Abstract:
In recent years, the northwestern part of the North Pacific areas of Costa Rica has un-
dergone rapid socioeconomic development. This situation, combined with the scarce available
information about the water quality of the Gulf of Papagayo, became the starting point to carry out a
study to investigate the spatiotemporal variations of physicochemical and biological parameters of
surface waters. Seven samplings were collected during the dry season and the rainy season from
October 2016 to February 2018. Water quality parameters such as: temperature, salinity, dissolved
oxygen, and chlorophyll a of six analytes: nitrate, nitrite, ammonia, phosphate, silicate and biological
oxygen demand were measured. The results showed that phosphate and ammonium levels were
lower during the rainy season (<6 µg P-PO4
3 L 1–9.53 µg P-PO4
3 L 1 and <11 µg N-NH4
+ L 1
–
9.57 µg N-NH4
+ L 1) than during the dry season (<6 µg P-PO4
3 L 1–13.64 µg P-PO4
3 L 1 and
<11 µg N-NH4
+ L 1–14.43 µg N-NH4
+ L 1), which may be related to low rainfall (0, 00–26, 16 mm)
winds from December to March. The physical, chemical, and biological indicators demonstrated that
the Gulf waters had adequate quality. Nonetheless, there are specific areas such as Culebra Bay with
conditions that could show deterioration of water quality.
