http://www.sciepub.com/journal/MARINE American Journal of Marine Science is a peer-reviewed, open access journal that provides rapid publication of articles in all areas of marine science. The goal of this journal is to provide a platform for scientists and academicians all over the world to promote, share, and discuss various new issues and developments in different areas of marine science. Science and Education Publishing en 2013 Science and Education Publishing Co. Ltd All rights reserved. American Journal of Marine Science 11 1 January 2024 2013 Science and Education Publishing Co. Ltd All rights reserved. http://pubs.sciepub.com/marine/11/1/1 2) emitted into the atmosphere. This process results in the production of carbonic acid, contributing to the acidification of the ocean and a decrease in seawater pH, which is referred to as ocean acidification. Human activities and natural sources primarily cause this acidification process, and it poses a significant threat to marine ecosystems. One of the key impacts of ocean acidification is the depletion of carbonate ions, which are essential for forming skeletons and shells in many marine organisms, including corals. there is a lack of detailed information regarding the fluctuation of seawater carbonate chemistry in Pacific island coastal regions like Samoa. To bridge this gap in knowledge, a study was conducted to examine the temporal variability of seawater carbonate chemistry at five locations along the North coast of Upolu Island. The mean pH was measured spectrophotometrically using the m-Cresol purple buffer. The total alkalinity (A_T) was measured through titration of seawater with standardized 0.101970 mol/kg HCl. The measured values from the spectrophotometer at three wavelengths: a non-absorbing wavelength (730 nm for m-Cresol purple) and at the wavelengths corresponding to the absorption maxima of the base (I^2–) and acid (HI^–) forms of the dye respectively (578 and 434 nm) and the EMF values from the seawater titration were used to calculate the actual pH and A_T. The results showed that these values varied across 5 sites. The overall distribution of mean pH across 5 sites fell below the mean average pH of 8.1 for open ocean water ranging from 7.944 ± 0.090 to 8.087 ±0.069, while the mean seawater A_T values fell within the normal A_T range of (2100-2500µmol kg^–1). Thus, the variability of these seawater parameters over the study area has indicated healthy coastal waters.]]> Tina Taitaifono Mareko, Patila Amosa, Faainuseimalie Latu, Tanuvasa Toetu Leasi 2024-07-02 Science and Education Publishing 2024-07-02 1 11 1 9 10.12691/marine-11-1-1