Marine-coastal water quality in the bays of San Juan del sur, Escameca, La Flor and El Ostional, Pacific Ocean coast of Nicaragua

Abstract

Coastal waters are habitat for marine species and provide environmental services to humans for different economic activities. Monitoring physicochemical variables, nutrients in the coasts of El Ostional, San Juan del Sur, Escameca and La Flor is of vital importance because it is a transit route for marine species and to understand the different factors that modify the composition of oceanic waters in the southern Pacific of Nicaragua, as well as being attractive for bathing and recreation of the population. The main objective of the research is to determine the quality of the marine-coastal waters through physicochemical composition, nutrients and Marine Water Quality Indicator (MWQI). Two samplings were conducted at each site, one in rainy period 2018 and another in dry period 2019, integral samples were taken from 20 m depth, physicochemical variables were performed on site and samples for laboratory analysis of nutrients, microbiological. The results indicate that the physicochemical behavior fluctuates according to the monitoring period and the depth of measurement, the physicochemical variables and nutrients depend primarily on the rainy season that provides nutrients either by atmospheric fixation or by runoff. Another factor that influences the chemical composition and nutrients in the dry season is the high wind conditions that produce an upwelling of nutrient-rich water. No evidence of fecal bacteria contamination was found. The ICAM water quality index places the bays in the optimal and adequate ranges, variation depending on the time of year.