Title: Macroalgal defense against competitors and herbivores

Abstract

Macroalgae are the source of many harmful allelopathic compounds, which are synthesized as a defense strategy against competitors and herbivores. Therefore, it can be predicted that certain species reduce aquaculture performance. Herein, the allelopathic ability of 123 different taxa of green, red, and brown algae have been summarized based on literature reports. Research on macroalgae and their allelopathic effects on other animal organisms was conducted primarily in Australia, Mexico, and the United States. Nevertheless, there are also several scientific reports in this field from South America and Asia; the study areas in the latter continents coincide with areas where aquaculture is highly developed and widely practiced. Therefore, the allelopathic activity of macroalgae on coexisting animals is an issue that is worth careful investigation. In this work, we characterize the distribution of allelopathic macroalgae and compare them with aquaculture locations, describe the methods for the study of macroalgal allelopathy, present the taxonomic position of allelopathic macroalgae and their impact on coexisting aquatic competitors (Cnidaria) and herbivores (Annelida, Echinodermata, Arthropoda, Mollusca, and Chordata), and compile information on allelopathic compounds produced by different macroalgae species. To recognize the allelopathy impact of macroalgae on coexisting animals, many investigation methods are necessary, from field observation to co-culturing experiments in mesocosms. Most studies on the allelopathic activity of macroalgae on target aquatic animals are characterized by a specific method suited to test those organisms and environment. The allelopathic activity of macroalgae can change according to the taxonomic position of the donor and target organisms, as well as their habitat. This work gathers the current knowledge on the phenomenon of macroalgal allelopathy and their allelochemicals affecting aquatic animal (competitors and predators) worldwide and it provides future research directions for this topic.

Biography

I. Bubak is an employee of the Institute of Geography at the University of Gdańsk. However, she is a marine biologist by training. Since the beginning of her scientific career her research interests have been focused on algae, in particular on diatoms. Her main topic was to describe and distinguish specific diatom communities characteristic for ecologically diverse water bodies (mainly lakes), and then to use them to reconstruct the development of lakes during the Holocene, taking into account the record of climate change. Research on diatoms turned her attention to other groups of algae. Therefore, her next research problem is, to determine how algae, especially phytoplankton, evolve today. Do they adapt to changing environmental conditions or do they succumb to pressure? How do they respond to changes, whether they are caused by human activity or natural processes? Is their role in the ecosystem changing? Are their impacts on other species changing?