Influence of Kingston Harbor on the Phytoplankton Community of the Nearshore Hellshire Coast, Southeast Jamaica

The phytoplankton community composition, abundance and size fractionated biomass (Chlorophyll a) were determined, over 17 months, from 22 stations at the mouth of Kingston Harbor and the Hellshire coast, Jamaica, This study was conducted to indicate the influence of eutrophic harbor outflow on the Hellshire coastline, The influence of this outflow varied in relation to the proximity of the areas to the Hellshire coast. Phytoplankton communities at offshore and inshore waters were found to be more similar (up to 60% similarity) to the harbor community than bay communities (maximum 40% similarity). On several occasions, harbor species such as Gyrodinium were found in offshore and inshore communities but never in bay communities. The eutrophic state of the harbor was confirmed with the outflow of the harbor having a phytoplankton abundance of >10⁶ cells˙ liter^-1 and a total biomass of 2.64 mg˙m^-3 chlorophyll a. These high values decreased exponentially among offshore and inshore stations with increased distance from the harbor and with a less predictable pattern for bay stations. At offshore stations, as much as 60% of the variation in total phytoplankton biomass was attributable to distance from the harbor while only 44% and 39% could be attributed to harbor distance at inshore and bay stations, respectively (R², P < 0.0001). The introduction of factors such as salinity changes and wind from different directions improved the R² at bay stations from 39 to 60%, inshore stations from 44 to 56%; but only 60 to 64% improvement was realized at offshore stations (P < 0.0001). The influence of Kingston Harbor was pronounced in offshore and inshore waters along the Hellshire coast, but minimal in the bays.