Re-shaping marine plankton communities: effects of diatom oxylipins on copepods and beyond

Abstract

Diatoms, ubiquitous primary producers in marine systems, synthesize oxylipins, which impair copepod fitness through a maternal effect. While oxylipins do not directly affect the adults, these chemicals alter basic cellular and developmental processes of copepod embryos, thereby negatively affecting egg hatching and naupliar survival. Inspecting the effects of oxylipins on copepod reproductive success is extremely challenging, because wide variations in their synthesis potentials among diatom genera, species, populations and strains have been detected. In parallel, distinct copepod species and populations can be differently sensitive to oxylipin-producing diatoms. Lately, application of chemical and molecular methods allowed to finely characterize the oxylipin profiles of single diatom strains and to highlight detoxification responses of copepods through the relative expression of selected genes of interest. Thus far, integrative experimental approaches encompassing physiological, chemical and molecular data were mostly applied to laboratory setups, whereas few in situ experiments were presented in this perspective. Moreover, only a restricted number of papers tested the effects of oxylipins on the plankton community as a whole. This review synthesizes latest advances in conceptual and methodological approaches in diatom–copepod interactions and aims at discussing possible re-shaping of the plankton community in response to oxylipin-producing diatom occurrence.