Chemical sea conditions in Miraflores Bay: summer and spring of 2013 and 2014

Abstract

This study presents findings on the chemical conditions of seawater in Miraflores Bay during the summer and spring of 2013 and 2014. Data were collected in March and between late September and early October, respectively. A total of 32 sampling stations were established along perpendicular profiles to the coast, with water samples collected at surface and bottom levels. Miraflores Bay, located in the central region of Peru, exhibits distinct characteristics in its northern and southern areas due to its geographical configuration. The formation of eddies in the northern region promotes water retention and creates physicochemical conditions favoring high phytoplankton biomass. Conversely, the southern region experiences greater water exchange influenced by coastal upwelling, resulting in lower temperature (< 16 °C), reduced oxygen content (< 4 mL/L), and lower pH (< 8.1). Anthropogenic impact from domestic wastewater discharge, particularly from the La Chira sewer outfall, is observed, leading to increased phosphate levels at the surface and bottom levels in the southern zone, exceeding normal values. In contrast, nitrates tend to decrease, with concentrations below 5 µM, particularly during the summer and spring seasons, indicating their consumption through biogeochemical processes facilitated by low oxygen levels.