Aldo Barreiro Felpeto1 and Vitor M. Vasconcelos1,2
1 CIIMAR/CIMAR – Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Rua dos Bragas 289, 4050-123 Porto, Portugal.
2 Faculty of Sciences, Porto University, Rua do Campo Alegre, 4069-007 Porto, Portugal.
The occurrence of antibiosis between aquatic phototrophic microorganisms was known since the beginning of the 20th century. This rapidly awaked the interest of ecologists that considered these kind of chemical interactions as potential drivers of seasonal species succession, as well as a factor that could promote phytoplankton community diversity. These chemical interactions were later termed as allelopathic, due to their analogy with those phenomena observed in terrestrial plants. More recently, in the last quarter of the 20th century, despite some empirical evidence of the effects of allelopathy in natural phytoplankton communities, mainstream experimental and theoretical ecologists did not focus at all on allelopathy as a relevant mechanism in aquatic ecosystem functioning. Inadequacy to natural selection theory and strong physical constrains for the effectiveness of allelopathy in aquatic systems were some reasons for this dismiss. However, empirical evidences of the existence of allelopathy in aquatic ecosystems are still reported, and, quite recently, it has been developed a strong theoretical body of knowledge that clearly shows the potential of allelopathy as a mechanism promoting phytoplankton diversity. Theoretical works have considered the interplay of allelopathy with nutrient competition, as well as the influence of other relevant factors such as medium homogeneity, temporal delays, feedbacks related with evolutionary adaptation, phenotypic changes, nutrient stress or nutrient dynamics. In our view, there is not enough evidence to dismiss allelopathy as a relevant factor in phytoplankton dynamics, although more works combining theoretical and experimental approaches are needed, as well as more development in the analysis of this phenomena from a functional point of view, since allelopathy could manifest its effects through completely different pathways (cell signaling, insidious long-term effects, contact micro-predation), and because genetic sub-population structure during population dynamics may also play a role in intraspecific dynamics of allelopathy.
RECEIVED: June 10, 2016
ACCEPTED: June 13, 2016