Towards a comprehension of Ceratium (Dinophyceae) invasion in Brazilian freshwaters: autecology of C. furcoides in subtropical reservoirs

Abstract

Ceratium species are not a common component of freshwater phytoplankton in South America. However, these dinoflagellates have often been observed in many water bodies over the past two and a half decades. We investigated Ceratium furcoides' abundance and morphological variation during its initial phase of colonization (2012)(2013) in two subtropical reservoirs in southern Brazil in order to explore which environmental factors were related to the occurrence, persistence and bloom formation of this dinoflagellate in those environments. Biomass of C. furcoides showed a strong seasonal pattern, in which warm seasons led to an increase in population density, resulting in cell-size reduction, while in the cold seasons cells increased in volume. Maximum densities over 2,500 cells ml -1 were observed in spring-summer periods in both reservoirs. C. furcoides' abundance in the studied reservoirs was associated, primarily, with a combination of optimal conditions of temperature, organic matter, and pH, and secondarily, with nutrient availability. The possible factors for the successful colonization performed by C. furcoides across distinct Brazilian waterbodies include good swimming performance, low herbivory pressure, and ability to form dense blooms, as strategies that allow maintenance of populations and effective dispersal.

A proxy for estimating the cell volume of Ceratium furcoides (Dinophyceae): basis for monitoring Brazilian reservoirs

“…The limnological characterization of these environments, as well as the population dynamics of C. furcoides during the study period, was previously reported by Cavalcante et al. ().…”

“…Ceratium furcoides (Levander) Langhans is a common dinoflagellate in the northern hemisphere, but was not reported in South America until 2003 (Cavalcante et al., ). Since that time, Brazilian phytoplanktologists have been surprised by the introduction and quick expansion of this dinoflagellate in freshwater systems in Brazil (Cavalcante, Cardoso, Sussella, & Becker, ).…”

“…A more recent approach, including 230 measurements of C. furcoides cells from 63 European waterbodies, indicated that cell body width (= cingulum width) is the most representative measure of the cell volume (Napiórkowska‐Krzebietke & Kobos, ). Considering the emerging importance of the dense blooms that have occurred in Brazilian tropical and subtropical reservoirs (Cavalcante et al., ), it is necessary to develop a model for calculating cell volume that is adapted to the features of these invasive populations.…”

Influence of light and mixing regime on bloom‐forming phytoplankton in a subtropical reservoir

“…Likewise, Ceratium seasonal dynamics was well represented by a niche response model based on temperature alone with an optimum of 21 °C (Grover & Chrzanowski, ). Cavalcante et al () reviewed the autoecology of C. furcoides in subtropical reservoirs confirming this growth temperature range.…”

“…Such modification in turbulence regimes enables the development of phytoplankton species that cannot develop in fast flowing waters but will progressively achieve large populations on behalf of frequently stratified water columns with sufficient nutrients and light conditions. Reservoirs worldwide are inhabited by phytoplankton assemblages dominated by Microcystis , Dolichospermum , or Ceratium species, forming either mixed or single blooms (Cavalcante, Cardoso, Sussella, & Becker, ; Crosetti & Bicudo, ; Dai, Yang, & Cai, ; Hu & Xiao, ; Jacoby & Kann, ; Matsumura‐Tundisi, Tundisi, Luzia, & Degani, ; Mwara, Koyo, & Zech, ; Oberholster, Botha, & Ashton, ; Te & Gin, ; Znachor et al, ). In South America, the proliferation of cyanobacteria as well as the recent invasion of Ceratium is largely a consequence of building cascades of reservoirs on large rivers (Padisák, Vasas, & Borics, ).…”