IOV - Distribución espacial y temporal del fitoplancton en el Golfo de Cariaco

Coastal phytoplankton is affected by natural and anthropic processes. To analyze the influence of some of these processes, the spatial and
temporal distribution of phytoplankton in the Gulf of Cariaco, Sucre state, was evaluated. Samples (0-10 m) were collected with Niskin
bottles (5 L) in seven stations between February 2014 and January 2015. Transparency (m), salinity (UPS), temperature (° C), chlorophyll
concentration a (mg m-3), and phytoplankton abundance (org mL-1) were measured. A nonparametric analysis of variance and multivariate methods
(PCA, CCA, and nMDS) were used to analyze the results. The 0 - 10 m stratum was homogeneous with respect to all variables except temperature
which ranged from 20.1 to 29.1 °C (March and October, respectively). Temporally, the variables were heterogeneous. Biomass fluctuates between
undetectable (ND) and 17.5 mg m-3 (December and March). While microalgal abundance oscillated between 0.24 and 1.85 x 103 org mL-1 (April and
February). The community was dominated by diatoms, nanoflagellates, and coccolithophorids. The first two groups were associated with turbulent,
nutrient-rich waters. The nMDS separated the community into the three periods previously described for the region. Likewise, the CCA detected
that wind speed and temperature were the most influential variables on the phytoplankton community during upwelling and relaxation period,
respectively. In the transition period, none of the variables studied affect the community. This is the first time that coccolithophores are reported as
part of the dominant flora in the Gulf of Cariaco. This change suggests modifications in the oceanographic conditions of the study area