Composition and dynamics of phytoplankton and aloricate ciliate communities in the Bahía Blanca Estuary

POPOVICH, C. A.; GUINDER, V. A.; PETTIGROSSO, R. E.

Perspectives on integrated coastal zone management in South America

IST Press. Scientific Publishers

Año: 2008; p. 257 - 272

Estuaries are extremely heterogeneous systems where physical, chemical, geological and biological factors closely interact. These heterogeneous conditions cause seasonal and spatial variation in the estuarine environment and therefore on the phytoplankton dynamics. Short-term variability (daily, monthly, seasonal) in phytoplankton community structure could be induced by duration of the photoperiod, light availability in the water column, vertical stratification, tides, horizontal advection, resuspension and sedimentation rates, precipitation, winds, vertical migration, nutrient loading and zooplankton pressure (e.g. Cushing, 1989; Cloern et al., 1985; Cloern, 1991; Cartensen, 2007). Interannual variation includes all these relatively short time scale variations as well as climatic global changes, droughts, floods and estuarine circulation, among others (e.g. Cloern, 1996; Smayda, 1998).  Therefore, in temperate estuaries, it is the combination of different environmental variables that interact with the biological properties of phytoplankton and induces changes in the community structure. In addition, the floristic composition of estuarine phytoplankton communities varies according to biogeographical aspects on both regional and local scales. Documenting phytoplankton dynamics is an essential step to assess the role of estuaries in biogeochemical cycles (Longhurst et al., 1995), as well as to determine the long-term responses of coastal ecosystems to anthropogenic stress (Harding and Perry, 1997). One of the most relevant features of long-time phytoplankton studies is that they allow detection of potential changes in the successional annual pattern and interannual variations. Long-term studies on phytoplankton dynamics and physicochemical parameters have been carried out in Bahía Blanca estuary covering taxonomic, ecological and experimental aspects. This chapter summarizes the whole historical information available about the phytoplankton community in the Bahía Blanca estuary. Data are discussed from an ecological perspective.