Spatial and temporal variations of phytoplankton chlorophyll a and suspended particulate matter in Mayagüez Bay, Puerto Rico

Abstract

Monthly measurements of chlorophyll a (Chl-a), suspended particulate matter (SPM), light penetration and salinity were taken from March 1990 to February 1991. These parameters were sampled at three different transects with respect to the Añasco, Yagüez and Guanajibo river discharge in Mayagüez Bay, off the western coast of Puerto Rico. A reduction in salinities occurred at all stations from August to November, and corresponded with high precipitation and large river discharge. Maximum Chl-a values were registered at inshore stations during the rainy season. Maximum values of SPM were recorded in October and November; the minimum values were found from March to June. The spatial correlation between Chl-a and SPM was significantly positive for the entire study period, but the temporal relationship was not significant. The relationship between Chl-a and SPM may reflect the relationship between nutrients and SPM, and the physiological adaptations of phytoplankton to light intensity.