Outlining the causes and effects of Algae bloom at Ghana’s West Coast

The first incidence of algal bloom within Ghana’s west coast was recorded in 1993, however many years down the line, the growth is still persistent in her territorial waters. A lasting solution is yet to be found. This has therefore led to several social, economic and environmental problems in the affected regions. The study outlined the possible causes and effects of algal bloom within Ghana’s West Coast. The perception of the local people with regards to the causes was also investigated. The method used was by direct observation and use of questionnaires following a case study approach in the Half Asini District. This was to address the pertinent question of what the people think is the cause of the bloom. The study found that the growth of Algae was alarming, with a newer breed having a much negative consequence on the economic livelihood of the people and environment. It was also found that current studies on the issue were minimal— with less than necessary attention being given by stakeholder. However, scientific investigations were underway, though a preliminary report suggested it is a migration of Sargasso Sea species. Recommendations included the need for consented government efforts to investigate, device a control measure to curtail its spread, and continuous public education as a control measure was recommended as well.

EVALUATION OF WASTEWATER TREATMENT IN NUSA DUA TOURISM AREA AND THEIR CHALLENGES TO ALGAE BLOOM

<p>The wastewater treatment plant (WWTP) in the Nusa Dua area has implemented a stabilization pond to reduce organic matter and nutrients. Because it has been operating since 1980, it is necessary to evaluate the existing conditions. The aim of this study was to determine the percentage of organic and nutrient reduction from the WWTP system. Organic removal in the form of BOD and COD parameters were 71.84% and 75.11%, respectively. Meanwhile, nutrient parameters in the form of NH3-N, TN, and TP have a percentage of 83.64%; 59.41%, and -375.81%, respectively. TP is the only parameter that has increased, causing a problem which is caused by the explosion of algae population in the reservoir. TP allowance should be a concern in choosing advanced treatment.<em></em></p>

Indirect assessment of biomass accumulation in a wastewater-based Chlorella vulgaris photobioreactor by pH variation

Algae bloom in coastal waters is partly supported by residual nutrients in treated wastewater (WW) released from coastally located treatment plants. In response, a Chlorella vulgaris-based photobioreactor was recently proposed for lowering nutrient levels in WW prior to release. However, the solution requires maintaining biomass accumulation to within a photobioreactor capacity for optimum operation. For high density Chlorella vulgaris suspensions, this is easily done by monitoring turbidity increase, a property directly related to biomass accumulation. For low density suspensions however, direct turbidity measurement would require a cumbersome process of concentrating large volumes of Chlorella vulgaris suspensions. Here, we demonstrate that by measuring pH of the suspensions, turbidity (T) can be estimated indirectly by the following wastewater-dependent expression: pH = aT + pH0, hence avoiding the need to concentrate large volumes. The term pH0 is the initial pH of the suspensions and a, a wastewater-dependent constant, can be computed independently from a = − 0.0061*pH0 + 0.052. In the event %WW is unknown, the following wastewater-independent Gaussian expression can be used to estimate T: pH = 8.71*exp(− [(T − 250)2]/[2*1.26E05]). These three equations should offer an avenue for monitoring the turbidity of dilute Chlorella vulgaris suspensions in large, stagnant municipal Chlorella vulgaris-based wastewater treatment system via pH measurements.

Thermal regime of the Dnipro Reservoirs

Based on the results of regular monitoring and remote sensing data the patterns of water temperature of the reservoirs cascade on the Dnipro River were identified. A characteristic feature of the thermal regime of the Dnipro Cascade has been the water temperature increase over the past decades. In the period 1977–2020 the water temperature in summer increased by 0.74 °C decade−1, and during May–October by 0.65 °C decade−1. An important factor influencing the thermal regime of the reservoirs is the influence of those ones, located upstream. Water from them is discharged from the lower layer, where the processes of heating and cooling are very slow. This has a significant influence on the water temperature of downstream reservoirs, especially on their upper part. The water temperature in this part during spring and summer seasons is lower compared to natural conditions. In autumn it is higher. The temperature of water also depends on the latitude: it rises in the reservoirs located both downstream and to the south. Another important factor influencing the water temperature is the wind, which can change the temperature in the surface layer by 5–6 °С. Water temperature also depends on the intensity of algae bloom – it is higher in the spots of a large bloom.

AlgaeMAp: Algae Bloom Monitoring Application for Inland Waters in Latin America

Due to increasing algae bloom occurrence and water degradation on a global scale, there is a demand for water quality monitoring systems based on remote sensing imagery. This paper describes the scientific, theoretical, and methodological background for creating a cloud-computing interface on Google Earth Engine (GEE) which allows end-users to access algae bloom related products with high spatial (30 m) and temporal (~5 day) resolution. The proposed methodology uses Sentinel-2 images corrected for atmospheric and sun-glint effects to generate an image collection of the Normalized Difference Chlorophyll-a Index (NDCI) for the entire time-series. NDCI is used to estimate both Chl-a concentration, based on a non-linear fitting model, and Trophic State Index (TSI), based on a tree-decision model classification into five classes. Once the Chl-a and TSI algorithms had been calibrated and validated they were implemented in GEE as an Earth Engine App, entitled Algae Bloom Monitoring Application (AlgaeMAp). AlgaeMAp is the first online platform built within the GEE platform that offers high spatial resolution of water quality parameters. The App benefits from the huge processing capability of GEE that allows any user with internet access to easily extract detailed spatial (30 m) and long temporal Chl-a and TSI information (from August 2015 and with images every 5 days) throughout the most important reservoirs in the State of São Paulo/Brazil. The application will be adapted to extend to other relevant areas in Latin America.