Annual cycle of phytoplankton in the Pacific ocean near Guatemala in relation to physicochemical parameters

Due to the lack of basic information on the behavior of the phytoplankton community of the Guatemalan Pacific, particularly of the factors that cause harmful algal blooms, monthly monitoring was performed during a year (January–December 2021), which included three hydrometeorological seasons at three sampling sites in Puerto Quetzal (Texaco Buoy, Recalada Buoy and Entre Morros Buoy) at two depths (1.5 m and 5.0 m). These sites are influenced by shipping and nearby human populations. The structure of the phytoplankton community (species composition, abundance, richness and diversity), with an emphasis on potentially toxic and non-toxic harmful species, were evaluated. A total of 53 diatom species from 26 genera and 13 orders and 42 dinoflagellate species from 14 genera and six orders were identified. No significant differences between the sampling depths and different quarters of the year were found. The comparison of the total cell abundance between the three sites showed no significant differences. The results obtained present novel information on the phytoplankton community of the Guatemalan Pacific, filling a gap in a region where algal blooms occur annually with consequent ecological impacts and human poisonings.