Evaluation of the behavior of Eichhornia crassipes during the drought in the Olomega and El Jocotal lagoons using remote sensors

Abstract

The algal bloom of Eichhornia crassipes is common in the lagoons of Olomega and El Jocotal, however, there is no accurate idea of the behavior of Eichhornia crassipes in both lagoons during the dry season. In the present study, the phenomenon was analyzed using remote sensors, first identifying the drought periods through the calculation of the standardized precipitation and evapotranspiration index with the data of monthly precipitation, monthly maximum temperature, and monthly minimum temperature, during the years from 2012 to 2021 in the Olomega and El Jocotal lagoons. Subsequently, with the use of satellite images taken from Landsat for the selected drought periods, the normalized difference vegetation indices were calculated to obtain the areas of the water mirror without and with algal bloom of Eichhornia crassipes for each lagoon. Finally, with geographical information systems, different transition matrices were created to evaluate the changes of algal bloom of Eichhornia crassipes during periods of drought, as well as of the area of water body without algal bloom. The results obtained showed that for both lagoons a higher drought index is not synonymous with a greater algal bloom of Eichhornia crassipes, so drought does not have an impact on the presence of Eichhornia crassipes, however, the water body without algal bloom does is affected during periods of drought.