerated industrialization and other human-driven activities have given way to abrupt spike in the carbon emissions. These carbon emissions are absorbed by the water bodies. As a resultant of this absorption, the carbon reacts with oxygen present in water, forming carbonic acid and causes the pH level of water to decrease, thus, causing water acidification. The acidity of water also increases due to discharge of wastes and pollutants into aquatic bodies. Also, the carbon induced global warming leads to an increase in the temperature of water which further leads to a decline in level of dissolved oxygen in aquatic bodies. Besides, these phenomena cause a rise in the growth of algal bloom, which depletes the dissolved oxygen concentration in water due to consumption of dissolved oxygen in algal decomposition process. To investigate these impacts of increasing acidity and rising carbon emissions on the aquatic populations, a non-linear mathematical model is proposed and analysed. Numerical simulations using MATLAB are performed in order to support the analytical results.

Phosphorous removal from anaerobically digested municipal sludge centrate by an electrocoagulation reactor using metal (Al, Fe and Al-Fe) scrap anodes

Phosphates are a major cause of eutrophication and growth of algal blooms in surface waters. The current study investigated phosphorus removal from sludge centrate effluent (SCE) of a municipal wastewater plant by packed-bed electrocoagulation (EC) reactor. Distinctively, iron (Fe), aluminum (Al) and Al-Fe hybrid scrap anodes were used. The influence of initial pHi, applied current and packed anode bed density were evaluated. Phosphorous removal efficiency of 99.99 % was obtained at applied current of 0.20A with anode bed densities of 0.18 kg Al/m3 (pHi 5.0) and 0.48 kg Fe/m3(pHi 7.0). Optimum operating costs entailing sludge disposal, chemical, energy and electrode consumption were calculated as 0.379 US $/m3 (6.04 $/kg PO4-P) for Fe scrap, 0.494 US $/m3 (9.46 $/kg PO4-P) for Al scrap and 0.501 US $/m3 (9.59 $/kg PO4-P) for Al-Fe hybrid scraps. Phosphorus removal per electrochemically generated metal was 191.22 mg P/g Al, 104.88 mg P/g Fe, and 61.08 mg P/g (Al + Fe). The molar metal to phosphorus ratio at optimum conditions were calculated as 5.41, 3.97 and 7.65 mol/mole for Al, Fe and Al-Fe, respectively. The key mechanisms for phosphorus removal were metal-phosphorus precipitation and adsorption. Herein, metal scrap anodes have been proved effective for phosphorous removal from SCE.

Trophic state of an urban coastal lagoon (northern Brazil), seasonal variation of the phytoplankton community and environmental variables

Jansen Lagoon is an urban coastal area formed by damming the Ana Jansen Creek, which is located in the northwest of São Luis Island (northern Brazil) and is influenced by semidiurnal macro-tides. This study aimed to characterize the seasonal variation of the phytoplankton communities and its relationship with environmental variables to determine the trophic conditions in the Jansen Lagoon. Samples were collected bimonthly in five fixed sites in 2011 and 2012 to analyze biological and physicochemical data. A total of 55 taxa were identified including Bacillariophyta (25), Cyanobacteria (17), Chlorophyta (5), Charophyta (2), Euglenophyta (4) and Miozoa (2). The Closterium setaceum, Pleurosigma elongatum e Oscillatoria sp3 occurrence had a positive correlation with the higher rainfall period, increase in dissolved oxygen concentrations and nutrients (DIP and NO2−) and elevated trophic levels (TRIX). Cyclotella stelligera and Microcystis aeruginosa were strongly correlated with chlorophyll a concentration (microphytoplankton) under turbidity and wind speed influence. The trophic state of Jansen Lagoon ranged from eutrophic to hypereutrophic according to the TRIX index, and this poor water quality is explained by an intense eutrophication process in the rainy season due to elevated nutrient availability. Hence, to change the scenario presented in this study the reduction of point and non-point sources is necessary to slow down the eutrophication and growth of algal blooms in Jansen Lagoon.

The Process of Algal Bloom Formation and the Effects of Wind - An Enclosure Experiment and <i>In Situ</i> Investigation in a Large Hyper-Eutrophic Shallow Lake in China

An enclosure experiment was conducted to evaluate the processes involved in algal bloom formation at different trophic levels in Chaohu Lake, which is a large hyper-eutrophic shallow lake in China. In situ investigations were conducted concurrently to quantitatively describe the effects of wind on the horizontal transference and vertical hybridization of algal blooms. The results revealed that certain nutrient trophic levels played a crucial role in the formation of algal blooms. Specifically, sediments were identified as an important source of nutrients and algal seeds that are necessary to maintain the trophic level and growth of algal blooms. In addition, the disturbance caused by wind accelerated the multiplication of algae, as well as their sedimentation and suspension at the water-sediment interface. Furthermore, when the wind speed was less than 3m•s-1, algal clusters drifted on the water surface at a speed that was exponentially related to the wind velocity with a coefficient of 0.9052. When the wind speed was greater than 3m•s-1, the algae mixed together vertically and then sank. The algal bloom distribution in the lake was dominated by leading wind directions. Moreover, the algal biomass of the surface lake water in leeward areas was 8.8 times greater than the biomass in the windward areas during the study period.

Environmental pollution of Udaisagar lake and impact of phosphate mine, Udaipur, Rajasthan, India

The study of water chemistry and sediment core samples from Udaisagar lake in Rajasthan has revealed high phosphate contents; 186 and 236 μg/l in surface and sub-surface waters and in core samples 0.157 wt % P2O5, low D.O. 4.61 and 3.50 mg/l on average in surface and depth waters and high E.C. 1316 and 1395 μs/cm and higher sedimentation rate 8.90 mm/year in this lake compared to other lakes in the vicinity. The enormous and wide-spread growth of algal bloom in lake water and Ahar river and occasional fish mortality are indications of eutrophic conditions prevailing in the lake. Such a situation is developing due to the discharge of pollutants from phosphorite mines, chemical factories, distillary, sewage and domestic waste from settlements, hotels throughout the length of River Ahar which during its journey receives and finally discharges pollution in this lake. This renders the water unhygenic for human consumption and deleterious to aquatic life.

Feedlots and Water Quality: A Comparison of Regulatory and Market-Based Approaches

Nutrients from the effluent of intensive livestock production can enter waterways and promote excessive growth of algal blooms. The first aim of this article is to examine the likely costs to the i...

Experimental Studies on the Effect of Arsenic on Microbial Degradation of Organic Matter and Algal Growth

Experiments were performed in tubes in Lake 303 at the Experimental Lakes Area to determine the effects of arsenate and arsenite on microbial degradation of organic matter, and to determine rates of reduction and oxidation of inorganic arsenic. Under winter ice, 40 μmol∙L−1 arsenate or arsenite inhibited microbial degradation of organic matter by 50%. Rates of oxidation of arsenite were about 2 μmol∙L−1∙d−1 under aerobic conditions, and rates of reduction of arsenate were about 1 μmol∙L−1∙d−1 under anaerobic conditions. During the ice-free season, arsenate and arsenite had little apparent effect upon rates of degradation of organic matter in lake tubes enriched with nutrients. Rates of formation of particulate phosphorus, and rates of planktonic uptake of dissolved phosphorus were depressed in the presence of arsenic. The observed rate of oxidation of arsenite in summer was similar to the winter value. Arsenate reduction rates ([Formula: see text]30 μmol∙L−1∙d−1) were very rapid under short periods of anaerobiosis. In the presence of large nutrient (N, P) concentrations, As did not inhibit the development of high algal biomass.Based on these experiments, we predict that addition of domestic sewage to arsenate-polluted Kam Lake (near Yellowknife, N.W.T.) will result in a state of restrained eutrophication. Degradation of organic matter will not be inhibited by As in summer, and dissolved phosphorus concentrations will remain high, due to As inhibition of P uptake by the plankton. During the summer, growth of algal blooms may be moderated by As, and more dissolved phosphorus will flow out of the lake to downstream waterbodies.Key words: arsenic, bacteria, algae, organic matter decomposition, eutrophication