Continental runoff is an important source of solutes and nutrients to coastal coral reefs. Nevertheless, they can also act as local stressors due to high coastal urbanization and the associated release of untreated effluents. Here we aimed to qualitatively investigate the effects of seasonality over reefs from the Costa dos Corais Marine Protected Area (Brazil) and to identify the influence of local rivers on the reefs' environmental status. Surface waters from the reef lagoon located at Maragogi (city from the state of Alagoas, northeast Brazil) and Japaratinga (city from the state of Alagoas, northeast Brazil) were sampled monthly from July 2018 to June 2019 and abiotic parameters were measured. Samples were taken with a 2 L Niskin bottle and stored for subsequent analyses of: total alkalinity (TA), pH, nitrate, nitrite, ammonium, dissolved inorganic phosphorus and silicate. For temperature, salinity and depth measurements it was used a RBR® C.T.D.