Diversity patterns of planktonic ciliates in Chautengo lagoon, Guerrero, Mexico

Abstract

The study of the spatial distribution of plankton diversity is important, as it contributes to gain insight about ecosystems structure and functioning. We studied the spatial organization of planktonic ciliate diversity in Chautengo lagoon, Guerrero. The objectives were 1) to identify and characterize the spatial patterns of ciliate diversity and their seasonal variability, and 2) to assess the influence of environmental factors on diversity distribution. Conditional simulation geostatistical analysis was applied to H (Shannon diversity index), computed from samples collected in 40-45 sites in the lagoon in rainy and dry seasons. The relationship between ciliate diversity and lagoonal environment was examined using principal component analysis (PCA). We identified 36 planktonic ciliate morphospecies; H ranged from 0.08 to 1.9 and was patchily distributed. PCA indicated that ciliate diversity changed according to the seasons and the hydrodynamics of the sand bar opening and closing. In the rainy season, when the sand bar was open, a higher spatial heterogeneity was prevalent, with many smaller patches (1.6 km) dominated by the phototrophic Myrionecta rubra. In contrast, during the dry season and when the sand bar was closed, two larger diversity patches (2.7 km) prevailed and the dominant ciliates were Lohmanniella oviformis and Tintinnopsis sp. The impact of the patchily distributed ciliate diversity on the food webs is discussed.